The time course of processing external and internal features of unfamiliar faces

The time course of processing internal and external facial features was studied in a sequential face matching task, where first a target face was presented, followed by a test face. The exposure duration of the test face was varied systematically (90, 120, 150 ms, and self-paced). In three tasks, participants were instructed to match either the whole face, only external features, or only internal features of the target and test face. Taken together, the results in all the three tasks provide evidence for very fast matching processes. For upright faces, maximal performance was achieved at 90 ms exposure duration and longer exposure durations (120, 150 ms, self-paced) did not improve accuracy. For inverted whole faces, reduced exposure duration resulted in an increase of matching errors, suggesting that below 150 ms of exposure duration, inverted faces cannot be matched reliably. When matching selected facial features only, no such inversion effect was found. Our data challenges previous claims that external features are matched faster than internal: no difference of time course was found between external and internal features. However, external features were matched more accurately.     

The relative importance of external and internal features of facial composites

Three experiments are reported that compare the quality of external with internal regions within a set of facial composites using two matching‐type tasks. Composites are constructed with the aim of triggering recognition from people familiar with the targets, and past research suggests internal face features dominate representations of familiar faces in memory. However the experiments reported here show that the internal regions of composites are very poorly matched against the faces they purport to represent, while external feature regions alone were matched almost as well as complete composites. In Experiments 1 and 2 the composites used were constructed by participant‐witnesses who were unfamiliar with the targets and therefore were predicted to demonstrate a bias towards the external parts of a face. In Experiment 3 we compared witnesses who were familiar or unfamiliar with the target items, but for both groups the external features were much better reproduced in the composites, suggesting it is the process of composite construction itself which is responsible for the poverty of the internal features. Practical implications of these results are discussed.     

Exploring levels of face familiarity by using an indirect face-matching measure

An experiment is reported in which participants matched complete images of unfamiliar, moderately familiar, and highly familiar faces with simultaneously presented images of internal and external features. Participants had to decide if the two images depicted same or different individuals. Matches to internal features were made faster to highly familiar faces than both to moderately familiar and to unfamiliar faces, and matches to moderately familiar faces were made faster than to unfamiliar faces. For external feature matches, this advantage was only found for "different" decision matches to highly familiar faces compared to unfamiliar faces. The results indicate that the differences in familiar and unfamiliar face processing are not the result of all-or-none effects, but seem to have a graded impact on matching performance. These findings extend the earlier work of Young et al (1985 Perception 14 737-746), and we discuss the possibility of using the matching task as an indirect measure of face familiarity.     

Matching familiar and unfamiliar faces on internal and external features

Two experiments are reported in which subjects were asked to match a photograph of a complete face and a simultaneously presented photograph of internal or external features of a face, deciding whether or not the two photographs were pictures of the same person. In experiment 1 'same' pairs were derived from different pictures of the same face, so that subjects had to match the faces and not the particular photographs used. Matches based on internal features were found to be faster for familiar than for unfamiliar faces, whereas there was no difference in reaction time between matches based on the external features of familiar and unfamiliar faces. Faster matching of internal features of familiar faces was found to hold equally for pairs of photographs that differed in orientation of the face or in facial expression. In experiment 2 'same' pairs were derived from the same photographs, which gave subjects the choice of matching on the basis of the features of the depicted faces or matching the photographs. Reaction times were faster than in experiment 1, and there were no differences between familiar and unfamiliar faces. The study confirms reports of differential saliency of the internal features of familiar faces, and shows that this only holds when stimuli are treated as faces. The finding thus reflects properties of structural rather than pictorial codes.     

