Context effects in the processing of familiar faces - Springer Link

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Psychol Res (1991) 53:296-304

© Springer-Verlag 1991

Context effects in the processing of familiar faces T i m B r e n n e n 1 and Vicki Bruce 2

1Laboratoirede PsychologieExpdrimentale,Universit~Pierre Mend~sFrance, F-38040 GrenobleCedex, France 2 Universityof Nottingham,UniversityPark, Nottingham,England ReceivedJanuary 11, 1991/AcceptedMay 22, 1991 S u m m a r y . In this paper we report five experiments that

investigate the influence of prime faces upon the speed with which familiar faces are recognized and named. Previously, priming had been reported when the prime and target faces were closely associated, e.g., Prince Charles and Princess Diana (Bruce & Valentine, 1986). In Experiment 1 we show that there is a reliable effect of relatedness on a double-familiarity decision, even when the faces are only categorially related, e.g., Kirk Douglas and Clint Eastwood. Then it was shown that such an effect emerges only on a double decision task (Experiments 2 and 3). Experiment 4 showed that on a primed naming task, faces preceded by a categorially related prime were responded to more quickly than those preceded by an unrelated prime, and the effect was due to inhibition. Experiment 5 replicated this effect and also showed that when associatively related primes were used, a facilitatory, and not an inhibitory, effect is found. It is argued that the facilitation of associative priming arises at an earlier locus than the inhibition of categorial priming.

A widely used way of investigating memory is the manipulation of subjects' state of preparedness before they perform a task. For instance, the effect of prior context upon the recognition of familiar stimuli has been studied for a range of stimulus domains, e.g., word, object, and face recognition. One design for such investigations consists of the presentation of a prime stimulus before the target stimulus on each trial. The manipulation of main interest in such investigations is the relationship between the prime and the target stimuli, in order to find whether a prime that is similar in some way to the target, e.g., semantically or visually, may lead to faster target processing than when the prime is not related to the target.

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Tim Brennen

One such task is the familiarity-decision task in which subjects discriminate between familiar and unfamiliar stimuli. Neely (1976), for example, presented subjects with letter strings, to which they had to respond "Yes" if it formed a word, and "No" if it did not - the lexical-decision task. In his variant of the task each such decision was primed. That is, before each of the target letter strings was shown, another letter string was briefly flashed up, and it was the effect of these primes on the reaction times that was of main interest. Neely's most important finding was that the targets preceded by a meaningfully related word, e.g., Doctor ---> Nurse, were responded to more quickly than those preceded by a row of Xs, (the Neutral conditon), and that words preceded by an unrelated word, e.g., Orange --+ Nurse, were responded to more slowly than those in the Neutral condition. Kroll and Potter (1984) investigated whether a meaningful context could influence the recognition of objects. They invented the object-decision task, an analogue of the lexical-decision task, in which subjects are required to discriminate between line drawings of real objects and those of made-up objects. Kroll and Potter used a doublefamiliarity-decision task in which subjects respond "Yes" only if both stimuli on any trial were judged to be pictures of real objects, and therefore respond "No" when either one or each of the two drawings was unfamiliar. There were two types of positive trial, those on which the two objects were related, e. g., a bucket and a spade, and those on which they were not, e. g., a saucer and a boat. They reported that the latencies were reliably quicker in the Related than in the Unrelated condition. Bruce and Valentine (1986) studied the effect of congruent contexts upon the recognition of familiar faces. They used a design akin to Neely's (1976), and so on each trial subjects saw a prime face, which was followed by the target face. The pairs in the Related condition were close associates, e.g., Oliver Hardy followed by Stan Laurel; the Neutral prime was an unfamiliar face, and the primes in the Unrelated condition were all familiar, but not associated with the experimental targets, e.g., Prince Charles followed by Paul Newman. They reported a significant prim-

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ing effect that was due to the latencies in the Related condition being shorter than either of the other two, which did not differ from each other. Thus there was facilitation from a related face, but no inhibition from an unrelated face, compared with when an unfamiliar face primed the targets. One explanation of such priming effects, which Neely (1976) offered for the priming of word recognition, and Bruce and Valentine (1986) offered for face recognition, draws upon the notion of the spread of activation within the semantic system. After the prime stimulus has been recognized, activation is deemed to spread from its representation in semantic memory via all adjoining links to all nearby concepts. This serves to lower the perceptual requirements for the recognition of any stimuli whose representations received activation, i. e., all related stimuli. A prediction that is thus implicit in spreading-activation accounts of access to memory is that priming should be observed even between pairs of stimuli that come from the same semantic category (but are not closely associated together). This issue has, in fact, already been investigated in all three stimulus domains. Fischler (1977) was the first to note that the priming effects in studies of word recognition, while referred to as semantic priming, were rather studies of associative priming; that is, in the Related condition, the pairs of stimuli were generally of high contiguity, and associative strength, e. g., knife ~ fork, rather than merely sharing category membership, e.g., chair --~ bed. So Fischler (1977) compared lexical-decision latencies to pairs of words that were associatively and semantically related, e.g., Nurse-Doctor, with latencies to pairs that were semantically, but not associatively, related, e.g., Nurse-Wife and with unrelated pairs of words, e.g., Nurse-Record. Both types of relatedness led to shorter latencies than the unrelated pairs. Lupker (1984) bolstered Fischler's report by finding a priming effect with different materials, using a single-familiarity-decision task, like Neely's (1976). In Kroll and Potter's (1984) study, semantically and associatively related pairs were also combined, and priming was found for both types of Related trial. This result is tempered by Lupker (1988), who reported no priming effect when using a primed sequential object-decision task. Since even unfamiliar faces have semantics associated with them (e. g., their sex, age, attractiveness), we prefer not to use the term semantic priming for faces; instead we shall use the term categorialpriming, which refers only to the semantic category to which the person belongs. Using a sequential familiarity-decision task for faces, Bruce (1983) used a mixture of categorial and associative pairs in her Related condition, e.g., any two newsreaders and Stan Laurel --~ Oliver Hardy, respectively. The latencies were indeed reliably shorter in the Related condition than in the Unrelated condition, and a post-hoc analysis showed no difference between the two strengths of Related trial. However, Brennen (1988) showed that in the absence of associatively related pairs, categorial priming was not found. This was the case at long and short Stimulus Onset Asynchronies (SOAs), and even for faces that in real life

