PSYCHOPATHY AND SEMANTIC PROCESSING ... - Open Collections

PSYCHOPATHY AND SEMANTIC PROCESSING by JEFFREY WILLIAM JUTAI B.Sc,

The U n i v e r s i t y o f Toronto, 1978

A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS in THE FACULTY OF GRADUATE STUDIES (Department

o f Psychology)

We a c c e p t t h i s t h e s i s as conforming t o the r e q u i r e d s t a n d a r d

THE UNIVERSITY OF BRITISH COLUMBIA November 1980

0

J e f f r e y W i l l i a m J u t a i , 1980

In presenting this thesis in partial

fulfilment of the requirements for

an advanced degree at the University of B r i t i s h Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives.

It

is understood that copying or publication

of this thesis for financial gain shall not be allowed without my written permission.

Department of

Psychology

The University of B r i t i s h Columbia 2075 Wesbrook P l a c e V a n c o u v e r , Canada V6T 1W5

D

a

t

e

November 17, 1980

-iiABSTRACT

The

performance of p s y c h o p a t h i c

(n=16) and

( n = l l ) r i g h t - h a n d e d male c r i m i n a l s was the v e r b a l semantic p r o c e s s i n g

compared on tasks

of f o u r - l e t t e r c o n c r e t e

p r e s e n t e d t a c h i s t o s c o p i c a l l y to e i t h e r the l e f t visual half-field. level and

Subjects

(Simple R e c o g n i t i o n ) ,

and

( l e f t or r i g h t ) was

analysed

separately

r e s p o n d i n g hand, and groups d i d not Statistically ER

nouns

superficial

at deeper l e v e l s (Lower-order "Yes/No" responses

t r i g g e r i n g microswitches.

counterbalanced across

measures were r e a c t i o n time (RT)

requiring

or the r i g h t

p r o c e s s e d s t i m u l i at a

Higher-order Categorization c o n d i t i o n s ) .

were made manually by

nonpsychopathic

and

Responding hand

conditions.

error rate

(ER),

Dependent and

as a f u n c t i o n o f group, p r o c e s s i n g visual half-field

d i f f e r with respect

were

level,

of p r e s e n t a t i o n .

The

to the p a t t e r n of RT r e s u l t s .

s i g n i f i c a n t group d i f f e r e n c e s d i d emerge i n the

r e s u l t s however, w i t h psychopaths making fewer e r r o r s than

nonpsychopaths i n the c a t e g o r i z a t i o n c o n d i t i o n s . are d i s c u s s e d

i n the context

These f i n d i n g s

of c u r r e n t n e u r o p s y c h o l o g i c a l

of v e r b a l semantic f u n c t i o n and

psychopathy.

models

-iii-

TABLE OF CONTENTS

Abstract

i i

L i s t of Tables

v

L i s t of Figures

v i i

Acknowledgements

viii

I. Introduction

1

I I . The neuropsychology o f psychopathy: C u r r e n t s t a t u s

4

I I I . Behaviour and memory: F r o n t a l and temporo-limbic contributions A. F r o n t a l c o r t e x B. Temporo-limbic

9 tissues

.......

10

IV. Semantic dementia: A n e u r o p s y c h o l o g i c a l t h e o r y

' ....

A. Brown's model o f n e u r a l o r g a n i z a t i o n

14

B. Semantic a p h a s i a and semantic dementia

17

V. A t a c h i s t o s c o p i c i n v e s t i g a t i o n o f semantic

dementia

A. A note on h e m i s p h e r i c s p e c i a l i z a t i o n

25

B. The l o g i c o f a t a c h i s t o s c o p i c approach

28

V I . Method A. S u b j e c t s

• 36

B. M a t e r i a l s

37

C. Apparatus

38

D. Procedure

39

-iv-

V I I . R e s u l t s and D i s c u s s i o n A. R e a c t i o n

41

time (RT)

42

• . 1. L e v e l s of p r o c e s s i n g

44

2. Psychopathy

62

B. E r r o r r a t e (ER)

62

1. L e v e l s of p r o c e s s i n g 2. Psychopathy C. R e a c t i o n

time and

63 ....

74

error rate: Joint considerations

75

R e f e r e n c e notes

79

References

79

Appendix I

T a c h i s t o s c o p i c performance s c o r e sheets

.............. 89

-v-

LIST OF TABLES

T a b l e 1.

Cleckley's

speech d i s o r d e r and p e r s o n a l i t y

disorder

continua

20.

T a b l e 2.

Mean r e a c t i o n times and standard

T a b l e 3.

A n a l y s i s of variance

T a b l e 4.

C o r r e l a t i o n s between r e a c t i o n time and e r r o r r a t e

T a b l e 5.

Test

f o r r e a c t i o n times

45.

f a c t o r a t t h e Simple R e c o g n i t i o n

f a c t o r at the Higher-order

level

level

Categorization 49.

T e s t o f simple main e f f e c t s f o r r e a c t i o n times f o r v i s u a l f a c t o r a t t h e Lower-order C a t e g o r i z a t i o n

level Mean e r r o r r a t e s and standard

T a b l e 9.