Demonstrating how unfamiliar faces become familiar using a face matching task

Two experiments examine a novel method of assessing face familiarity that does not require explicit identification of presented faces. Earlier research (Clutterbuck & Johnston, 2002; Young, Hay, McWeeny, Flude, & Ellis, 1985) has shown that different views of the same face can be matched more quickly for familiar than for unfamiliar faces. This study examines whether exposure to previously novel faces allows the speed with which they can be matched to be increased, thus allowing a means of assessing how faces become familiar. In Experiment 1, participants viewed two sets of unfamiliar faces presented for either many, short intervals or for few, long intervals. At test, previously familiar (famous) faces were matched more quickly than novel faces or learned faces. In addition, learned faces seen on many, brief occasions were matched more quickly than the novel faces or faces seen on fewer, longer occasions. However, this was only observed when participants performed “different” decision matches. In Experiment 2, the similarity between face pairs was controlled more strictly. Once again, matches were performed on familiar faces more quickly than on unfamiliar or learned items. However, matches made to learned faces were significantly faster than those made to completely novel faces. This was now observed for both same and different match decisions. The use of this matching task as a means of tracking how unfamiliar faces become familiar is discussed.     

Effect of inversion on the recognition of external and internal facial features

The purpose of the present study was to find out whether inversion affects recognition of external and internal facial features. 24 participants matched, under two experimental conditions (pair and multiple-choice matchings), upright target faces with three categories of facial test stimuli: full faces, external features and internal features, which were presented in either upright or inverted orientations. Data analysis showed that matching of facial stimuli was faster, more accurate and more consistent under upright than under inverted orientations for all stimulus categories; mostly for full faces, and least for internal features. As a rule, there were no speed-accuracy trade-offs. Implications of the data for accounts of the inversion effect in face recognition in terms of a shift from configurational to componential processing were discussed.     

The influence of flankers on race categorization of faces

Context affects multiple cognitive and perceptual processes. In the present study, we asked how the context of a set of faces would affect the perception of a target face??s race in two distinct tasks. In Experiments 1 and 2, participants categorized target faces according to perceived racial category (Black or White). In Experiment 1, the target face was presented alone or with Black or White flanker faces. The orientation of flanker faces was also manipulated to investigate how face inversion effect would interact with the influences of flanker faces on the target face. The results showed that participants were more likely to categorize the target face as White when it was surrounded by inverted White faces (an assimilation effect). Experiment 2 further examined how different aspects of the visual context would affect the perception of the target face by manipulating flanker faces?? shape and pigmentation, as well as their orientation. The results showed that flanker faces?? shape and pigmentation affected the perception of the target face differently. While shape elicited a contrast effect, pigmentation appeared to be assimilative. These novel findings suggest that the perceived race of a face is modulated by the appearance of other faces and their distinct shape and pigmentation properties. However, the contrast and assimilation effects elicited by flanker faces?? shape and pigmentation may be specific to race categorization, since the same stimuli used in a delayed matching task (Experiment 3) revealed that flanker pigmentation induced a contrast effect on the perception of target pigmentation.     

Does matching of internal and external facial features depend on orientation and viewpoint?

Although it is recognized that external (hair, head and face outline, ears) and internal (eyes, eyebrows, nose, mouth) features contribute differently to face recognition it is unclear whether both feature classes predominately stimulate different sensory pathways. We employed a sequential speed-matching task to study face perception with internal and external features in the context of intact faces, and at two levels of contextual congruency. Both internal and external features were matched faster and more accurately in the context of totally congruent/incongruent facial stimuli compared to just featurally congruent/incongruent faces. Matching of totally congruent/incongruent faces was not affected by the matching criteria, but was strongly modulated by orientation and viewpoint. On the contrary, matching of just featurally congruent/incongruent faces was found to depend on the feature class to be attended, with strong effects of orientation and viewpoint only for matching of internal features, but not of external features. The data support the notion that different processing mechanisms are involved for both feature types, with internal features being handled by configuration sensitive mechanisms whereas featural processing modes dominate when external features are the focus.     

