Eye movements are functional during face learning

Looking at faces from different angles: Europeans fixate different features in Asian and Caucasian faces

Race categorization of faces is a fast and automatic process and is known to affect further face processing profoundly and at earliest stages. Whether processing of own- and other-race faces might rely on different facial cues, as indicated by diverging viewing behavior, is much under debate. We therefore aimed to investigate two open questions in our study: (1) Do observers consider information from distinct facial features informative for race categorization or do they prefer to gain global face information by fixating the geometrical center of the face? (2) Does the fixation pattern, or, if facial features are considered relevant, do these features differ between own- and other-race faces? We used eye tracking to test where European observers look when viewing Asian and Caucasian faces in a race categorization task. Importantly, in order to disentangle centrally located fixations from those towards individual facial features, we presented faces in frontal, half-profile and profile views. We found that observers showed no general bias towards looking at the geometrical center of faces, but rather directed their first fixations towards distinct facial features, regardless of face race. However, participants looked at the eyes more often in Caucasian faces than in Asian faces, and there were significantly more fixations to the nose for Asian compared to Caucasian faces. Thus, observers rely on information from distinct facial features rather than facial information gained by centrally fixating the face. To what extent specific features are looked at is determined by the face's race.

Configural processing in body posture recognition: an eye-tracking study

The body inversion effect is the finding that inverted body posture pictures are more difficult to recognize than upright body posture pictures are. The present study reinvestigated the body inversion effect in human observers using behavioral and eye movement measures to explore whether the body inversion effect correlates with specific eye movement features. Results showed that body postures elicited a robust and stable body inversion effect in reaction time throughout the experimental sessions. Eye-tracking data showed that the body inversion effect was robust only in the first fixation duration, but not in the second fixation duration. The analysis of the regions of interest showed that most fixations were located in the upper body for both the upright and the inverted body postures. Compared with inverted body postures, the upright postures led to a shorter reaction time and a shorter first fixation duration, but a larger portion of time to fixate on the head region, suggesting that participants tended to use head as a reference point to process upright body postures. For both the behavioral and the eye movement measures, the body inversion effect was robust for biomechanically possible body postures. However, for biomechanically impossible body postures (with angular manipulation of two joints), the effect was mixed. Although the error rate failed to show the body inversion effect, the reaction time measure and most eye movement measures, however, showed a body inversion effect. Overall, these results suggested that upright body postures are processed in expertise recognition and are processed configurally by human observers.

Face perception is whole or none: disentangling the role of spatial contiguity and interfeature distances in the composite face illusion

Compelling evidence that faces are perceived holistically or configurally comes from the composite face illusion: identical top halves of a face are perceived as being different if they are aligned with different bottom halves. The visual illusion disappears when the top and bottom face halves are spatially misaligned. Whether this is because the two halves no longer form a whole face (ie they form two segmented parts), or because of an increase in interfeatures distance in the misaligned condition (eg eyes-mouth distance) remains unclear. Here, thirty-four participants performed a delayed matching composite task in which the amount of spatial misalignment between face halves varied parametrically (from 8.33% of face width to 100%). The difference in performance between aligned and misaligned faces (ie the composite face effect) was already of full magnitude at the smallest level of misalignment. These results imply that a small spatial misalignment is sufficient to measure the composite face effect. From a theoretical standpoint, they indicate that it is the breaking of a whole configuration rather than the increase in relative distance between the face parts that explains the presence or absence of the composite face effect, clarifying an outstanding issue concerning the nature of holistic face perception.

The influence of banner advertisements on attention and memory: human faces with averted gaze can enhance advertising effectiveness

Research suggests that banner advertisements used in online marketing are often overlooked, especially when positioned horizontally on webpages. Such inattention invariably gives rise to an inability to remember advertising brands and messages, undermining the effectiveness of this marketing method. Recent interest has focused on whether human faces within banner advertisements can increase attention to the information they contain, since the gaze cues conveyed by faces can influence where observers look. We report an experiment that investigated the efficacy of faces located in banner advertisements to enhance the attentional processing and memorability of banner contents. We tracked participants' eye movements when they examined webpages containing either bottom-right vertical banners or bottom-center horizontal banners. We also manipulated facial information such that banners either contained no face, a face with mutual gaze or a face with averted gaze. We additionally assessed people's memories for brands and advertising messages. Results indicated that relative to other conditions, the condition involving faces with averted gaze increased attention to the banner overall, as well as to the advertising text and product. Memorability of the brand and advertising message was also enhanced. Conversely, in the condition involving faces with mutual gaze, the focus of attention was localized more on the face region rather than on the text or product, weakening any memory benefits for the brand and advertising message. This detrimental impact of mutual gaze on attention to advertised products was especially marked for vertical banners. These results demonstrate that the inclusion of human faces with averted gaze in banner advertisements provides a promising means for marketers to increase the attention paid to such adverts, thereby enhancing memory for advertising information.

The Muslim headscarf and face perception: "they all look the same, don't they?"