A n a l y s i s of variance

64.

f o r error rates

the Simple R e c o g n i t i o n

Test at

65.

level

68.

o f the Group x Hand i n t e r a c t i o n f o r e r r o r r a t e s

the Higher-order C a t e g o r i z a t i o n l e v e l

T e s t o f t h e Group x Hand i n t e r a c t i o n f o r e r r o r at

T a b l e 13.

deviations

T e s t o f the Group x Hand i n t e r a c t i o n f o r e r r o r r a t e s at

T a b l e 12.

50.

T a b l e 8.

T a b l e 11.

48.

....

half-field

T a b l e 10.

47.

T e s t o f simple main e f f e c t s f o r r e a c t i o n times f o r v i s u a l half-field

T a b l e 7.

43.

o f s i m p l e main e f f e c t s f o r r e a c t i o n times f o r v i s u a l

half-field T a b l e 6.

deviations

69. rates

t h e Lower-order C a t e g o r i z a t i o n l e v e l

Test

70.

o f simple main e f f e c t s f o r e r r o r r a t e s f o r t h e

visual half-field

f a c t o r i n t h e r i g h t hand

71.

-vi-

T a b l e 14.

T e s t o f simple main e f f e c t s f o r e r r o r visual half-field

rates

f a c t o r i n the l e f t hand

f o r the 72.

-vii-

LIST OF FIGURES

F i g u r e 1.

Brown's l e v e l s of b r a i n o r g a n i z a t i o n and disorders

....

22.

F i g u r e 2.

L e v e l s of c o g n i t i o n i n p e r s o n a l i t y and

F i g u r e 3.

A p a r t i a l map

Mean r e a c t i o n times

The

24. described

Q u i l l i a n model

.31.

( a c r o s s groups) as a f u n c t i o n of

p r o c e s s i n g l e v e l and F i g u r e 5a.

aphasia

of l o n g - t e r m semantic memory as

i n the C o l l i n s and F i g u r e 4.

language

v i s u a l h a l f - f i e l d of p r e s e n t a t i o n

o p e r a t i o n of the semantic h i e r a r c h y w i t h i n

. 51.

the

l e f t hemisphere F i g u r e 5b.

58.

Hemispheric p r o c e s s i n g o p e r a t i o n s

under c o n d i t i o n s of

v i s u a l h a l f - f i e l d of p r e s e n t a t i o n and c a t e g o r i z a t i o n level F i g u r e 6.

E r r o r r a t e s as a f u n c t i o n of group, responding and

F i g u r e 7.

F i g u r e 8.

. 60. hand,

processing l e v e l

Error rates

66.

( a c r o s s groups) as a f u n c t i o n of

h a l f - f i e l d of p r e s e n t a t i o n and

responding

The most e f f i c i e n t hemispheric

p r o c e s s i n g and

i n i t i a t i o n operations psychopathic

visual

hand .........

f o r the non-psychopathic

groups i n the Lower-order and

o r d e r semantic c a t e g o r i z a t i o n c o n d i t i o n s

67.

response and

Higher76.

-viii-

ACKNOWLEDGEMENTS

I would l i k e t o thank my committee members, Dr. A. R. H a k s t i a n and

D r . J . C. Y u i l l e f o r t h e i r a d v i c e and f o r c o n s t r u c t i v e

of e a r l i e r d r a f t s

of t h i s t h e s i s .

efforts of Janice Frazelle selection

and t e s t i n g

Special

I gratefully

criticisms

acknowledge t h e

and Brent M c N e i l , who a s s i s t e d

i n the

of subjects.

thanks a r e extended t o my s u p e r v i s o r , Dr. R. D. Hare,

for h i s insights,

encouragement, and p a t i e n c e .

-1I.

Introduction Psychopathy is undoubtedly one of the most complex and puzzling

psychological "disorders".

The generally accepted c l i n i c a l profile

of the psychopath, as outlined by Cleckley (1976), consists of the following: superficial charm and good intelligence; absence of delusions and other signs of irrational thinking; absence of "nervousness" or psychoneurotic manifestations; unreliability; untruthfulness and insincerity; lack of remorse or shame; inadequately motivated antisocial behaviour; poor judgment and failure to learn by experience; pathologic egocentricity and incapacity for love; general poverty in major affective reactions; specific loss of insight; unresponsiveness in general interpersonal relations; fantastic and uninviting behaviour with drink and sometimes without; suicide threats rarely carried out; sex l i f e impersonal, t r i v i a l , and poorly integrated; failure to follow any l i f e plan.

The mixture of both positive (e.g., the f i r s t three)

and negative characteristics indicates that psychopathy does not represent a simple mental disturbance (Hare, 1970). The neuropsychology of psychopathy is poorly understood at present. In general, research has not yielded consistent support for hypotheses of c l i n i c a l l y significant cortical dysfunction in psychopaths. Hypotheses of this type typically follow observations that lesions of certain neuroanatomical structures result in the appearance of symptoms which seem quite similar to some of those typically ascribed to the psychopath (Elliott, 1978; Schalling, 1978a). The basic problem with this "cortical dysfunction" approach is that the core psychopathic symptoms (Cleckley, 1976) demonstrate

-2quantitative and qualitative differences from those typically reported for cortical damage (Elliott, 1978).