Incomplete Faces Don't Show the Whole Picture: Repetition Priming from Jumbled Faces

Four experiments examined repetition priming of familiarity decisions to faces of famous people by the prior exposure of intact or jumbled faces. In Experiments 1 and 2 the primes were either the identical picture of the target face or a picture of the face with the internal features jumbled up. (In Experiment 2 the external features were also removed from all faces.) Compared with response times to previously unseen faces, familiarity decisions were made more rapidly if the subject had seen and identified the famous face in the pre-training stage; this was independent of whether they saw an intact or jumbled face. Priming was not shown if the face was not recognized earlier. Experiment 3 demonstrated that, if faces were not recognized spontaneously in the pre-training stage, being prompted as to their identity by the experimenter still did not yield priming at test-a result that replicated a previous study using incomplete faces (Brunas-Wagstaff, Young, & Ellis, 1992). Experiment 4 showed that it was the situation in which the information was given that was critical in determining whether priming occurred. The findings of this study are related to mechanisms for repetition priming of faces and used to discuss the necessity of modifications to the Bruce and Young (1986) model such as those offered by Burton, Bruce, and Johnston (1990).     

Infrequent identity mismatches are frequently undetected

The ability to quickly and accurately match faces to photographs bears critically on many domains, from controlling purchase of age-restricted goods to law enforcement and airport security. Despite its pervasiveness and importance, research has shown that face matching is surprisingly error prone. The majority of face-matching research is conducted under idealized conditions (e.g., using photographs of individuals taken on the same day) and with equal proportions of match and mismatch trials, a rate that is likely not observed in everyday face matching. In four experiments, we presented observers with photographs of faces taken an average of 1.5 years apart and tested whether face-matching performance is affected by the prevalence of identity mismatches, comparing conditions of low (10 %) and high (50 %) mismatch prevalence. Like the low-prevalence effect in visual search, we observed inflated miss rates under low-prevalence conditions. This effect persisted when participants were allowed to correct their initial responses (Experiment 2), when they had to verify every decision with a certainty judgment (Experiment 3) and when they were permitted “second looks” at face pairs (Experiment 4). These results suggest that, under realistic viewing conditions, the low-prevalence effect in face matching is a large, persistent source of errors.     

Improving Discrimination and Face Matching with Caricature

Identification of faces from photographs is a common security measure, but matching unfamiliar faces produces high rates of error. Caricatures of familiar people are highly identifiable because they exaggerate distinctive features. We investigated whether exaggerating unfamiliar faces through caricaturing could also improve face‐matching accuracy. In Experiment 1, face‐matching arrays were caricatured relative to an average by 30%, 50% and 70%. Correct rejection of the target‐absent arrays was improved at all levels. Accurate matches increased at 30%, but at 70%, the transformation was too extreme, and all of the arrays were more likely to be rejected. In Experiment 2, photographic identification (ID) images were caricatured by 30% and 50% and matched to life‐size photographs. Rejection of foils improved, but the ID of matching images was impaired. Modest levels of caricature may improve discrimination in unfamiliar face matching, but at stronger levels, a conservative response bias may inhibit accurate ID. Copyright © 2013 John Wiley & Sons, Ltd.     

Integration of internal and external facial features in 8- to 10-year-old children and adults

Investigation of whole-part and composite effects in 4- to 6-year-old children gave rise to claims that face perception is fully mature within the first decade of life (Crookes & McKone, 2009). However, only internal features were tested, and the role of external features was not addressed, although external features are highly relevant for holistic face perception (Sinha & Poggio, 1996; Axelrod & Yovel, 2010, 2011). In this study, 8- to 10-year-old children and adults performed a same–different matching task with faces and watches. In this task participants attended to either internal or external features. Holistic face perception was tested using a congruency paradigm, in which face and non-face stimuli either agreed or disagreed in both features (congruent contexts) or just in the attended ones (incongruent contexts). In both age groups, pronounced context congruency and inversion effects were found for faces, but not for watches. These findings indicate holistic feature integration for faces. While inversion effects were highly similar in both age groups, context congruency effects were stronger for children. Moreover, children's face matching performance was generally better when attending to external compared to internal features. Adults tended to perform better when attending to internal features. Our results indicate that both adults and 8- to 10-year-old children integrate external and internal facial features into holistic face representations. However, in children's face representations external features are much more relevant. These findings suggest that face perception is holistic but still not adult-like at the end of the first decade of life.     

