It is often assumed that the recognition of facial expressions is impaired in autism. However, re... more It is often assumed that the recognition of facial expressions is impaired in autism. However, recent evidence suggests that reports of expression recognition difficulties in autistic participants may be attributable to co-occurring alexithymia – a trait associated with difficulties interpreting interoceptive and emotional states – not autism per se. Due to problems fixating on the eye-region, autistic individuals may be more reliant on information from the mouth region when judging facial expressions. As such, it may be easier to detect expression recognition deficits attributable to autism, not alexithymia, when participants are forced to base expression judgements on the eye-region alone. To test this possibility, we compared the ability of autistic participants (with and without high levels of alexithymia) and non-autistic controls to categorize facial expressions i) when the whole face was visible, and ii) when the lower portion of the face was covered with a surgical mask. High-alexithymic autistic participants showed clear evidence of expression recognition difficulties: they correctly categorised fewer expressions than non-autistic controls. In contrast, low-alexithymic autistic participants were unimpaired relative to non-autistic controls. The same pattern of results was seen when judging masked and unmasked expression stimuli. In sum, we find no evidence for an expression recognition deficit attributable to autism, in the absence of high levels of co-occurring alexithymia, either when participants judge whole-face stimuli or just the eye-region. These findings underscore the influence of co-occurring alexithymia on expression recognition in autism.
Central to Perceptual Dehumanization Theory is the claim that full engagement of a putative modul... more Central to Perceptual Dehumanization Theory is the claim that full engagement of a putative module for the visual analysis of faces is necessary in order to recognize the humanity or personhood of observed individuals. According to this view, the faces of outgroup members do not engage domain-specific face processing fully or typically and are instead processed in a manner akin to how the brain processes objects. Consequently, outgroup members are attributed less humanity than are ingroup members. To the extent that groups are perceptually dehumanized, they are hypothesised to be vulnerable to harm. In our article, we challenge several of the fundamental assumptions underlying this theory and question the empirical evidence in its favour. We begin by illustrating the extent to which the existence of domain-specific face processing is contested within the vision science literature. Next, we interrogate empirical evidence that appears to support Perceptual Dehumanization Theory and suggest that alternative explanations for prominent findings in the field are more likely. In the closing sections of the paper, we reflect on the broader logic of the theory and highlight some underlying inconsistencies.
We spontaneously attribute to strangers a wide variety of character traits based on their facial ... more We spontaneously attribute to strangers a wide variety of character traits based on their facial appearance. While these first impressions have little or no basis in reality, they exert a strong influence over our behaviour. Cognitive scientists have revealed a great deal about first impressions from faces including their factor structure, the cues on which they are based, the neurocognitive mechanisms responsible, and their developmental trajectory. In this field, authors frequently strive to remove as much ethnic variability from stimulus sets as possible. Typically, this convention means that participants are asked to judge the likely traits of White faces only. In the present article, we consider four possible reasons for the lack of facial diversity in this literature and find that it is unjustified. Next, we illustrate how the focus on White faces has undermined scientific efforts to understand first impressions from faces and argue that it reinforces socially regressive ideas about 'race' and status. We go on to articulate our concern that opportunities may be lost to leverage the knowledge derived from the study of first impressions against the dire consequences of prejudice and discrimination. Finally, we highlight some promising developments in the field.
There is growing interest in the visual and attentional processes recruited when human observers ... more There is growing interest in the visual and attentional processes recruited when human observers view social scenes containing multiple people. Findings from visual search paradigms have helped shape this emerging literature. Previous research has established that, when hidden amongst pairs of individuals facing in the same direction (leftwards or rightwards), pairs of individuals arranged front-to-front are found faster than pairs of individuals arranged back-to-back. Here, we describe a second, closely-related effect with important theoretical implications. When searching for a pair of individuals facing in the same direction (leftwards or rightwards), target dyads are found faster when hidden amongst distractor pairs arranged front-to-front, than when hidden amongst distractor pairs arranged back-to-back. This distractor arrangement effect was also obtained with target and distractor pairs constructed from arrows and types of common objects that cue visuospatial attention. These findings argue against the view that pairs of people arranged front-to-front capture exogenous attention due to a domain-specific orienting mechanism. Rather, it appears that salient direction cues (e.g., gaze direction, body orientation, arrows) hamper systematic search and impede efficient interpretation, when distractor pairs are arranged back-to-back.