Neural "impairment" in psychopathy,

if i t exists, is probably more subtle than that which standard neuropsychological tests are designed to reveal.

The "cortical dysfunction" logic

does not provide an adequate theoretical framework for research in this area.

Its symptom-oriented, inductive nature belies a disjoint and

superficial appreciation of the basic psychopathic syndrome. In devoting attention to the neural bases of individual symptoms, and in assuming cortical disruption at this level, the collective neuropsychological

significance of the psychopathic symptom constellation

has been largely ignored.

This constellation, described by Cleckley

(1976), is the basis of recent work on the formulation of diagnostic criteria for psychopathy.

From a l i s t of the personality traits,

behaviours, indicants and counterindicants which form the basis of a reliable global c l i n i c a l assessment of psychopathy, Hare (1980) assembled a 22-item psychopathy checklist. A principal components analysis of the checklist produced five factors which can be summarized as follows: 1)

impulsive, unstable life-style; 2) self-centeredness, callousness,

and lack of empathy; 3) superficial interpersonal relationships; 4) chronic anitsocial behaviour; 5) inadequately motivated criminal acts. A similar analysis was performed on the scores of prison inmates on Cleckley's (1976) sixteen criteria for psychopathy, and five factors were extracted.

A canonical correlation between factors derived from

the checklist items and the Cleckley criteria revealed an excellent f i t between the two sets of factors. Hare's efforts emphasize the multidimensional nature of psychopathy, and demonstrate that the essential

-3i n g r e d i e n t s o f the c l i n i c i a n ' s c o n c e p t i o n of the symptom c o n s t e l l a t i o n can be c a p t u r e d n i c e l y i n an o b j e c t i v e , o p e r a t i o n a l l y d e f i n e d

assessment

procedure. Cleckley

(1976) argues t h a t the psychopath wears a "mask of s a n i t y " ,

i m i t a t i n g normal behaviour remarkably w e l l .

Consequently, any

dysfunction

must be s u b t l e and deep-seated, and not r e a d i l y r e c o g n i z e d i n the cons i d e r a t i o n of i n d i v i d u a l symptoms.

He suggests that the c o r e p s y c h o p a t h i c

symptoms a r e a l l r o o t e d i n some c e n t r a l p e r s o n a l i t y d i s o r d e r . The cons t e l l a t i o n as a whole i n d i c a t e s a c o n d i t i o n he l a b e l s as, "semantic dementia", marked by, ". . . a

s e l e c t i v e d e f e c t or e l i m i n a t i o n which

p r e v e n t s important components of normal e x p e r i e n c e from b e i n g i n t e g r a t e d i n t o the whole human r e a c t i o n

. . ."(P. 410).

D e s p i t e i t s importance i n

C l e c k l e y ' s i n f l u e n t i a l t h e o r e t i c a l scheme, the concept o f semantic dementia has r e c e i v e d s c a n t e x p e r i m e n t a l a t t e n t i o n . i s o r g a n i c i t y i m p l i e d i n semantic dementia? u n i t a r y phenomenon?

Is semantic d y s f u n c t i o n a

What type of e x p e r i m e n t a l m a n i p u l a t i o n s might

expected to be s e n s i t i v e to semantic d i s r u p t i o n ? have f a i l e d

To what e x t e n t

be

Researchers g e n e r a l l y

to note the r e l e v a n c e of C l e c k l e y ' s (1976) " p e r i p h e r a l

v s . c e n t r a l " dimension of p e r s o n a l i t y d i s o r d e r s t o the n e u r o p s y c h o l o g i c a l i n v e s t i g a t i o n of psychopathy. It

i s my

i n t e n t i o n to p r e s e n t groundwork f o r n e u r o p s y c h o l o g i c a l

study based upon the h y p o t h e s i s t h a t some form o f "semantic dementia" u n d e r l i e s the w i d e l y a c c e p t e d c l i n i c a l p i c t u r e o f the psychopath. approach w i l l ,

firstly,

i n v o l v e a b r i e f r e v i e w of c u r r e n t

l o g i c a l r e s e a r c h i n psychopathy.

My

neuropsycho-

T h i s w i l l be f o l l o w e d by a more d e t a i l e d

d i s c u s s i o n of s p e c i f i c n e u r o a n a t o m i c a l s t r u c t u r e s c o n s i d e r e d to be

crucial

-4to the support of both semantic c a p a b i l i t y and performance.

Then w i l l

come an e l a b o r a t i o n o f the t h e o r y proper - l a r g e l y a s y n t h e s i s of schemes developed by Brown (1977) and C l e c k l e y

(1976). F i n a l l y ,

I will

r e l a t e t h e r a t i o n a l e behind, and the d e s c r i p t i o n o f , a t a c h i s t o s c o p i c experiment designed t o b e g i n the s y s t e m a t i c i n v e s t i g a t i o n o f semantic dementia.

II.