The headscarf conceals hair and other external features of a head (such as the ears). It therefore may have implications for the way in which such faces are perceived. Images of faces with hair (H) or alternatively, covered by a headscarf (HS) were used in three experiments. In Experiment 1 participants saw both H and HS faces in a yes/no recognition task in which the external features either remained the same between learning and test (Same) or switched (Switch). Performance was similar for H and HS faces in both the Same and Switch condition, but in the Switch condition it dropped substantially compared to the Same condition. This implies that the mere presence of the headscarf does not reduce performance, rather, the change between the type of external feature (hair or headscarf) causes the drop in performance. In Experiment 2, which used eye-tracking methodology, it was found that almost all fixations were to internal regions, and that there was no difference in the proportion of fixations to external features between the Same and Switch conditions, implying that the headscarf influenced processing by virtue of extrafoveal viewing. In Experiment 3, similarity ratings of the internal features of pairs of HS faces were higher than pairs of H faces, confirming that the internal and external features of a face are perceived as a whole rather than as separate components.

Some effects of alcohol and eye movements on cross-race face learning

This study examines the impact of acute alcohol intoxication on visual scanning in cross-race face learning. The eye movements of a group of white British participants were recorded as they encoded a series of own-and different-race faces, under alcohol and placebo conditions. Intoxication reduced the rate and extent of visual scanning during face encoding, reorienting the focus of foveal attention away from the eyes and towards the nose. Differences in encoding eye movements also varied between own-and different-race face conditions as a function of alcohol. Fixations to both face types were less frequent and more lingering following intoxication, but in the placebo condition this was only the case for different-race faces. While reducing visual scanning, however, alcohol had no adverse effect on memory, only encoding restrictions associated with sober different-race face processing led to poorer recognition. These results support perceptual expertise accounts of own-race face processing, but suggest the adverse effects of alcohol on face learning published previously are not caused by foveal encoding restrictions. The implications of these findings for alcohol myopia theory are discussed.

Face engagement during infancy predicts later face recognition ability in younger siblings of children with autism

Face recognition difficulties are frequently documented in children with autism spectrum disorders (ASD). It has been hypothesized that these difficulties result from a reduced interest in faces early in life, leading to decreased cortical specialization and atypical development of the neural circuitry for face processing. However, a recent study by our lab demonstrated that infants at increased familial risk for ASD, irrespective of their diagnostic status at 3 years, exhibit a clear orienting response to faces. The present study was conducted as a follow-up on the same cohort to investigate how measures of early engagement with faces relate to face-processing abilities later in life. We also investigated whether face recognition difficulties are specifically related to an ASD diagnosis, or whether they are present at a higher rate in all those at familial risk. At 3 years we found a reduced ability to recognize unfamiliar faces in the high-risk group that was not specific to those children who received an ASD diagnosis, consistent with face recognition difficulties being an endophenotype of the disorder. Furthermore, we found that longer looking at faces at 7 months was associated with poorer performance on the face recognition task at 3 years in the high-risk group. These findings suggest that longer looking at faces in infants at risk for ASD might reflect early face-processing difficulties and predicts difficulties with recognizing faces later in life.

Learning optimal eye movements to unusual faces

Eye movements, which guide the fovea's high resolution and computational power to relevant areas of the visual scene, are integral to efficient, successful completion of many visual tasks. How humans modify their eye movements through experience with their perceptual environments, and its functional role in learning new tasks, has not been fully investigated. Here, we used a face identification task where only the mouth discriminated exemplars to assess if, how, and when eye movement modulation may mediate learning. By interleaving trials of unconstrained eye movements with trials of forced fixation, we attempted to separate the contributions of eye movements and covert mechanisms to performance improvements. Without instruction, a majority of observers substantially increased accuracy and learned to direct their initial eye movements towards the optimal fixation point. The proximity of an observer's default face identification eye movement behavior to the new optimal fixation point and the observer's peripheral processing ability were predictive of performance gains and eye movement learning. After practice in a subsequent condition in which observers were directed to fixate different locations along the face, including the relevant mouth region, all observers learned to make eye movements to the optimal fixation point. In this fully learned state, augmented fixation strategy accounted for 43% of total efficiency improvements while covert mechanisms accounted for the remaining 57%. The findings suggest a critical role for eye movement planning to perceptual learning, and elucidate factors that can predict when and how well an observer can learn a new task with unusual exemplars.

Behavioral and neural evidence of increased attention to the bottom half of the face in deaf signers

PURPOSE

This study examined the effects of deafness and sign language use on the distribution of attention across the top and bottom halves of faces.

METHODS

In a composite face task, congenitally deaf signers and typically hearing controls made same/different judgments of the top or bottom halves of faces presented with the halves aligned or spatially misaligned, while event-related potentials (ERPs) were recorded.

RESULTS

Both groups were more accurate when judging misaligned than aligned faces, which indicates holistic face processing. Misalignment affected all ERP components examined, with effects on the N170 resembling those of face inversion. Hearing adults were similarly accurate when judging the top and bottom halves of the faces, but deaf signers were more accurate when attending to the bottom than the top. Attending to the top elicited faster P1 and N170 latencies for both groups; within the deaf group, this effect was greatest for individuals who produced the highest accuracies when attending to the top.

CONCLUSIONS

These findings dovetail with previous research by providing behavioral and neural evidence of increased attention to the bottom half of the face in deaf signers, and by documenting that these effects generalize to a speeded task, in the absence of gaze shifts, with neutral facial expressions.