When hidden amongst pairs of individuals facing in the same direction, pairs of individuals arran... more When hidden amongst pairs of individuals facing in the same direction, pairs of individuals arranged front-to-front are found faster in visual search tasks than pairs of individuals arranged back-to-back. Two rival explanations have been advanced to explain this search advantage for facing dyads. According to one account, the search advantage reflects the fact that front-to-front targets engage domain-specific social interaction processing that helps stimuli compete more effectively for limited attentional resources. Another view is that the effect is a by-product of the ability of individual heads and bodies to direct observers’ visuospatial attention. Here, we describe a two-part investigation that sought to test these accounts. First, we found that it is possible to replicate the search advantage with non-social objects. Next, we employed a cueing paradigm to investigate whether it is the ability of individual items to direct observers’ visuospatial attention that determines if an object category produces the search advantage for facing dyads. We found that the strength of the cueing effect produced by an object category correlated closely with the strength of the search advantage produced by that object category. Taken together, these results provide strong support for the directional cueing account.
There is growing interest in how human observers perceive social scenes containing multiple peopl... more There is growing interest in how human observers perceive social scenes containing multiple people. Interpersonal distance is a critical feature when appraising these scenes; proxemic cues are used by observers to infer whether two people are interacting, the nature of their relationship, and the valence of their current interaction. Presently, however, remarkably little is known about how interpersonal distance is encoded within the human visual system. Here we show that the perception of interpersonal distance is distorted by the Müller-Lyer illusion. Participants perceived the distance between two target points to be compressed or expanded depending on whether face pairs were positioned inside or outside the to-be-judged interval. This illusory bias was found to be unaffected by manipulations of face direction. These findings aid our understanding of how human observers perceive interpersonal distance and may inform theoretical accounts of the Müller-Lyer illusion.
In recent years, there has been growing interest in how human observers perceive, attend to, and ... more In recent years, there has been growing interest in how human observers perceive, attend to, and recall, social interactions viewed from third-person perspectives. One of the interesting findings to emerge from this new literature is the search advantage for facing dyads. When hidden amongst pairs of individuals facing in the same direction, pairs of individuals arranged front-to-front are found faster in visual search tasks than pairs of individuals arranged back-to-back. Interestingly, the search advantage for facing dyads appears to be sensitive to the orientation of the people depicted. While front-to-front target pairs are found faster than back-to-back targets when target and distractor pairings are shown upright, front-to-front and back-to-back targets are found equally quickly when pairings are shown upside-down. In the present study, we sought to better understand why the search advantage for facing dyads is sensitive to the orientation of the people depicted. To begin, we show that the orientation sensitivity of the search advantage is seen with dyads constructed from faces only, and from bodies with the head and face occluded. We replicate these effects using two different visual search paradigms. We go on to show that individual faces and bodies, viewed in profile, produce strong attentional cueing effects when shown upright, but not when presented upside-down. Together with recent evidence that arrows arranged front-to-front also produce the search advantage for facing dyads, these findings support the view that the search advantage is a by-product of the ability of constituent elements to direct observers’ visuo-spatial attention.
Developmental prosopagnosia (DP) is a condition characterised by lifelong face recognition diffic... more Developmental prosopagnosia (DP) is a condition characterised by lifelong face recognition difficulties. Recent neuroimaging findings suggest that DP may be associated with aberrant structure and function in multimodal regions of cortex implicated in the processing of both facial and vocal identity. These findings suggest that both facial and vocal recognition may be impaired in DP. To test this possibility, we compared the performance of 22 DPs and a group of typical controls, on closely matched tasks that assessed famous face and famous voice recognition ability. As expected, the DPs showed severe impairment on the face recognition task, relative to typical controls. In contrast, however, the DPs and controls identified a similar number of voices. Despite evidence of interactions between facial and vocal processing, these findings suggest some degree of dissociation between the two processing pathways, whereby one can be impaired while the other develops typically. A possible explanation for this dissociation in DP could be that the deficit originates in the early perceptual encoding of face structure, rather than at later, post-perceptual stages of face identity processing, which may be more likely to involve interactions with other modalities.
Previous research indicates that first impressions from faces are the products of automatic and r... more Previous research indicates that first impressions from faces are the products of automatic and rapid processing and emerge early in development. These features have been taken as evidence that first impressions have a phylogenetic origin. We examine whether first impressions acquired through learning can also possess these features. First, we confirm that adults rate a person as more intelligent when they are wearing glasses (Study 1). Next, we show this inference persists when participants are instructed to ignore the glasses (Study 2) and when viewing time is restricted to 100 milliseconds (Study 3). Finally, we show that six-year-old, but not 4-year-old, children perceive individuals wearing glasses to be more intelligent, indicating that the effect is seen relatively early in development (Study 4). These data indicate that automaticity, rapid access, and early emergence are not evidence that first impressions have an innate origin. Rather, these features are equally compatible with a learning model.