The neuropsychology o f psychopathy:

Current status

The most p o p u l a r n e u r o p s y c h o l o g i c a l e x p l a n a t i o n of psychopathy to be t h a t o f f r o n t a l l o b e p a t h o l o g y .

seems

A s i z e a b l e amount of animal and

human r e s e a r c h has documented t h e f o l l o w i n g e f f e c t s o f p r e f r o n t a l and f r o n t a l damage; i m p u l s i v e n e s s , d e f e c t i v e g o a l - o r i e n t e d b e h a v i o u r , diminished a f f e c t ,

impairments

o f s e l e c t i v e a t t e n t i o n , f a i l u r e to l e a r n

from p a s t e x p e r i e n c e , l a c k o f f o r e s i g h t and p l a n n i n g ( E l l i o t t , 1978; S c h a l l i n g , 1978a).

These

symptoms bear a s t r i k i n g resemblance

to p a r t

of the p s y c h o p a t h i c symptom c o n s t e l l a t i o n as d e s c r i b e d by C l e c k l e y an o b s e r v a t i o n which has encouraged t e s t i n g procedures on psychopaths

the r e c e n t use of n e u r o p s y c h o l o g i c a l

(see S c h a l l i n g , 1978a,

1978b).

S c h a l l i n g and her c o l l e a g u e s found t h a t psychopaths, l i k e lobotomy

patients

frontal

(see, eg., Meier and S t o r y , 1967), o b t a i n h i g h e r

Q-scores on t h e P o r t e u s maze t e s t than do non-psychopaths 1978a).

(1976),

(Schalling,

A l s o , i t seems that more i m p u l s i v e - p s y c h o p a t h i c s u b j e c t s

r e p o r t a g r e a t e r r a t e of change i n the Necker

cube, a r e v e r s i b l e

figure

s e n s i t i v e to b i l a t e r a l f r o n t a l l e s i o n , than do l e s s i m p u l s i v e - p s y c h o p a t h i c s u b j e c t s ( S c h a l l i n g , 1978a).

The Porteus f i n d i n g s a r e somewhat

c o n t r o v e r s i a l as they have not been r e p l i c a t e d by some o t h e r i n v e s t i g a t o r s

-5(Sutker, Moan, and Swanson, 1972; Hare and Jutai, (Note 1)). There are however, as E l l i o t t (1978) reports, important differences to consider between the frontal patient and the psychopath.

For example,

the psychopath tends toward episodicity rather than consistency in his abnormal behaviour.

Also, there i s no obvious impairment of memory in

psychopathy (see Hare, Frazelle, Bus, and Jutai, 1980).

In fact, the

long-term memory of psychopaths has been reported as being superior to that of non-psychopaths (Sherman, 1957).

Furthermore, unlike the frontal

patient, the psychopath often displays unusual s k i l l in the arts of persuasion and ingratiation. Other notable differences exist. Cleckley (1976) characterizes the psychopath as possessing a specific loss of insight, in the sense of realistic evaluation of self and circumstances.

It is unlikely that

the psychopath behaves inappropriately because of an inability to act upon the dictates of a sound evaluative system.

Rather, his verbal

dexterity and good intelligence permit excellent mimicry of insight despite grossly defective evaluative capabilities. and Pribram (1970), neuropsychological

According to Konow

research strongly supports a

dissociation between "utilization" and "evaluation" of environmental input.

Frontal lesions primarily disturb the former, while the latter

has functional substrates in more posterior brain areas (Pribram, 1969). Luria (1966) had suggested that frontal lesion-induced disruptions stem from damaged response regulatory mechanisms. Recent work elaborates upon these notions, allocating response regulation to certain frontal areas and evaluation to limbic (especially, hippocampal) tissues (Iverson, 1976; Numan, 1978).

-6-

A key f e a t u r e o f the p s y c h o p a t h ' s e v a l u a t i v e p r o c e s s i s emotional poverty.

The v e r b a l accompaniments of h i s

"soul-searching"

i n a c l i n i c a l i n t e r v i e w p o s s e s s no a f f e c t i v e c o n v i c t i o n , communicated i n a l i g h t - h e a r t e d , 1976).

A comparison of t h i s

aphasic patients disability

to t h e i r

superficially

its

and a r e o f t e n

humourous manner

(Cleckley,

o b s e r v a t i o n w i t h the e m o t i o n a l r e a c t i o n of

illness

is

illuminating.

A p h a s i c s whose

has r e s u l t e d from f r o n t a l l e s i o n u s u a l l y demonstrate a c u t e

awareness of t h e i r

c o n d i t i o n and a r e t y p i c a l l y

depressed

(Geschwind,

1974), w h i l e temporal l e s i o n - i n d u c e d a p h a s i c s i n f r e q u e n t l y i l l n e s s and a r e o f t e n e u p h o r i c

display

insight

into their

(Brown, 1977; Geschwind,

1974) .

Geschwind (1974) suggests t h a t temporal l e s i o n i n these p a t i e n t s

might a l s o sever t e m p o r o - l i m b i c c o n n e c t i o n s thereby

impairing arousal

of e m o t i o n a l r e s p o n s e s t o t h e d i s o r d e r .

T h i s severance might a l s o

disrupt

rehabilitatory

v e r b a l l e a r n i n g and so f r u s t r a t e

efforts.

