Disrupting perceptual grouping of face parts impairs holistic face processing

Face perception is widely believed to involve integration of facial features into a holistic perceptual unit, but the mechanisms underlying this integration are relatively unknown. We examined whether perceptual grouping cues influence a classic marker of holistic face perception, the “composite-face effect.” Participants made same–different judgments about a cued part of sequentially presented chimeric faces, and holistic processing was indexed as the degree to which the task-irrelevant face halves impacted performance. Grouping was encouraged or discouraged by adjusting the backgrounds behind the face halves: Although the face halves were always aligned, their respective backgrounds could be misaligned and of different colors. Holistic processing of face, but not of nonface, stimuli was significantly reduced when the backgrounds were misaligned and of different colors, cues that discouraged grouping of the face halves into a cohesive unit (Exp. 1). This effect was sensitive to stimulus orientation at short (200 ms) but not at long (2,500 ms) encoding durations, consistent with the previously documented temporal properties of the holistic processing of upright and inverted faces (Exps. 2 and 3). These results suggest that grouping mechanisms, typically involved in the perception of objecthood more generally, might contribute in important ways to the holistic perception of faces.     

Temporal integration in face perception: evidence of configural processing of temporally separated face parts

Temporal integration is the process by which temporally separated visual components are combined into a unified representation. Although this process has been studied in object recognition, little is known about temporal integration in face perception and recognition. In the present study, the authors investigated the characteristics and time boundaries of facial temporal integration. Whole faces of nonfamous and famous people were segmented horizontally into 3 parts and presented in sequence, with varying interval lengths between parts. Inversion and misalignment effects were found at short intervals (0-200 ms). Moreover, their magnitude was comparable to those found with whole-face presentations. These effects were eliminated, or substantially reduced, when the delay interval was 700 ms. Order of parts presentation did not influence the pattern of inversion effects obtained within each temporal delay condition. These results demonstrate that temporal integration of faces occurs in a temporary and limited visual buffer. Moreover, they indicate that only integrated faces can undergo configural processing.     

The perception of a face is no more than the sum of its parts

When you see a person's face, how do you go about combining his or her facial features to make a decision about who that person is? Most current theories of face perception assert that the ability to recognize a human face is not simply the result of an independent analysis of individual features, but instead involves a holistic coding of the relationships among features. This coding is thought to enhance people's ability to recognize a face beyond what would be expected if each feature were shown in isolation. In the study reported here, we explicitly tested this idea by comparing human performance on facial-feature integration with that of an optimal Bayesian integrator. Contrary to the predictions of most current notions of face perception, our findings showed that human observers integrate facial features in a manner that is no better than would be predicted by their ability to use each individual feature when shown in isolation. That is, a face is perceived no better than the sum of its individual parts.     

The perception of a familiar face is no more than the sum of its parts

Why do faces become easier to recognize with repeated exposure? Previous research has suggested that familiarity may induce a qualitative shift in visual processing from an independent analysis of individual facial features to analysis that includes information about the relationships among features (Farah, Wilson, Drain, & Tanaka Psychological Review, 105, 482–498, 1998; Maurer, Grand, & Mondloch Trends in Cognitive Science, 6, 255–260, 2002). We tested this idea by using a “summation-at-threshold” technique (Gold, Mundy, & Tjan Psychological Science, 23, 427–434, 2012; Nandy & Tjan Journal of Vision, 8, 3.1–20, 2008), in which an observer’s ability to recognize each individual facial feature shown independently is used to predict their ability to recognize all of the features shown in combination. We find that, although people are better overall at recognizing familiar as opposed to unfamiliar faces, their ability to integrate information across features is similar for unfamiliar and highly familiar faces and is well predicted by their ability to recognize each of the facial features shown in isolation. These results are consistent with the idea that familiarity has a quantitative effect on the efficiency with which information is extracted from individual features, rather than a qualitative effect on the process by which features are combined.     

The role of inner and outer face parts in holistic processing: A developmental study

The effects of inner–outer feature interactions with unfamiliar faces were investigated in 6- and 10-year-old children and adults (20–30 years) to determine their contribution in holistic face vision. Participants completed a two-alternative forced-choice (2AFC) task under two conditions. The congruent condition used whole, inner-only, and outer-only stimuli. The incongruent condition used stimuli combining the inner features from one face with outer features from a novel face, or vice versa. Results yielded strong congruency effects which were moderated by pronounced feature-type asymmetries specific to developmental stage. Adults showed an inner-feature preference during congruent trials, but no asymmetry for incongruent trials. Children showed no asymmetry for congruent trials, but an outer-feature preference for incongruent trials. These findings concur with recent theoretical developments indicating that adults and children are likely to differ in the types of feature-specific information they preferentially encode in face perception, and that holistic effects are moderated differently in adults and children as a function of feature type.     