The nature of the perceptual deficit seen in developmental prosopagnosia remains poorly understoo... more The nature of the perceptual deficit seen in developmental prosopagnosia remains poorly understood. One possibility is that these individuals experience face recognition difficulties because they fail to process faces holistically; they may be less able to analyze distal regions in parallel and therefore struggle to integrate information from different regions into a unified perceptual whole. Consequently, developmental prosopagnosics may be forced to base perceptual decisions on a slow, effortful piecemeal analysis of local facial features. In the present study, we sought to test this view by comparing the face recognition of developmental prosopagnosics and typical observers under two viewing conditions: when target faces were briefly presented in their entirety, and when they were inspected region-byregion through a dynamic aperture. If developmental prosopagnosics are forced to base perceptual decisions on information accumulated from a serial piecemeal analysis, one would expect little if any decrement in performance when target faces are viewed through apertures. Contrary to this prediction, however, developmental prosopagnosics showed strong aperture effects comparable with typical observers; their perceptual decisions were more accurate in the whole-face condition than when targets were viewed through the aperture. As expected, the developmental prosopagnosics were less accurate than typical controls when judging briefly presented faces shown in their entirety. Strikingly, however, they were also less able to accumulate perceptual evidence from a serial region-by-region analysis, than typical observers. Our results suggest that the perceptual problems seen in this population arise from imprecise descriptions of local regions, not aberrant holistic processing.
When asked to find a target dyad amongst non-interacting individuals, participants respond faster... more When asked to find a target dyad amongst non-interacting individuals, participants respond faster when the individuals in the target dyad are shown face-to-face (suggestive of a social interaction), than when they are presented back-to-back. Face-to-face dyads may be found faster because social interactions recruit specialized processing. However, human faces and bodies are salient directional cues that exert a strong influence on how observers distribute their attention. Here we report that a similar search advantage exists for ‘point-to-point’ and ‘point-to-face’ target arrangements constructed using arrows – a non-social directional cue. These findings indicate that the search advantage seen for face-to-face dyads is a product of the directional cues present within arrangements, not the fact that they are processed as social interactions, per se. One possibility is that, when arranged in the face-to-face or point-to-point configuration, pairs of directional cues (faces, bodies, arrows) create an attentional ‘hot-spot’ – a region of space in between the elements to which attention is directed by multiple cues. Due to the presence of this hot-spot, observers’ attention may be drawn to the target location earlier in a serial visual search.
When encountering a stranger for the first time, adults spontaneously attribute to them a wide va... more When encountering a stranger for the first time, adults spontaneously attribute to them a wide variety of character traits based solely on their physical appearance, most notably from their face. While these trait inferences exert a pervasive influence over our behaviour, their origins remain unclear. Whereas nativist accounts hold that first impressions are a product of gene-based natural selection, the Trait Inference Mapping framework (TIM) posits that we learn face-trait mappings ontogenetically as a result of correlated face-trait experience. Here, we examine the available anthropological evidence on ritual in order to better understand the mechanism by which first impressions from faces are acquired. Consistent with the TIM framework, we argue that examination of ritual body modification performed by communities around the world demonstrates far greater cross-cultural variability in face-trait mappings than currently appreciated. Furthermore, rituals of this type may be a powerful mechanism through which face-trait associations are transmitted from one generation to the next.
Developmental prosopagnosia (DP) is a neurodevelopmental condition characterised by difficulties ... more Developmental prosopagnosia (DP) is a neurodevelopmental condition characterised by difficulties recognising and discriminating faces. It is currently unclear whether the perceptual impairments seen in DP are restricted to identity information, or also affect the perception of other facial characteristics. To address this question, we compared the performance of 17 DPs and matched controls on two sensitive sex categorisation tasks. First, in a morph categorisation task, participants made binary decisions about faces drawn from a morph continuum that blended incrementally an average male face and an average female face. We found that judgement precision was significantly lower in the DPs than in the typical controls. Second, we used a sex discrimination task, where female or male facial identities were blended with an androgynous average face. We manipulated the relative weighting of each facial identity and the androgynous average to create four levels of signal strength. We found that DPs were significantly less sensitive than controls at each level of difficulty. Together, these results suggest that the visual processing difficulties in DP extend beyond the extraction of facial identity and affects the extraction of other facial characteristics. Deficits of facial sex categorisation accord with an apperceptive characterisation of DP.
When the upper half of one face (‘target region’) is spatially aligned with the lower half of ano... more When the upper half of one face (‘target region’) is spatially aligned with the lower half of another (‘distractor region’), the two halves appear to fuse together perceptually, changing observers’ subjective perception of the target region. This ‘composite face illusion’ is regarded as a key hallmark of holistic face processing. Importantly, distractor regions bias observers’ subjective perception of target regions in systematic, predictable ways. For example, male and female distractor regions make target regions appear masculine and feminine; young and old distractor regions make target regions appear younger and older. In the present study, we first describe a novel psychophysical paradigm that yields precise reliable estimates of these perceptual biases. Next, we use this novel procedure to establish a clear relationship between observers’ susceptibility to the age and gender biases induced by the composite face illusion. This relationship is seen in a lab-based sample (N = 100) and replicated in an independent sample tested online (N = 121). Our findings suggest that age and gender variants of the composite illusion may be different measures of a common structural binding process, with an origin early in the face processing stream.