In

a s i m i l a r manner, the f a i l u r e of behaviour m o d i f i c a t i o n approaches to the treatment of psychopathy,

and the d e f i c i e n c i e s i n l e a r n i n g shown by

psychopaths i n c e r t a i n e x p e r i m e n t a l s i t u a t i o n s

(Hare,

1970, 1978;

S u e d f e l d and Landon, 1978) might i n d i c a t e l i m b i c d i s r u p t i o n , in particular,

l i m b i c s u b s t r a t e s of punishment (see Fowles,

Gascon and G i l l e s

behavioural aberrations

i n c l u d e d d e n i a l of

j o c u l a r i t y , negativism, hyperactivity,

dementia",

1979).

(1973) d e s c r i b e d the case of a t w e n t y - s i x year

woman w i t h c o m p l e t e , but s e l e c t i v e l i m b i c l o b e damage.

distractability.

involving,

illness,

old

The p a t i e n t ' s

inappropriate

s h o r t a t t e n t i o n s p a n , and

Gascon and G i l l e s l a b e l l e d the syndrome,

"limbic

-7... . t o emphasize that, although on superficial examination she may have appeared demented in the usual sense, the functions primarily lost were not those cognitive functions usually associated with 'intelligence', usually measured by psychometric tests, and often based on language, but those which imprint an affective quality, thereby giving meaning, to daily survival interactions with the environment and imprinting them into memory. Moreover, the neuropathological lesions were not those of the usual cortical dementias, but were confined essentially to hemispheral structures within the limbic system, (p. 429). There"is very l i t t l e mention in the literature of the effects of frontal lesions on naturally occurring social interactions in man. This is unfortunate since these interactions represent situations of particular importance in the study of the subtleties of psychopathic social behaviour (Rime, Bouvy, Leborgne, and Rouillon, 1978). However, one recent study has described frontal patients as "social isolates", with marked impairment in desire and ability to form social relationships (Deutsch, Kling, and Stelkis, 1979).

This description contrasts

sharply with the friendly attitude, extraordinary poise, and easy social graces which usually dominate one's c l i n i c a l impression of the psychopath (Cleckley, 1976).

Furthermore, the paralinguistic and proxemic behaviours

of the frontal patients of Deutsch et a l . (1979) did not appear to share the intrusive, reactive character of psychopathic performance in interpersonal situations as observed by Rime et a l . (1978).

In general, i t

seems that pathology of the frontal lobes is insufficient (or even i n appropriate) to account for some of the core features of psychopathy. A major difficulty exists in the interpretation of frontal lobe research with humans. E l l i o t t (1978) has noted the inconsistency of

-8frontal lobotomy effects on human personality. The main problem stems from the great variability reported in lesion sites.

In particular,

most posterior ablations involve limbic structures as well as frontal cortex, promoting a mixture of cognitive and affective symptoms. Thus, the label "frontal" means different things to different researchers. The problem is somewhat unavoidable since the vast majority of human subjects are c l i n i c a l patients - victims of accident or disease. Another interesting neuropsychological approach to psychopathy is Flor-Henry's (1976) suggestion that lateralized (i.e., dominant hemisphere) frontal/temporal dysfunction may foster psychopathic symptomatology.

Flor-Henry provides no direct evidence to substantiate

his hypothesis, and available physiological data do not entirely support such a notion (Hare, 1978, 1979).

Hare (1979) tested the hypothesis

as i t would apply to verbal tachistoscopic recognition (i.e. i t would predict impaired right visual field relative to left visual field recognition) using well defined groups of psychopaths and non-psychopathic controls (see Hare and Cox, 1978; Hare, 1980), and reported nothing unusual about the performance of psychopaths.

Also, the Porteus maze

test, on which the psychopathic subjects of Schalling (1978a) obtained high scores, has been found to be more sensitive to right rather than to left frontal insult (Meier and Story, 1967). While there is l i t t l e evidence in the current literature to implicate lateralized hemispheric dysfunction in psychopathy, most of this research has been unfocused theoretically.

The psychopath is not just impulsive,

or incorrigible, or cold; he is a l l of these at once, and more. A theoretical framework faithful to the integral, c l i n i c a l picture of the psychopath is necessary to guide neuropsychological investigation.

-9At t h i s point, a more detailed s p e c i f i c a t i o n of relevant neuroanatomy w i l l be presented.

The limbic system and possible fronto-limbic con-

nections, i n p a r t i c u l a r , merit attention.

III.

Behaviour and memory: Frontal and temporo-limbic contributions A.

Frontal cortex

Stanley and Jaynes (1949) proposed a " c o r t i c a l a c t - i n h i b i t i o n " theory of f r o n t a l lobe function. They suggested that f r o n t a l ablationinduced learning d e f i c i t s were due to impaired

performance, rather than

to an i n a b i l i t y to i n h i b i t previously learned response sequences. sequent work has resulted i n the elaboration of this p o s i t i o n .

Sub-

Frontal

areas have been described as being heavily involved i n the u t i l i z a t i o n of feedback relevant to the consequences of behaviour (Luria, 1966; Numan, 1978).

Nauta (1971) proposed that f r o n t a l areas are central

participants i n behavioural a n t i c i p a t i o n and i n the o v e r a l l course and temporal s t a b i l i t y of complex goal-oriented behaviours.

A distinction

has been made between o r b i t a l and dorsolateral f r o n t a l influences on behaviour.