Ranking fluctuating asymmetry in a dot figure and the significant impact of imagining a face

Fluctuating asymmetry and averageness is correlated with our perception of beauty in human faces. Yet, whether deviations of centrality in the positioning of the eyes, the nose, and the mouth have different effects on our perception of asymmetry in a holistic human face, is still uncertain. In this study we aimed to test the relative effect of decentralising the horizontal position of three sets of paired dots representing eyes, nostrils, or mouth from the vertical midline of ambiguous dot figures, vaguely resembling a face. The figures were ranked according to perceived asymmetry by human observers. When associating the figures with non-facial objects (eg a butterfly), none of the figures' rank distribution differed from each other. However, when observers imagined the figures to represent a human face, the figure with the decentralised pair of dots representing the nostrils was significantly ranked as more asymmetric than the other figures. This result provides indications that the brain may deal with information about facial asymmetry and averageness heavily depending on the centrality of the nasal region.

Young children's difficulty in disregarding information from external features when matching unfamiliar faces

Three experiments were conducted to examine developmental differences in reliance on internal (i.e., eyes, nose, mouth, and cheeks) or external (i.e., hairstyle) facial features between young children and adults when matching two unfamiliar faces. Participants viewed two facial images and were asked to decide whether the images showed the identical person or two different people. Four different types of stimuli were presented: two incongruent stimuli, in which the two images showed either the same internal face (i.e., same person) with different hairstyles or two different internal faces (i.e., different people) with the same hairstyle, and two congruent stimuli, in which the two images showed either the same face and hairstyle or two different faces and hairstyles. We found that children were more likely to base their responses on external hairstyles for the incongruent stimuli, unlike adults (Experiment 1), even when they were instructed to attend to internal features (Experiment 2). Eye movement data showed that both children and adults spent the most time gazing on the internal features and gave little attention to the external hairstyle, and children attended to each part of the internal features as long as, or even longer than, adults (Experiment 3). Children's response based on external hairstyles was due to their inability to disregard external information and was not attributed to their tendency to attend more frequently to external parts rather than internal parts.

What interests them in the pictures?--differences in eye-tracking between rhesus monkeys and humans

Studies estimating eye movements have demonstrated that non-human primates have fixation patterns similar to humans at the first sight of a picture. In the current study, three sets of pictures containing monkeys, humans or both were presented to rhesus monkeys and humans. The eye movements on these pictures by the two species were recorded using a Tobii eye-tracking system. We found that monkeys paid more attention to the head and body in pictures containing monkeys, whereas both monkeys and humans paid more attention to the head in pictures containing humans. The humans always concentrated on the eyes and head in all the pictures, indicating the social role of facial cues in society. Although humans paid more attention to the hands than monkeys, both monkeys and humans were interested in the hands and what was being done with them in the pictures. This may suggest the importance and necessity of hands for survival. Finally, monkeys scored lower in eye-tracking when fixating on the pictures, as if they were less interested in looking at the screen than humans. The locations of fixation in monkeys may provide insight into the role of eye movements in an evolutionary context.

Abnormal fixation in individuals with age-related macular degeneration when viewing an image of a face

PURPOSE

It has been reported that patients with macular disease have difficulties with face perception. Some of this difficulty may be caused by the sensory and perceptual consequences of using peripheral retina. However, strong correlations have not always been found between performance on face tasks and clinical measure of function. Based on the evidence of abnormal eye movements by patients with age-related macular degeneration (AMD), we explored whether abnormal fixation patterns occur when these patients view an image of a face.

METHODS

An OPKO OCT/SLO was used to collect structural and functional data. For each subject, the structural location of disease was determined, and the locus and stability of fixation were quantified. A SLO movie of fundus movements was recorded while the subject viewed an image of a face.

RESULTS

The number of fixations on internal (eyes, nose, and mouth) and external features were measured. A two-way repeated-measures analysis of variance found significant differences between the control and patient groups and among locations. A significant interaction between group and location was also found. Post hoc comparisons found a significantly greater proportion of fixations on external features for the AMD group than that in the control group.

CONCLUSIONS

The observed patterns of fixations of our subjects with AMD were similar to those observed in other groups of patients who have difficulties with face perception. For example, individuals with social phobias, Williams syndrome, autism, schizophrenia, or prosopagnosia have altered face perceptions and also have a significantly greater proportion of fixations on external features of faces. Abnormal eye movement patterns and fixations may contribute to deficits in face perception in AMD patients.

Individual differences in eye movements during face identification reflect observer-specific optimal points of fixation

In general, humans tend to first look just below the eyes when identifying another person. Does everybody look at the same place on a face during identification, and, if not, does this variability in fixation behavior lead to functional consequences? In two conditions, observers had their free eye movements recorded while they performed a face-identification task. In another condition, the same observers identified faces while their gaze was restricted to specific locations on each face. We found substantial differences, which persisted over time, in where individuals chose to first move their eyes. Observers' systematic departure from a canonical, theoretically optimal fixation point did not correlate with performance degradation. Instead, each individual's looking preference corresponded to an idiosyncratic performance-maximizing point of fixation: Those who looked lower on the face performed better when forced to fixate the lower part of the face. The results suggest an observer-specific synergy between the face-recognition and eye movement systems that optimizes face-identification performance.

