the private vacillations of a graduate student alternately loving and loathing his ..... behind a screen or beneath a cloth than when it was placed under a cup or in a box. ...... the first year and that its appearance depends on the ability to process .... discriminate speech stimuli according to adult phonetic category boundaries.
AN INVESTIGATION OF THE RELATIONS AMONG OBJECT SEARCH SKILLS, CROSS-LANGUAGE SPEECH PERCEPTION, AND VISUAL CATEGORIZATION IN INFANCY By CHRISTOPHER EDWARD LALONDE B.A., The University of British Columbia, 1986
A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS
in THE FACULTY OF GRADUATE STUDIES Department of Psychology
We accept this thesis as conforming to the required standard
THE UNIVERSITY OF BRITISH COLUMBIA September
1989
© Christopher Edward Lalonde, 1989
In presenting degree
this
at the
thesis
in
University of
freely available for reference copying
of
department
this or
partial
fulfilment
British Columbia, and study.
of
I agree
his
or
her
requirements that the
I further agree
thesis for scholarly purposes by
the
representatives.
may be It
Department of
Psychology
The University of British Columbia Vancouver, Canada
~
Date t
DE-6 (2/88)
October 20, 1989 '
Library shall make it
that permission for extensive granted
is
publication of this thesis for financial gain shall not be permission.
for an advanced
by the
understood
head
that
allowed without
of my
copying
or
my written
ABSTRACT
The different
present
research
cognitive/perceptual
the first year of life. search
skill,
object
search
task
delay,
hidden under one
cross-language
/da/
and
abilities
cross-language tested the
speech
English
stimuli
examined
to
/ba/
and
performance
would be expected of
individual
changes.
and
results in
raise
more
synchrony.
of
retrieve
categorization.
an object,
after
a 3
the
infant.
placed in front of
the
The
that
infants' /da/)
ability
and
visual
to
non-native
indicate
on
the
reported that
second The
Hindi task
three
infant
both
(dental
measured of line
tasks
was
in
task
changes
while
The
discriminate
categorization
performance
previously
Results
sets
suggests of
the
possibility
that as
skills
the
at
least
cognitive the
to
infant a
systematic
acquisition
these
of
these
that
a
emerges
expression
ways
suggests
information
the
of
10 months, were tested on measures and visual
second
three of
Subject
performance
finding
substantial
application
the
which
performance
to change on all three tasks at about 9 months of age, the pattern
separate
permits
during
to
correlations among the attributes of a set
hypothesis
subjects'
This
coordinate
in
extent
half
dental/alveolar
formation.
the
occur
tested
contrasts.
the
integrated
ability to
task
speech
category
test
assess
identical cloths
perception
/Da/)
in
become
infants'
the infants' ability to detect and use drawn
to
speech perception,
of two
(bilabial
retroflex
designed
Forty infants, aged 8 to
object
native
was
at
three
broader
range
an
more
of
9
capabilities
to
cognitive
of
skills.
become
increasingly and
the
mentally
months
sophisticated
allowing
among
ability
approximately
and perceptual develops,
of
relation
age The
related accurate
perceptual
phenomena.
ii
TABLE OF CONTENTS ABSTRACT
ii
LIST OF T A B L E S
iv
LIST OF FIGURES
v
ACKNOWLELX3EMENT
vi
INTRODUCTION
1
LITERATURE REVIEW
5
The The The
Development of Object Search Skills Development of Visual Categorization Development of Cross-Language Speech
Perception
POSSIBLE RELATIONS A M O N G T H E T A S K S Object Search and Speech Perception Object Search and Categorization Categorization and Speech Perception Summary and predictions DESIGN Subjects Object Search Measures Scoring criteria for A B task Speech Perception Measures Stimuli Procedure Visual Categorization Measures RESULTS
5 23 40 49 49 55 58 60 63 63 64 65 65 66 67 70 71
Stage 1 - Analyses of the A B Pass & Fail Groups Speech Perception Task Categorization Task Cluster Analyses Speech Data Categorization Data Prediction Analysis
71 71 73 74 75 75 77
Stage 2 - Analyses including the A B Error group Speech Perception Task Categorization Task Cluster Analyses Speech Data Categorization Data Prediction Analysis
79 79 80 81 81 81 82
DISCUSSION
85
BIBLIOGRAPHY
92
iii
LIST OF TABLES Table 1
Stimulus
dimension
Table 2
Dimension
values from Younger and Cohen (1983).
values of
experimental
stimuli
used
by
32
Younger
& Cohen (1983).
33
Table 3
Scoring criteria for A B task.
65
Table 4
Percent
Table 5
group (Pass & Fail). Fixations times on the categorization group (Pass & Fail).
Table 6
Table 7
Table 8
correct on the English and Hindi
Frequencies of task (Pass & Fail).
for the
performance
73
speech data 75
categorization
data 76
profiles
by
A B group 77
Table 9
Hit cell matrix used in Prediction Analysis of Model I.
Table 10
Percentage
correct
72
test stimuli by A B
Three- and 2-cluster solutions for the (AB Pass & Fail).
Three- and 2-cluster solutions (AB Pass & Fail).
contrasts by A B
on
the
English and Hindi
78
contrasts
by A B group.
79
Table 11
Fixations times on the categorization
Table 12
Three- and 2-cluster solutions for the
Table 13
b y A B group. Three- and 2-cluster solutions for the AB
test stimuli by A B group.
Hindi
speech task
80
data 81
categorization
task
group.
data.by 82
Table 14
Frequencies
of
task
performance
profiles
by
A B group.
Table 15
Hit cell matrix used in Prediction Analysis of Model II.
83
83
iv
L l S T O F F I G U P v E S
Figure
1
Experimental stimuli used by Younger & Cohen (1983).
97
Figure
2
Experimental set
up the
98
Figure
3
Experimental
set
up for the
cross-language
Figure 4
Experimental
set
up for the
visual
object search
task.
speech task.
categorization
task.
99
100
v
ACKNOWLEDGMENT A
few words of thanks to those without whom...
To
my supervisor, Janet Werker, for allowing me the freedom to learn from my
mistakes,
and
members interest,
of
with slyly
the who
babies,
there
Victoria
their
fathers, great
really
their
Michael
of
Chapman,
grandparents,
trek to the
was
science
learning
on.
curve.
Jim Enns,
A n d to
and Peter
the
Graf,
other
for
their
on all stages of this work.
nannies,
lab - we
going
and
other
weren't just
A n d especially
assorted
interested to
the
baby
in playing infants
who
secrets.
Lee and Valerie Lloyd relentless
Waters
that
disturbingly insightful comments
made the
Lesley
collection,
monitoring
committee,
mothers,
revealed To
to
my
patient
aid, and often
To handlers
her
for
skepticism
subject
of
for their cheerful the
scheduling
status quo, and making
and unerring help
in data
and their camaraderie. sure
nothing
got
lost
And in
the
shuffle. Finally, to my family.
T o Laurie, who had the strength to endure this, to Peter
who had the wisdom to know when dad should "put his thesis to bed", and to Riley who had
the
serenity
to
giggle when
strength
and wisdom
faltered.
iNTRODUCnON The reported
research changes
perceptual skill,
presented in
infant
and cognitive
cross-language
representative
of
here
development
abilities. speech
Infants
achievements
in
The
of
conceptual,
specific
delay
in
changes
a two-location
speech
contrast,
visual
categorization
performance
previous
determine:
of
to
these
(i.e.,
is
i)
the
assessment individual changes
these
changes
the
this
subject observed
task
cognitive-developmental independent It is a
more
among
and
appear
Introduction
use
separate
object
of
search
chosen
as
previously
of
shown 8 and
that
10 months
dependence);
by
the
it
sequence;
expression
wrought
major
search Hindi
to
is
possible
to
whether
it
is one
other capabilities
the
present
whether
the
three
in task performance at around 9 months
reflect
happenstance
of
of
of
processes.
attainment
the
prediction
concerned
the
By
single
and
by
age.
whether
permit
tested
in
acquisition of
of the
and iii)
changes
of
ii)
that successful
precise
second
discriminate a
design,
a fixed
are
a 3
correlational information in a
measures
in
to
respectively.
a
or
form
of
skill
overcome
The main hypothesis
developmental
to
integration
development
ability
has
for the
sufficiently
capability,
capacity of
the
research
performance
unrelated
products
ii)
repeated
argued here that changes
pervasive the
is
performance. in
ability to
make
developmental
relation
previously
categorization
information-processing
task,
or sufficient
of
three
systematic
perceptual
timing of these changes
necessary
relation one of
visual
these tasks occurs between a
which
tested on measures
and
the
to
a
to
The tasks used have been characterized as
i)
Previous
in
infer from is
ability
extent
and
and
search
findings
whether
skills
the
task. of
another.
were:
object
iii)
on each
replicating
possible
and
were
cognitive
perceptual,
examined
the
represent
perception,
thought to be independent of one measures
assessed
confluence
pathways.
then
manipulate
Previously
a
higher
order
relation
task-specific
skills
become
1
coordinated skills
to
and applied across
emerge.
search task
Specifically, the
signals
the
emergence
and perceptual processes is
also
several domains permitting a more sophisticated
in the
ability to
of
overcome
search
delays
a more general capacity to
service
of
intentional action.
a prerequisite to success on the speech
set
in the
coordinate
of
object
cognitive
Since this coordination
and categorization tasks, the ability to
succeed on one of the tasks should ensure success on all three. In
1790
Laurence Stern made
is the nature of an hypothesis, everything begetting
to it,
itself it
as
generally
grows
the
the
vacillations
of
The bitter-sweet
a
stronger
of
about
hypotheses:
and, by
from
the
everything
first you
assimilates
moment see,
"It
of
hear,
your
read or
Stern's words capture more about this work than
graduate
utility
observation
a man has conceived it, that it
proper nourishment;
This is of great use."
thesis.
following
when once
understand. private
the
student
such
alternately
hypotheses
is
loving
evident
and
both
loathing
in
the
his
science
from which this work issues and, if the thesis is correct, in the lives of the subjects it investigates. The field of infancy research, like all of social science, researchers
hold of the
procedures
devised,
we
conceptualize
news, on
the
of their subjects.
interpretations
given
perceptual and cognitive
The hypotheses
research
capacities
nor should it be considered a cautionary note.
generated,
about
nor discourage
the
subject
as
reflected
the
and the
prior assumptions
appear.
inner lives
of
the
investigation.
here,
two
The present
researcher. Such
of
Often
the
investigations
research assesses the
not
two
the
But this
taint
assumptions
hypotheses
the way
is
knowledge
the
knowledge become
appropriate when, 'of
great
use'
such competing views
in infancy.
not
of
themselves
particularly
validity of two
and perceptual development
reflect
of infants.
need
are -
findings,
generated,
The dependence
interest
contradictory conceptions
nature of cognitive
Introduction
a phenomenon
is shaped by the vision
On the
one
of
hand is
2
the
view
that the
the
other,
that
The how
changes
the
changes
work centres
and
when
in
result from
a single
developmental
the
and cognitive
clear
infants
event, on
are unrelated.
on an exploration of meaning making — on the
perceptual that
under study
course
of
abilities
their
development
in the
is
The
of their sensory
products of these processes do not constitute yet
intentional
as
sensory
phenomenon.
obvious
that
infants
more specific result,
are
to.'go
an active construction of reality, nor are resolving
in
development,
however,
it
becomes
are bringing both perceptual
and cognitive
capacities
to
bear on
At
some
able
to
beyond
later
by
point
the
infant
problems in a deliberate
extract
the
aimed
experience,
at
and sophisticated
they
display,
consciously
that
it
part these perceptual systems seem simply to do what they were 'designed' to do.
they
capabilities
While
most
1
perceptual
action.
their
for the
'blooming, buzzing confusion
of
intentional
coordinate
bring
the
a set
of
first
of
help
order to
arrive armed with
service
infants
question
information
which
information given',
is
and to
a particular
and focussed
manner.
not
in
inherent
make
sense
of
seem conceptual hair-splitting since
there
is
the
the
As a sensory
previously
insensible. Much that
of this
infants
birth.
capable
of
directing
But it is nevertheless
perceptual later.
are
may
processes
in
the
and modifying
true that the service
of
a
their perceptual
meaning-making
is
accomplished.
higher
order
The
aim of
light on how it is that infants come to form the specific of
their perceptual
their commerce developmental developing
with the problem
processes.
Introduction
and cognitive world.
processes
that
intention
processes
from
of
harnessing
separate
In
essence,
argue
abilities
that
at
arrives
somewhat
when and how this feat of this
work
is
to
shed
some
relations among the products
afford them
The research outlines
I
evidence
ability to coordinate the products of these
It is a matter of some contention, however, exactly
infantile
ample
one with
about
this
greater
possible
success
solution
respect
to
these
9 months
of
age,
to
in the
three infants
3
acquire
a
new
and
itself,
and in doing
world
around
Introduction
imminently so,
'useful'
hypothesis
changes what they
see,
which
and hear,
'assimilates
everything
and understand
about
to the
them.
4
LITERATURE REVIEW The
literature
respectively,
the
cross-language theoretical The
review
is
divided
development
of
object
speech
perception.
and empirical
following section
summary have
of Piaget's
been
shown
theoretical
notions
(1952)
"the
affect
to
put
situations" "objectified negotiation she strives. reached
infant
categorization
concern is
of object
through a review
of
to
performance,
to
of the tasks
of the a
skills,
introduce some
and
of
I have
search skills will some
describe,
the
chosen.
proceed from a
task
variations which
discussion
of
alternative
subject work,
(p.211).
barriers
intelligent
must
aim to
with
this
This
from
which
trying
With reference
stage
of
his
sensorimotor
behavior patterns" by
the
(p.210).
intention,
the
the
which
self"
appear between
schemata results
(p.211), the
adaptations These
"intercoordination of
attain an end which is
achievement,
What distinguishes
and of
fourth
their predecessors
and...detached of
the
actually
from
to
Development of Object Search Skills
describes
first
distinguished
schemata...the and
visual
which
accounts.
Piaget
are
The present
sections
issues which arise from the use
The
comprising
three
search,
on the development
to
into
not
the
directly
thitherto
as
patterns secondary
within reach
related
to
other
in
the
universe
becoming
arises
out
of
successful
infant
and the
goal
the
toward which
stage IV behavior is "keeping in mind the 'goal' to be
different
known means
of
surmounting the
to object
search, Piaget
notes:
difficulty." (p.213)
"It is to the extent that the child learns to coordinate two separate schemata that is to say, two actions until then independent of each other - that he becomes capable of seeking objects which have disappeared and of attributing to them a consistency independent of the self. Searching for the object which has disappeared is, in effect, to set aside the screens which mask it and to conceive it as being situated behind them; it is, in short, to think of it in its relations with things seen at the present time and not only in its relations with the action." (p.211) Literature Review
- Object Search
5
It
is
noteworthy
that
throughout
his
to take for granted what later researchers
discussion
of
object
search, Piaget
do not: that what limits the
to overcome the barrier is not that she has forgotten lacks a means of removing the obstacle.
seems
infants' ability
where the object is, nor that
she
I will return to these issues again below, but
suffice it to say that in Piaget's scheme at least, a child may be possessed of both these capacities
and yet
fail to recover the object
search
successfully
related
to
rather
than
the
is
goal
on
laid
on
(grasping
simple
the
the
of her desire.
inability
object),
forgetting.
In
to
and
coordinate the
addition,
intended
about
the
to do, once the
'successful'
in
his
to
elicit
therefore,
to
resolve
ultimate
goal
Piaget and
in the
the
as
initial
the
while
provides
entirely.
object
search
sufficient
the
object
Despite
has been
the
while
grappling with the
bargain, opens
the
more
by
door to
Faced with two identical locations
B),
infant,
in order to
successfully
the
the
or not the
the
the
to
obstacle)
remove
what
it
was
that
can
remember the
goal,
but forgets
infant
thus the infant will be successful somehow always
be
had
infant is nevertheless uncovered
object
can retain knowledge
removing the infant
based
the
is
of
barrier.
opportunity
explanations
of
to
object
fail,
search
at which the object may be hidden (A and
retrieve
the
object,
must
and the location success is the
have
he
now
avoid the
pitfalls of forgetting the goal or the location at which the object now resides. infant can remember both the goal
the
Something more is required,
problem of giving
schemata
infant may, in fact,
partially
object'.
memory
errors. the
of
'grasp the
issue of whether
something
attempting
forgetting
sight
separate
(removing
partially revealed, the
mere
schema
the
barrier
barrier (that is, prior to the reappearance of the object) forgotten
The blame for failing to
correct
only by chance.
location,
assured.
search
will
If the be
twin If the infant
random and
If, on the other hand, the infant is
able to retain the correct location but loses sight of the goal, the infant will successful
Literature Review
(despite having forgotten
- Object Search
what
she
was
looking for),
given
that
6
the sight goal
of the object
and the
will
location,
search
where two
hiding places
coordinate
previously
problem
of
revive the desire. and success,
separate
remembering
possibility,
having
return to
search
recovered
source (eg.,
of
growing
the
Kagan,
Graber,
1974),
response
exhaustive
accounts
of this
search
his
of
in
a
demonstration
of
the
object
in
of
has
1985). For
the
been
maturation
A B task,
found ability to
overcome
search
at
one
the
additional
-
the
location
AB
error.