Selective damage to the former area disturbs emotionality

and autonomic regulation, while dorsolateral i n s u l t disrupts actual response modulation (Girgis, 1971; Numan, 1978). Milner

(1964) attributed the poor performance i n memory tasks of

frontal-lesioned human subjects, not only to poor memory, but also to an i n a b i l i t y to maintain concentration on current s t i m u l i and to suppress the memory of p r i o r s t i m u l i (see also Butters, Samuels, Goodglass, and Brody, 1970; Perret, 1974).

She concluded that good performance on

these tasks requires the functional i n t e g r i t y of both lower f r o n t a l

-10and temporal areas.

Milner (1970, 1971) has also reported research which

found that patients with left frontal lesions demonstrated excellent recognition memory for familiar stimuli, but were very poor at judging when these stimuli had appeared.

Iverson (1976) suggests that the

frontal lobe in humans plays a sophisticated role in the memory storage process, namely, the coding of order in time. In a recent review of contemporary animal (especially primate) research, Numan (1978) conduced that the frontal association cortex was not directly involved in general memory processes.

He points out

that current work favours a response modulation explanation of frontal function.

Impairments are described in terms of inefficient utilization

of feedback, and the dorsolateral area in particular is implicated. Human research generally places memory (particularly semantic memory) systems in a more posterior locus (eg., Warrington, 1975). Ojemann (1978) described evidence which indicates that the posterior frontal lobe, adjacent to the anterior language area of the brain, houses the retrieval mechanism of short-term verbal memory in man. In summary, the frontal lobe appears to be an executor, rather than a container or a generator of mnestic processes, directing the coding, retrieval, and utilization"of stored information. B.

Temporo-limbic tissues

Douglas and Pribram (1966) suggested that the hippocampus and amygdala were jointly involved in the learning process, with the amygdala recording stimulus meaningfulness and the hippocampus evaluating response strategies (see also Numan, 1978), strengthening correct and weakening incorrect responses to stimuli. The two structures comprise an hypothesis-

-litest ing or strategy-searching mechanism selectively impaired by limbic lesion (Iverson, 1976). The hippocampus also appears to play a crucial role in the fixing of attention to relevant stimuli, and in behavioural habituation (Iverson, 1976).

Hippocampal-lesioned animals seem less distractable

in goal-directed activity, and often show slower rates of habituation than controls (Jarrard, 1973).

Kimble (1968) interpreted the habituation

findings as evidence of response disinhibition.

While rat studies seem

to support such a notion, the simple loss of response control is not easily ascribed to the deficits observed in hippocampal-lesioned monkeys (Iverson, 1976). The hippocampus also appears to exert considerable influence on general activity. Jarrard (1973) reports that, in situations requiring goal-oriented behaviour, lesloned animals often display greater activity than controls, especially bilateral.

in cases where the lesion is extensive and

Furthermore, he has observed a selective effect on reactivity

to auditory or photic stimuli, with lesions resulting in increases only when stimulation is intense. In interpreting the literature, species differences constitute an important consideration.

It seems that the rat, unlike the monkey, has

poorly developed frontal cortex, disconnected (Nauta, 1964; Numan, 1978).

from limbic structures

In the rat, i t is limbic rather than frontal

damage that results in classical frontal-like effects (Numan, 1978). Nauta (1964) suggested that frontal association cortex i s the neocortical extension of limbic mechanisms. Numan (1978) contends that the hippocampus forms a significant

-12functional and structural link between frontal and limbic mechanism. Once again, dorsolateral and orbital frontal cortex can be separately treated.

From the analysis of fiber distributions in monkeys, i t appears

that the former i s closely related to the hippocampus, while the latter is closely tied to the amygdala and temporal lobe (Nauta, 1964). A review of the literature leaves l i t t l e to doubt the existence of a fundamental relationship between temporal structures and memory (see, eg., Fedio and Van Buren, 1974; Hagberg, 1978; Milner, 1967, 1968, 1970). Verbal memory i s selectively impaired by left (i.e., where the left i s dominant) temporal damage (Iverson, 1976),'with the degree of impairment related to the extent of limbic lesion (Omaya and Fedio, 1972).

Semantic

memory and semantic retrieval appear to be particularly vulnerable to temporal lobe damage (Coughlan and Warrington, 1978).

The left anterior

temporal area i s especially important (Fedio and Van Buren, 1974; Hagberg, 1978), and seems to be heavily involved in the registration and/or storage of verbal information (Fedio and Van Buren, 1974; Iverson, 1976).

Right

anterior temporal lobe damage disrupts the recognition and retention of nonverbal material (Milner, 1967, 1968, 1970). Fedio and Van Buren (1974) suggest that in the left posterior temporoparietal area of the brain may be located a common mechanism for the retrieval of information from both long- and short-term memory. However, their opinion i s not shared by a l l researchers. Ojemann (1978), for example, contends that short-term verbal memory storage, rather than retrieval, i s supported by posterior temporal structures. It may be more reasonable to look elsewhere in the brain for the executor of retrieval processes.

As was mentioned earlier (Section III. A.),

-13-

Ojemann (1978) offers the posterior frontal lobe as a likely

candidate.