The Kent Face Matching Test

This study presents the Kent Face Matching Test (KFMT), which comprises 200 same-identity and 20 different-identity pairs of unfamiliar faces. Each face pair consists of a photograph from a student ID card and a high-quality portrait that was taken at least three months later. The test is designed to complement existing resources for face-matching research, by providing a more ecologically valid stimulus set that captures the natural variability that can arise in a person's appearance over time. Two experiments are presented to demonstrate that the KFMT provides a challenging measure of face matching but correlates with established tests. Experiment 1 compares a short version of this test with the optimized Glasgow Face Matching Test (GFMT). In Experiment 2, a longer version of the KFMT, with infrequent identity mismatches, is correlated with performance on the Cambridge Face Memory Test (CFMT) and the Cambridge Face Perception Test (CFPT). The KFMT is freely available for use in face-matching research.     

Recovering faces from memory: the distracting influence of external facial features

Recognition memory for unfamiliar faces is facilitated when contextual cues (e.g., head pose, background environment, hair and clothing) are consistent between study and test. By contrast, inconsistencies in external features, especially hair, promote errors in unfamiliar face-matching tasks. For the construction of facial composites, as carried out by witnesses and victims of crime, the role of external features (hair, ears, and neck) is less clear, although research does suggest their involvement. Here, over three experiments, we investigate the impact of external features for recovering facial memories using a modern, recognition-based composite system, EvoFIT. Participant-constructors inspected an unfamiliar target face and, one day later, repeatedly selected items from arrays of whole faces, with "breeding," to "evolve" a composite with EvoFIT; further participants (evaluators) named the resulting composites. In Experiment 1, the important internal-features (eyes, brows, nose, and mouth) were constructed more identifiably when the visual presence of external features was decreased by Gaussian blur during construction: higher blur yielded more identifiable internal-features. In Experiment 2, increasing the visible extent of external features (to match the target's) in the presented face-arrays also improved internal-features quality, although less so than when external features were masked throughout construction. Experiment 3 demonstrated that masking external-features promoted substantially more identifiable images than using the previous method of blurring external-features. Overall, the research indicates that external features are a distractive rather than a beneficial cue for face construction; the results also provide a much better method to construct composites, one that should dramatically increase identification of offenders.     

Getting to know you: How we learn new faces

Previous work has shown an advantage for matching the internal features of familiar faces in contrast to an advantage for the external features of unfamiliar faces. In the current experiment, we tracked this shift towards an internal feature advantage as subjects were familiarized with a set of initially unfamiliar faces. They were asked to learn a set of 24 faces from video images and complete a face matching task on 3 consecutive days. Half of the faces were learned from moving images while the others were learned from static images to determine whether movement was necessary to produce the internal advantage found when matching familiar faces. We found that by the end of the 3 days, performance on the internal features had improved and was equivalent to performance on the external features. In contrast, matching of the external features remained at a relatively constant level across the experiment. Faces were learned equally well from moving and static images suggesting that movement is not necessary to promote learning of the internal features.     

7-11-year-old children show an advantage for matching and recognizing the internal features of familiar faces: Evidence against a developmental shift

Adults are better at recognizing familiar faces from the internal facial features (eyes, nose, mouth) than from the external facial features (hair, face outline). However, previous research suggests that this “internal advantage” does not appear until relatively late in childhood, and some studies suggest that children rely on external features to recognize all faces, whether familiar or not. We use a matching task to examine face processing in 7-8- and 10-11-year-old children. We use a design in which all face stimuli can be used as familiar items (for participants who are classmates) and unfamiliar items (for participants from a different school). Using this design, we find an internal feature advantage for matching familiar faces, for both groups of children. The same children were then shown the external and internal features of their classmates and were asked to name or otherwise identify them. Again, both age groups identified more of their classmates correctly from the internal than the external features. This is the first time an internal advantage has been reported in this age group. Results suggest that children as young as 7 process faces in the same way as do adults, and that once procedural difficulties are overcome, the standard effects of familiarity are observed.     