(A)
an
location
A After
infant
(B).
will
Piaget's
of
is
explanation of the error in terms of
permanence sought
certain
inability The
the
skills,
in
extent
present
the
brain
to
infant's
(eg.,
of
literature
a
the
factors
previously
short
the
capacity
Baillargeon
a
this
objects,
memory
suppress
of
the
physical
centres
purpose
a discussion
of
reinforced
precludes
description
main classes which most
of
&
an
of
the
theoretical
strongly
affect
offered.
object the
search
changing of
was
development
development
understanding
must
hidden at a second
and a summary of
into
the
hidden is
brain-based
sequence,
of
incorrect
object
error
search
investigation
In the
might predict either correct or random search.
an
here.
interest
description
emerging
the
performance
Piaget's agenda
in
object
infant
In addition to Piaget's
(Diamond,
of
random.
look.
understanding
discussion
development
object
and
become
of hundreds of studies using dozens of variations on this
perseverative
1988),
motor
theme.
the
systematic,
at A when the
basic two-location infant's
to we
is
finding has been the subject
the
schemata,
where
however,
successfully
again
are involved, in order to show-case her new
Given these possibilities third
Finally, if the infant forgets both the
1
nature
but of
a
single
intelligence.
of
object
of
representational
physical
item
search
causality
Within
skills and
on
can spatial
which
a much broader this be
framework seen
abilities.
underpins
as
a
The these
If this is seems an unlikely combination, imagine that you find yourself in your office suddenly unable to remember what it was you were looking for. When you catch sight of a book sitting on your desk, you immediately recall that you intended to read it that evening. Literature Review - Object Search 7 1
demonstrations
is
the
interpretations
of
search
be
in
a
laid
out
wrangling
link
reflexive
birth
sequence
until
activity
and
the
various
behaviour in infancy.
surrounding the
From
between
of
AB
the
stages
The
age
responses
disappearance
of an object
The results
which
provide
tasks
of
the
this
basis
and
investigation of
the
of
4
months
circular
observed
(i.e.,
reactions), by
Piaget
the
sensorimotor
infants to
exhibit
the
no
movement,
At 4 to 8 months of age
movement toy,
(1983)
of objects"
substantial direct
prior to
progress
a
"minimal
objects
now
infant
taken place.
disappearance.
for
hidden
(coordination of
fully
secondary
screens that mask' the
schemata)
error.
The
phenomenon
representational active even
powers
object, of
is
overt
at
occlusion,
short
or
delays
to
perseverative
between
problem.
or to
begins
the
skills
the
onset
Nevertheless,
the
renders the
actions
of
Though the
the
infant
either
initiated
infant
ability
now
is
'set
4
now aside
— the A B
attribution can
object,
substage
can mentally
restriction attends this search
adjustments
seem tied
of
or
stolen
a fully hidden
an extension
12 months.
a suddenly
Though these
search
with
develop
disappearance
after
retrieve
infants'
At best, the
disappearance.
which suggests that she
a crucial
questionable.
the
8 to
search for the missing object in the overcome
of
search
infants begin to
adjustments
unable to
object,
objects
able to retrieve a fully hidden object, the
of
little
Still,
of the
complete
Search
set
present
sense that the has
circular reactions)
In addition to groping along
(if partial) perception its
(secondary
(p. 715).
partially covered
are minimal in the
to
terms
empirical
were limited to continued gazing in the same direction the
infant is able to track the object but shows little reaction to its
Harris
can
substages
object occupied prior to the motion, or at the point at which it vanished.
what
Piaget's
task.
primary
behaviour.
search
of
initiate
full an
absence of direct perceptual cues, and can object's
disappearance
and
the
onset
of
search.
Literature Review
- Object Search
8
By difficulty delays
12
to
18
which
the
required to
months infant
of
is
disrupt
age
able
search
(tertiary
to
has
of
hiding location,
hand.
Thus,
experimenter the
from
conceals
the
little
of
object
hand.
present
18 months
infant
remnants
experimenter's
containers,
the
have as
reactions), increased.
have
the
still be
the
AB
during
Visible
thwarted by
error
the
persist
hiding,
By the final
degrees
of
The
duration
of
sequential
to the effects of a
an experimenter's when,
leading
displacements,
the
number of
While no longer susceptible
may
difficulty.
of age
overcome increased,
hidings the infant is able to tolerate. second
circular
for
the
however,
example,
child
even
substage of the
sleight
to
the
search
across
in
several
sensorimotor period,
onward, even these invisible displacements
are overcome
with
ease. Given would
the
question
many
the
and
varied
validity of this
however, has not fared so well. Piaget
attributed to
replications sequence.
a lack of object
for
that
stages
1 and 2
permanence causes whereas
(eg.,
the
tracking
evince
intervention
in
the
present
perceptual
expectancies
vanished object
behaviour.
active
search,
expectations.
which
Such
Literature Review
are
events
researchers
interpretation of the
sequence,
either
1967).
and
maintains do
interpreted as reflecting It has
expectation
search
which
patterns
allow
exploited
Several
infants
few
"true
solely
there
is
extend
simple
the as
researchers surprised include
- Object Search
infant
to
a possible have by
noted
anticipate
of
is
active
challenge that
'impossible'
perturbations
of
to
events the
object and
or else
Still, these
reappearance
to Piaget's
prior
in
interrupted action,
expectation,
the
seen
grasp
search
a
suggested,
reappearance
a precocious
that
not
of
been
the earlier act of accommodation" (1954, p. 10).
have been
search
of
Piaget
movements
behavior
the search only continues
findings,
has been
(Bower,
and the
form
1967).
of
deficit
ability
an early
Bower,
Piaget's
permanence,
rather than a conceptual the
these
The infants' failure to search in stages 1 and 2, which
motor skills, instance,
of
of
a
explanation
of
the
development
of
which
violate
expected
trajectory
their of
a
9
moving
object
(Mundy-Castle & Anglin,
seen hidden behind a screen 1972),
and the
apparent
(Baillargeon & Graber, The
implication
competence
and
he
the
utility
imputes
that
the
to
the
infant
attributing behaviour
an as
from
these
these
evidence
findings
may
later of
exist.
that
The
absence of
removed
a single
(Bower
location
is
of
the
is
an
object
& Patterson,
by two
remains at the mercy of the infant's
of
distinction these
cognitive does not
objects.
objects
the
arriving
however.
To
capacities
which
necessarily
imply
Piaget
existential
between
early
Indeed,
causality,
that
action.
the
of
physical
belief
to
abilities
permanence
a mistaken
important
a matter of debate,
secondary
of
an
contribution
of search skills
understanding of
is
Acknowledging these
cognizant
early
is
occupation
responses
infant.
is
screen
unexplained
1988).
development of
the
simultaneous
performance
expectancies to the Piaget,
when
1974), the
rather
than
interprets
status
of
the
such object
What is at issue here is whether or not —i
such capacities seen
long
helpful
signal a change
after
these
evidence
for
infants
capabilities a well
in the conceptual
show may
developed
perceptual
expectancies,
prove
in
search
concept
of
object
behaviour will serve to press home this point. voice
when
I answer
my ringing telephone,
that I have anything but the faintest phone. object
Similarly,
perceptual
tasks,
indicates they
permanence.
that,
however
be
taken
A n analogy
to
as
adult
Though I may rightly expect to hear a
we
would be mistaken to infer from
notion of how the voice
expectancies
cannot
The A B error,
tell
us
little
this
I will hear got into the
about
the
infants'
notions
of
permanence. In sum then, Piaget
of
successful
of
the
AB
component now
status of the object.
turn
is
less interested
searches than in the error
so
in Piaget's our
late
in
the
explanation
in strategies that increase
development object of
search
search
of
object game,
behaviour.
permanence. therefore, It
is
to
the likelihood The
remains this
presence a
crucial
error that
we
attention.
Literature Review
- Object Search
10
The
proto-search
which have reference
been
to
investigated
the
likelihood
of
likelihood
of the
behaviours
AB
error
operant
itself,
perseverative
from 30 studies,
as
described
the
error
under
2s
of
been
age
is
a
list
object
shown the
In a meta-analysis
factors
search.
to
most
of
With
influence
obvious of
89
the
— the
conditions
increased 7.5
Also obvious is the effect of delay.
error increases
Wellman et
at
have
head
Wellman, Cross, and Bartsch (1986), report an overall correlation of -
al.
proportion of A B errors. the
factors
A B error decreases with age.
probability of
increases.
merely
development
Among these,
.49 between age and perseverative error. age,
in the
several
search.
above
at
(1986)
the
report
a
delay
between hiding and search
correlation
of
Diamond (1985) found that the
a constant
months
as
to
over
A t every
+.56
between
delay
of
approximately
2
10s
by
12
Increasing
months.
delay
necessary
rate
seconds
onset
to produce
per month the
and
delay
from which
produced the error by 2s led to random search, while a 2s decrease resulted in correct search. Interestingly, performance. begin
showing
approximately age
Baby girls are able to perseverative 2
also
reports
find
a hidden object
errors at a younger
weeks in task
a significant
performance.
age.
delay
sex
and age
of
general measures
trend
for
of
infant
Several revealed
the
effects
on
which
error.
of the
Literature Review
A B error in that
girls
to
than are boys,
girls precede
outperform
child" their
that,
one's ability to
(p.878). same
aged
This
and
boys
by
"although
an infant can tolerate,
improves
in A B
knowing
predict the
finding mirrors a
male
peers
on
most
task
have
development.
variations
probability of
distinctiveness
infant
difference
Diamond (1985) reports
an infant significantly
that will produce the
sex
sooner
Overall,
is the single best predictor of the length of delay
both the
the
Diamond (1985)
the the
standard
number
and
two-location nature
In some cases Piaget
locations
of
of
the
particular locations
seems to
should carry no weight,
- Object Search
version
imply that
that is,
the
have
on
number or
search should proceed
11
either
correctly
or
erroneously
dependent
sophistication ("Go look in my room and see regard to number, Wellman et with
an
increasing
number
on
the
infants'
degree
if I am there" Piaget,
of
1954,
conceptual p.59).
With
al. (1986) report a decrease in the proportion of error
of
locations.
An
important
restriction
on
this
finding
applies: the direction of errors is predominantly toward A rather than to the 'far' side of
B.
Some
et
al.,
1986),
locations
may
covered when
controversy
last
all
likely
urgent
age
location tasks,
multiple covered
location are
the
error becomes of
of
are
two
surprisingly,
(1989)
or sex.
location
procedures)
and uncovered
results
more
concerning
distinctive
(Wellman et
infants
shown
hiding procedure.
al.,
addition to
the type of concealment
(1982) found that
recently
(see
Harris* reply in Wellman
that
the
effect
When the
multiple
correct location
performance
simultaneously,
of
the
is
is
enhanced,
but
probability of
the
tasks.
the
In
finding, however, has
an artifact of the
locations
More
that
be
Diamond
(typical
error matches
not
and
attends this
or
the
nature
discriminable
1986), though differences
this
of the
between
successful
locations.
locations
effect
also plays a role.
were more often
the
the
are,
Perhaps the
less
is much weaker
than
hiding places
in
two-
Dunst, Brooks, and Doxsey
when
the
object
was
concealed
behind a screen or beneath a cloth than when it was placed under a cup or in a box. The
authors contend
between
self
and
that object'
the
first two
while
the
events are interpreted by the latter
two
constitute
'barrier
child as
'barrier
replaces
object'.
Piaget also notes the effects of more 'difficult' hiding places: "Gerard, at 13 months, knows how to walk, and is playing ball in a large room. He throws the ball, or rather lets it drop in front of him and, either on his feet or on all fours, hurries to pick it up. At a given moment the ball rolls under an armchair. Gerard sees it and, not without some difficulty, takes it out in order to resume the game. Then the ball rolls under a sofa at the other end of the room. Gerard has seen it pass under the fringe of the sofa; he bends down to recover it. But as the sofa is deeper than the armchair and the fringe does prevent a clear view, Gerard gives up after a moment; he gets up, crosses the room, goes right under the armchair and carefully explores the place where the ball was before." (1954, p.59)
Literature Review
- Object Search
12
The linear effect be
demonstrated
substage 4 require
is
in
no
active
go
guarantee
search,
about
Corter, When
the
successful
though
'subjective of
or
person
child's
wherewithal
in
an
is
not
Piaget,
conceptual
the
age,
is
the still
which
relation
that perseverative
suggests
that
the
of
looking
time,
search can
attainment
In addition, procedures
& Graber,
the
suggest that
1988).
importance
of
the
mother,
search
seen.
Though
Piaget
account
between
active
for
the
search
how
Furthermore,
the
infants'
could
of
which don't
to look long before they know
Baillargeon
errors are
the
fact
measures
object
itself.
more
often
is
acknowledged
a
early
appearance
and
non-search
specified. A B task
and the
understanding of
resulting
objects.
of the task may prolong the life expectancy
increasing
the
of
the
complexity
of the error should do little to disuade the
The stipulation that the infant must "aim to attain an end...and to put to work,
underscores
the
the
of
that
limits
object.
intention,
infants
The fact
the
of
this
idea that
A B error reveal
faithful
with
the
of
demonstrate
task
permanence'
fully
on
(eg.,
(1980)
perseverative
affective
year
to know where
object
AB
permanence,
equivalents For
relying instead
and Galligan
'object'
one
and the
of error free-search.
retrieving the
Zucker,
and delay,
children over
infant may have the to
for age
schemata
importance
less than one
thitherto
Piaget
places
related on
active
year have
to
other
a fragile
situations"
notion
(1952,
of
the
p.211),
search:
"...we do not believe that the coordination of schemata suffices to explain the permanence belonging to the object. So long as the child does not undertake special searches to find objects which disappear, that is, so long as he does not succeed in deducing their displacements in space when he no longer sees them, one should not yet speak of object conservation"(1954, p.90). Without
active
demands,
the permanence
the universe (1954, p.94).
search,
and
the
of the
is not detached
reciprocal object
from
is
assimilation
of
secondary
schemata
"only practical and not substantial,
action nor objectified
in a system of
it
because
relationships"
Just as the ability to anticipate the reappearance of the object adds only
Literature Review
- Object Search
13
a
false
cloak
of
sophistication
to
the
infants'
behaviour,
discussion
no
distinction
so
too
would
non-search
equivalents to an A B task. In
the
preceding
is
drawn
between
object
search
tasks in general and the A B task in particular.
The relation between the two is by no
means
in
a
simple
coordination ability
to
recalling
of
not
two
tolerate the
imposition of and its
one.
If
Piaget
previously
two
correct
searching.
In
the
should
at
increases
causes are different.
correct
independent
locations
location
a delay
is
which the
schemata,
depend to
apply
infant
correct
search
somewhat
on
one's
the
later
added
efforts.
to
the
arriving
dimension
of
In
both
cases
failure, though the
type
of failure
simple object
the
the
only
probability of
In the
A B task,
attributing
search task,
may,
the
failure is restricted to
additionally,
search
in
the
wrong
place. The demands of the object search task are such that the infants may fail in two ways:
by forgetting
what they
were doing (losing
sight
of the
how to do it (inability to coordinate secondary schemata). the problem of deciding where to look. where
the object
is,
armchair when his are
often
when
perseverative
are
search
processing
know
may
confusion
that
not,
activity
the
therefore, but
interest to speculate
Literature Review
sofa
is frustrated. the
attempt
to
disappeared require
alternative
an
'special
at
(made
exist.
The
improvement searches'
the
accounts
contends
that
through
the
The infant may
ability to
Piaget
likely
object
object.
in
more
resolve
memory
the A B
capacity
or
describes. it is
of
as to what happens during the delay to cause the infant to err.
It
- Object Search
theoretical
all the
Piaget
recreate
B.
the
While it is likely that errors
locations
possibilities
rather, the
taking up the
The A B task adds to this list
which earlier produced the
object
forgetting
This is not simply a matter of remembering
between
an
or by
would be no reason for Gerard to return to
other
implies
search
efficiency,
Before
to
identical),
application of the nonetheless
there
search under the
attributable
these
dilemma
otherwise
goal),
of the
A B error,
14
is
conceivable
priority
that
over the
the
specific
coordination acquired during
location at which the
object
the probability of committing the
A B error is
A
we
trials
(Wellman et
learned well.
al.,
course of a single
the
object,
Given
that no
found with increases
conclude
that
the
trial(s)
is
given
change
they
abandon
that despite
the
the
hold
stubbornly to
search
ability to
at
A
when
coordinate the
lesson
learned once
inappropriate strategy.
left
empty
handed
necessary
is
over
step behind
this
schemata
in
in the number of
session suggests that the infant is not simply one
but rather, that they
that
contention
must
found.
A
The fact that the error can be made to 'float' between the locations
the
finding
1986),
was
the
The
supports to
the
search for
hidden objects
in general (i.e., in object search tasks, or on A trials in an A B task),
the
still
infant
is
perseverative
bound
search,
by
albeit
an
egocentric
under
thus be seen as the persistence
an
search
increasingly
strategy. narrow
The
set
of
of a contextual understanding of the
persistence
conditions,
of may
object:
"In order that these things really become objects the awareness of relations of position and displacement must be acquired. The child will have to understand the how of the appearance and disappearance of these objects and thus will have to abandon belief in the possibility of their mysterious reappearance at the place they have left and where action itself has discovered them. In short, a truly geometric rationalism will have to supersede the phenomenalism of immediate perception and the dynamism of practical efficacy." (Piaget, 1954, p. 65) The overcome to
inability
more complex
travel.
the
Piaget's
discovery
more
of
and
conception
the
the
geometric
AB
otherwise
task
able
action.
reveals of
both
active
permanence.
to
find
merely indicates
rationalism begins
through
importance
of its
child,
hiding situations,
objects
demanding
object
of
The the
search
What then
the
hidden
objects,
to
length of the road
yet
with empirical success, that insufficiency
nature in
fully
the
separates
of
the
of
with
this
strategy
in
the
infantile
concept
of
the
a more
mature
construction the
is,
three
of
classes of performance
on the A B task?
The infant able to solve the A B task appears more sophisticated than
one
by
still
difference
plagued
the
A B error,
between these two
Literature Review
is
at least
in terms
not in their ability to
- Object Search
of
overall
coordinate
success.
But
the
secondary
schemata 15
, for both infants possess this skill. free
of
the
potential
quashed
by
'geometric
difference substage
between
err until
these infants
to
find
in
In Piaget's
unless
that
importance of the
able
their belief
rationalism'.
V , an achievement
theoretical infants
to
Indeed, the infant able to pass the A B task is not
is
the
not
'mysterious
account,
infant
able
measured
hidden
objects
-
that
then, there to
by the
A B error lies in the
reappearance'
pass the
no
attained
For Piaget,
limitations
success
been
conceptual
A B has
A B task.
conceptual
empirical
is
has
may
the
it reveals
mask
in
underlying
deficits. All
of the
variations defect
on
in
structural.
memory.