A smile biases the recognition of eye expressions: Configural projection from a salient mouth

A smile is visually highly salient and grabs attention automatically. We investigated how extrafoveally seen smiles influence the viewers' perception of non-happy eyes in a face. A smiling mouth appeared in composite faces with incongruent non-happy (fearful, neutral, etc.) eyes, thus producing blended expressions, or it appeared in intact faces with genuine expressions. Attention to the eye region was spatially cued while foveal vision of the mouth was blocked by gaze-contingent masking. Participants judged whether the eyes were happy or not. Results indicated that the smile biased the evaluation of the eye expression: The same non-happy eyes were more likely to be judged as happy and categorized more slowly as not happy in a face with a smiling mouth than in a face with a non-smiling mouth or with no mouth. This bias occurred when the mouth and the eyes appeared simultaneously and aligned, but also to some extent when they were misaligned and when the mouth appeared after the eyes. We conclude that the highly salient smile projects to other facial regions, thus influencing the perception of the eye expression. Projection serves spatial and temporal integration of face parts and changes.

First report of generalized face processing difficulties in möbius sequence

Reverse simulation models of facial expression recognition suggest that we recognize the emotions of others by running implicit motor programmes responsible for the production of that expression. Previous work has tested this theory by examining facial expression recognition in participants with Möbius sequence, a condition characterized by congenital bilateral facial paralysis. However, a mixed pattern of findings has emerged, and it has not yet been tested whether these individuals can imagine facial expressions, a process also hypothesized to be underpinned by proprioceptive feedback from the face. We investigated this issue by examining expression recognition and imagery in six participants with Möbius sequence, and also carried out tests assessing facial identity and object recognition, as well as basic visual processing. While five of the six participants presented with expression recognition impairments, only one was impaired at the imagery of facial expressions. Further, five participants presented with other difficulties in the recognition of facial identity or objects, or in lower-level visual processing. We discuss the implications of our findings for the reverse simulation model, and suggest that facial identity recognition impairments may be more severe in the condition than has previously been noted.

Age and beauty are in the eye of the beholder

How "old" and "attractive" an individual appears has increasingly become an individual concern leading to the utilisation of various cosmetic surgical procedures aimed at enhancing appearance. Using eyetracking, in the present study we aimed to investigate how individuals perceive age and attractiveness of younger and older faces and what "bottom-up" facial cues are used in this process. One hundred and twenty eight digital images of neutral faces of ages ranging from 20 to 89 years were paired and presented to subjects who judged age and attractiveness levels while having their eye movements recorded. There was an effect of face attractiveness on age-rating accuracy, with attractive faces being rated younger than their true age. Similarly, stimulus age affected attractiveness ratings, with younger faces being perceived as more attractive. Judgments of age and attractiveness were tightly linked to fixations on the eye region, along with the nose and mouth. It is thus likely that cosmetic surgical procedures targeted at the eyes, nose, and mouth may be most efficacious at enhancing one's physical appearance.

Category Processing and the human likeness dimension of the Uncanny Valley Hypothesis: Eye-Tracking Data

The Uncanny Valley Hypothesis (Mori, 1970) predicts that perceptual difficulty distinguishing between a humanlike object (e.g., lifelike prosthetic hand, mannequin) and its human counterpart evokes negative affect. Research has focused on affect, with inconsistent results, but little is known about how objects along the hypothesis' dimension of human likeness (DHL) are actually perceived. This study used morph continua based on human and highly realistic computer-generated (avatar) faces to represent the DHL. Total number and dwell time of fixations to facial features were recorded while participants (N = 60) judged avatar versus human category membership of the faces in a forced choice categorization task. Fixation and dwell data confirmed the face feature hierarchy (eyes, nose, and mouth in this order of importance) across the DHL. There were no further findings for fixation. A change in the relative importance of these features was found for dwell time, with greater preferential processing of eyes and mouth of categorically ambiguous faces compared with unambiguous avatar faces. There were no significant differences between ambiguous and human faces. These findings applied for men and women, though women generally dwelled more on the eyes to the disadvantage of the nose. The mouth was unaffected by gender. In summary, the relative importance of facial features changed on the DHL's non-human side as a function of categorization ambiguity. This change was indicated by dwell time only, suggesting greater depth of perceptual processing of the eyes and mouth of ambiguous faces compared with these features in unambiguous avatar faces.

Mapping Face Recognition Information Use across Cultures

Face recognition is not rooted in a universal eye movement information-gathering strategy. Western observers favor a local facial feature sampling strategy, whereas Eastern observers prefer sampling face information from a global, central fixation strategy. Yet, the precise qualitative (the diagnostic) and quantitative (the amount) information underlying these cultural perceptual biases in face recognition remains undetermined. To this end, we monitored the eye movements of Western and Eastern observers during a face recognition task, with a novel gaze-contingent technique: the Expanding Spotlight. We used 2° Gaussian apertures centered on the observers' fixations expanding dynamically at a rate of 1° every 25 ms at each fixation - the longer the fixation duration, the larger the aperture size. Identity-specific face information was only displayed within the Gaussian aperture; outside the aperture, an average face template was displayed to facilitate saccade planning. Thus, the Expanding Spotlight simultaneously maps out the facial information span at each fixation location. Data obtained with the Expanding Spotlight technique confirmed that Westerners extract more information from the eye region, whereas Easterners extract more information from the nose region. Interestingly, this quantitative difference was paired with a qualitative disparity. Retinal filters based on spatial-frequency decomposition built from the fixations maps revealed that Westerners used local high-spatial-frequency information sampling, covering all the features critical for effective face recognition (the eyes and the mouth). In contrast, Easterners achieved a similar result by using global low-spatial-frequency information from those facial features. Our data show that the face system flexibly engages into local or global eye movement strategies across cultures, by relying on distinct facial information span and culturally tuned spatially filtered information. Overall, our findings challenge the view of a unique putative process for face recognition.