Glucose enhancement of face recognition is unaffected by alterations of face features

Glucose improves memory on a variety of tasks has been well established in both the animal and human literature. Of particular relevance to the present experiment is the finding that administration of glucose improves face recognition performance in both healthy, young adults and in Alzheimer's patients. This experiment attempted to expand on these findings to determine if glucose-enhanced performance for face recognition is specific to certain face features (e.g., nose, eyes, or hair). In a between subjects experiment that tested healthy, young adults, a pre-training administration of glucose (50 g) was shown to improve face recognition performance relative to placebo (27.3mg saccharin); however, the significant improvement on the task was not specific to a particular feature. This result suggests that glucose did not enhance memory for individual face features, but rather enhanced overall memory for face stimuli.     

Becoming a face expert

Expertise in recognizing facial identity, and, in particular, sensitivity to subtle differences in the spacing among facial features, improves into adolescence. To assess the influence of experience, we tested adults and 8-year-olds with faces differing only in the spacing of facial features. Stimuli were human adult, human 8-year-old, and monkey faces. We show that adults' expertise is shaped by experience: They were 9% more accurate in seeing differences in the spacing of features in upright human faces than in upright monkey faces. Eight-year-olds were 14% less accurate than adults for both human and monkey faces (Experiment 1), and their accuracy for human faces was not higher for children's faces than for adults' faces (Experiment 2). The results indicate that improvements in face recognition after age 8 are not related to experience with human faces and may be related to general improvements in memory or in perception (e.g., hyperacuity and spatial integration).     

Predicting face similarity judgements with a computational model of face space

Current models of face representation involve the notion of a high-dimensional face space. Computational models of face space based on principal components analysis (PCA) have been successfully used to predict human judgements of face sex or race. In this work the capability of PCA-based face spaces to predict human judgements of face similarity is examined. Three different paradigms were used. In Experiment 1 subjects learned face-name associations for 18 faces and identified these faces on tachistoscopic presentation. The number of confusions was used as a measure of face similarity. In Experiment 2 the same subjects subjectively rated the similarity of all 153 possible face pairs. In Experiment 3 reaction time to identify a face in an odd-man-out task was measured as an index of face similarity. These empirical measures were correlated with distance of the faces in PCA-based spaces of different dimensionalities. For Experiments 1 and 2 these correlations were highest for one-or two-dimensional face spaces (r=−0.27 vs. −0.28). For Experiment 3 the correlation was highest for a space consisting of 13 dimensions (r=−0.51). Thus PCA-based spaces seem capable to predict human similarity judgements to some extent. Possible reasons for the differences in predictability between paradigms are discussed.     

Insights into the development of face recognition mechanisms revealed by face aftereffects

An important question in person perception is how we acquire the perceptual/cognitive mechanisms that characterize adult expertise. Children's performance on face recognition tests improves dramatically between age 4 and adolescence suggesting that our face recognition system may change during childhood. Yet, the source of this improvement is controversial. In this review, we consider whether changes in the way identity is represented/coded in face space could contribute to this age-related improvement. Face aftereffects have been extensively applied to studying face coding in adults and more recently they have been applied to studying the mechanisms of face coding in children. Face aftereffects are temporary distortions of perception induced by exposure to faces and are thought to reflect the mechanisms underlying face perception. Face aftereffect techniques have revealed that children as young as 4 years of age show evidence of adult-like face space organization, with opponent coding of face dimensions. These findings are consistent with an emerging picture that the key mechanisms of face perception are present early in childhood.     

What's in a face: Individual differences in face perception

White and black females judged the similarity of all pairs of white and black male faces. An individual difference multidimensional scaling analysis of the similarity judgments indicated that most of the dimensions underlying the perceptions of male faces involved affective (honest, tense, attractive) characteristics rather than simple physical features (eye width, mouth height). The major physical dimension was face shape (long vs. wide). The dimensions were similar for black and white subjects. An individual difference hypothesis that we pay attention to those characteristics that we possess was partially confirmed.     

Attentional capture by object appearance and disappearance

In two experiments we examined whether the appearance of a new object has attentional priority over disappearance. Previous failures to show differences are possibly due to onsets and offsets always being presented as a sole visual transient. Rather than presenting each alone, we presented onset and offset singletons simultaneously with a display-wide luminance transient in order to force each to compete with other visual events. Results from Experiment 1 showed that targets associated with onsets accrued a reaction time benefit whilst targets associated with offsets did not. Experiment 2 showed that onsets attracted attention even when observers were attentionally set to look for offset. By contrast, offsets needed a relevant attentional set in order to attract attention. We argue that the appearance of an object has attentional priority over disappearance.     