Such
accounts
fidelity,
or
application
explanations
are
of
efficiency,
Memory
based
object,
but by an inability to cope
Functional accounts
accurate
immaturities these two
capacity,
account of the A B error inevitably reduce to
In both cases the infant is not necessarily
of the
of
to Piaget's
theme:
search.
of the task. use
single
memory
perseverative
concept
a
alternatives
memory
in the
for
the
hardware of
location,
memory.
infant
which
with
results
a in
kinds: functional
and
limited by a faulty or immature
with the
while
specific
structural
One hybrid
memory
demands
account
theories
point
to
(Diamond's)
combines
of a memory-based explanation:
"Gerard,
of neurological
(1954) discusses the possibility
having known perfectly
two
the
seek an answer to the A B riddle in the inappropriate
in an account that smacks
Piaget
burden
fideism.
well at first that the ball had left the armchair and was to be
found under the sofa, little by little lost all memory of the events; no longer knowing very
well
what
he
was
doing under the
under the
armchair and immediately
this
relies
sort
corresponding
on
decay
the for
information-processing the
memory
for
Literature Review
the
decay the
account B
A
of
followed
he
his
remembered having found the impulse"(p.
the
memory
location
memory.
proposes
location
- Object Search
sofa,
does
just not
such
for
60).
the
B
Sophian uneven
decay,
the
ball
A n explanation location
of
without
a
and
Wellman's
(1983)
memory
decay.
Where
infant
is
said
to
rely
16
inappropriately
on
remember
locations
(object
both at
B)
Perseverative reliance
prior
takes
search
on
rather
than
correctly, precedence
then
results
Without
but
fails
over
either
improper information
current
that
a direct test of the
information.
to
appreciate
prior
decay
faithfully
relative
that
information
from the is
of
more rapidly, we
Wellman et
choosing
prior
al.'s
over
number of locations Wellman et
(1986) current
was for
at
B
A).
or from
memory. location,
If the memory for the
should expect some effect to obtain when
As noted
above, no effect for A trials was
meta-analysis.
If
information,
would result
in
may
information
strength of the memory for each
B
from
(object
represented
about the adequacy of this explanation.
number of A trials is increased.
infant
current
memory
one can only speculate location does decay
The
we
in an increase
al. (1986) report an increase
the
infant
should
is
prone
expect
that
in random search.
to
the
derived
incorrectly
increasing
the
On the contrary,
in correct search.
Kagan (Fox, Kagan, & Weiskopf, 1979; Kagan & Hamburg, 1981) proposes a twopronged which and
solution
facilitates
to
the
A B error:
a comparison of past
a concomitant
increase
these two points in time. memory
for
discrepancy (object
an
event
between the
in hand).
scene rather late. to recognize object)
This
in the
image
desire
present
of
state of
improvement
present
to
across
resolve
in
the
recognition
interference
discrepancies
object)
the
and
world (no
motivational
one must
is
of
perceived
motivated
object)
change
to
and the
seems to
delay,
between the
resolve desired
the state
arrive on
the
assume that it could not predate the ability
resulting in an infant 'all dressed up with no where to go'.
skills.
presuppose
memory
10 months is now better able to retrieve
the
rather mystical
Nonetheless,
an
with
The infant of
(the
is
and recall the event (i.e., to encode the event as the disappearance of the
clear how the search
there
the
increase
in motivation is
A n increase
in the
ability
coordination of schemata,
Literature Review
- Object Search
a separable to
component
resolve
in the development
discrepancies
and thus Kagan
Further, it is not
would
of
necessarily
would be forced to
attribute
17
the
same
both
infants
account two
motivational
both
different
both
where
a
difference
successful
motivational
Bower's infant
(1974, has
with respect which 3-4
to
equivalent
for
young
change
changes
1977,
already
to object
and
solved
AB
'pass'
is
sought.
the
more
the
and
radical
problem
object
persuade would
this
show when
be
such
the
anticipated
stationary.
that
grasp
the
child
of
cannot
specifying
pass.
assumes
that
the
very
and falters
only
reactions
an occluded
object
they
state (from
capable
of maintaining the
is little in this
must
unconvincing
possessed
of
a
a more
problems
recognize to
identity
of
detailed related
the
rephrasing
the
of
his
else
attempt
to
object
permanence
of
problem
or vice
either
identity
versa).
which
authors
argue,
moves of
an
Finally,
in
or
more
of infant search.
local
remains
object
they
disappearances.
terms
of
objects
to
the
that
must
While
on the extent or strength of the
problem
does little to explain the mysteries
First, the
that
across
the
identifying
search.
continued
object
account that directly depends
location,
in
account
to
an object
the
moving
of
concept
location (why
errors.
identity
stationary
of object
is
offer
three
Though it is clear that the A B
Bower
search
continued
its
object
error to
reappearance
prior to the onset of successful
Second,
for
the
suggesting
changes
memory
without
permanence
immature notions
interest),
fundamental
by
must be overcome must
any
and Meltzoff (1978)
location
infants
of
reader
exhibit
object
alternative
The importance of these perceptual expectancies to the acquisition of a
error
Moore
rendering
In support of this, Bower cites the surprise
error has much to do with the infant's the
error
alternative
of
infants,
Kagan's
sequence from
fully developed concept of the object was noted above.
would
'error'
perseverative
within the
1979)
location.
month olds
fails to occur.
search
the
be
there
infant's hidden
In order to 'maintain the
identity of the object' the infant must represent
it in its
absence and thus, Moore and
Meltzoff
presuppose
the
The fact
that
allowed
to
without
search
Literature Review
memory
component.
delay,
- Object Search
supports
the
contention
infants that
rarely err when
the
AB
error
is
18
indicative
of
a failure
account
suffers
multiple
well
more
complex
than this
from a disturbing silence versions
of
the
task
-
with
when
loss
of
respect
faced
identity. to
with
the
Additionally, this
direction
many
of
alternative
errors in
possibilities,
infants invariably err in the direction of A rather than to the 'far' side of B . Butterworth (1978) and Bremner (1980) opt for an even more detailed listing of the
abilities
may
deduce
positions the
which the
underpin
identity
of
or manifestations
position
of
overcoming
the
the
search.
an
by
object
relative
predictable
to
behaviour
by Bremner (1980) who
describes
which
the
locate
maintains
infant the
develops
object's
to
location
more
herself,
refined
the
object
to
the
its
stable term.
within of
proposes
together
the
in
as
This
infants
successive may
The
position
of
triangulation
is
code'
self-related
and,
use
a means
and a 'framework
space.
infant's
various
room etc..
code'
that
The infant
object.
a 'self-related
the
relative
Butterworth
linking
through a third,
object
less
successful
for
code
infants
not
yet able to crawl, this code provides the only means of locating the object.
Once able
to
relative
move
relative
landmarks
- the
to
the
object
It must be
object
the
infant may begin
to
code
stressed that alternative
the
other
infant hand,
accounts
such as these hold that the
searches where allows
the
he believes the
infant
to
search
object
where
he
search is applied. to
be.
that the object disappeared at B but believe
that effort
In
the
Piaget's.
sense,
memory
accounts
grant
The acquisition of rules by which to
identification Indeed,
the
these
aids
do
not
are merely
Literature Review
relieve
the
reformulations
- Object Search
child of
of
the
Piaget's
believes
rewarded but where the object need not, at present, be located.
this
to
'under the chair'.
fully expects the object to be found at the location where words, the
for position
his
account,
efforts
will
recall ability
necessity
concept
of
on be
The infant may know
search, of location codes, the
In other
at A will reproduce the
child greater
infant
the
of
object
object,
object.
than and
does object
permanence.
for the
infant
19
must
be
able to
do all of these things
if search is
to be
successful
at levels
above
chance. In child
is
all
of
these
capable
of
alternative
remembering
tripped up by the demands memory of
(Bremner)
for
is
more
an
than
or
rules
there
for
maintaining
Were the
anticipate
Adele attributes
seconds,
but
that
is
search.
the
somehow
If it is not
more than simply a lack
identity
of
limiting factor in object
should be no difference
the
between an object
objects
through
search the
search task
ability
and the A B
reappearance
Diamond (1985;
the
AB
error
limiting
factor
in
rewarded
motor
action.
to
unable
to
object
for
How is it that
which
they
have
infants no
re-
a
offers
to
what
I have
combination begins
of her
called
neuronal analysis
a hybrid
account
that
immaturity
with
a
primate behaviour in a Delayed Response
infant
performance The
inhibit the
infant act
of
is
is
an
inability
rewarded
reaching
by
to
finding
toward
A
even
an
comparison
of
(DR) task.
inhibit the
and
a
previously
object
when
The
at
aware
A
and
that
the
This lack of control is in turn blamed on immaturity of the
cortex.
Diamond's from
specific
until
the
damaged
an
Diamond
is no longer there.
prefrontal
1988)
interaction.
A B performance
becomes
of
search.
rules?
action/memory
object
admission
If one blames failure on a lack of rules it is not at all clear why infants show
identification
infant
3
the
perceptual expectancies prior to the onset of successful can
implicit
of overcoming a barrier to immediate
(Moore & Meltzoff).
locomote,
task.
things
there
se which fools the tot, it is certainly something
mobility
occlusions to
per
accounts
argument
forms
prefrontal (eg.,
by
Literature Review
of
depends on a combination
organic
cortex
is
dorsolateral
-
brain mature
damage
(approx.
prefrontal
Object Search
in
of primate
adults. 9
lesioning
The
months or
studies and evidence
in
story
runs
humans)
localized
or
cooling),
like if
this: it
is
primates,
20
and
by
extension
human infants,
with actions necessary To
of
brain
sufficient possible
of to
is
a sort of neural fideism
made in this
some
account
without
portion
some degree
application
search behaviours
is
of
memory
progress.
tissue
may
be
which
sculpt
It
is
that
some
is
a familiar one.
The
necessary
While Piaget's
The argument can even
obvious
the
'special
but
it
searches'
is
hardly
may not by
the
be run in the reverse, that it is
the
the
brain
need not be caused
be
in the
manner suggested by
In any case, even if Diamond is correct (and I have no reason to
otherwise),
behaviour
processes
is not simply to nay say
of prefrontal maturity, they
activity.
believe
brain
for the behaviour.
Diamond's account.
the
regard, but my objection
of
advent of this of
coordinate
maturation in developmental
large contribution is maturation
to
to solve the A B task.
suggest that this
importance
are unable
that
the it
be
only
restriction
consistent
with
on
a
this
Piagetian
interpretation
underlying neurological
of
search
event.
Since
there are no compelling reasons to think that it is not, we can cling to the belief that whatever more this
the
general
contribution of
brain
than A B success.
contribution might
maturation to
The question
object
of
search
interest
concerns just
the
discussion
by these
alternative
distance toward a statement of the prerequisites to successful than
simply
anticipate
deduce
and predict
across
a
disruption
intentional
action
permanence conceptual onset
of
memory
of
its of
the
location, some
reappearance form
objects.
The
To
of
search,
and planful
action.
it
Piaget
result
how
discussed
must
- Object Search
involve
goal
of
the
search.
retrieve
is
general
it
-
they
one
do
must
and implement the
beginnings
limited knowledge,
above
of
this of the
little
to
shake
this
chooses
to
explain
the
processes
of
coordination
present
goes some
Infants must do
object
represents
albeit
miracle
the
accounts
vanished
this
some knowledge,
accounts
The
a
plan to
Whatever developmental
successful
Literature Review
some
kind.
and presupposes
foundation.
the
be.
The precision added to
more
skills,
research
of is
the to
determine
the
21
extent
to
which
this
new
found
ability
influences
other
domains
of
infant
functioning.
Literature Review
- Object
Search
22
The
Development
The purpose of the present of
the
developmental
changes
of Visual Categorization
review
evident
is to provide a framework for a discussion
in
the
form
formed by infants across the first year of life. of
the
theoretical
and
categorization
task.
categorization
in
infants
categorize)
Attention
then
cognitive
abilities
representation
infancy as
well
of
to
typically
what
definition
First, 'to
The
ignored.
or
It is
change
Literature
Review
objects
and
out
its
of
use
(what
categorization
is
other
infancy, of
a of
it
on the
and
a discussion
of
evidence
with emphasis
during
categories
the
the
content
that latter.
related
specifically
the
theoretical
to
intellectual
infancy.
events
is
fundamental
perception, learning, all rely commonly
on the
defined
as
or events, as equivalent.
differences
among
important for what
word "treatment*.
behave
toward
in
which
the follows
ability to the
of
that we
a
form
treatment
At least one
members
category
understand
of
rider be
exactly
some
may
be
The common usage of
the
specified
(Oxford
Dictionary).
private,
mental
an
way'
entirely
The act of categorizing is public.
and mentally
is rooted in action.
in attitude
for
the
will introduce some
categorization,
with
in
of
implies.
categorization involves action.
what I do
arise
develop
ends
categorization
the
representation,
quietly
both
and
section
properties, objects, that
of
between
Categorization is
consider the act
to
I may sit
present
on
which
definition
relationship
are
Again, the section
issues
examined
structure
empirical measurement,
categorize
attached:
yet
contrast
the
categories.
recognized
action:
be
Thought, language,
manipulate
this
to
research
ability
a
as its
which
discriminable entities, is
will
and memory.
functioning. and
Following
turns
underpinning's The
methodological
and
term
implies In
process,
While it is true that
sort through a hypothetical pile of imaginary objects, Even at its most
subjective,
categorization implies a
or mental posture toward something based not on its
- Categorization
individual or
23
unique
character
(as
with
representation)
but,
rather,
on
its
larger
implied
character as a member of some group. The
provision in the definition
differences
are recognized
between
appropriate
recognition one
must
ignore
yet ignored
action
of category still
that -
allows
given
membership perceptible
the entities
a critical
an exemplar in this
differences
among
does not exist outside
the
of unleaded gas but does not recognize
'gases'.
The issue
reality' (Nelson,
is
1985).
whether
thing.
means
some
category,
T o construct true
members
produce
of holding
and the categories,
of the same
category.
the basis
it as a member of the category
for discrimination retains
are not.
any 'cognitive
In essence we're playing a sort of
in which we are pretending that one thing is equivalent
must
to be drawn
The key is that we are acting as though these things were the
T h e equivalence
category,
distinction
- that the
of this recognition - my car acts appropriately in
same while we are fully aware that they pretend game
of
exemplar.
The category presence
be discriminable
created
both
perceptible
among
members,
that
the criteria of category differences
among
is,
the
membership
exemplars
to some other
structure as well
of the as some
in abeyance.
If categorization is, as I have suggested, a kind of pretend game, then what are the rules by which it is played and how do we know when infants are playing it? categorization Though
implies
infants
may sit
ignore this possibility the
specification
some evidence discriminate need
action,
we can demand
and hypothetically
of pretending.
be sure that
sort
exemplars,
will
count
they
the infant is not either
most
Literature
important,
Review
evidence
concerning
- Categorization
W e may also demand that the infants
so while
incapable of detecting as a single
the
manner
we can safely
some difficulty may attend
some evidence
are doing
has forgotten them and is treating all exemplars and
Still,
objects
as evidence.
That is, not only but that
act on the part of the infant.
imaginary
in favour of overt behaviour.
of which behaviours
among
some
If
categorizing.
We
such differences or
object or event. in
can
which
Finally,
within-category
24
differences given.
are
In
suppressed
summary,
observable,
structure
among
category
Since
the
great
using
repeated
bulk
of
variations
of
categorization
that
signals
subject
is
forgotten and
said the
again
a
s set
of
test
to
is
that
the
stimuli,
and
the
discrepancy. after news'
other
In the
responding
to
the
of
To
most
number of
to
measured level.
a novel
(in ensure
procedures
description
Review
an
category(s),
that
in
2)
of
infancy
the
has
been
a
short
techniques,
stimulus or
the
the
case,
the
continued
in
infant
reintroduce
this
differences
in
not
original
by
a the
merely stimulus
procedure,
infants
presentation
response
between
responding
in response the
levels
to
infant
sees the
attention.
At
from due
the
processing.
The
to
perceived
familiarity -
repeated presentation
dishabituation
renewed
level.
habituation and test
results
the
- Categorization
of
terms)
has
the
in responding is
reflects
below
member
relative
decrement
stimulus
the
acquisition.
difference(s)
change the
(or
'familiarization' trials followed
infer category
involve
At this point habituation is
absolute that
generally
the
infants'
as 'old
increased
The 'novelty'
novel stimulus is thus defined in terms of the habituation stimuli.
Literature
be
1)
responding drops
In a variation of
familiarization procedure,
recognizes
first
novel
include:
a
categorization
of
increases
an initial period of processing, unworthy
must
a
3)
are made on the basis of these changes
infant
-
of
categorization
defined)
in response.
test stimuli are used
Two inferences first
this
on
assess
presentation
stimuli,
a fixed In
and
stimuli, until
dishabituated.
a decrement
stimuli.
different
on
responding
have
with
must
formation
habituation/dishabituation
designed
If,
habituation
show
are presented of
to
category
infancy
of
occurred.
category),
the
research
said
contrasting
the
of
the
(preset) or relative (subject
have
in
exemplars,
some absolute to
structure
is in order.
procedures
presentation
the
formed.
discussion of this methodology Habituation
of
within-category
the
out
of
response
of
carried
evidence
evidence
unambiguous
discrimination
-
of
the
In other words, it
25
is
not
simply
new,
but
new
when
compared
to
the
stimuli
which
produced
this
technique
the
habituation. When satisfy
the
properly set
of
dishabituation ambiguous. clearly most
designed,
rules
are,
studies
developed
without
which
above.
exception,
employ
Since
the
behavioural,
measures
the
satisfies
this
criterion.
include
In
order
to
satisfy
the
habituation phase. insight
The
the
be
distinguishable
from
one
is
of
the
met.