Importance of the inverted control in measuring holistic face processing with the composite effect and part-whole effect

Holistic coding for faces is shown in several illusions that demonstrate integration of the percept across the entire face. The illusions occur upright but, crucially, not inverted. Converting the illusions into experimental tasks that measure their strength – and thus index degree of holistic coding – is often considered straightforward yet in fact relies on a hidden assumption, namely that there is no contribution to the experimental measure from secondary cognitive factors. For the composite effect, a relevant secondary factor is size of the “spotlight” of visuospatial attention. The composite task assumes this spotlight can be easily restricted to the target half (e.g., top-half) of the compound face stimulus. Yet, if this assumption were not true then a large spotlight, in the absence of holistic perception, could produce a false composite effect, present even for inverted faces and contributing partially to the score for upright faces. We review evidence that various factors can influence spotlight size: race/culture (Asians often prefer a more global distribution of attention than Caucasians); sex (females can be more global); appearance of the join or gap between face halves; and location of the eyes, which typically attract attention. Results from five experiments then show inverted faces can sometimes produce large false composite effects, and imply that whether this happens or not depends on complex interactions between causal factors. We also report, for both identity and expression, that only top-half face targets (containing eyes) produce valid composite measures. A sixth experiment demonstrates an example of a false inverted part-whole effect, where encoding-specificity is the secondary cognitive factor. We conclude the inverted face control should be tested in all composite and part-whole studies, and an effect for upright faces should be interpreted as a pure measure of holistic processing only when the experimental design produces no effect inverted.

Precedence of the eye region in neural processing of faces

Functional magnetic resonance imaging (fMRI) has revealed multiple subregions in monkey inferior temporal cortex (IT) that are selective for images of faces over other objects. The earliest of these subregions, the posterior lateral face patch (PL), has not been studied previously at the neurophysiological level. Perhaps not surprisingly, we found that PL contains a high concentration of "face-selective" cells when tested with standard image sets comparable to those used previously to define the region at the level of fMRI. However, we here report that several different image sets and analytical approaches converge to show that nearly all face-selective PL cells are driven by the presence of a single eye in the context of a face outline. Most strikingly, images containing only an eye, even when incorrectly positioned in an outline, drove neurons nearly as well as full-face images, and face images lacking only this feature led to longer latency responses. Thus, bottom-up face processing is relatively local and linearly integrates features-consistent with parts-based models-grounding investigation of how the presence of a face is first inferred in the IT face processing hierarchy.

First fixations in face processing: the more diagnostic they are the smaller the face-inversion effect

Hills, Ross, and Lewis (2011) introduced the concept that the face-inversion effect may, in part, be carried by the first feature attended to, since the first feature fixated upon is different for upright and inverted faces. An eye-tracking study that directly assesses this hypothesis by using fixation crosses to guide attention to the eye or mouth region of the to-be-presented upright and inverted faces was devised. Recognition was better when the fixation cross appeared at the eye region than at the mouth region. The face-inversion effect was smaller when the eyes were cued than when the mouth was cued or when there was no cueing. The eye-tracking measures confirmed that the fixation crosses attracted the first fixation but did not affect other measures of eye-movements. Furthermore, the location of the first fixation predicted recognition accuracy: when the first fixation was to the eyes, recognition accuracy was higher than when the first fixation was to the mouth, irrespective of facial orientation. The results suggest that the first facial feature attended to is more predictive of recognition accuracy than the face orientation in which they are presented.

Distinct Contributions to Facial Emotion Perception of Foveated versus Nonfoveated Facial Features

Foveated stimuli receive visual processing that is quantitatively and qualitatively different from nonfoveated stimuli. At normal interpersonal distances, people move their eyes around another’s face so that certain features receive foveal processing; on any given fixation, other features therefore project extrafoveally. Yet little is known about the processing of extrafoveally presented facial features, how informative those extrafoveally presented features are for face perception (e.g., for assessing another’s emotion), or what processes extract task-relevant (e.g., emotion-related) cues from facial features that first appear outside the fovea, and how these processes are implemented in the brain.

The Gender Typicality of Faces and Its Impact on Visual Processing and on Hiring Decisions

Past research has shown that the gender typicality of applicants’ faces affects leadership selection irrespective of a candidate’s gender: A masculine facial appearance is congruent with masculine-typed leadership roles, thus masculine-looking applicants are hired more certainly than feminine-looking ones. In the present study, we extended this line of research by investigating hiring decisions for both masculine- and feminine-typed professional roles. Furthermore, we used eye tracking to examine the visual exploration of applicants’ portraits. Our results indicate that masculine-looking applicants were favored for the masculine-typed role (leader) and feminine-looking applicants for the feminine-typed role (team member). Eye movement patterns showed that information about gender category and facial appearance was integrated during first fixations of the portraits. Hiring decisions, however, were not based on this initial analysis, but occurred at a second stage, when the portrait was viewed in the context of considering the applicant for a specific job.