Wobbling on a One-Legged Stool: The Decline of American Pluralism and the Academic Treatment of Corporate Social Responsibility

B. Readings (University in Ruins. Cambridge: Harvard University Press, 1996) argued that universities have abandoned their original project of promoting a national culture and have tried to substitute by embracing globalization, but the vagueness and incoherence of the concept has failed to return purpose to the University. The academic treatment of corporate social responsibility illustrates this dilemma. For a generation after H.R. Bowen (Social Responsibilities of the Businessman. New York: Harper & Row, 1953) founded the field, scholars struggled to fit the concept within a national system of pluralistic power-sharing among a variety of institutions that would define and enforce standards of responsibility necessary for the general good of American society. That understanding changed in the nineteen eighties, shortly after corporate executives had united to an unprecedented degree to direct the power of government in their interests, influence the public agenda, and roll back the power of unions. In response, business ethicists began to reformulate corporate social responsibility as a voluntary practice on the part of these same executives. Since the Kantian and Lockean principles upon which this approach was based were themselves problematic, it is not surprising that the experience gained over the last generation casts doubt on the efficacy of this reliance on voluntary restraint and personal initiative. However, circumstances that include the failure of globalization to deliver on its promises may have changed sufficiently in recent years to revive interest in approaches that acknowledge the importance of countervailing power for encouraging greater corporate social responsibility.     

Emotionally meaningful targets enhance orienting triggered by a fearful gazing face

Studies investigating the effect of emotional expression on spatial orienting to a gazed-at location have produced mixed results. The present study investigated the role of affective context in the integration of emotion processing and gaze-triggered orienting. In three experiments, a face gazed nonpredictively to the left or right, and then its expression became fearful or happy. Participants identified (Experiments 1 and 2) or detected (Experiment 3) a peripheral target presented 225 or 525 ms after the gaze cue onset. In Experiments 1 and 3 the targets were either threatening (a snarling dog) or nonthreatening (a smiling baby); in Experiment 2 the targets were neutral. With emotionally-valenced targets, the gaze-cuing effect was larger when the face was fearful compared to happy--but only with the longer cue-target interval. With neutral targets, there was no interaction between gaze and expression. Our results indicate that a meaningful context optimizes attentional integration of gaze and expression information.     

Viewing a face (especially one's own face) being touched enhances tactile perception on the face

Observing touch on another person's body activates brain regions involved in tactile perception, even when the observer's body is not directly stimulated. Previous work has shown that in some synaesthetes, this effect induces a sensation of being touched. The present study shows that if perceptual thresholds are experimentally manipulated, viewing touch can modulate tactile experience in nonsynaesthetes as well. When observers saw a face being touched by hands, rather than a face being merely approached by hands, they demonstrated enhanced detection of subthreshold tactile stimuli on their own faces. This effect was specific to observing touch on a body part, and was not found for touch on a nonbodily stimulus, namely, a picture of a house. In addition, the effect was stronger when subjects viewed their own faces rather than another person's face. Thus, observing touch can activate the tactile system, and if perceptual thresholds are manipulated, such activation can result in a behavioral effect in nonsynaesthetes. The effect is maximum if the observed body matches the observer's body.     

Finding a face in a face-like object

Humans have the tendency to perceive a face even in a non-living object. Previous studies report that people perceive facial features and even interpret a personality in a car front. Following these findings, we investigated whether the perception of a face in a face-like object is mediated by human face processing, which involves both featural and configural processing. In our experiment, participants were presented with 30 face-like objects and were asked about the existence of facial features, the intensity of typicality/distinctiveness, and the intensity of facial expression. Using multiple regression analysis, which predicts the perception of a face in a face-like object, we found that the existence of eyes was a significant predictor of variance in perceiving a face in a face-like object.     

Binocular masking induced by a moving object

Movement in a part of either of two binocular fields can, under some conditions, produce temporary obliteration of the corresponding part of the other field. This paper is a mainly qualitative study of this rather surprising phenomenon. The effect is found to increase from the fovea to the periphery, to be greatest at a velocity of about 20° visual angle per sec. and to vary with the orientation of the fixation point in the visual field. Some further lines of research designed to elucidate the relation of the effect described here to certain other visual phenomena are suggested.     

Newborn preference for a new face vs. a previously seen communicative or motionless face

Newborn infants prefer to look at a new face compared to a known face (still-face). This effect does not happen with the mother-face. The newborns could be attracted by the mother-face because, unlike the still-face, it confirms an expectation of communication.Fifty newborns were video-recorded. Sixteen of them were recruited in the final sample: nine were exposed to a communicative face and seven to a still-face. All the 16 newborns were successively exposed to two preference-tasks where a new face was compared with the known face.Only newborns previously exposed to a still-face preferred to look at a new face instead of the known face. The results suggest that the newborns are able to build a dynamic representation of faces.