Upright faces are thought to engage holistic processing whereby local regions are integrated into... more Upright faces are thought to engage holistic processing whereby local regions are integrated into a unified whole for the purposes of rapid, efficient analysis. In contrast, inverted faces are thought to recruit a slower, less-accurate serial analysis of local features. Aperture paradigms, whereby a target face is revealed by a dynamic viewing window that shifts over the stimulus image, offer a compelling test of this view. If upright faces are processed holistically, perceptual judgements ought to be substantially disrupted when stimuli are viewed through apertures. In contrast, aperture viewing should produce little or no decrement in perceptual decisions when judging inverted faces, as they are thought to be subjected to serial feature-based analysis. Here we present four experiments that elucidate the effects of aperture viewing on the perception of upright and inverted faces. In our first two experiments, we find evidence of disproportionate aperture effects for upright faces relative to inverted faces. However, these findings are qualified by the fact that observers found it harder to discriminate inverted faces presented in the ‘baseline’ whole-face condition. When observers’ ability to discriminate faces in the whole-face condition was matched for difficulty (Experiments 3 and 4), we show that upright and inverted faces produce very similar aperture effects. These findings indicate that both upright and inverted faces benefit from whole-face processing and accord with other lines of evidence that faces engage qualitatively similar types of processing in both orientations.
• Individuals with and without autism completed a composite face procedure • The strength of faci... more • Individuals with and without autism completed a composite face procedure • The strength of facial emotion cues in the distractor regions was manipulated • High-emotion distractor regions produced stronger composite face effects • Similar modulation by facial emotion was seen in both groups • Typical composite effects in autism suggest intact holistic face processing Abstract Individuals with Autism Spectrum Disorder (ASD; autistic individuals) may exhibit atypical face perception because they fail to process faces holistically. In the context of this hypothesis, it is critical to determine whether autistic individuals exhibit diminished susceptibility to the composite face illusion, widely regarded as key marker of holistic face processing. To date, however, previous studies have yielded inconsistent findings. In light of recent evidence suggesting that facial emotion cues increase the strength of the composite face illusion in typical individuals, the present study sought to determine whether the presence of facial emotion also modulates the strength of the composite face illusion in autistic individuals, many of whom experience difficulties recognizing facial expressions. We therefore measured composite face effects in a sample of autistic individuals (N = 20) and matched typical controls (N = 29) using an incidental emotion procedure in which distractor regions varied systematically in their emotion strength. As expected, the presence of facial emotion in the distractor regions of composite face arrangements increased the strength of the illusory distortion induced. The extent of the modulation by facial emotion was similar in the two groups. The composite effects seen in the ASD group were qualitatively and quantitatively similar to those seen in the typical group, suggestive of intact holistic processing in this population.
• Caucasian DPs and controls judged whether pairs of faces were identical or not • As expected, t... more • Caucasian DPs and controls judged whether pairs of faces were identical or not • As expected, the DPs exhibited poor discrimination of same-ethnicity faces • Relative to controls, the DPs also exhibited impairment when judging Black faces
Individuals with developmental prosopagnosia (DP) sometimes experience object identification diff... more Individuals with developmental prosopagnosia (DP) sometimes experience object identification difficulties in addition to problems recognising faces. To better understand the distribution of non-face object recognition ability in this population, we administered the Cambridge Car Memory Test (CCMT)a leading, standardised measure of object recognition abilityto a large sample of DPs (N = 46). When considered as a single group, the DPs scored lower than matched controls. This finding provides further evidence that developmental object agnosia (DOA) may be more common in DP than in the general population. Relative to the DPs' face recognition deficits, however, car matching deficits were small and inconsistent. In fact, we observed a striking range of CCMT performance in our DP sample. While some DPs performed extremely poorly, many more achieved scores within one standard deviation of the typical mean, and several DP participants achieved excellent CCMT scores comparable with the best controls.
Traditionally, developmental prosopagnosia (DP) has been thought of as an apperceptive condition ... more Traditionally, developmental prosopagnosia (DP) has been thought of as an apperceptive condition that hinders individuals' ability to encode face structure. However, several authors have recently raised the possibility that many DPs may be able to form accurate percepts, but be unable to maintain those percepts over time. The present study sought to distinguish these possibilities. In our first experiment 16 DPs and 22 typical controls completed a delayed match-to-sample task with face and car stimuli, with a retention interval of 1-second (low demand) or 6-seconds (high demand). As expected, the participants with DP were worse than the controls at face matching, and were disproportionately impaired at matching faces relative to cars. However, the relative degree of impairment seen in the DPs did not interact with retention interval; they exhibited similar levels of impairment when matching faces with 1-and 6-second delays. Next, we compared the performance of 72 DPs and 54 typical controls on the Cambridge Face Perception Test (CFPT), a task that measures face perception ability in a way that minimises the memory demands. As expected, we found that the DPs were impaired at the group level. This difference was not attributable to a few individuals with an apperceptive profile; rather we found evidence that the distribution of CFPT scores seen in the DP sample was shifted relative to that of typical controls. Some heterogeneity is likely in any neurodevelopmental population, and DP is no different.