By
which is
technique
of these two In
the
studies
exhibits
the
the
fixation time,
demonstrate
the
between exemplars used in the
though
specific
categorization
Review
a
in
interpretations
the
researchers
particularly
techniques using
the
some
simultaneously claimed that
other may be taken as evidence is
that
persuasive
the
event
a
with two
systematic
to
be
object.
that
this
test stimuli,
preference
consistent
of categorical responding.
or
assurance
of categorization.
since
ability
categorization
formerly encountered
infant have
on
It was noted that this
order
habituation procedure provides
presenting
novel,
of
This
for
paired
preference
for
The logic behind the
requires some explanation. habituation
procedure stages:
information in some unstated
a lack of
Literature
of
categorizing
decrement in responding is given in two processes
category,
definition
recognition
either stimulus is taken as evidence use
of
while
simple
stimuli over the
comparison
in
made
variation of
requirement one
structure
placed
discrimination
only
infants
among category members should be recalled here.
clever
rarely
debate.
stress
discriminate
is
Finally, the use of multiple test or dishabituation stimuli allows us
into
remain open to
One
response
discrimination requirement
a control condition or group in which
ability to detect and respond to the critical differences
easily
habituation and
The most common measure in visual categorization studies,
studies
some
infant's
of
can
way
1) the and, 2)
attention to further presentations.
- Categorization
the
explanation
for
infant encodes,
the
initial
assimilates
having completed
that
or
task,
The problem is that the infant
26
may
have
detected
or constructed the
and, having validated this with the game. infant
to
novelty,
While in
course
prior to
of
the
subsequent
decrement
categorical the
a paired
the experimenter.
presentations,
responding
habituation
in
technique
comparison the
infant
continued
a category
advantage
of
that the
preference
relies
may
solely
prefer the
for a completely
on
the
familiar
different
and a variation on a newly
(novel) whether
the
'memorized' set
of
Giving
infant
category
yet bored with the game. there
should be no
since
both
are
novel
has
infant
simply
a choice
category
preference and still
for
please
of the acquisition
stimulus ensue.
The great
preference
novel.
forgotten
the
(new
for
the
completely
exemplar), we can
differences
among
formed the desired category
for one
Preference
between something
acquired theme
If the infant has somehow
category
armed with
the
exemplars or has
systematic
equally
indicates Thus
to
the
a paired comparison procedure is that it provides some insight into category.
which)
now bored
Although this sounds a bit like having your cake and eating it too,
structure of the
decide
is
attention
the logic is difficult to fault since it is not a necessary consequence of
in responding
The beauty of the paired comparison procedure is that it allows
evidence
members.
over the
category
the
but is
not
memorized the previous stimuli,
of the one
test
over
stimuli over the
the
other
other
(regardless
of
formation.
a definition
of
categorization,
techniques
for testing
infants,
and a set
of rules by which to judge the results, we move to an examination of the
research.
In any literature review, one
of
the
rarely
published
research.
satisfies many readers.
demonstrations months, example,
of
colour
essentially
stable
Literature
Review
The justification
change
investigations perception),
into
given
Recognizing this, the
developmental
forsaking
must of necessity
of
which
adulthood.
- Categorization
in
basic
for
particular
present
review
category
structure
perceptual
emerge
The exclusion
early
neglect some large portion
in
exclusion confines
between
categorization development
rule follows,
6
rules
itself
to
and
12
skills and
(for
remain
unapologetically,
from
27
Neisser's
(1967) observation
of
an "unmistakable difference
things look similar and judging Rosch
may
be
exist
1976)
between
such show
more
outside
manipulated
by
natural kind the
category
abstract
laboratory
lies
experimenter.
category
into
categories),
the
we
By
lab
a category
invariant features
in
or
kinds
not
sure that the
can be teased
and events
Where
Studies are
that
have
can
be
that
the
with
perceptual, or
formed is
In addition, the
of
guided by
unlikely to
information
possible
category
out from
is
wings
discontinuities
categories
possibility
be
categories and
form.
subject of
natural
feathers
boundaries
eliminating the
procedure.
which objects
fur.
stimuli the
may
Johnson &
Instead,
'unnatural'
the
(which
can be
available in the
employs to form the
the
the
stimuli made
occur,
and
that two
Gray,
For example,
wings
The attraction of using
encountered
the
attributes
frequency.
attributes. do
by
seeing
category"(p.95).
Rosch, Mervis,
all attributes
equal
than
acquisition of
such considerations.
bringing
of
with
correlated
frequently
the
Rosch, 1978;
argued that not
of
clusters
that
(eg.,
occur together
collections
together
adults
have
categorized
around
occur
that they belong in the same
and her colleagues
Boyes-Braem,
between
subject
based
strategies
is
only
the
on
subject
the problems of familiarity with
of the stimuli.
The process that allows
us to take advantage of such discontinuities, natural or
otherwise, is a matter of debate.
One phenomenon which has fueled this debate is the
prototype
are reported as
been
effect:
previously
formed
around
some
exemplars
experienced. prototypes
category.
By
some
calculated to
way
resemblance mental
this
representation
Members
Literature
are added to
Review
that
account,
which is
One explanation summarize
the
produce
for this crucial
even
effect
when is
they
that
of
a 'best'
exemplar,
a central tendency,
category.
The prototype
the
through
a category
- Categorization
an
exemplars
analysis
have
not
categories
are
information about
features
prototypical of formed
the
'familiar'
of
are
counted,
the
by virtue of their distance
a
particular
averaged,
is
attributes
or
or in
a family
regarded as of
a
exemplars.
from the centre of
the
28
category
- that
concept's
is,
from
extension
the
as
prototype:
graded,
"Prototype
determined
by
theory
construes
similarity
exemplar (or by some other measure of central tendency)" the
prototype
is
often
experienced
as
'familiar'
even
to
in a
concept's
'best'
the
(Lakoff,
when
membership
it
1987,
has
p.43).
never
Thus
been
seen
previously. An
alternate
that prototype
effects
on prototype new is
this
case,
central
of
the
member
the
of
but
The
the
of
categorization
form.
to
category
formation.
constitutes to
an
store.
a
selected
Literature
global
Review
or
-
higher
results
number
of
not
the
of the infant,
prototype
3)
the
take
model
depend
The new similarity
with
a
single,
already
in the
from
the
previously
exemplar to
these
abstract, set.
In
abstraction
stored
of
exemplars
similar to more
a it
stored
of
categories
unnatural
of of
the
should be
or
stimuli
categorization,
one
asks infants
unfamiliar that
applied to
are
the
and
model,
on
the
number
there
are
at
of
least
here in ascending featural of
such
are
employed
in
infant
invariants,
correlations
instances
three
should
possibilities
among
average
or
attributes.
be
what
they
order of complexity: 2)
to
stimuli
stimuli and memory capacity, that is, by
advantage
Categorization
sorts of
use
infant presented focussing
argue
individually and each
of these interpretations
properties
instance
the
that does not
its
not
who
other.
make
specific
to
impression
features,
member
'prototype'
that
the
strategies available to the form
to
with
in part on
complexity
By
according
every
(1978)
stimuli.
is
but
than any
the
'instance'
one
comparison
which, if either,
By
process,
appears more familiar because it is
tasks
determine
limited only by the
The
the
and Schaffer
encountered
non-member
the
depends
Categorization
designed
able
from
category
question
or
of
Medin
all instances are stored
previously
best member,
The prototype
exemplars
view,
stimuli.
familiarity
tendency,
resembles.
infant
a
by
a much different
In this
remembered
representation
offered
compared to the
judged
previously
is
result from
abstraction.
exemplar is then
explanation
are or 1)
count The
29
acquisition
of
colleagues age
these
strategies
and demonstrates
(Hussaim & Cohen,
has
been
chronicled
a clear developmental
1981;
Strauss, 1979;
1981;
by
Leslie
sequence
from
Younger,
Cohen
4
1985;
to
and
10 months
his of
Younger & Cohen,
1983; 1985). The
progression
associates
may
be
development
is
information.
Part
in
categorization
summarized
the
level
of the
of
as
strategies
follows.
abstraction
infants
explanation for this
change
lies
be
only
figure-ground relations.
become are
texture
themselves
the
processed.
discontinuities
etc.,
The between
Later,
units
of
processing,
ability
to
clusters
of
form
unit
can
the
course
process
in the
becomes
his of
relational
changing nature of
specific
objects
features
that
and classes
match
in
attributes, which Rosch contends
average
ability
patterns,
categories
mind
the
over
and
such
as
and still later, as these lower order elements and relations
step.
demand
Cohen
For the newborn this basic unit may
the
world, does not appear until this last should
by
changes
which
basic unit of information being processed.
size,
What
at
the
colour,
suggested
to
of
objects
complexity exist
in the
the real
Categorization of the type Rosch has in attributes
and
to
detect correlational
structures. If, skills
in
prior
10
selected
habituation suggest
to
to
that
domains
stimuli the
resisted.
Younger strategies
and
has
Cohen
which
Review
of
age,
little
infants
else,
represent arrived
show
and after
subordinate at
a
basic 10
perceptual
months,
begin
categories,
watershed
in
categorization
one the
to
is
generalize
tempted
development
to of
It is my task to convince the reader that this temptation should
The attempt
categorization tasks
Literature
but
which
infant
categorization skills. not be
months
(1983)
might
will
be made through a more detailed
task
and
account
for
in general.
the the
proposed
sequence
developmental
of
analysis
of
the
categorization
changes
found
in
The remainder of the discussion of research is taken
- Categorization
30
from
this
research
programme
and
will
compare
the
ability
of
the
two
models
described above to account for this set of data. In a series of studies, shown
that
at
10
one of Cohen's students,
months
of
age,
infants
photographs or drawings of human faces. varying
along
length)
Strauss
selected
dimensions
reports
features.
Like
features
(i.e..,
averaged novel
four
exemplar
discriminate stimuli.
faces
that
separation,
infants
prototype)
as
Although easily,
they
begin
can
treat more
nose
attribute
of
values
category
experienced
during
width,
are unable to
from
the
exemplars and
is
acquisition. yet
Schaffer
independent using
of
these
(1978).
Second,
it
experience
with faces
able to recognize Using
One wonders store
an instance
unable
to
model
line
drawn
previously months,
averaging
composed
of
encountered
or
are
able
to
comprising these
ability to construct a prototypical
set
of
exemplars
by
averaging
how
the
instances
in the that
required to
animals
to
an infant able to discriminate between
suggests is
is not in itself sufficient
manner proposed by
a
developmental
account
for this
clear why the
are unable to form the
'nonsense'
face
head
First, it suggests, not surprisingly, that
it is not immediately
particular faces,
and
stimuli by
a category
the ability to discriminate among exemplars of a category category
to
familiarization.
This finding is telling for two reasons.
allow
length
unseen
5-6
form
categorically
nose
these
familiar than infants,
1981), has
'Identikit' to construct faces
a previously
younger
membership
respond
categorize
The 10 month old is distinguished by the
representative
to
Using a police
10-month-olds
adults,
faces. quite
(eye
Marc Strauss (1979;
composed
Medin
component
ability.
younger infants,
Again, though
category. of
features
which
can
be
interchanged to produce variations on head, tail, ear, body and leg type, Younger and Cohen infancy among
(Younger, of
another
attributes.
Literature
1985;
Review
Younger & Cohen,
adult-like
categorization
1983; skill:
Younger and Cohen (1985)
- Categorization
1985), document the
argue
ability that
to
younger
the
appearance in
detect infants
correlations (4
and 7
31
months)
fail
discriminate strategy
pertains
that even
take
among
whether the
not
to
advantage
the
to
stimuli,
specific
subjects
of for
such they
features.
if these infants
responding on the
clearly
From
relied on a single
correlations can,
not
but
of the
because
their data it is
they
It is
to
determine
nevertheless
of the features,
correlations among those
cannot
their overriding
impossible
or multiple features.
were sensitive to more than one
basis
because
clear
they
were
features.
The ability of the 10 month olds to form a category on the basis of correlations among
attributes
since
it
allows
differences Cohen's
represents the
between
a
significant
formation the
of
more
complex
age
groups
that
10 month olds
(1981) contention
are
improvement
over
this
categories.
characterized
earlier The
succinctly
apply their new
in
strategy
strategy
performance Husaim with
and
relative
ease to such tasks. The stimuli used by Younger and Cohen (1983) are nonsense animals of
five
different
in Table values
1.
The advantage
can
be
resemblance'. across
the
attributes, each of which can take on one
combined The
of this to
design
produce
resemblance
is
composed
of three values
as
lies in the ways in which these attribute
stimuli
produced
that by
bear
a
correlating
quantifiable the
attribute
'family values
stimuli.
Dimension
Body
Tail
Feet
Ears
Legs
Values
a
b
c
d
e
1
Giraffe
Feathered
Webbed
Antlers
2
2
Cow
Fluffy
Club
Round
4
3
Elephant
Horse
Hoofed
Human
6
Table 1:
Stimulus dimension values from Younger and Cohen (19831
Table 2 lists the dimension values for experimental stimuli used in the stimuli are shown in Figure
Literature
shown
Review
1983
study, the
1.
- Categorization
32
H a b i t u a t i on
Stimuli Dimension
Stimulus
a
b
c
d
e
1
1
1
1
1
2
2
1
1
1
2
1
3
2
2
2
1
1
4
2
2
2
2
2
Test
Table 2:
the
of
four
2
2
2
1
2
UNCORRELATED
2
1
1
1
2
NOVEL
3
3
3
3
3
trials.
phase
randomized across to
the
is
each
followed
by
is
of
investigation
suggest
absent
that
generous
one
is
seen of
stimuli
twice.
the
The
the
in
uncorrelated
correlated and 4
violates the the
stimuli
three
too
test
test
ill-defined
save
or two
animals
are
the
novel
specific equally
test
that
animal.
features. 'familiar',
stimuli
stimulus
stimuli. to
The
be
or
(order
fixation
conserves
novel results
reliably
is
the
a, b, and stimulus of
is
their
categorized
by
These infants typically show low fixation times to the
stimulus
category
habituation
among dimension values
complex
randomized
trials, the infant's
correlation, and the
habituation are
in two The
and
recover
to
the
novel
stimulus.
interpretation of the data would grant that 7 month olds
and
stimuli,
habituation
presentation
in habituation stimuli 3
features
and
stimulus
recorded.
infants under 7 months of age. correlated
the
During each of the 20 second
The uncorrelated test stimulus
composed
large
are shown
Thus,
subjects).
stimulus
correlation present c.
CORRELATED
procedure, infants
familiarization
time
Stimuli
Dimension values of experimental stimuli used by Younger & Cohen (19831
In blocks
Values
encompasses More
likely,
all they
In that case, both the and
looking
time
of
the
are
A
very
are able to form a
habituation
simply
and
test
concentrating
on
correlated and uncorrelated test
should
rise
only
to
the
novel
stimulus.
Literature
Review
-
Categorization
33
In contrast,
10-month-old
infants
show
high
as well as the novel stimulus (Younger & Cohen, argued, 2,
are
capable
and the
1).
uncorrelated equally
stimuli
may
uncorrelated the
forming two
high
garner
and
novel
levels
of
the
stimulus
is
a more
increased
looking time
continued
processing
categories
formed
attention
to in
by
visual
attractive
to
of
for
neither
the
very
(see
category
uncorrelated
different
for
Figure
and
and
are
novel
reasons.
The given
stimulus is, by definition, novel.
The
The
category
1,
membership
could, therefore,
determine
a novelty
in
But
candidate
familiarization.
virtue
containing habituation stimuli
attention.
attention
attempt
the uncorrelated
The older infants, it can be
belong
uncorrelated stimulus
an
during
one
stimuli
while the novel
the
1983).
to
other habituation stimuli 3 and 4
test
infants'
familiarity of its features,
visual
categories,
correlated test stimulus, the
The
accorded
of
looking times
its
novel
be
status
relative
stimulus
attracts
preference
inculcated
categories
rests
in
the
construed to
as
the
two
equally
high
familiarization
phase. The underlying
ability
to
form
these
correlational structures
recognition should be taken as use
of
it
is
instance
of
a new
judge
that
serial
fashion,
the
enough
to
sort
of
the
return to
the
stimulus
this
ability to The
Review
recognition
argued below
belongs
information
in
of
that
action.
form
categories
these
neither
detected
two infant
is
category during
the such
ability to make
with intentional
10-month-old
by
the
For the is
an
able
to
applying,
in
now
familiarization 10
months
able to segregate a series of items into two distinct categories based
the
attributes
issue
of
of the
prototype
items. versus
instance
types of findings argue against the instance view.
Literature
be
a
Indeed, Younger (1985) has demonstrated that by
on correlations among the To
It will
coordinate
categorization.
correlational
of the procedure.
stimuli.
on
indicative of a more general cognitive
claim that
uncorrelated
of age infants are
two
of the
relational information and to
moment,
phase
two
- Categorization
models
of
categorization,
First, an instance model would
34
demand There
memory
is
their
memory
after delays prototype
for
specific
overtraining,
to
items
15
5
infants
as
a
whole,
incomplete
Second,
phase
stimulus to
are
of the three
1983
familiarization
(211),
were and
correlation correlated responded stimulus
habituation
phase
these infants
to
seen
on
Strauss'
exemplars
evidence
of
In addition, Sherman (1981) effects
specific
indicate
many
tested of
showed
phase.
when
forced,
items.
that
As
formation
exemplars,
Cohen notes:
of
rather
through
a
prototype
than
complete
the
contend
specific
that
exemplars
When the task is
infants seen
in
in
the
correlated
the
familiarization
simplified such that stimuli vary
to construct a set of test stimuli which directly
contention.
Younger and Cohen (1985) report a variation
study in which infants were shown more simple stimuli composed of only
attributes
Infants
When
of memory for previously
would
on only three attributes, it is possible theorists'
familiarization
explanation.
the
or three
of
the
p.32).
theorists
rather than the correlation.
instance
during
prototype
seems
(in press,
recalling
this
presentations.
show
then,
during
Nevertheless,
processing
instance
studies
test the
against
evidence
seconds.
fail
seen
presented
second
processing of only a few"
attribute
weighing
remember more than two
evidence
accompanies
as
with
that
exemplars
displayed no
as brief
effects
specific
evidence
infants
shown
"The
the
considerable
(1981) study,
has
of
which trials
then
with
tested
a novel
stimulus
The
Literature
Review
stimuli
with
a
of
three
values.
having the
correlated
(333).
first two
basis
be
reversed.