Hagberg (1978) points out that recognition memory tests require a planned, serial activity (i.e., an active search for the right answer) within a given space of time coupled with differential judgment, as well as mnestic ability.

The former type of activity, as earlier noted

(Section III. A.), seems to be quite dependent upon frontal regions, while mnestic ability (i.e., encoding and storage) per-se remains the province of temporo-limbic areas. An impressive amount of research indicates that the integrity of limbic (especially hippocampal) tissues is essential to normal memory processes (eg., Brion, 1969; Isaacson, 1975; Iverson, 1976; Milner, 1967, 1970; Numan, 1978; Ojemann, 1978; Stepien and Sierpinski, 1964). Korsakoff's syndrome is always accompanied by bilateral limbic lesion (Brion, 1969) , and i t s associated memory defects are equally reproducible by bilateral hippocampal resection (Barbizet and Cany, 1969).

Milner

(1972; 1978) suggests that bilateral hippocampal lesion might disturb the consolidation process required for proper transition of information from the short- to the long-term store.

McLardy (1970) proposed that

the hippocampus and anterior lateral temporal cortex support a recent memory system, with immediate access to a long-term store. Kinsbourne and Wood (1975) have hypothesized that subcortical and limbic system (and not cortical) structures are the most deeply involved in memory processing, especially in the retrieval- of information. In the dominant hemisphere, verbal recent (i.e., short-term) memory processes, including both learning and retention, are dependent upon the hippocampus (Ojemann, 1978; Stepien and Sierpinski, 1964). There i s

-14some evidence that right (non-dominant) hippocampal insult disrupts visuo-spatial short-term memory (Ojemann, 1978) . The hippocampus has also been described as the memory mechanism of the response regulation system (Numan, 1978).

In this context i t s

duties involve the coding of sensory input and response to input and laying down a record of the correlation between the two (Iverson, 1976). As i t is generally accepted that the properties of human motor memory differ from those of verbal memory (Milner, 1972), i t is interesting to note the c r i t i c a l participation of the hippocampus in both of two qualitatively dissimilar memory systems (Iverson, 1976). In summary, the temporo-limbic tissues seem to be directly involved in attention and memory processing, and in the evaluation of behavioural response strategies. It is important to note the distinction made between frontal (planned, serial, regulatory) and temporo-limbic

(mnestic,

evaluative) functions because of the implications i t has for the concurrent analysis of reaction time and error rate data in tachistoscopic memory paradigms (see section V. B.). IV.

Semantic dementia: A neuropsychological A.

theory

Brown's model of neural organization

Brown (1978, 1977, 1976) has recently proposed a model which maps linguistic disorders onto levels of phylogenic and ontogenic brain organization.

The model involves a cognitive hierarchy of "limbic-

presentational", "cortical-representational", and "asymmetric-symbolic" stages.

The f i r s t two stages are phylogenic, corresponding roughly to

the "paleomammalian" and "neomammalian" components of McLean's (1972)

-15tri-partite model. The last level is a maturational achievement. Active structures at the limbic-presentational level include familiar constituents of the limbic lobe (i.e. hippocampus, anterior thalamus, cingulate gyrus, hypothalamus, and associated interconnections), orbito-frontal, pyriform and possibly insular cortex, and some subcortical participants (e.g., amygdala, septial nuclei, dorsomedial thalamus).

In cognitive terms, this stage is marked by a fundamental

semantic processing of a l l emerging thought.

At this level, objects

are not perceived as fully exteriorized, but rather are incorporated by the organism.

The rudiments of semantic operations are evident here

as affects accompany a l l object perceptions and responses, giving environmental interaction a highly subjective flavour.

Semantic develop-

ment, then, originates as a true empathy^", as an indistinction of object from self.

The functional integrity of paleomammalian tissues is

crucial in cognitive phylogeny for the grasping of meaning, and in particular, for the optimal development of affective self - object bonds. Neomammalian cortex is a phylogenic latecomer, emergent in the higher mammalian species. Anatomical constituents are the frontal and parietal "integration" cortices which surround primary sensory regions.

Both

areas have comparable thalamic, and medial and lateral limbic connections, and cortico-cortical connections.

The hallmark of cognition

at the cortical-representational stage is object awareness - objects are

Cf. Ax's (1962) related discussion of limbic involvement in the "inappropriateness of affect" or "impairment of empathy" in schizophrenia.

-16externalized and divorced from the self.

Differential affective states

develop with this new perceptual capacity. Says Brown (1977), "the object and i t s affective component are like arborizations of the affect-laden image that precedes them" (pp.20-21).

The self, too, is

seen as an object. At the asymmetric-symbolic level, core differentiation in frontal and temporo-parietal

cortex produces new functional zones. According

to Brown, asymmetry in the form of lateralization, or cerebral dominance, represents the extension of phylogenic encephalization into ontogeny, and is a response to size restrictions on cortical expansion. level, action is volitional, or consciously guided.

At this

Language develops

to articulate the mind, as objects had formerly described the environment. Language further permits the awareness of the self as a subject in the awareness of the object.