It is often assumed that the recognition of facial expressions is impaired in autism. However, re... more It is often assumed that the recognition of facial expressions is impaired in autism. However, recent evidence suggests that reports of expression recognition difficulties in autistic participants may be attributable to co-occurring alexithymia – a trait associated with difficulties interpreting interoceptive and emotional states – not autism per se. Due to problems fixating on the eye-region, autistic individuals may be more reliant on information from the mouth region when judging facial expressions. As such, it may be easier to detect expression recognition deficits attributable to autism, not alexithymia, when participants are forced to base expression judgements on the eye-region alone. To test this possibility, we compared the ability of autistic participants (with and without high levels of alexithymia) and non-autistic controls to categorize facial expressions i) when the whole face was visible, and ii) when the lower portion of the face was covered with a surgical mask. High-alexithymic autistic participants showed clear evidence of expression recognition difficulties: they correctly categorised fewer expressions than non-autistic controls. In contrast, low-alexithymic autistic participants were unimpaired relative to non-autistic controls. The same pattern of results was seen when judging masked and unmasked expression stimuli. In sum, we find no evidence for an expression recognition deficit attributable to autism, in the absence of high levels of co-occurring alexithymia, either when participants judge whole-face stimuli or just the eye-region. These findings underscore the influence of co-occurring alexithymia on expression recognition in autism.
Central to Perceptual Dehumanization Theory is the claim that full engagement of a putative modul... more Central to Perceptual Dehumanization Theory is the claim that full engagement of a putative module for the visual analysis of faces is necessary in order to recognize the humanity or personhood of observed individuals. According to this view, the faces of outgroup members do not engage domain-specific face processing fully or typically and are instead processed in a manner akin to how the brain processes objects. Consequently, outgroup members are attributed less humanity than are ingroup members. To the extent that groups are perceptually dehumanized, they are hypothesised to be vulnerable to harm. In our article, we challenge several of the fundamental assumptions underlying this theory and question the empirical evidence in its favour. We begin by illustrating the extent to which the existence of domain-specific face processing is contested within the vision science literature. Next, we interrogate empirical evidence that appears to support Perceptual Dehumanization Theory and suggest that alternative explanations for prominent findings in the field are more likely. In the closing sections of the paper, we reflect on the broader logic of the theory and highlight some underlying inconsistencies.
We spontaneously attribute to strangers a wide variety of character traits based on their facial ... more We spontaneously attribute to strangers a wide variety of character traits based on their facial appearance. While these first impressions have little or no basis in reality, they exert a strong influence over our behaviour. Cognitive scientists have revealed a great deal about first impressions from faces including their factor structure, the cues on which they are based, the neurocognitive mechanisms responsible, and their developmental trajectory. In this field, authors frequently strive to remove as much ethnic variability from stimulus sets as possible. Typically, this convention means that participants are asked to judge the likely traits of White faces only. In the present article, we consider four possible reasons for the lack of facial diversity in this literature and find that it is unjustified. Next, we illustrate how the focus on White faces has undermined scientific efforts to understand first impressions from faces and argue that it reinforces socially regressive ideas about 'race' and status. We go on to articulate our concern that opportunities may be lost to leverage the knowledge derived from the study of first impressions against the dire consequences of prejudice and discrimination. Finally, we highlight some promising developments in the field.
There is growing interest in the visual and attentional processes recruited when human observers ... more There is growing interest in the visual and attentional processes recruited when human observers view social scenes containing multiple people. Findings from visual search paradigms have helped shape this emerging literature. Previous research has established that, when hidden amongst pairs of individuals facing in the same direction (leftwards or rightwards), pairs of individuals arranged front-to-front are found faster than pairs of individuals arranged back-to-back. Here, we describe a second, closely-related effect with important theoretical implications. When searching for a pair of individuals facing in the same direction (leftwards or rightwards), target dyads are found faster when hidden amongst distractor pairs arranged front-to-front, than when hidden amongst distractor pairs arranged back-to-back. This distractor arrangement effect was also obtained with target and distractor pairs constructed from arrows and types of common objects that cue visuospatial attention. These findings argue against the view that pairs of people arranged front-to-front capture exogenous attention due to a domain-specific orienting mechanism. Rather, it appears that salient direction cues (e.g., gaze direction, body orientation, arrows) hamper systematic search and impede efficient interpretation, when distractor pairs are arranged back-to-back.