Looking just below the eyes is optimal across face recognition tasks

When viewing a human face, people often look toward the eyes. Maintaining good eye contact carries significant social value and allows for the extraction of information about gaze direction. When identifying faces, humans also look toward the eyes, but it is unclear whether this behavior is solely a byproduct of the socially important eye movement behavior or whether it has functional importance in basic perceptual tasks. Here, we propose that gaze behavior while determining a person's identity, emotional state, or gender can be explained as an adaptive brain strategy to learn eye movement plans that optimize performance in these evolutionarily important perceptual tasks. We show that humans move their eyes to locations that maximize perceptual performance determining the identity, gender, and emotional state of a face. These optimal fixation points, which differ moderately across tasks, are predicted correctly by a Bayesian ideal observer that integrates information optimally across the face but is constrained by the decrease in resolution and sensitivity from the fovea toward the visual periphery (foveated ideal observer). Neither a model that disregards the foveated nature of the visual system and makes fixations on the local region with maximal information, nor a model that makes center-of-gravity fixations correctly predict human eye movements. Extension of the foveated ideal observer framework to a large database of real-world faces shows that the optimality of these strategies generalizes across the population. These results suggest that the human visual system optimizes face recognition performance through guidance of eye movements not only toward but, more precisely, just below the eyes.

How do we update faces? Effects of gaze direction and facial expressions on working memory updating

The aim of the study was to investigate how the biological binding between different facial dimensions, and their social and communicative relevance, may impact updating processes in working memory (WM). We focused on WM updating because it plays a key role in ongoing processing. Gaze direction and facial expression are crucial and changeable components of face processing. Direct gaze enhances the processing of approach-oriented facial emotional expressions (e.g., joy), while averted gaze enhances the processing of avoidance-oriented facial emotional expressions (e.g., fear). Thus, the way in which these two facial dimensions are combined communicates to the observer important behavioral and social information. Updating of these two facial dimensions and their bindings has not been investigated before, despite the fact that they provide a piece of social information essential for building and maintaining an internal ongoing representation of our social environment. In Experiment 1 we created a task in which the binding between gaze direction and facial expression was manipulated: high binding conditions (e.g., joy-direct gaze) were compared to low binding conditions (e.g., joy-averted gaze). Participants had to study and update continuously a number of faces, displaying different bindings between the two dimensions. In Experiment 2 we tested whether updating was affected by the social and communicative value of the facial dimension binding; to this end, we manipulated bindings between eye and hair color, two less communicative facial dimensions. Two new results emerged. First, faster response times were found in updating combinations of facial dimensions highly bound together. Second, our data showed that the ease of the ongoing updating processing varied depending on the communicative meaning of the binding that had to be updated. The results are discussed with reference to the role of WM updating in social cognition and appraisal processes.

Electrocortical and ocular indices of attention to fearful and neutral faces presented under high and low working memory load

Working memory load reduces the late positive potential (LPP), consistent with the notion that functional activation of the DLPFC attenuates neural indices of sustained attention. Visual attention also modulates the LPP. In the present study, we sought to determine whether working memory load might exert its influence on ERPs by reducing fixations to arousing picture regions. We simultaneously recorded eye-tracking and EEG while participants performed a working memory task interspersed with the presentation of task-irrelevant fearful and neutral faces. As expected, fearful compared to neutral faces elicited larger N170 and LPP amplitudes; in addition, working memory load reduced the N170 and the LPP. Participants made more fixations to arousing regions of neutral faces and faces presented under high working memory load. Therefore, working memory load did not induce avoidance of arousing picture regions and visual attention cannot explain load effects on the N170 and LPP.

Holistic gaze strategy to categorize facial expression of varying intensities

Using faces representing exaggerated emotional expressions, recent behaviour and eye-tracking studies have suggested a dominant role of individual facial features in transmitting diagnostic cues for decoding facial expressions. Considering that in everyday life we frequently view low-intensity expressive faces in which local facial cues are more ambiguous, we probably need to combine expressive cues from more than one facial feature to reliably decode naturalistic facial affects. In this study we applied a morphing technique to systematically vary intensities of six basic facial expressions of emotion, and employed a self-paced expression categorization task to measure participants' categorization performance and associated gaze patterns. The analysis of pooled data from all expressions showed that increasing expression intensity would improve categorization accuracy, shorten reaction time and reduce number of fixations directed at faces. The proportion of fixations and viewing time directed at internal facial features (eyes, nose and mouth region), however, was not affected by varying levels of intensity. Further comparison between individual facial expressions revealed that although proportional gaze allocation at individual facial features was quantitatively modulated by the viewed expressions, the overall gaze distribution in face viewing was qualitatively similar across different facial expressions and different intensities. It seems that we adopt a holistic viewing strategy to extract expressive cues from all internal facial features in processing of naturalistic facial expressions.

Spatial interference between gaze direction and gaze location: A study on the eye contact effect

Perceived gaze in faces is an important social cue that influences spatial orienting of attention. In three experiments, we examined whether the social relevance of gaze direction modulated spatial interference in response selection, using three different stimuli: faces, isolated eyes, and symbolic eyes (Experiments 1, 2, and 3, respectively). Each experiment employed a variant of the spatial Stroop paradigm in which face location and gaze direction were put into conflict. Results showed a reverse congruency effect between face location to the right or left of fixation and gaze direction only for stimuli with a social meaning to participants (Experiments 1 and 2). The opposite was observed for the nonsocial stimuli used in Experiment 3. Results are explained as facilitation in response to eye contact.