Furthermore, as Brown (1977) suggests, "awareness

is a type of affect", since cognition develops as a, "unitary arborization of affect, awareness, and language together into a new inner or private space" (p. 23). Brown's is not a static "sandwich" or "layer cake" model, but one of growth in the organic sense.

New structures not only develop out of

predecessors, they make new structures of progenitor substances as is required to nurture emergent abstract

representation.

The realization of a new performance level w i l l affect cognition at preceding stages . . . in the forward development of cognition, structure acts as medium for a transformation and is not irrevocably bound to function. As in evolution or embryogenesis, cognition does not advance as an elaboration of the previous endstage. Each new level is not simply a continuation but as a differentiation of an earlier, less specialized stage. (1977; pp.23-24)

-17Th is premise is important in the construction of a framework within which Cleckley's (1976) concept of semantic dementia can be represented in actual neural organization.

I w i l l propose that Cleckley's (1976)

dementia - aphasia analysis can proceed beyond the level of analogy provided i t is accepted that, as Brown (1977) contends, "language is not 'added on' to prelinguistic cognition, but rather in i t s development recapitulates a l l of the preceding stages" (p.24). B.

Semantic aphasia and semantic dementia

The semantic aphasic patient has been described as possessing the following: a lack of recognition of the f u l l significance of words and phrases apart from their verbal meaning; an inability to anticipate the f i n a l result of an action; a failure to synthesize perceived details into a general conception; only a partial insight into his malaise; a tendency toward logorrhea and euphoria; a general absence of hallucination and paranoia (Brown, 1977, 1972; Chapey and Lubinski, 1979; Green and Boiler, 1974;

Schuell, Jenkins, and Jimenez-Pabon, 1964; Von Stockert,

1972; Wepman, 1972;

Zurif, Green, Caramazza, and Goodenough, 1976).

According to Cleckley (1976), the psychopath possesses a "semantic dementia" - he i s incapable of finding meaning in l i f e .

The symptom

constellation includes: poor judgment; failure to learn by experience; specific loss of insight; superficial charm; good intelligence; and absence of delusions and

other signs of irrational thinking.

As he repeatedly points out in his book, Cleckley (1976) is describing a gross personality disorder with a marked absence of superficial symptomatology (in the sense of c l i n i c a l deficits). The psychopath is said to

-18be quite adept at the technical conveyance of linguistic and intellectual competence, while completely lacking in adequate motivation and any sense of value.

The power of this "mask of sanity" was recently displayed in

a study by Hare et a l . (1980). Prison inmates were divided into three groups on the basis of highly reliable assessments of psychopathy, and a comprehensive battery of primary ability tests (the CAB) was administered. No significant differences were reported between the high-, medium-, and low-psychopathy groups on any of the eighteen measures.

There was nothing

in the pattern of test results for the high-psychopathy group indicative of any obvious intellectual or linguistic impairment.. Cleckley (1976) proposes an analogy between speech disorders and disorders of personality in order to illustrate the centrality of the psychopathic condition.

In his scheme, both kinds of disorder are

arranged along a continuum bounded by endpoints representing periphery and centrality.

An injured tongue constitutes a def ect in the distal

organ of vocal speech - a peripheral speech impairment.

One of the most

central of such problems i s represented in the semantic aphasia produced by a lesion in language area neocortex, a problem which is often well disguised by the integrity of more superficial structures.

In the

personality domain, delirium is an obvious, peripheral, manifestation of psychosis.

In psychopathy, "psychosis" i s deep-set, well-concealed

by adept mechanical reproduction of appropriate behaviour. Cleckley's analogy is presented in Table 1. To the extent that he develops i t , Cleckley's analogy is interesting but vague.

Several questions come to mind. Are linguistic disorders

intended to be thought of as independent of those of personality (hence,

-19parallel continua)?

How similar are the semantic components of aphasia

and dementia?

Can substrates of the personality analogues be located

in the brain?

The answers to these questions require a more detailed

examination of the neuropsychology of both disorders. Brown (1977) has interpreted c l i n i c a l and neurological aspects of language disorders within his aforementioned model of neural organization. The various aphasias

1

tend to be restricted to certain cortical areas,

namely, limbic cortex (semantic aphasia), generalized

(temporo-parietal)

cortex (nominal aphasia), and specialized (dominant posterior-superior temporal gyrus and supramarginal gyrus) cortex (phonemic aphasia).

These

anatomic structures support the limbic-presentational, cortical-representational, and asymmetric-symbolic levels, respectively, in Brown's (1977) cognitive hierarchy.

The process involved in any given act of language

production proceeds through these structural levels in an invariant sequence.

First, there is semantic encoding (limbic stage), followed

by word selection (generalized stage), terminating in phonemic realization (specialized stage).

The disorders which can affect these aspects of

linguistic production are not by nature nested within each other, but are quite independent.

Thus, a disruption at the limbic level which may

result in semantic aphasia w i l l not necessarily alter the technical capabilities of the generalized and specialized structures.

To put i t

I do not include here the nonfluent aphasias. These action, speech (as opposed to perceptual, linguistic (fluent)) aphasias are discussed in detail by Brown (1977). The two classes of aphasias are organized in parallel within the cognitive hierarchy.

Table 1 Speech and personality continua.

(adapted from Cleckley, 1976)

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