When hidden amongst pairs of individuals facing in the same direction, pairs of individuals arran... more When hidden amongst pairs of individuals facing in the same direction, pairs of individuals arranged front-to-front are found faster in visual search tasks than pairs of individuals arranged back-to-back. Two rival explanations have been advanced to explain this search advantage for facing dyads. According to one account, the search advantage reflects the fact that front-to-front targets engage domain-specific social interaction processing that helps stimuli compete more effectively for limited attentional resources. Another view is that the effect is a by-product of the ability of individual heads and bodies to direct observers’ visuospatial attention. Here, we describe a two-part investigation that sought to test these accounts. First, we found that it is possible to replicate the search advantage with non-social objects. Next, we employed a cueing paradigm to investigate whether it is the ability of individual items to direct observers’ visuospatial attention that determines if an object category produces the search advantage for facing dyads. We found that the strength of the cueing effect produced by an object category correlated closely with the strength of the search advantage produced by that object category. Taken together, these results provide strong support for the directional cueing account.
There is growing interest in how human observers perceive social scenes containing multiple peopl... more There is growing interest in how human observers perceive social scenes containing multiple people. Interpersonal distance is a critical feature when appraising these scenes; proxemic cues are used by observers to infer whether two people are interacting, the nature of their relationship, and the valence of their current interaction. Presently, however, remarkably little is known about how interpersonal distance is encoded within the human visual system. Here we show that the perception of interpersonal distance is distorted by the Müller-Lyer illusion. Participants perceived the distance between two target points to be compressed or expanded depending on whether face pairs were positioned inside or outside the to-be-judged interval. This illusory bias was found to be unaffected by manipulations of face direction. These findings aid our understanding of how human observers perceive interpersonal distance and may inform theoretical accounts of the Müller-Lyer illusion.
In recent years, there has been growing interest in how human observers perceive, attend to, and ... more In recent years, there has been growing interest in how human observers perceive, attend to, and recall, social interactions viewed from third-person perspectives. One of the interesting findings to emerge from this new literature is the search advantage for facing dyads. When hidden amongst pairs of individuals facing in the same direction, pairs of individuals arranged front-to-front are found faster in visual search tasks than pairs of individuals arranged back-to-back. Interestingly, the search advantage for facing dyads appears to be sensitive to the orientation of the people depicted. While front-to-front target pairs are found faster than back-to-back targets when target and distractor pairings are shown upright, front-to-front and back-to-back targets are found equally quickly when pairings are shown upside-down. In the present study, we sought to better understand why the search advantage for facing dyads is sensitive to the orientation of the people depicted. To begin, we show that the orientation sensitivity of the search advantage is seen with dyads constructed from faces only, and from bodies with the head and face occluded. We replicate these effects using two different visual search paradigms. We go on to show that individual faces and bodies, viewed in profile, produce strong attentional cueing effects when shown upright, but not when presented upside-down. Together with recent evidence that arrows arranged front-to-front also produce the search advantage for facing dyads, these findings support the view that the search advantage is a by-product of the ability of constituent elements to direct observers’ visuo-spatial attention.
Developmental prosopagnosia (DP) is a condition characterised by lifelong face recognition diffic... more Developmental prosopagnosia (DP) is a condition characterised by lifelong face recognition difficulties. Recent neuroimaging findings suggest that DP may be associated with aberrant structure and function in multimodal regions of cortex implicated in the processing of both facial and vocal identity. These findings suggest that both facial and vocal recognition may be impaired in DP. To test this possibility, we compared the performance of 22 DPs and a group of typical controls, on closely matched tasks that assessed famous face and famous voice recognition ability. As expected, the DPs showed severe impairment on the face recognition task, relative to typical controls. In contrast, however, the DPs and controls identified a similar number of voices. Despite evidence of interactions between facial and vocal processing, these findings suggest some degree of dissociation between the two processing pathways, whereby one can be impaired while the other develops typically. A possible explanation for this dissociation in DP could be that the deficit originates in the early perceptual encoding of face structure, rather than at later, post-perceptual stages of face identity processing, which may be more likely to involve interactions with other modalities.
Previous research indicates that first impressions from faces are the products of automatic and r... more Previous research indicates that first impressions from faces are the products of automatic and rapid processing and emerge early in development. These features have been taken as evidence that first impressions have a phylogenetic origin. We examine whether first impressions acquired through learning can also possess these features. First, we confirm that adults rate a person as more intelligent when they are wearing glasses (Study 1). Next, we show this inference persists when participants are instructed to ignore the glasses (Study 2) and when viewing time is restricted to 100 milliseconds (Study 3). Finally, we show that six-year-old, but not 4-year-old, children perceive individuals wearing glasses to be more intelligent, indicating that the effect is seen relatively early in development (Study 4). These data indicate that automaticity, rapid access, and early emergence are not evidence that first impressions have an innate origin. Rather, these features are equally compatible with a learning model.