Visual cognition during real social interaction

Laboratory studies of social visual cognition often simulate the critical aspects of joint attention by having participants interact with a computer-generated avatar. Recently, there has been a movement toward examining these processes during authentic social interaction. In this review, we will focus on attention to faces, attentional misdirection, and a phenomenon we have termed social inhibition of return (Social IOR), that have revealed aspects of social cognition that were hitherto unknown. We attribute these discoveries to the use of paradigms that allow for more realistic social interactions to take place. We also point to an area that has begun to attract a considerable amount of interest-that of Theory of Mind (ToM) and automatic perspective taking-and suggest that this too might benefit from adopting a similar approach.

Using eye movement measures to investigate effects of age on memory for objects in a scene

We examined whether there were age-related differences in eye movements during intentional encoding of a photographed scene that might account for age-related differences in memory of objects in the scene. Younger and older adults exhibited similar scan path patterns, and visited each region of interest in the scene with similar frequency and duration. Despite the similarity in viewing, there were fundamental differences in the viewing-memory relationship. Although overall recognition was poorer in the older than younger adults, there was no age effect on recognition probability for objects visited only once. More importantly, re-visits to objects brought gain in recognition probability for the younger adults, but not for the older adults. These results suggest that the age-related differences in object recognition performance are in part due to inefficient integration of information from working memory to longer-term memory.

How children with specific language impairment view social situations: an eye tracking study

OBJECTIVE

Children with specific language impairment (SLI) face risks for social difficulties. However, the nature and developmental course of these difficulties remain unclear. Gaze behaviors have been studied by using eye tracking among those with autism spectrum disorders (ASDs). Using this method, we compared the gaze behaviors of children with SLI with those of individuals with ASD and typically developing (TD) children to explore the social perception of children with SLI.

METHODS

The eye gazes of 66 children (16 with SLI, 25 with ASD, and 25 TD) were studied while viewing videos of social interactions. Gaze behaviors were summarized with multidimensional scaling, and participants with similar gaze behaviors were represented proximally in a 2-dimensional plane.

RESULTS

The SLI and TD groups each formed a cluster near the center of the multidimensional scaling plane, whereas the ASD group was distributed around the periphery. Frame-by-frame analyses showed that children with SLI and TD children viewed faces in a manner consistent with the story line, but children with ASD devoted less attention to faces and social interactions. During speech scenes, children with SLI were significantly more fixated on the mouth, whereas TD children viewed the eyes and the mouth.

CONCLUSIONS

Children with SLI viewed social situations in ways similar to those of TD children but different from those of children with ASD. However, children with SLI concentrated on the speaker's mouth, possibly to compensate for audiovisual processing deficits. Because eyes carry important information, this difference may influence the social development of children with SLI.

Visual scan paths and recognition of facial identity in autism spectrum disorder and typical development

Background

Previous research suggests that many individuals with autism spectrum disorder (ASD) have impaired facial identity recognition, and also exhibit abnormal visual scanning of faces. Here, two hypotheses accounting for an association between these observations were tested: i) better facial identity recognition is associated with increased gaze time on the Eye region; ii) better facial identity recognition is associated with increased eye-movements around the face.

Methodology and Principal Findings

Eye-movements of 11 children with ASD and 11 age-matched typically developing (TD) controls were recorded whilst they viewed a series of faces, and then completed a two alternative forced-choice recognition memory test for the faces. Scores on the memory task were standardized according to age. In both groups, there was no evidence of an association between the proportion of time spent looking at the Eye region of faces and age-standardized recognition performance, thus the first hypothesis was rejected. However, the ‘Dynamic Scanning Index’ – which was incremented each time the participant saccaded into and out of one of the core-feature interest areas – was strongly associated with age-standardized face recognition scores in both groups, even after controlling for various other potential predictors of performance.

Conclusions and Significance

In support of the second hypothesis, results suggested that increased saccading between core-features was associated with more accurate face recognition ability, both in typical development and ASD. Causal directions of this relationship remain undetermined.

Social attention with real versus reel stimuli: toward an empirical approach to concerns about ecological validity

Cognitive neuroscientists often study social cognition by using simple but socially relevant stimuli, such as schematic faces or images of other people. Whilst this research is valuable, important aspects of genuine social encounters are absent from these studies, a fact that has recently drawn criticism. In the present review we argue for an empirical approach to the determination of the equivalence of different social stimuli. This approach involves the systematic comparison of different types of social stimuli ranging in their approximation to a real social interaction. In garnering support for this cognitive ethological approach, we focus on recent research in social attention that has involved stimuli ranging from simple schematic faces to real social interactions. We highlight both meaningful similarities and differences in various social attentional phenomena across these different types of social stimuli thus validating the utility of the research initiative. Furthermore, we argue that exploring these similarities and differences will provide new insights into social cognition and social neuroscience.

Prejudice Concerns and Race-Based Attentional Bias

The present study used eyetracking methodology to assess whether individuals high in external motivation (EM) to appear nonprejudiced exhibit an early bias in visual attention toward Black faces indicative of social threat perception. Drawing on previous work examining visual attention to socially threatening stimuli, the authors predicted that high-EM participants, but not lower-EM participants, would initially look toward Black faces and then subsequently direct their attention away from these faces. Participants viewed pairs of images, some of which consisted of one White and one Black male face, while a desk-mounted eyetracking camera recorded their eye movements. Results showed that, as predicted, high-EM, but not lower-EM, individuals exhibited patterns of visual attention indicative of social threat perception.