3
one
If
stimulus
the
attributes,
attribute
infants
the
of
more
results
the
similarity
to
infants
values
(222),
On the
previous
to
the
habituation
conformed
to
the
first
111,
were 112,
given and
an uncorrelated
responded
similar
- Categorization
The
looking times
and high for the uncorrelated.
the
should
on
stimulus
between the
on
took
on
the
low
of
set,
prediction.
and The
the
the
the
for the
other hand, if the instances,
221.
stimulus
basis
should be
9
infants
uncorrelated
looking
infants
times
generalize
35
habituation
to
the
correlated stimulus
and look
longer
at the
uncorrelated and novel
stimuli. Two
findings
emphasized.
First,
correlations forming
from
among
to
research by Cohen,
infants
of
stimulus
categories.
attributes
the
Like
group
10
months,
attributes
adults,
and
they
can
discriminably different
Younger and Strauss
but are
not
able
use
younger, to
use
into
a
are
that
discontinuities
entities
in
the
single
of
one
category
presentations the
such categories.
ability
but
of to
process
and
subsequent
exemplars
the
first
Since
memory,
of
To
to
both
its
al.'s
model,
and. use
of two
into one
the
the
must
category,
categorization depends of
on
these
relations
will based
respond based
in
variability of Second,
into one or the
habituation feat
be
able
and
must
to
further
depends
on
detect
the
to
then
compare
ability appears near the the
ability
findings
to
process
need
to
be
end of
relational addressed.
of
categorization
derives
of
categorization
to
representation,
the
object,
concept
of
from
is
an
left
address these concerns. on
correlational information, the
on a prototype they
such categories, Two questions
infant has
information
structures.
section
or structures.
imply that
a
explanation
a category
segregate items
necessarily
form
acquisition - particularly Piaget's
to
both prototypes
to
generalize
Infants
to
which preserve the correlation
In both cases the
information.
implications
The remainder of this acquire
category.
appearance
et
to items
month-olds
category
must make the decision
to
either
that this new
Cohen
processing
10
information
theoretical
and concept
unstated.
from
that
and that
the
much
information
use
other,
relational
established
year
information,
the
exemplars
correlation
Having
not
Given exposure
sensitive
category.
infants of this age, but not those younger, are able to segregate items other of two
should be re-
seen.
To
the infant must compare a new
item
arise
have never
infant
immediately.
formed a representation
of
the
First, object
does
this
or event
similar in complexity to that of an adult's, and second, does the demonstration of these
Literature
Review
- Categorization
36
categorization
skills
in
infancy
challenge
possesses
a still
questions
is no, and offer the following
First,
immature concept
impressive
require the concept the
object
may
respond.
the
this
be
such
notion
resides
in
differences,
and,
of
membership
category
that
whether
fragile
category
the
the
in of
the
therefore,
object
not
I propose
to
both
skills
may
be,
they
do
not
"recreates"
the
or
the
in
without
need the
month-old
out, memory for
acknowledgement
and
10
As Sophian (1980) points
search
object
infants
the
The response
categorization
infant
the
that
defense.
infant's
the
contention
object?
of object permanence.
Success,
validates
though
of
Piaget's
the
its
of
of
themselves
any
decision of
Further,
within with
to
objects,
permanence.
disregard
concern
permanence
in
categorization
entailing
and
only
object
category
the
criteria
particular exemplar.
The
decision: is X a member of Y , is made with X present, thus relieving the infant of the burden of X's existence beyond this moment. for
objects The
not
but not reasoning
have
an
membership (Strauss, based does
stimuli
is
of A
regard to
category
illustrate
are
of
becomes visibly
the
this
acquisition
simply
without the
concept
perturbed when
her any
Categorization
in
preverbal
infants
can
Literature
Review
-
this
infancy
respond
to
the
which her of
the
favourite
to
criteria
based
can
of
and
yet
which
can
is
procedure The
be
properly
the
infant's
based.
I
objects
number.
require
category
need
numerosity
a habituation
that
toy,
on
by
discriminate
concept
concept
My
cat
am confident
in
justice.
impressive
categorically
Categorization
mathematical
explanations
upon
an
infants
The infant
the
categorization That
of
concept is
only
discrimination in
the
robbed of
appreciation of the
of
point.
of
acquisition.
membership,
instantiations
resorting
abstract
concept
demonstration
number and generalize
such
understanding
denying
notion
demonstrate
as
similar with
serves to
presented
treated
permanence.
determined.
their
not
is
abstract
1979)
on
their
T o be sure, these feats require memory
events
achievement and
objects
indeed. by
That
processing
37
correlations seriously
among
underestimated
categorization however, more
features
from
reveals
likely
the
seems,
infant list
interpret
categories,
representation
of
While
is,
the
membership
categorization
exemplars.
This
infants'
found
new
recognition one
of
cannot
must at
be
this
appear
stressed, early
infant's arriving,
and
to
experience
general,
his
objects
of
and
report
skill. only
in
reality' beyond
these
of
new
the
necessary
receptive
vocabulary
and
recognize
abstract
categories
Literature
Review
- Categorization
look,
emerging
such of
to
precisely
presence the
concepts
a
they
of
they
make
category of
the
on
the
exemplars,
but
underpin
this
ability
rests
can
categorize
strategies.
depends
It
exists
jointly
particular concept
and
even
on
the
the later
representation.
these
infants serves
allows to
to
kind.
may
The
depend
Further,
to
dissect
development
of the type Cohen
mapping
capabilities.
phonology
them
further
that categorization
prerequisite
this
made.
limitations
which
though
concepts
and likely
language
functional
in
here-and-now
infants
to
conceptual
are
ways
information-processing
for example,
onto
remove
identical
abstract,
month-old's
the
conceptual
ways
formally
for realizing these concepts
of
available
a
of
for
potential
10
specific
sophisticated
persons
a
describing
The
instantiations
is
to
have
A closer
inclusion decisions
understanding
kind
lack.
an
in
It is possible,
colleagues
trouble
form
important
ability
the
to
category
understanding
in qualitatively
in other domains. and
is
recognize
Categorization their
is
perhaps,
we
The infant, though able to
continued
that the
The
more
as
the
highly
however,
to
infancy
require
'cognitive
be
stage.
ability
some
membership
any
which infants
unable
which
categorization
category
in
adult,
infants
Such knowledge
what
the
have
distinction
claim
recognition. using
may
suggest that
tempted,
This is clearly not the case.
unlike
decisions,
is
to
Looking from the 'top down', we may simply be
principles by
adults
at least,
One
adult abilities
a different picture.
to
surface
capabilities.
of the
categorization in adulthood. acquire
on the
knowledge
acquisition on
the
the ability
of
ability to
of a to
apply
38
language fix
labels
category
to
category
boundaries.
type of categorization. and a sail for the
exemplars,
In this
sense,
The possibility
of
such
arrives much later, helps
language
both profits
that language
abilities.
The 'cognitive
economy'
that
categorization
notion
it
developmental processing
Literature
but
from
the
implications
such
Review
information
-
preceding of
in
define
and
and enables
this
provide an anchor
It is also likely that conceptual knowledge
of the object.
well,
to
of these categorization
crucial step toward the acquisition of the concept as
from
may, at once,
realization of the conceptual potential
will be reprised in a later section. out
which
this
review
emerging
importantly
Categorization
may
grows be
a
I will return to this
seems
evident
ability,
infants
adaptive
allows
skills
that, are
whatever capable
the of
ways.
39
The The
Development
purpose
methodological perception
of
issues
measure.
adult
perception,
more
recent
results
section
which
arise
from
acoustically
categorical
-
effortlessly discrete, picture not
an
in
and continuous More benefits linguistic
classic months time shown
of
boundary.
Literature
Review
the
the
theoretical
cross-language research
findings,
speech,
as
phoneme of
continuum research
but
have
not
Speech
have
of
of
the
some
(ABX
Repp,
1983
one-month
of
age,
pairs
which
of
straddled
stimuli an
those pairs of
been
Perception
of
picture. those
Go/No-Go
rule
the
have
for
fact
been
speech
that
shown
one-
In
to a
and four-
/ba/-/pa/ voice
phonetic
the
by pre-
boundaries.
onset
boundary,
stimuli which crossed
reported for place
Perhaps
are enjoyed
category
English
into
review).
sounds
the
to
a clear
match
ISI,
the
bent) is
from
sounds
simple
long
for a
listener
sounds.
demands
infants
phonetic
the
This
painted
this
remains
a developmental
adult
adults
procedures,
perception
are able to
speech
with
processing
speech
to
of
complicated
and
(see
allows
non-speech,
of
with three of
area
equivalent.
Siqueland, Jusczyk, & Vigorito (1971), infants
one
and
speech
in the
and
as
language
processing
according
results
-
these
single
categorical
reliably discriminate only Similar
of
Early
(for those of
young
stimuli
only
of
ambiguous
processing
and accurate
presented
continuum, to
still
by Eimas,
age,
a
results
tokens),
As
speech
the
some
- perception
perception for non-speech
infants.
study
of
characteristics
speech
rapid
of
of
infants.
for
recent
multiple
this
discriminate
outline
some
use
implications
continuous
stimulus
fascinating
of
the
instances
more
where
with
of
will
perception
everyday
procedures
out
appropriate categories.
surprisingly,
found
introduce
acoustically
categorical
Nevertheless,
to
Perception
intriguing aspects of speech perception is that we
rather than
language
is
work with
distinct
divide
of
review
developmental
One of the most treat
Cross-Language Speech
this
The
the
of
the
articulation, voice
were
English onset,
40
stop, lateral, and fricative consonants (eg., Eimas,
1975;
Holmberg,
Importantly, included, that
when
infants
infants
syllable
show
utterances perception.
rate of
speaking.
differentiating transitions. talking well
into
speech
the
range slowly
sounds
parameters
of
of
in
speech
to
phonetic
synthesized
to
sensitivity
speaker,
one
speech
is
of
discriminate
1979). this
they
different
a
the
formant
transitions
for
transitions
for
higher to
findings
the
order
context
been suggest
duration
such
acoustic
of
of as
cues
the formant
When a speaker is
will
normal
adults compensate
single
aspects
effects
principle
/ba/ a
have
lengthen, /wa/.
for the
reaching
Rather
than
rate of speaking
Eimas and Miller (1980) have shown that young infants kind
of
contextual
by
the
cue,
indicating that their processing of
relational
rather
than
absolute
acoustic
hear.
sensitivity
Greiser and Kuhl
formant
determined
what
across
the
1973).
information in
of the is
(Trehub,
stimuli
these
1977;
discriminative capacities.
sensitivity
show
spoken /ba/ as /wa/,
to
similar
instances
of
adult English
/wa/
however,
sensitive
A
question
as vowels
Together
sensitivity
for instance,
T o the
& Liberman,
also
colour
Adults,
the
linguistically relevant,
infant
the
to
well
Typically, these transitions are much shorter for /b/.
perceive this
are
of
as
discrimination.
based,
begged
/ba/ from
slowly,
(Miller
broad
1987; Eilers, Wilson, & Moore,
1979),
counterparts
continuous
demonstrations
speech
& Kuhl,
non-speech
possess
These
Morgan,
Aslin,
extends
speakers
to
and
vowels.
Young
intonation
infants
contours
can categorize
(Kuhl,
1979).
vowel
Recently,
(1989) have shown that young infants can even generalize to novel
single
between
category
members,
members
are
greater
vowel
category.
categories even than
but
when those
As
show
the
with
little
acoustic
between
two
phonetic
sensitivity differences instances
contrasts, to
the
differences
between which
infants
two
cross
a
easily among
category category
boundary.
Literature
Review
-
Speech Perception
41
The discovery the
infant
led
developmental constancy further
to fate
of
of such unexpected a
shift
in
of
these
skills
phonetic
perceptual
segments
development
perceptual
categorization
comment.
While
absence
of
categories,
the
within
categorical perceptual
of
that
adults
have
phonemic
have
difficulty
Best,
& Strange,
1975).
The
of
perceptual
skills
categorization
follows
have
from
determine birth,
in their native
using
Miyawaki, different
and
the
demands
that
both
contrasts,
and that by
adults
adults
to have
acquired this
nurture,
researchers
1-4
months
began
contrast.
-
have
and infants
ability.
changes of
little
English
of
Perception
perceptual evidence
these
feats
sophisticated, nature
of to
escape the
of
the
effort .-- it is
the
course
similar to
that
a different
sort of ability.
occur in the
perception of
Japanese
speech
speakers,
of
the
perception
contrasts
/ r / and / l / (Goto,
revealed
that
for
do
instance,
1971;
MacKain,
Jenkins, & Fujimura,
similar results
(for
reviews,
to
have
learn to
non-native
contrasts
discriminate
phonetic
already had enough
experience
potential confound between nature and
prior
such
discriminating
have
infants
T o remove the
The goal
the
Strange, 1986).
might
infants
to
is the extent to which the
cross-language
language.
difficulty
of age
testing
Speech
to serve
have
the
cannot
exhaustive
discriminating phonetic
Strange & Jenkins, 1978;
finding
section
Strange, Verbrugge, Liberman,
contrasts
if
remarkably
a developmental
difficulty
turned
or whether
previous are
studies
now
on the part of
The similarity of
of speech
developmental
often
1981;
Review
at
the
in becoming co-opted
came
that
Literature
to
obtained. in
speech
status
1986;
phonetic
given
discussed
speech
suggested
native
be
Attention
attempt
simply
discriminating between the
Studies
see Burnham,
an
discrimination
indication that
aspects
showing not
perception
first
focus.
On the agenda of the present section
categorization
The
in
could
infants'
suggest that the
research
was
category
nature of the beast.
formal
as
and remarkable sophistication
to
their
first
exposure
investigations
was
to
to
determine
a
non-
whether
42
young
infants
sensitive
only
The learning
to
sensitivity
those
rewards
of
infants,
distinction Lasky,
show
& Klein,
sensitivities
that
this
the
of
timing To
Werker
1975).
of
infants
/d a/) h
this
her
as
are
may
sensitive,
a
categories,
developmental
the
effect
of
aged
6-8
syllables
voiceless,
biological
began
by
months,
both
Hindi
English-speaking The
(unvoiced,
adults
contrasts failed
developmental using
a
Northwest
Indian
language
and
distinction,
native
but
the
contrast
the
infants'
1975).
old
Kikuyu-
/ba/-/pa/
voicing
olds
(Lasky,
broad-based of
adults
to
Effort
Syrdalphonetic
led to
the
discriminate
the
now
Hindi-speaking (which
the
speech
as a
focussed
perception,
English-speaking
is
adults
also
unaspirated retroflex
on
used
versus
adults, their
on
dental
breathy, voiced
as
1981).
well the
as
the
infancy
Inslekampx
(/ki/-/qi/).
as
to well
/ta/-/Ta/,
stop
/t a/n
description
While virtually all of the infants could Hindi-speaking adults,
non-English
between
ability
stop
dental
Janet
English-
in Hindi),
in Hindi but not in English (for a full
from
of
month
predisposition
comparing
Inslekampx-speaking majority
4-6
cross-language
stop versus
both
change
replicated
months
on
and
see Werker, Gilbert, Humphrey, & Tees, discriminate
month
English
capabilities
(Eimas,
are
change.
experience
contrasts
or
environment. Two
the
contrasts,
and that there is a decline in this sensitivity
aspirated dental
that are phonemic
to
between
English /ba/-/da/ distinction
pairs of
phonetic
plentiful.
Spanish-learning
have
of
language
limited (language-specific)
colleagues
infants
discriminate
and the
are
set
their
been
acquiring a particular language
and
as two
in
The comparison
more
assess the
learning
universal
present
instance,
universal set of phonetic function
the
approach have
1976),
and the
hypothesis
contrasts
for
(Streeter,
to
Again,
most
of
the
contrasts. and
adulthood
(Thompson),
an
English-learning
was
subsequently
Interior infants
Salish
aged
6-8 this
adults
were
able
to
discriminate
English-speaking
adults
were
not
(Werker &
Tees,
1984a).
Literature
Review
-
Speech
Perception
43
Werker in
the
ability
puberty, the a
originally
foreign
age
that
were
more
no
incorrectly)
discriminate
predicted
non-native
that
phonetic
the
developmental
contrasts
would
at which Lenneberg (1967) had claimed that the
language
indicated
speaking
to
(and
without
12-year able
adults.
an
old, to
accent
and
declines.
even
discriminate
8-
and
the
Contrary 4-year
old
non-English
Even more surprising, the 4-year
to
occur
flexibility
expectation,
around to learn
her
work
English-speaking children
syllables
olds
change
than
were
actually had more
Englishdifficulty
on the Hindi voicing contrast than did the older children and adults (Werker & Tees, 1983). A tested
further
under
sensitivity
set
more
to
the the
favourable
testing
discrimination
markedly
simply
not
adult
English-speakers
these
readily accessible
retroflex/dental
contrast
evidence
of
studies
non-native
when
the
were
able
to
when
given
suggest
that
of
these
1984b).
sensitive procedure (Werker & Logan, These
when
For example,
(Werker & Tees,
differentiating
that
conditions,
contrasts,
improved
as
revealed
contrasts.
of
cues
experiments
non-native
portions
acoustic
of
adult
English-speakers
they
did
when
presented
now
non
Thus the contrasts
show
to
not
sufficient
the
practice
and
tested
the
apparent
decline
language
in
perceptual
the
stimuli
When
the
stimuli less
situation
are perceived speech-like
discrimination
Literature
in
Review
as
most
discrimination some
-
closely
speech-like,
testing
Speech
in
the was
Further, Hindi a
more
resemble
the
mimics
the
discrimination is improves,
procedures
Perception
sensitivity
system rather than an absolute
which
testing
it
full-syllable
It may be that performance depends
and
discriminate
sounds.
or simple decline in sensitivity. demands
stimuli
1985).
a reorganization within the
task
truncated
disappeared,
stimuli are language-like discriminate
with
latent
speech-like
ability
had
some
were
thus
and not
natural natural poor. subjects
others.
environment.
environment, the show
The
loss
on the extent to
speech
As
is
stimuli
and
the
become
evidence
of
reorganization
may
44
represent
a developmental
shift
in the
speech stimuli, with each level
level
of
analysis
affording its own set
applied to
speech
and non-
of boundaries.