Who do you look like? Evidence of facial stereotypes for male names

The present research provides evidence that people use facial prototypes when they encounter different names. In Experiment 1, participants created face exemplars for fifteen common male names, subsets of which were endorsed as good examples by a second set of participants. These most typical faces were morphed to create face-name prototypes. In Experiment 2, participants matched one of the names to each of the prototype faces from Experiment 1. Participants’ matching choices showed convergence in naming the prototypes for many of the names. Experiment 3 utilized these same prototypes in a learning task designed to investigate if the face-name associations revealed in Experiment 2 impacted the learnability of the names. Participants learned face-name pairings that had a higher association (based on frequencies from Experiment 2) faster than pairings with a low association. Results suggest a more direct relationship between faces and names than has been previously proposed.     

Attention to internal face features in unfamiliar face matching

Accurate matching of unfamiliar faces is vital in security and forensic applications, yet previous research has suggested that humans often perform poorly when matching unfamiliar faces. Hairstyle and facial hair can strongly influence unfamiliar face matching but are potentially unreliable cues. This study investigated whether increased attention to the more stable internal face features of eyes, nose, and mouth was associated with more accurate face‐matching performance. Forty‐three first‐year psychology students decided whether two simultaneously presented faces were of the same person or not. The faces were displayed for either 2 or 6 seconds, and had either similar or dissimilar hairstyles. The level of attention to internal features was measured by the proportion of fixation time spent on the internal face features and the sensitivity of discrimination to changes in external feature similarity. Increased attention to internal features was associated with increased discrimination in the 2‐second display‐time condition, but no significant relationship was found in the 6‐second condition. Individual differences in eye‐movements were highly stable across the experimental conditions.     

Semantic interpretation effects on memory for faces

Five experiments investigated the effects of semantically interpreting faces on their recognition. Experiment 1 demonstrated that faces could meaningfully be related to occupational categories. In Experiments 2–5, each of a set of faces was presented with either the label of a congruent occupational category or a noncongruent label. Presenting a face with a congruent occupational label was found to enhance recognition that the face had previously been seen (Experiments 2–4), but congruent labeling also impaired the detection of distractor faces that matched previously seen faces’ categories (Experiments 3 and 4). In a forced-choice recognition test, in which distractors were highly similar to originally seen faces, congruent occupational labeling failed to increase recognition of previously seen faces (Experiment 5). These results indicate that interpreting faces, with respect to stereotyped categories, ratherthan improving a physical codein memory, led to theformation of a semantic code, which increased recognition of old items at the expense of the detection of new items. Another general finding was that faces that were rated more stereotypical were more recognizable, regardless of the accompanying label.     

Does PAULA prime PAUL? Does WAITER prime WAITRESS? Implicit transfer across gender forms of verbal stimuli

Repetition-priming effects were investigated with a speeded verification task as an indirect or implicit test. Subjects were asked to verify whether items were instances of the categories first name and profession. In Experiment 1, instances were repeated in their alternate gender form (e.g., PAUL as PAULA, or WAITRESS as WAITER) and performance was compared to new instances. Facilitation in terms of faster response latencies for old instances (i.e., repetitions in the alternative gender form) was restricted to the category profession. In Experiment 2, facilitation was found for names studied and tested in the same gender form (e.g., PAUL-PAUL). Instances of professions were repeated in either the same or the alternative gender form; the amount of facilitation was identical for the two repetition conditions. However, transfer across gender forms was affected by the study-test order (facilitation was larger from male to female than from female to male) and by the gender dominance of specific instances. In Experiment 3, the interfering effect of gender dominance was not replicated. Response accuracy tended to parallel the latency results in all experiments, but without reaching statistical reliability. Therefore, the faster response latencies for old items are by no means the result of a speed-accuracy trade-off. The central finding of the experiments reported is the material-dependent dissociation of repetition transfer across gender forms that occurred for instances of professions, but was absent for names. This dissociation is interpreted to indicate that the stimulus-driven speeded verification test is sensitive to conceptual, but not to perceptual, processing aspects of a study event.