The nature of the perceptual deficit seen in developmental prosopagnosia remains poorly understoo... more The nature of the perceptual deficit seen in developmental prosopagnosia remains poorly understood. One possibility is that these individuals experience face recognition difficulties because they fail to process faces holistically; they may be less able to analyze distal regions in parallel and therefore struggle to integrate information from different regions into a unified perceptual whole. Consequently, developmental prosopagnosics may be forced to base perceptual decisions on a slow, effortful piecemeal analysis of local facial features. In the present study, we sought to test this view by comparing the face recognition of developmental prosopagnosics and typical observers under two viewing conditions: when target faces were briefly presented in their entirety, and when they were inspected region-byregion through a dynamic aperture. If developmental prosopagnosics are forced to base perceptual decisions on information accumulated from a serial piecemeal analysis, one would expect little if any decrement in performance when target faces are viewed through apertures. Contrary to this prediction, however, developmental prosopagnosics showed strong aperture effects comparable with typical observers; their perceptual decisions were more accurate in the whole-face condition than when targets were viewed through the aperture. As expected, the developmental prosopagnosics were less accurate than typical controls when judging briefly presented faces shown in their entirety. Strikingly, however, they were also less able to accumulate perceptual evidence from a serial region-by-region analysis, than typical observers. Our results suggest that the perceptual problems seen in this population arise from imprecise descriptions of local regions, not aberrant holistic processing.
When asked to find a target dyad amongst non-interacting individuals, participants respond faster... more When asked to find a target dyad amongst non-interacting individuals, participants respond faster when the individuals in the target dyad are shown face-to-face (suggestive of a social interaction), than when they are presented back-to-back. Face-to-face dyads may be found faster because social interactions recruit specialized processing. However, human faces and bodies are salient directional cues that exert a strong influence on how observers distribute their attention. Here we report that a similar search advantage exists for ‘point-to-point’ and ‘point-to-face’ target arrangements constructed using arrows – a non-social directional cue. These findings indicate that the search advantage seen for face-to-face dyads is a product of the directional cues present within arrangements, not the fact that they are processed as social interactions, per se. One possibility is that, when arranged in the face-to-face or point-to-point configuration, pairs of directional cues (faces, bodies, arrows) create an attentional ‘hot-spot’ – a region of space in between the elements to which attention is directed by multiple cues. Due to the presence of this hot-spot, observers’ attention may be drawn to the target location earlier in a serial visual search.
When encountering a stranger for the first time, adults spontaneously attribute to them a wide va... more When encountering a stranger for the first time, adults spontaneously attribute to them a wide variety of character traits based solely on their physical appearance, most notably from their face. While these trait inferences exert a pervasive influence over our behaviour, their origins remain unclear. Whereas nativist accounts hold that first impressions are a product of gene-based natural selection, the Trait Inference Mapping framework (TIM) posits that we learn face-trait mappings ontogenetically as a result of correlated face-trait experience. Here, we examine the available anthropological evidence on ritual in order to better understand the mechanism by which first impressions from faces are acquired. Consistent with the TIM framework, we argue that examination of ritual body modification performed by communities around the world demonstrates far greater cross-cultural variability in face-trait mappings than currently appreciated. Furthermore, rituals of this type may be a powerful mechanism through which face-trait associations are transmitted from one generation to the next.
Developmental prosopagnosia (DP) is a neurodevelopmental condition characterised by difficulties ... more Developmental prosopagnosia (DP) is a neurodevelopmental condition characterised by difficulties recognising and discriminating faces. It is currently unclear whether the perceptual impairments seen in DP are restricted to identity information, or also affect the perception of other facial characteristics. To address this question, we compared the performance of 17 DPs and matched controls on two sensitive sex categorisation tasks. First, in a morph categorisation task, participants made binary decisions about faces drawn from a morph continuum that blended incrementally an average male face and an average female face. We found that judgement precision was significantly lower in the DPs than in the typical controls. Second, we used a sex discrimination task, where female or male facial identities were blended with an androgynous average face. We manipulated the relative weighting of each facial identity and the androgynous average to create four levels of signal strength. We found that DPs were significantly less sensitive than controls at each level of difficulty. Together, these results suggest that the visual processing difficulties in DP extend beyond the extraction of facial identity and affects the extraction of other facial characteristics. Deficits of facial sex categorisation accord with an apperceptive characterisation of DP.