Having ascertained that children as young as age 4 perform as poorly as adults on
non-native
predicted
contrasts,
that
the
coincide
with
children
between
Werker
reorganization
the
"explosion" 8
months
and
her
would
in
colleagues
be
apparent
at
next
(again
18-24
months
productive vocabulary.
and 4
years
of
age,
it
However,
quickly
incorrectly)
in
of
age
pilot
became
to
testing
apparent
that
something was happening by the end of the first year of life. At
this
point
the
twelve months of age. compared and
on
the
their
to
discriminate both
globalized
all the
infants
native contrasts, whereas
velar/uvular
aged
6-8
the
infants
aged
discriminate the (Werker those
8-10
months
Inslekampx,
& Tees,
described
concentrating
1984a)
above
the
(/ki/-/qi/)
months
were
with
was
12
the
aged
a longitudinal design
all
subjects
8
Hindi.
infants
and 10-12
under
months were
retro flex/dental
able
intermediate,
on
(/Ta/-/ta/),
distinctions.
of the ten the Hindi
and 8 of
using
8-10,
Hindi
only one of the ten infants
discriminate the Inslekampx, and two of
narrowed,
Three groups of infants aged 6-8,
ability
Inslekampx
Virtually
investigation
to
discriminate both non-
10-12
months was
contrast. of
the
This
14
The performance infants
experiment
yielding results
able to
was
able
to
repeated
consistent
with
discriminating both non-English contrasts
at
6-8 months, and none at 10-12 months of age. Finally, performance learning
We continuum phonetic
Literature
for
11-12
difficulty
to
make
sure that
difficult month
contrasts
olds
were
discriminating their recently which
replicated allowed
categories.
Review
-
the
The
Speech
at
results 10-12
tested
native
were
months,
on
these
due
to
a few
a general
Hindi-
decline
in
and Inslekampx-
contrasts.
These
infants
a
synthetic
had
no
contrast.
this
finding
using
precise
control
of
continuum
Perception
not
was
the
16-step differences
constructed
by
/ba/-/da/-/Da/
within
and
between
varying
the
starting
45
frequency for
of
the
a detailed
into
two
dental
second
description).
categories,
/da/, We
and third
and
/ba/
tested
speaking
adults
on
according
to
exemplars
from
presented
using
Common,
corresponded
both
continuum
their
the
pairing,
the
side
no
relevant
listeners
three
the
clearly
to
& Lalonde,
divide
into
boundary
boundary
between
indicated the
this
three
1988,
continuum
categories,
between
from
boundary along
first bilabial
/ba/,
was
make
infants
chosen
near
6-8
and
inability
other
to
11-13
month
discriminate
specificity
studies
contention
that
of
of
infant
the
have
could
speech
called
dental/alveolar
Da
the
end
Hindi of
the
and Hindi-speaking but
not
only
the
Neither
discriminate
the
irrelevant boundary
perception.
perception,
special
were
distinction.
months
speech
location,
/ D a / for
a linguistically
infant
infants
olds
Three
location, called Hindi-only,
a category aged
continuum
continuum
and
/da/ and retroflex
Neither,
English-
locations.
this
/ba/
and
the
boundary
The second
dental
that
stimuli
locations The
and Hindi-
Common and Hindi-only pairings,
phonetic
the
months
irrelevant
procedure.
English adults
with
11-13
and
is known to
the
phonetic
this
research
capacities
which
reorganized by the end of the first year of life to match what is required by
native
language
Recent aspects of been
Werker
shown
discriminate
language
confirms
supports
and
called
(Neither)
the
Hindi
location,
This
become
were
and English listeners.
pairing.
strongly
to
Turn
to
Common
Together
ability
of
Head
discriminate
whereas
6-8
boundary
third
results
could
and
aged
phonetically
either
where
The adults
to
A
and /da/,
infants
/da/ for both the Hindi
listeners.
English listeners
(see
retroflex / D a / .
then
corresponded
formant transitions
Literature
indicates
that
infant speech perception may
shown,
boundaries,
evidence
for example, and
this
Review
-
that
ability
Speech
is
infants
important also be as
young
particularly
Perception
developmental
occurring in this as
striking
4-6
months
when
the
changes
to
first year. can perceive clausal
other It
has
clausal
boundary
is
46
exaggerated
with
the
timing
Nelson,
Jusczyk, Wright
phrasal
boundaries,
(Jusczyk,
Hirsh-Pasek,
facilitate
colleagues
have
boundaries
in
capacity
has
indicates
that
tuned
of
perception
both
narrowed
to
are
the
to
formal serve
bring
some
of
measure
communicative
I
have
argued
will
narrow to
apparent
that
suprasegmental
that
newborn
reflect
suprasegmental formal
the
comparable
Review
-
of
the
9-months
&
Piwoz,
of
in
same kinds of
addition,
months but
This
during early
6
press)
and
perceive
by
age
abilities
Jusczyk
can
that
boundaries.
his
clausal
months
the
research
further
development
become
ability
to
abilities
perceive
segment speech into order to
infant
newborn
the
harness
speech
simple
these
for
the
task
contrasts
in a
and phrases
chaos
more than the
must
hold
clauses
seeming
arrives
of
As
of the
demands
of the
infants'
the
Speech
are The
occurring perceptual
a broad base of
noted native
above,
this
language.
Perception
with
able to categorize course
speech. to
armed
Over the
changes
a sensitivity features.
perceive
input.
The infant is
conform to
requirements
Literature
the
boundaries.
aspects
4
remarkable perceptual
of
The ability to
of
her
allows
linguistic
detection
perceptual
of
abilities
the to
function.
speech perception skills. phonetic
the
In
as
present
learning demands
language:
a
universal
linguistic
ability to
But language
properties
sensitivities
Kemler
Woodward,
languages,
language
self-evident:
manner and the
young
(Hirsh-Pasek,
approximately
boundaries.
non-native
these
until
1987).
may build from the
as
native
which
categorical
environment.
and
specific
advantages
"motherese"
Kennedy,
clausal
infants
broad based
acquiring language
infant
apparent
Nelson,
of
that
native
in accord with The
not
Kemler
shown
the
is
perception of phrases
the
of
Cassidy, Druss, & Kennedy,
however,
suggesting that the that
characteristics
an
first year of native in
life
these
language.
the
It
perception
that
linguistically universal
array
of
speech stimuli according to
biases
These
impressive
are
evident
relevant
sensitivity changes,
skills
is
also
of
the
in
segmental
far outstrips
evident
before
the and the the
47
infant
utters
his
first
real
word,
represent
abilities which match what is required of
a
a native
specific
narrowing
to
developmental
argued that the considered. and
changes
contribution of
By
developing
highlighting infant
the
some
in
infant
speech
of the processes perception.
infants' emerging cognitive of
competencies
the
ways
may
perceptual
listener.
The intent of this review has been to describe some contribute
of
in
which
influence
the
abilities
both fate
It
that may has
must
contextual of
early
been
also
be
variables speech
perception abilities, I hope to have set the stage for a discussion of the developmental relations
Literature
among the three competencies
Review
-
Speech
Perception
I have
chosen
to
study.
48
POSSIBLE RELATIONS AMONG THE TASKS To
suggest
categorization,
that
and
the
developmental
speech
perception
description of the relations I see will
be
addressed
perception, common
object
theme of
across
form
some
pursuit of
potential once
of
processes
general.
information. non-native
is
phonetic Tison,
the
common
is
and
or
that
the
object
origin,
success
ambiguity.
or separate
sets
outlined
reflect
emergence
object
on
each
infants' first
of
in object of
These
coordinate
search,
this
to
speech
coordination
a
products
carried
attempts
The
requires
their
information becomes
a
search/speech
task
manipulation
The ability to
of
demands
pairings.
The coordination is
the
search,
perception/categorization.
mental
and represents
the
comparisons:
speech
The changes
reorganization
characterized
speech
a
in
out
realize what
in the
were
objectified,
and
perception
and
as
a
general
strategy.
The
level
and
coordination ability holds.
Object
the
share
pair-wise
comparisons
interference
categorization
cognitive
following
goal
evident
between each of the three possible
processes
a specific
which this
more
visual
these
separate
independent
made
the
tasks
search/categorization,
in
coordination
the
by
changes
as
a
The speech
of
finding sounds,
added the perception
cross-language
developmental
processing
in press,
of
Search and Speech
that, they
has
have
not
occurred.
with
Mehler,
respect
to
the
may
lost the
have
ability,
can
be
phonetic
discriminating
suggests that
a change
speech
in
and non-
and more narrow native
Halsted,
language).
of
difficulty
distinction between
Lambertz,
whole
capabilities
processing
'universal' phonetic,
Jusczyk, the
perception
in
adults
T o the
distinction between (cf.
speech
transition
although
Perception
Bertoncini &
Further,
if
the
Amiel-
speech/non-
speech distinction is made by the machinery of perception (i.e., it is the nature of the beast),
the
Relations
initial
among the
speech
tasks
processing
capabilities
represent
a
form
of
perceptual
49
overkill. grained in
While
non-speech
discriminations
category
contrasts
easily
environments
made,
infants
require.
from
with
The
the
native
language
native
category,
exactly.
The task
facing
the
boundaries
and erase
the phonetic
entirely
sublimation revived
lost. of
Still, arises
occurs
some
within
out
of
latter is
indeed the
the
development
of
Consider
as
object one
of
search the
of
abilities.
or
goals
of
absent,
should
relationships observation sudden
expect
between that
noises,
localization. the
very
Relations
intermediary
real
the must
the
experience
among
the
prior
of
us
are
as
most to
to
a formal
is
then
distinguished
be
that
tasks
the
equipped
contrast 12
the
and
the
with from
reflex
month-old
not
an
resemble
whether
nature only
the
process,
module,
or
is
similarity between
in
this
appreciation nature
orienting
later,
easily
skills.
development
full
a
to persuade the reader that
of
a
are
involves
begins
speech perception
to
certain
discriminations
therefore,
phonetic/linguistic
In an effort
sound
newborn
We can easily sense
steps
others
to move
domain
recognition that sound is a cue to the localization of its source in space. we
by
distinction
maturational/experiential
perceptual
speech
activated
perceptual
speech
inform
a demonstration
and native
with-
language
phonetic
interestingly,
non-native
phonetic
is
it, is
categories,
way
their
fine
But the initial capabilities
which,
no
making
virtually
formalize
possible
these
than
native
with
non-native
category
are
language.
which
case, I offer
each
some
independent
encapsulated
discriminate
match the
set
of
in
an
yoked to other developing
the
the
manner,
categorically,
categories
were to
categories
findings
--
others
if we
in
to
which
differs
reorganization
these
reorganization
with
that
conditions
perceived
capacity
in the native
extraneous
special
non-speech.
such
is
in a continuous
perceptual
still
infant,
used
The
the
under
somehow
others set
The
frequency
a single
not
speech
more
subdivide
matches
are perceived
discrimination difficult.
provides
exemplars
sounds
more of
the
correctly
of
its
If this is so, of
the
causal
source.
response
The
triggered
sophisticated newborn's locates
the
by
forms
of
response
to
the
sound
in
50
space,
expects
but
incompletely,
that
a
specific
sounds
are
source.
'caused'
by
While persons
this and
orients more or less correctly in the direction of the first
months
sound,
and
movements The information
of
life
will
infants
coordinate
to
to
sound
evince
with
contingent
with the speech
limits of
such expectancies
events,
sound.
in the
perceptual one
expectancy,
are found in the
infant's
wishes
conception
of
in
space,
to
which time,
an to
world to
the
couch
The crucial question then becomes:
newborn
expectancy
beginning
infant's
this
of
to
surrounding
expect
causal is
and, therefore,
of
1979).
sounds
that
from
transition from
relations
(using
intertwined
with
mouth
The connection of sound,
then, the
process)
if
merely
inability to use
differentiation
Clearly
appreciation
causality
the
understands,
Over the course of the
perceptual
perhaps
child
directed toward them (Muir & Field,
that produce them, comes gradually.
terms
a
things,
as a guide to action beyond simple orientation.
and events or images objects
begin
older
with
her concept
of
the
reflex,
whatever the
child's
the
object.
Can the same be said of the child's perception of
speech? Having differently
acknowledged
than
that
speech
I
intend
non-speech,
is
'special' in the
to
argue
that
sense that
a
similar
described above lies behind the reorganization of perceptual abilities. must
be
stressed
receptive infant This
that
vocabulary.
have
I
the
correspondence
— that
inseparable
is,
them.
Speech
Relations
that
constituent
sense that speech is
the
thus
not
tasks
9
month-old
speech
more properly be
may
event.
a
to
At the outset it large,
functional, is
that
and events in the
termed
that
a perceptual
the
world.
expectancy.
and events are correlated in time but not
attend
an
The
infant
overlap, or follow
simply
with
processed
process
argument that follows
between
is that speech
speech
of
the
required for the
may
may precede,
among the
endow
correspondence
The nature of the expectancy unitary
not
A l l that is
a sense of
sense of
do
it is
event must
without have
being the
a
causal
beginnings
of
or a
events, but is not isomorphic with
background noise,
nor does
it yet
have
meaning
51
beyond the
immediate context.
that which attaches content
of
any
recognition
have
on the The
degrees
one
to
of
the
conceived
events
space
of
as
a part
on
the
the
receptive
(i.e.,
vocabulary
this
time,
emerge
is
a word
and
of
which
the
the
that as
independent
more
somewhat
is
understood
from
are
between
precisely
the
'vocabulary', showing of
position of
having
evidence
of
be as
save
a cue
concept
nebulous,
to
simple
an immanent
this expectancy might
of
speech
the
'object'
differing and non-
related events,
cause-effect and
the
relation,
are,
the
be
must
be
therefore,
object. is
to
more
Speech related referent
or
If the infant has developed an expectancy separate
contains
only
from) a
acquired
this
sense
investing
speech
of
events,
single,
9 month-old with
the
'objects'
of
the
to
reinforced by
non-speech a
restricted
The
sounds.
objects,
the process of constructing a concept of the speech is
may
distinction is
difference
development
hand,
point
and non-native speech
which
emanating
other
attends
has no meaning unto itself,
The task is to explain the effect
The key
and
of
at
correspondence of
communicative intent of the speaker. speech
speech
speech/non-speech
correspondence
in
obviously
one
perception of native
related events.
localized
vocabulary
"bye-bye").
utility
of
speech
receptive
(eg.,
way
to it as a function of this loose correspondence with events.
of the
object/event
In this
and
even
this
that
with
item,
'object' has already begun.
This
a simple
with
a
and restricted receptive
surrounding global,
speech,
subjective
and
measure
'meaning'. The recognition that speech may correspond to events in some specific way
do the items out
of
ability Just
a
context-dependent,
expectancy
in general
couples
the
the to
as
coordination of differentiate
the
appearance
Relations
in a receptive vocabulary), and that there
barking may
between of
predict
among the
the
tasks
the
perceptual expectancies objects
family
in general dog
always
from
are objects
of speech,
surrounding
speech
the
predicts
events that his
(as
arises
with
the
attend them.
appearance,
so
the
barking.
52
If
this
speech
is indeed the case, we speech
as
meaning-making, the
relation
not
to
sound
take
between
non-speech
is
be
a function
by the
that the
their
elaborated
is
by
of
non-native
conspicuous by the increasingly (images,
relation
of
the
speech
and
bolstered
infant's
in
the
by
developing
bargain
in
a direct
the
the
growing
theme
of
awareness
of
visual
of
between
properties
tactile as
native
and
the of
overdetermination
non-native The
thus
made
contrasts.
The
is
internalized
motherese,
categorically
divide
of
'referent'
reinforces
speech
their
and
talk.
caregivers of native
events.
speech
infant directed
of
and
and
events
between
presentation
to
This is
correspondence
kinesthetic
speech
sound
capacity
with
speech and non-speech sounds
exists
the
special
reduces
of
and
that
between the
infant's
special character
contrasts
relation
the
between
specialized emphasis in the
'palatable'
events),
utility
speech
aware
visual
speech sounds as presented within the absence
of
keeping
correspondence to
between the
In
the processing of
domain of speech perception.
distinction
differential
relation
that over time,
predominate.
10 month-old
only
reinforced of
to
to
sound and referent in the
and meaning,
emphasis
come
this
suggest that the
becomes The
I
should
should expect
and
the non-
speech processing
capabilities. This permanence speech
process, of
transition
The to
it
becomes
speech 'objects'
categories
experience.
as
the
pays mill
off
a
sort
and is thus in
adapts
a
to
consolidation
the
of
tactile and visual domains evident
better
of
consolidates
the
correspondence
between
of
the
permanence
in the
triage,
self-validating:
nature
the
perceptual
ability
grist. of
investment
The
physical
to coordinate
in
native
processing similarity
objects
separate
the
of
and this
across
the
schemata in a
successful search can now be established.
What the infant is beginning to acquire in
both
triangulating
to
instances,
these
images,
is
an
awareness
a more
behaviour can be attained.