were seen together. It may nevertheless be inappropriate to conclude that there is no influence of categorially related primes on a face-familiarity-decision task; a close reading of the semantic-priming literature in word and object recognition reveals that the precise demands of the familiarity-decision task employed may determine whether or not such priming is observed. Fischler (1977) used a double-lexical-decision task, in which subjects respond affirmatively only if both stimuli on any trial are familiar. He found a reliable priming effect with categorially related stimuli in the Related condition. Kroll and Potter's (1984) object-decision task also used a double-familiarity decision, which also yielded a reliable category-priming effect. The fertility of the single-familiarity-decision task for categorially related pairs is modest by comparison. Lupker (1984) found a much reduced priming effect on a sequential lexical-decision task, and later reported no trace of an effect on a sequential object-decision task (Lupker, 1988). These observations suggest that categorial priming may be observed on a double-face-familiarity-decision task, and this prediction formed the basis of Experiment 1. It is not possible to gauge the baseline performance within a double-familiarity-decision experiment; typically subjects are not required to respond to primes, and thus the neutral prime can be repeated without difficulty. The problem is that, since in a double-familiarity-decision experiment both faces are responded to on each trial, recognition of a face presented many times would be speeded up, and would thus not provide an estimate of baseline performance.

Experiment 1 Method Subjects. Twenty subjects were recruited from the undergraduate and postgraduate populations of Nottingham University.

Apparatus. A BBC microcomputer was programmed to control the shutters on two Kodak SAV 2050 projectors. The slides were projected onto a white wall, each one subtending a visual angle of approximately 5 °. The visual angle between the centre of the two faces was approximately 10 °. The computer was programmed to produce the following sequence on each trial: a warning tone 500 ms before the wesentation of the faces; presentation of the faces for 2,500 ms, and a 2,500-ms response ~ next trial interval. Subjects responded by pushing one of two buttons on a panel: one for "Yes" (i. e., both faces are familiar), and the other for "No" (i. e., there is at least one unfamiliar face).

Materials. The slides in these experiments were made by mounting photographs of faces in a circle, in order to cut out as much of the background and clothing as possible. There were 50 slides of famous people's faces (see Appendix) and 30 slides of unfamiliar people's faces, matched for frequency of occurrence of glasses and beards.

Design. A mixed design was used in this experiment. The within-subjects factor was that of Trial Type. The two conditions to which the correct response was "Yes" were (1) Related - in which both faces were familiar and categorially related, and (2) Unrelated - in which both faces were familiar, yet not from the same category. The two conditions in which the correct response was "No" were the Negfam condition, in which one of the faces was familiar and the other

298 unfamiliar, and the Doubleneg condition in which both faces were unfamiliar. In each of these four conditions there were 10 trials. The between-subjects factor was that of Subject Subgroup, which was a balancing factor allowing all familiar faces to appear in both the Related and the Unrelated conditions. In order to ensure that the Subgroups factor would not yield an interaction with Trial Type, an attempt was made to create two groups of faces of equal familiarity. Four subjects gave ratings on a scale of 0 to 10 of the familiarity of the 40 familiar faces that would appear in the familiar-face conditions, and a mean rating was obtained for each face. The familiarity of each of the 20 related pairs of faces was obtained from the mean of the familiarity ratings of the two people. The pairs were then rank-ordered according to their familiarity; one group was formed from the pair with the highest-rated familiarity, the fourth- and fifth-highest, the eighth- and ninth-highest, and so on, to the pair with the lowest rating. The second group consisted of the remaining pairs. The mean familiarity rating for both groups was 7.8.

Procedure. Subjects were informed that on each trial two faces would be flashed up simultaneously, side by side on the wall. Their task was to press "Yes" if both faces were familiar to them, and "No" if either one or each of the two faces was unfamiliar to them. It was stressed that because their reaction times were being recorded, they were to press the button as soon as they had reached a decision. There were 10 practice trials preceding the 40 experimental trials.

ResuI~ D a t a points were d i s c a r d e d w h e n the r e s p o n s e was different to that expected. A certain p r o p o r t i o n o f such responses m a y not b e true errors, i n s t e a d due m e r e l y to a l a c k o f f a m i l i a r i t y with s o m e faces. T h e t i m e criterion for the r e m o v a l o f a d a t u m point was 3,000 ms. The error criterion was set at 20%, i.e., 8 errors was the m a x i m u m tolerated. N o subject e x c e e d e d this criterion, and for each subject the m e a n reaction times for the four conditions w e r e c o m p u t e d . T h e overall m e a n latencies for the hits w e r e 1,274 ms for the R e l a t e d condition and 1,380 m s for the U n r e l a t e d condition. The m e a n p e r c e n t a g e error rates w e r e 16% and 19% respectively, s h o w i n g no sign o f a s p e e d - a c c u r a c y trade-off. A split-plot A N O V A on the hits, with a withinsubjects factor o f Trial Type, and a b e t w e e n - s u b j e c t s factor o f S u b g r o u p , g a v e significant m a i n effects o f both, F (1,18) = 10.00, p