Saccades during object viewing modulate oscillatory phase in the superior temporal sulcus

Saccadic eye movements (SEMs) are the primary means of gating visual information in primates and strongly influence visual perception. The active exploration of the visual environment ("active vision") via SEMs produces suppression during saccades and enhancement afterward (i.e., during fixation) in occipital visual areas. In lateral temporal lobe visual areas, the influence, if any, of eye movements is less well understood, despite the necessity of these areas for forming coherent percepts of objects. The upper bank of the superior temporal sulcus (uSTS) is one such area whose sensitivity to SEMs is unknown. We therefore examined how saccades modulate local field potentials (LFPs) in the uSTS of macaque monkeys while they viewed face and nonface object stimuli. LFP phase concentration increased following fixation onset in the alpha (8-14 Hz), beta (14-30 Hz), and gamma (30-60 Hz) bands and was distinct from the image-evoked response. Furthermore, near-coincident onsets of fixation and image presentation--like those occurring in active vision--led to enhanced responses through greater phase concentration in the same frequency bands. Finally, single-unit activity was modulated by the phase of alpha, beta, and gamma oscillations, suggesting that the observed phase-locking influences spike timing in uSTS. Previous research implicates phase concentration in these frequency bands as a correlate of perceptual performance (Womelsdorf et al., 2006; Bosman et al., 2009). Together, these results demonstrate sensitivity to eye movements in an object-processing region of the brain and represent a plausible neural basis for the enhancement of object processing during active vision.

Start position strongly influences fixation patterns during face processing: difficulties with eye movements as a measure of information use

Fixation patterns are thought to reflect cognitive processing and, thus, index the most informative stimulus features for task performance. During face recognition, initial fixations to the center of the nose have been taken to indicate this location is optimal for information extraction. However, the use of fixations as a marker for information use rests on the assumption that fixation patterns are predominantly determined by stimulus and task, despite the fact that fixations are also influenced by visuo-motor factors. Here, we tested the effect of starting position on fixation patterns during a face recognition task with upright and inverted faces. While we observed differences in fixations between upright and inverted faces, likely reflecting differences in cognitive processing, there was also a strong effect of start position. Over the first five saccades, fixation patterns across start positions were only coarsely similar, with most fixations around the eyes. Importantly, however, the precise fixation pattern was highly dependent on start position with a strong tendency toward facial features furthest from the start position. For example, the often-reported tendency toward the left over right eye was reversed for the left starting position. Further, delayed initial saccades for central versus peripheral start positions suggest greater information processing prior to the initial saccade, highlighting the experimental bias introduced by the commonly used center start position. Finally, the precise effect of face inversion on fixation patterns was also dependent on start position. These results demonstrate the importance of a non-stimulus, non-task factor in determining fixation patterns. The patterns observed likely reflect a complex combination of visuo-motor effects and simple sampling strategies as well as cognitive factors. These different factors are very difficult to tease apart and therefore great caution must be applied when interpreting absolute fixation locations as indicative of information use, particularly at a fine spatial scale.

Recognising Faces Seen Alone or with Others: Why are Two Heads Worse Than One?

The ability to identify an unfamiliar target face from an identity lineup declines when the target is accompanied by a second face during visual encoding. This two-face disadvantage is still little studied and its basis remains poorly understood. We investigated several possible explanations for this phenomenon. Experiments 1 and 2 varied the number of potential targets (1 or 2) and the number of faces in a lineup (5 or 10) to explore if this effect arises from the number of identity comparisons that need to be made to detect a target in a lineup. We also explored if this effect arises from an uncertainty concerning which is the to-be-identified target in two-face displays, by cueing the relevant face during encoding. In experiment 3 we then examined whether the two-face disadvantage reflects the depth of face encoding or a memory effect. The results show that this effect arises from the additional comparisons that are necessary to compare two potential targets to an identity lineup when memory demands are minimised (experiment 1), but it reflects a difficulty in remembering several faces when targets and lineups cannot be viewed simultaneously (experiments 2 and 3). However, in both cases the two-face disadvantage could not be eliminated fully by cueing the target. This hints at a further possible locus for this effect, which might reflect perceptual interference during the initial encoding of the target. The implications of these findings are discussed.

The Glasses Stereotype Revisited

In face perception, besides physiognomic changes, accessories like eyeglasses can influence facial appearance. According to a stereotype, people who wear glasses are more intelligent, but less attractive. In a series of four experiments, we showed how full-rim and rimless glasses, differing with respect to the amount of face they cover, affect face perception, recognition, distinctiveness, and the attribution of stereotypes. Eyeglasses generally directed observers’ gaze to the eye regions; rimless glasses made faces appear less distinctive and resulted in reduced distinctiveness in matching and in recognition tasks. Moreover, the stereotype was confirmed but depended on the kind of glasses – rimless glasses yielded an increase in perceived trustworthiness, but not a decrease in attractiveness. Thus, glasses affect how we perceive the faces of the people wearing them and, in accordance with an old stereotype, they can lower how attractive, but increase how intelligent and trustworthy people wearing them appear. These effects depend on the kind of glasses worn.