Relations
among the
tasks
that
by
successful strategy
for
the
permanence
coping with the
Just as the coordination of the
they
vagaries
of
ascribe object
successes of tactile search
53
through
the
extension
search leads to the the of
distinction refining
their the
perceptual
empirically validity
assumptions result
of
a
the
against
this
capable
of
processed
has
non-native
changes object
automatic that
in
demonstration
Relations
to
and
of
the
among
the
that
fact
analogous abilities
is
of the
notion
that
that
it
is
a
rests
that
to
coordination
rather
linguistic
still
Werker
linguistic to
weigh
speech, is &
meaning
speech-like meaning
adds
that
match between
is the
their
hear. skills
of
is
related
to
schemata
evident
in
of the native categories.
condition,
a
than
are
as
1984b;
if one
as
discriminate
adults
analysis
perfect
certain
findings
perceived
signal
The
argued that,
Research
to
on
atrophy
perception
these
process.
ability
speech they
speech
of
this
more plausible
sufficient
appearance
of
the
related
a more
the
acquisition
phonetic
condition for the emergence
simultaneous
tasks
of
the
objects
contrasts
native
reorganization implies
of
than
(Werker & Tees,
a native
made
by
for
when
in
consumed
contention
speech,
available
fact,
perceptual
dimension
nature
skill
of
speech
and the the
loses
process
in
It could be
the
only
that
more
phonology.
support
consists
search
the
native
infant
search, is a necessary
weight
a
the
that
object
form
the
categories
speech
some
application of
infant's by
and
begins
unused are,
visual
to placing faith in
comprehension.
account
merely
categories
some
to
infant
discrimination but
on the
suggest
of
however,
adult, the
categories
To
through
In the
apprehended
perceptual
the
phonetic
idea
required
so
extended
speech
categories
speech perception.
input,
native
in the
imposed
physical
construction
argument
The
between of
the
of
categories
Something
is
process of
phonetic
'objects'
contrasts
the
1985).
meaning
add
of
resulted
being
the
native
ignore
boundaries.
successes
speech
required for simply
the
hidden object,
non-native
Non-native
analogy
with
a completely
than
category
absence
using
sounds.
more
speech
speech
result
Logan,
native
the
searching
and
skills
arsenal.
about
non-native as
do
useful
of
native
perceptual
infants
spreading
manual
ability to find
between
the
But
of
requires
To
an empirical
changes.
54
Object The formal
relation
similarity
require
the
between
of
the
sequential
experience.
For the
related to the
goal
or intention
discussion
is
visual
not
words,
attributes
into the
of
sets
distinct the
infant
of
the
solve
consists the
information
must
intention
unrelated to
review
to
of the
convince
categorization
coordinate
at bay),
goal).
must
with
in
the
either
by two
Both
derived
from
information
an appropriate
Successful
search
is
infant
must
in
either
the
present
set
of
familiarization or
category
structures
differences
is
as a whole,
category
based
prototypes is
on
at this task, must
of the
have
made,
with which
ambiguous
there
both
no
correlation
any
the
category
the
other,
category
choosing
that
between
is, the
no
stimulus
is not 'burned'
rather a product of
acquisition
overlap.
the
In
such categories which
If
of
category
the
structure
uncorrelated test
reasons) be that observed
separated,
structure
experienced
among
categories formed during habituation.
been is
previously
form two
and
process
which he never sees.
Thus the
structures
negate
for different
not
a
similar
a category
featural redundancy, but is
or overlaps
two
a set
This
task.
acquire or
both
The purpose of
a sufficiently
(1983) categorization
related correlational structures.
drop into one
the
a
reader that
the
tasks.
the
search literature.
the
from the
acquire
object
task,
apparent
data pattern would (though If
required to
infants' head by virtue of its
history
would
is
abstractable he
representations of
is
categorization
coordination
task,
and, in order to succeed
are defined
the
visual
(and hold this
(which
immediately
stimuli, but is other
and
inferred from Younger and Cohen's In the
that
search
made clear in the
following
can be
search
intentional
object
and Categorization
of this ability as well as a measure of the infants' concept of the object.
much was the
object
application
barrier removal strategy evidence
Search
stimulus
The resulting
for 7 month
accounting
correlated
and
of
olds.
category
uncorrelated
test stimuli, and the infant will dishabituate only to the novel test stimulus.
Relations
among
the
tasks
55
In
any
case,
the
assumption
match the stimulus to the category novel
test
stimulus
is
stimulus
readily
intent.
This
could
account
for
the
novel
features
that
bear no
that
dishabituation
needs to be fleshed
apparent
is meant
to
to
the
the
decrement
in
responding
relationship
to
and
the
attempt
attention
to assimilate
For the 'new
visual
it to one
10 month old subject,
news'; and the Younger's
formed
other
As
required
to
resolve
possible
and that
this
for test
this
stimulus
item
belongs
basis of the two
categories,
the
perform
infant
must
of the
shares in in
is
the
researchers'
that some form of
is
explicitly
fatigue
designed
The same,
features.
stimulus
is
of
using course,
It seems plausible
the
result
of
a
that
sustained preference.
is judged 'old news'; the
segregation
the
enough either
of
attributes
hypothesis'
items into
provides
makes
recognition of
the
neither.
Any
confusion
attributes
comparisons
in
In
the
will
the
two
attributes
of
novel,
to
the
any
this
are
warrant
however,
the
of
for
coordination
each
about
absence
categories
categories
truth,
derail
two
support
clear, that
category.
or mismatch of
these
to
This stimulus is composed entirely of
stimulus
involves
membership
inability
or the other rather than a novelty
'segregation
puzzle
an
puzzlement.
among
Younger's
this
this
stimuli.
the correlated stimulus
uncorrelated, a
correlations
interpretation.
uncorrelated
category
(1985) demonstration
using
consideration
accorded
it
from
The dissimilarity of the
and
rule out the possibility
familiar in both categories using no novel
increased
out.
infant
cannot be said of the uncorrelated test stimulus. features
results
the
correlational
child.
Further,
true
category
exemplars. In both tasks the infant must do the following: sets of
information which
in
object
the
categorization
search task),
task;
and (2)
then goal in the
object
Relations
the
among
are not
present
structures
of
in the two
access or recall two distinct
display
mutually
apply these sequentially
search; "member category
tasks
(1)
to
(goal
and barrier
exclusive the
categories
schemata in
the
problem at hand (barrier
A?", then "member category
B?" in
56
the
categorization
recall
crucial
task).
Both tasks share
information
leads
between sets of information. infant be
must
surmount
applied.
test
This
is not to
The object
objects
that for
categories to
the
and
is
a
best.
intention
infants'
'goal ,
to
to
1
The
formation is vantage might,
as
their
resolve
The
some demands
Younger
and
such,
lack
of
inability to coordination
In the A B task
at
which
search
the problem of shared features to
both
of
between the two
everyday
lives.
task.
allows
the
ability
to
the
the
might — the
categories
to
for there
are
of
the
adult
to
the
the
attribution of
the
infant's norms,
of
abstract
but no
nature among
of the
claim
cannot
'real
of
basic
to
level
real
sophisticated
specification
that
some category
per
exemplars
world'
the task used
stimuli
can,
be
here world
structure it is se.
the The
nevertheless,
of the problems faced in real world categorization.
infants'
accounts,
be
grasp of the
seemingly the
'real
world'
Cohen's
task
deprives
result
sophisticated of
its
the
infant
skill
comparative
categorization. of
We
on
to
from the
this
simplicity
should
access
is to make any sense at all of the uncorrelated stimulus,
tasks
in 'real world' category
adult norm only
provides only the structures of the now vanished exemplars
the
tasks,
same
significance
infants
discrepancies
The
While
apprehension
10 month-old
of
among
the
similar to the problems of finding hidden
(1983)
as a step toward a better
complex
Relations
a
ability to detect and encode such correlations
point. by
forgetting:
locations
common
correspondence
match this
be seen as an extension the
is
features
gradual
structural and as
infants'
there
application of such teleological
categories formed by
Still,
in
Cohen's
reflect
the
at
task
contains
encounter
tasks
tentative
readily
identical
gloss over the differences
Younger
categories etc.,
two
search task is obviously
infants
categorization
as
of
assigned.
many.
is
problem of
stimulus
which it might be
failure
pitfalls
A n d both tasks share red herrings.
In the categorization
uncorrelated
made
the
to
the
recall
category
as a guide.
adult's
artificial to
the
task more
however,
that
exemplars
and
If the
infant
he must do so by applying a
57
strategy
which has
no objective
standard of
success,
for the
categorizing the stimuli, and does so only as an extension dealings
with
real
realization of its to
real
The
objects
potential — the
appearance
comes,
world objects.
of
therefore,
at
The flexibility
in this
creation
situation
of
this
change
the
precisely
'real' in
results
time
this
that
strategy,
child
has
nothing by
gained in his
and the
success of its
carry
categorization
the
gains
of a strategy
from the
categories
the
this strategy holds in more the more
of
infant
of
subjective
nonsense
begun
to
application significance.
line
realize
drawings
the
potential
tangible pursuit of hidden objects.
Categorization
and
Speech
Perception
That a logical relation exists between these two tasks is based on the that the speech task is a proper analogue section
is
by this
analogy.
the
to
convince
speech task
secondly
the
reader that
This conviction is
not
only
champion
a
of
will
be
a test of
the
pre-linguistic
speech
they
infants
sensitivity
above,
this
hear
through
speech
has
The
sought
ability
the
wonder
the
undergoes
well
discrimination.
adult phonetic
Relations
rather than
seduced
stages: first by arguing that categorization,
and
of the processes that account for this
among the
spaced
tasks
of
of
categorical set
young
overcome
of
the
infants
confusing
perception.
phonetic
between
to speech contrasts
In
distinctions. 8
and
10
facing the
infant subject
categorize
intervals
along
a
multiple
the
one
exemplars
continuum
T o be successful,
is
of
typically babble
very As
exactly
outlined of
age
language. the
kind
of categorization of
synthetic
of
young
months
not heard in the native
Werker's research programme are of
Infants
boundaries.
skills
naively
reorganization
prove that the task
equally
to
universal
a
speech stimuli from to
at
compelled
in two
perception
able
extends to
necessary as
been
The purpose of this
discrimination, but also of
infant
resulting in a loss of sensitivity
cross
s/he
skill.
contention
ability.
Investigators
chosen
of categorization
via an appeal for a formal equivalence
categorical
infants'
speech stimuli
as
tokens which
infant must ignore the within-
58
category natural
variability speech
phonetically
stimuli
relevant
non-phonetic the
may
exists between
reduce
In
the
considered
between
only
the
To
the
that
of
expense
the
increasing
however,
Werker's
notion
differences.
variability
of
the
speech
categorization
accept
perception
category
instances,
measure
tasks.
speech
both
between-category
within
at
conclusion
a
to
the
information but
Still,
be
relation
respond
information.
stimuli.
properly
and
may that
the
infant
an
must
down
to
categorize
task
to
ontogenetic
demands
respect
variability of
perception
boil
and visual categorization
with
Using
a
should semantic
relation
also
a small but vital
leap of faith. In tasks,
the
I emphasized
present
needs
formation
tasks
infants
are
the
relation
can
argued
the
attribution of a degree
exceeds
correspondence information exemplars,
a
a
sense
perceptual
demands
and the
the
case
an
of
an underlying equivalence
as
with the
be
the a
avoided now
speech
the
beginnings
goal.
speech
The
longer.
becomes
of
and The
in
the
service
intentionality:
application
perception
no
past
between
of
visual absence
conspicuous.
that
of the
same
categorization of
What
the is
word
it
that
task?
reorganization
evident
in
of 'permanence' to speech correspondence
expectancy
in
appreciation of
ability to
for
this
discussions
that
for
recruit information about
between
which
previous
characterized by
which
to
connection
remembering in the
have
the
in
issue
the
ability
above
characterized
plan
an
in
I
is
to
raises
'memory'
a
presented
the
and
of
explanation
from
arguments
coordinate
between
an the
as
an underlying formal
yet
perception
'objects'. speech
manner.
between
sets in order to
equivalence
follows
The permanence
and physical
unstated
difference
these
speech
past
If
this
and current
categorize
between the
events
tasks
present can
be
made. If the second
reorganization in speech
process
Relations
of
among the
categorization
tasks
perception occurs
based
on
the
through the
distinctions
t
application of
between
'native'
a
and
59
'universal'
speech,
and then
among the
versus
defining
arbitrary features
sounds, some means of coordinating these as analyses is required. another context, there
are
which
that:
two
one
"...there
principles
is
in force
must
then
at
be just
there
any
one
must
moment,
be
the
is
the
ability to
growing awareness Clearly,
the
of the
'meaning'
a
and it
becomes the one principle" (Loevinger, 1966). these processes
human conduct, for if
superordinate
will
the
separate
relation between a
of
It has been said, in
principle
the
attribution
appreciation of the fragments infant
fall
acquires
the
coordinate with
the
The the
sense
fragment
speech of
of
results
building acquisition
info
blocks of
native
distinctions
of this
constructed categories
(i.e.,
Summary The prediction: respond
discussion that
of
possible
infants
differently
to
able
the
to
three
the
for
example,
/ba/,
I am
sound
/ba/
is
not
suggesting
precedes
an
for
the
speech
categories,
construction
phonology
universal
of
requires
set
of
of native
a
the
speech
the
receptive ability
to
distinctions
speech perception.
predictions
relations coordinate
tasks
the
universal
'objects')
and
analysis with
By reducing the likelihood that such
functional
among
to
and
necessary
this
that
and meaning.
speech,
permanence
meaning of words.
alternately
'given'
newly
a
specific
will
vocabulary.
of
decide
superordinate principle
equivalent to the meaning of a word which contains it, like "ball". that
to
The one principle I wish to place over
coordinate the
of
principle
of native
among
the
separate
than those
who
tasks sources
lack
this
reduces of
to
a
single
information
will
coordination ability.
To be more precise, infants who pass any one of the tasks are assumed to possess the required coordination skill, and are predicted to pass all three tasks.
Infants who fail
any of the tasks are assumed to lack the coordination skill, and are predicted to fail on all of the tasks. On present
the
A B task,
purpose, infants
Relations
among the
three
outcomes
able to
tasks
tolerate
are possible: a 3
second
pass, delay
fail,
and error.
in the
A B task
For the will
be
60
assumed
to
possess this
coordination skill
and categorization tasks.
and are predicted to pass both the
speech
Thus, infants who pass the A B task, or commit the A B error
are considered to possess this coordination skill, while those who fail the task will be said
to
lack
typically
the
skill.
measured
exhibit
the
at one
location
in
Though
a simple,
perseverative
the
one
search
ability
to
location,
error
are
(A), and, by this
measure,
the
task
coordinate
object
search
nonetheless they
too
secondary task,
capable
those
of
possess the
schemata infants
successful
is who
search
required coordination
skill. 'Passing' the
correlated
Failure
on
correlated These
categorization
stimulus
this and
task
in the
will
defined
as the
definition
is
considered
"native
able At
that
to
though
of
infants
involve
who
listeners"
bottom
the
differences
coordination
coordination of previously
interference,
delay,
these
should
tasks
assumptions,
Relations
or barrier.
however.
among
the
predict First
tasks
all
Hindi
three
novel
and 7
stimuli.
both
stimulus
month-old
sources
the
and foremost,
the
speech
contrast. the
the only.
subjects
perception
The logic
Hindi
more
tasks
categorization
The argument on
the
to
to
contrast
sophisticated
of
this
may than
be
those
sounds.
of a goal.
success
habituation
'passing'
and thus
sequential
unrelated
to
discriminate
speech
and
uncorrelated and novel
generalized
appear,
1989),
and
habituation
respectively.
between
memory
generalized
the TO month-old
to
(Werker,
as
dishabituation
may
fail
non-native
measure
the
this
information or action in the service the
and
by
failure to discriminate the
discriminate
A l l three
three
stimuli,
here
both the
characterized
Younger and Cohen (1983) study,
tasks is
real.
be
are characteristic
Counter-intuitive,
still
defined
and dishabituation to
uncorrelated
performances
is
in
seem
one
application
more
form of
or
apparent
than
another.
All
separate
sources
of
And all three can be characterized as of information despite that
successful
others, there
is
rests the
some form
performance on
several
assumption
that
on one rather there
of of
large is
a
61
common tasks.
ability
or
strategy
which
underpins
successful
performance
on
all
three
This, in turn, stems from my belief that the infants' more or less direct control
of physical objects allows relations
between
formation
and
the formation of firm
action
and
successful
object
execution
and reliable mental correlates
behaviour
of
the
(schemata)
intentional
action
which
of
permit
sequences
the the
required
to
solve the A B task.
Finally, there is the assumption that the empirical success of such
sequences
a more
than
engenders
either
should
warrant on
obvious
that
interest
to
and the
categorization
To also
able
the
the
recovery
infant,
demonstrate to
confident
of
the
the a
application of
basis
hidden
benefits
of
of
object the
of nonsense figures that infants
categorize
visual
alternative:
simply
an epiphenomenon
that
I might
further
Relations
that
wish
to
the
the
ability
of my
is
speech
to
analysis
of
stimuli
in
only
other
goal.
of
and
adult
of the
manner
tasks
While
speech
by the
demands the
the
immediate
perception
the
to
it
of the
separate
sets
segments observer.
A B task
described
research to date.
results
would merely
of
form
are
above,
information
Thus,
is
concrete
Such a feat would merely rule out
coordinate
contrary, positive
task
some
are calculated
able to overcome
and
strategy
immediate
successful
would in no way validate these assumptions. pesky
the
the
one is
despite all
a petition
for
research.
among
the
tasks
62
DESIGN The
study consisted
days of testing.
of four experimental sessions per subject
Testing for each infant was
most sessions held within a two day period. object
search,
cross-language
categorization. Infancy
A l l testing
Research Laboratory,
completed within a 7 day period, with
perception
were
at the
two
Each subject was tested for three abilities:
speech
sessions
spread across
held
(two
in
University of
the
sessions),
Department
British
and
of
visual
Psychology,
Columbia.
Portions of the data were collected in March and April of 1986 (sample 1, n=14), with the remainder collected from April to August, 1989 (sample 2, n=26). sample
1 were
(1988).
tested
Subjects
with the
in sample
Werker and Tees (1984a). an
equal number of
were
synthetic
2
were
speech
tested
tokens
used
the
natural
with
of
section),
the
subjects
two
before
passed
samples
being
Werker and Lalonde
speech
tokens
used
by
The data collection period for both samples continued until and failed the A B task.
made in the design or experimental protocols used
results
by
Subjects in
were
combined
compared
for
further
and
No procedural
with the two
analyzed
separately
changes
samples. (see
The
Results
analysis.
Subjects Seventy-eight for
full-term,
participation in
parents
recruited at
Infancy
Research
Twelve
infants
reach
a pre-set
age
younger
Design
would
criterion of the
infants
The subjects
local maternity hospitals
who
from
1985).
study.
Program.
excluded and
the
healthy
study are
as
able
A
total
not
of
perform
38
to
been
male,
were for the infants
in the
performance on it has
(36
the
discriminate these
selected
female)
were
from
contrast
(eg.,
files
(see
Eimas,
of
Columbia the
study.
procedure, or failed
demonstrated that
sounds
recruited
British
excluded
Turn
English
were
randomly from
University of
Head
repeatedly
42
below), infants
of
to
were this
1975;
Mehler,
Ten infants were unable or unwilling to return for the second testing
session.
63
Nine
subjects
were
experimenter infections,
error.
which
eliminated.
eliminated An
has
fussiness,
additional
been
shown
three
to
2
for
infants
adversely
completed testing.
months, range = 8.25 - 10.09, s.d. = .526;
equipment with
affect
The data reported here are from the final
male and 21 female subjects
Object
for
failure,
histories
auditory
and
of
2
for
middle
ear
development,
sample of 40 infants.
were
Nineteen
The mean age of the subjects was
9.2
s.d. = .540 (male subjects: mean = 9.35, range = 8.28-10.09,
female subjects:.mean = 9.06, range = 8.25-10.09, s.d. = .527).
Search Measures All
Infants
infants were tested using the standard A B object
were
seated on their parents' lap facing
search task (Piaget,
an experimental
assistant
(El)
1954). across
a small table (see Figure 2).
A video camera (JVC G X - N 7 U camera, J V C BR-1600U video
cassette
the
The
recorder)
subject
recorded
was presented
infant's
responses
with an object
the
of plastic keys,
session.
small toy) by E l
the test object.
E l then placed the object under a cloth at location A , ensuring that
gently
attended
but firmly
to
this
event.
The parent
throughout the hiding.
in the object
who
infant was
infant
interested
experimental
ensured that the
the
sufficiently
(set
during
was
instructed to
A n on-screen
later coding.
At the
stop-watch end of the
hidden object for a period of removed
the
beginning
the
Ten location. fourth
cover
of
these
3s
10s.
and allowed
next
was
used
to
delay, the
verify
the
infant was
as
infant
1 to 3 in order
delay between hiding and
length
of the
allowed to
delay
during
search for the
If the infant was unable to retrieve the object E l
the
infant
to
play
with
the
object
for 5s
prior
to
trial. trials
were
repeated
with
the
following
constraints
on
object
The object was hidden at location A for the first 3 trials, then at B on the
trial.
If
the
infant
was
successful
in
retrieving
the
object
location of hiding on the next trial was switched to A on trial 5.
Design
restrain the
E l then counted aloud from
to distract the infant from the display and to provide a 3s search.
to warrant its use
on
trial
4,
the
This rule applied to
64
all
trials
object,
on
which
or initially
object
was
the
searched
was
successful.
at the
incorrect
If
the
location,
infant
on
any
failed trial
hidden again at the same location until the infant was
trials had occurred. failed
infant
attempts.
The rule reduces
to:
switch
to
after
retrieve
the
trial
the
successful,
location if successful
4,
or three
or after three
Search attempts were scored from the video tape record according to
the criteria shown in Table 3 below:
Score
Search
description
Location
0 - Loses interest in object once it is covered. A
B
1 - Reacts to loss of object, but does not search. 2 - Pulls at cloth but does not uncover object.
A
B
3 - Uncovers but does not retrieve object. 4 - Makes errors 0 - 3 5 - Immediately
The subject's used:
but corrects within 10s. A object.
A
B
video tape records of these sessions were scored by two raters, blind to the
age
and performance
on
any
other
procedure.
The following
criteria were
if the total score for the 10 trial session fell within the range 40 - 50, the infant
'Failed'
the
infant
task.
removes
'Error'.
trials
on
The occurrence
the
Since which
cover
infants
invariably
the
their overall
Speech
Perception The
turn
stimuli,
Design
A B error scores
The
Infants scoring 0 - 3 9
more
initially)
than one on
correct
perseverative
change their
occurred were
from falling within
trials
AB
then
pass
search
resulted
mistakes
scored
the
were judged to have
as
in
within
'0'
error
a
(i.e.,
judgement
10
seconds,
rather than
'4'
to
range.
Measures
cross-language
procedure.
of
wrong
prevent
head
B
Scoring criteria for A B task.
was judged to have 'Passed' the procedure.
of
B
A
searches for and obtains
Table 3:
B
A
speech
procedure
in
response
and is
used
to
to
measures
involves changes
measure
were
conditioning in
the
the
gathered the
phonetic
infants'
ability
using
the
infant
to
provide
category
of
a
to
Head
series
discriminate native
an of
Turn
operant speech
and non-
65
native
speech
tokens
of
contrasts.
an
Subjects
English,
discrimination
were
percentage
correct
of
Stimuli.
and
used:
a
were
Hindi
the
ability
responses
in
presented
a series
language
speech
to
a pre-set
reach
the
The stimuli used
with
contrast.
the
voiced the
place-of-articulation
stop consonants
unvoiced,
in testing
language
distinguishes
three.
Thus,
places
as
articulation computer tokens
the
first
same
used,
formants produce
with an
as
sample
the
continuum
description).
The stimuli
tape
and
controlled and for
collation this
a
stimulus of
with
subjects
the
The
&
101
stimuli
the
and
synthetic on
were
category in
composed
formants
Lalonde,
1988
for
tape
using
computer
synthetic
category,
third
visual
dental
place-of-
within
and
reel
only
a V A X 11/780
any
phonetic
loudspeaker.
of a
to
Hindi
distinguishes
Multiple
ignore
1 was
The
retroflex a
alveolar
for sample
/da/-/Da/.
from
to
and
reinforcer,
varied
a full
A n Apple
11+ and
5 to
acoustic
a Teac
program designed
of
the
3340S
computer collection
specifically
purpose.
employed by Werker and Tees (1984a). sound
Design
have
from reel-to
using
used
Connecticut.
second
Werker
The stimuli used in testing the second
each
subjects'
(n=14), were
bilabial
English
both
according
the
activation
responses
while
taken
processing. of
which
distinction
Haven,
sounds
(see
of
The English contrast used
Mattingly synthesizer
would
driver Bose
presentation,
subject
the
were presented
single
were
New
frequency
measures
of infants
contrast
categorize
stimuli
discriminate
starting
dental
articulation,
natural language
eight-step
recorder
the
in
The Hindi
typically
The
that
and
in
of
Laboratories,
so
variability
manner
speakers
constructed
Haskins
were
/ba/-/da/,
versus
places
stops.
continuum at
acoustic
four
English
alveolar
distinction,
retroflex
Two
procedure.
are differentiated.
unaspirated
digitized natural
criterion, and the
identical to those employed by Werker and Lalonde (1988). was
of
were used,
since
infants
sample of infants were identical to those
For this sample, multiple natural exemplars of in sample
1 had more
difficulty
than
expected
66
discriminating the Hindi
contrast
synthetic
used
was
English contrast the
/ta/-/Ta/.
Four
naturally
exemplars
were
equated
intonation
contour.
voiceless, produced on
Results
unaspirated exemplars
intensity,
A n acoustic
the main cues differentiating
(see
analysis
section).
retroflex
of
each
fundamental
acoustic
Analog 1801
to
description).
The
Digital conversion
stimuli
computer
analog-to-digital/digital-to-analog
sound
were
were
2,
the
distinction
used.
All
duration,
(1984a),
and
revealed
that
amplitude of the burst, and Werker & Tees,
digitized
from
program interfaced
conversion
dental
frequency,
are the
the slope of the second and third formant transitions (see full
versus
by Werker and Tees
these speech sounds
For sample
board.
audio
with The
1984a, for a
tapes
using
an
a Data Transmission stimuli
were
digitized
at a 10 kHz sampling rate, via a 4500 H z low-pass filter, and presented over a single driver
Bose
101
audio
stimulus
presentation,
collation
of
this
subject
across
90
of
using
Compac
the a
Deskpro-286
visual
computer
reinforcer, program
computer and
designed
In the Head Turn procedure the infant was
a small
angle
covered
during
conditioning
correct
responses
speech The
table
to
the
box
an experimental
controlled
collection
and
specifically
for
infant.
containing
observed
The
visual
mechanical
a correct
provides
(E2),
in a sound
attenuated
reinforcer toy
of
of
which
were
animals
response
a measure
consisted
was
the
observed.
infant's
a
smoked activated
The number of
ability
to
discriminate
presented.
procedure consists of stage
assistant
seated on the parents'
A visual reinforcer and loudspeaker were located at
and whenever
contrast
conditioning
1,
the
which repeats
at fixed
experimenter
whenever
Design
from
Figure 3, page 84).
degree
plexiglass
the
A
purpose.
chamber (see a
activation
responses
Procedure. lap
loudspeaker.
infant
a series of conditioning is
intervals of the
speech
and testing
with
1500ms.
The visual reinforcer is activated by change
from
sound,
During
presented
tokens
a speech
stages.
one
for example
phonetic
/ba/,
category
the to
67
another,
for example,
speech the
tokens
in
the
response
activation
and
responded
to
the
reinforcer
before
stage is
the
no-change).
was
The reinforcer is
The infant is to
of
this
the
change
conditioned to
change
from
reinforcer on
in the
the
the
testing
speech
reinforcer
stage, the
computer (Compac 286
through
to /da/'s.
is
/ba/
three
to
turned off
when
the
turn his/her head toward /da/.
consecutive
When trials
the
(i.e.,
stream
by
turning his/her
activated
by
the
infant detected
head toward
experimenter),
the
testing
entered.
During a
/ba/'s
return to /ba/.
reinforcer
anticipates
from
Desk
A n experimenter
a one-way
selected a trial type
Pro)
in the
which
window
speech
category
randomly selected
( E l ) , seated
observation
in a state of readiness
change
outside
and
the
signaled
(i.e., not fussing,
trial
controlled by
type
(change
chamber, observed the
computer
watching the
and awaited a button press
was
response
when
assistant).
from E l .
vs.
the
infant
the
infant
The computer The experimenter
was unable to hear the stimuli and was therefore blind as to whether a change or nochange
trial
button
press
had
occurred.
if the
The
experimenter
infant turned his/her head
then
during
signaled the
the
computer
a head turn resulted
reinforcement
from
the
"hits" by the computer.
in the
computer activating the
experimental If,
assistant.
These
reinforcer as responses
from /ba/ to well
are
as
social
recorded
as
on a change trial, the infant failed to turn his/her head,
the reinforcer was not activated and a "miss" was recorded. trials, where no change in the speech "false
a
trial.
On change trials, that is, when the stimuli changed, for example, /da/,
via
On no-change, or control
stream occurred, a head turn was recorded as a
alarm" and the absence of a head turn as a "correct rejection". Infants
determine
were
whether
tested
they
first
on
the
could (or would)
English
contrasts
perform in this
/ba/
procedure.
(or unwilling) to perform in the procedure were excluded from the performance
Design
on
this
contrast
was
followed
by testing
on
versus
the
/da/
Infants
to
unable
study.
Successful
non-native,
Hindi /da/-
68
/Da/,
speech
contrast.
short
re-presentation
perform
in the
native
contrasts
Testing on of
the
phases
Two
of
a
correct
of
series
trials. 25
of
testing
the
7
session
.001
remove
The
in to
when
use
of
the
the
infant
.05.
a 25
they
reached
of
the
first.
use
perform in the
correct responses for each contrast was
correct
responses
correct
rejections)
misses + correct rejections
+ false
alarms).
the
responses to
conclusion each
trial
criterion had been alarms, and average Visual
Design
met,
of
each
in the the
testing
reaction times
out
to of
was
8
to of
judged together
consecutive criterion, or
were
Head
and
ability
string
required to remaining in
Turn
procedure
attaining 7
correct
Probability estimates a screening
procedure and report the
by
session
session was
percentages
infant
able
criterion as
the
percentage
a condition of
sample.
to
range
tool
to
percentage
of
For all subjects
a percentage
calculated by dividing the total number of
+
At
(hits
the
probability of
the
the
overall
the
still
out.
pre-established
with
correct responses as the measure of success on the task. of
carried
A l l infants as
the
trial
were
would
responses
taken:
rejections)
common
Most published reports
unwilling to
criterion method,
by a
competence
then
the
preceded
subject
correct
were
and
contrast
surrounds calculations
the
was
contrasts
came
English
in
stimuli
if
was
continued
correct
criterion is
trials
of
presented plus
that
consecutive
responses,
(hits
sounds
ensure
speech
By the
the
preset
8 consecutive
subjects
on
contrast
criterion on
some debate
responses
non-native
contrast.
ended
speech
evidence
the
responses
to
three
had occurred, whichever
preset
study.
from
correct
trials
the
although
each
of
consecutive
discriminating the
The
reached
to
contrast
as
success of
non-native
series
with
criterion
responses
capable a
measures
preset
A taken
conditioning/testing
reach
English
procedure. was
the
of
the
number
of
trials
a computer printout of
made. hits,
total
This misses,
for each type of
the
included whether correct
rejections,
(hits
+
infants'
or not and
the false
response.
Categorization Measures
69
The
categorization
procedure During
designed
the
habituation
sequence of line Figure
to
1, page
measure assess
or
was
a
visual
categorization
skills
familiarization
drawn stimuli 82).
the
used
phase,
(2 presentations
The infant
was seated
the
habituation/dishabituation of
infant
of each
prelinguistic was
infants.
presented
with
a
of 4 habituation stimuli, see
on the parents'
lap facing
a
television
monitor (see Figure 4, page 85).
Each stimulus was presented on the monitor for 18s
during
fixation
which
through
the
a one-way
infants'
visual
observation
was
window.
recorded
In the test phase
with the three test stimuli (see Figure 1, page 82). stimulus
being
presented
and stimulus
by
an experimenter the infant
was
peering presented
The experimenter was blind to the
presentation
order
was
randomized
across
subjects. Trial ES/12).
presentation
A small fixation
experimenter stimulus the
signaled
was presented
was light
controlled
was activated
the computer
when
on the monitor.
monitor to darken and the fixation
conducted:
eight
by
computer
(Hewlett-Packard,
at the beginning
the infant
had fixated
of each
Vectra
trial.
on the light
The and a
The expiration of the 18s trial period caused light
familiarization trials, followed
to begin
flashing.
by the three
Eleven trials
test trials.
were
A computer
printout of the total looking time and number of looks per trial was then made.
Design
70
RESULTS The
data analysis
was carried out in two stages.
exception
that
the infants
stage
the
analysis.
of
who exhibited Since
these
the A B error
infants
behave
'failers' and tend to 'muddy the waters' somewhat, the
first
stage of the analysis
Both
is a strategic,
are identical with the
are excluded alternately
from
like
the first
'passers' and
the decision to exclude them
rather than scientific,
one.
from
The first
stage is intended to provide a clearer picture of the data before turning to the added complications of the error group. are
analyzed separately.
strong
developmental
motivated
by three
This
is followed
synchrony
basic
In both stages, the speech
exists
and categorization tasks
by a test of the overall hypothesis
among
the tasks.
The data
that a
analysis
was
questions:
1.
Will a significant main effect emerge when A B task performance (pass/fail) is used as an independent variable in the analysis of the speech and categorization data? Previous investigations using the speech and categorization tasks have used age as an independent variable (Werker & Lalonde, 1988; Younger & Cohen, 1983). The purpose of this set of analyses is to determine whether the data pattern obtained using A B status resembles these previous reports.
2.
Can performance on the speech and categorization characterized as either 'pass' or 'fail'?
3.
When subjects are assigned a 'pass/fail' overall pass/fail task profiles express among the three tasks?
tasks
be accurately
status on each task, do their a logical underlying relation
Stage 1 - Analyses of the A B Pass & Fail Groups. Question
1:
A B performance as an independent variable.
Speech defined
as the percentage
displayed was
Perception
to each
calculated
Task
of correct
of the speech
by dividing
The measure responses
contrasts.
Results
to both
change
The percentage
the number of hits
number of trials presented for each contrast.
of success on the speech
and correct
task was
and no-change
correct for each rejections
trials subject
by the total
T o ensure that no differences
could be 71
attributed
to
the
use
of
both natural
was conducted comparing the scores plot A N O V A
of infants in sample
> .0001, and contrast: F (1, 24) = 38.920, p
due to the lower scores
of infants in sample
(78.6% versus 71.2% correct). Hindi
contrasts
subsequent The
(57.1%
scores
repeated
The split-
A sample X contrast
Post hoc comparisons revealed this 1 on the synthetic English contrast
versus
61.6%).
The
sample
groups
the samples on the
were
combined
for all
were then compared across the two A B groups in a split-plot design The between
within-group
factor
groups factor was A B task status (Pass, Fail), and was
the
speech
AB
contrast
(English,
Hindi).
The
by group is shown in Table 4 below: Speech
Task
Status
The
> .0001.
No difference was obtained between
proportion of correct responses
Table 4:
1 and sample 2.
analysis
analyses.
analysis of variance. the
a preliminary
Main effects were obtained for A B group: F (1, 24) =
interaction also appeared: F (1, 24) = 5.640, p < .05. was
contrasts,
(2 samples X 2 A B groups X 2 speech contrasts) revealed no main effect
for sample: F (1, 24) = .382, p > .50. 44.799, p
and synthetic
Contrast
English
Hindi
Fail
77.4
72.2
Pass
72.4
46.5
Percent correct on the English and Hindi contrasts by A B groupCPass & Faill. overall
analysis
of
variance
(ANOVA)
indicated
that
there
were
main
effects for both the between-group factor (AB group), F (1, 26) = 44.955, p < .0001, and the
within-group factor (Contrast), F (1, 26) = 33.88, p < .0001, as well as a significant
AB
group X Contrast interaction, F (1, 26) = 14.948 p