When the upper half of one face (‘target region’) is spatially aligned with the lower half of ano... more When the upper half of one face (‘target region’) is spatially aligned with the lower half of another (‘distractor region’), the two halves appear to fuse together perceptually, changing observers’ subjective perception of the target region. This ‘composite face illusion’ is regarded as a key hallmark of holistic face processing. Importantly, distractor regions bias observers’ subjective perception of target regions in systematic, predictable ways. For example, male and female distractor regions make target regions appear masculine and feminine; young and old distractor regions make target regions appear younger and older. In the present study, we first describe a novel psychophysical paradigm that yields precise reliable estimates of these perceptual biases. Next, we use this novel procedure to establish a clear relationship between observers’ susceptibility to the age and gender biases induced by the composite face illusion. This relationship is seen in a lab-based sample (N = 100) and replicated in an independent sample tested online (N = 121). Our findings suggest that age and gender variants of the composite illusion may be different measures of a common structural binding process, with an origin early in the face processing stream.
Upright faces are thought to engage holistic processing whereby local regions are integrated into... more Upright faces are thought to engage holistic processing whereby local regions are integrated into a unified whole for the purposes of rapid, efficient analysis. In contrast, inverted faces are thought to recruit a slower, less-accurate serial analysis of local features. Aperture paradigms, whereby a target face is revealed by a dynamic viewing window that shifts over the stimulus image, offer a compelling test of this view. If upright faces are processed holistically, perceptual judgements ought to be substantially disrupted when stimuli are viewed through apertures. In contrast, aperture viewing should produce little or no decrement in perceptual decisions when judging inverted faces, as they are thought to be subjected to serial feature-based analysis. Here we present four experiments that elucidate the effects of aperture viewing on the perception of upright and inverted faces. In our first two experiments, we find evidence of disproportionate aperture effects for upright faces relative to inverted faces. However, these findings are qualified by the fact that observers found it harder to discriminate inverted faces presented in the ‘baseline’ whole-face condition. When observers’ ability to discriminate faces in the whole-face condition was matched for difficulty (Experiments 3 and 4), we show that upright and inverted faces produce very similar aperture effects. These findings indicate that both upright and inverted faces benefit from whole-face processing and accord with other lines of evidence that faces engage qualitatively similar types of processing in both orientations.
• Individuals with and without autism completed a composite face procedure • The strength of faci... more • Individuals with and without autism completed a composite face procedure • The strength of facial emotion cues in the distractor regions was manipulated • High-emotion distractor regions produced stronger composite face effects • Similar modulation by facial emotion was seen in both groups • Typical composite effects in autism suggest intact holistic face processing Abstract Individuals with Autism Spectrum Disorder (ASD; autistic individuals) may exhibit atypical face perception because they fail to process faces holistically. In the context of this hypothesis, it is critical to determine whether autistic individuals exhibit diminished susceptibility to the composite face illusion, widely regarded as key marker of holistic face processing. To date, however, previous studies have yielded inconsistent findings. In light of recent evidence suggesting that facial emotion cues increase the strength of the composite face illusion in typical individuals, the present study sought to determine whether the presence of facial emotion also modulates the strength of the composite face illusion in autistic individuals, many of whom experience difficulties recognizing facial expressions. We therefore measured composite face effects in a sample of autistic individuals (N = 20) and matched typical controls (N = 29) using an incidental emotion procedure in which distractor regions varied systematically in their emotion strength. As expected, the presence of facial emotion in the distractor regions of composite face arrangements increased the strength of the illusory distortion induced. The extent of the modulation by facial emotion was similar in the two groups. The composite effects seen in the ASD group were qualitatively and quantitatively similar to those seen in the typical group, suggestive of intact holistic processing in this population.
• Caucasian DPs and controls judged whether pairs of faces were identical or not • As expected, t... more • Caucasian DPs and controls judged whether pairs of faces were identical or not • As expected, the DPs exhibited poor discrimination of same-ethnicity faces • Relative to controls, the DPs also exhibited impairment when judging Black faces
Individuals with developmental prosopagnosia (DP) sometimes experience object identification diff... more Individuals with developmental prosopagnosia (DP) sometimes experience object identification difficulties in addition to problems recognising faces. To better understand the distribution of non-face object recognition ability in this population, we administered the Cambridge Car Memory Test (CCMT)a leading, standardised measure of object recognition abilityto a large sample of DPs (N = 46). When considered as a single group, the DPs scored lower than matched controls. This finding provides further evidence that developmental object agnosia (DOA) may be more common in DP than in the general population. Relative to the DPs' face recognition deficits, however, car matching deficits were small and inconsistent. In fact, we observed a striking range of CCMT performance in our DP sample. While some DPs performed extremely poorly, many more achieved scores within one standard deviation of the typical mean, and several DP participants achieved excellent CCMT scores comparable with the best controls.
Traditionally, developmental prosopagnosia (DP) has been thought of as an apperceptive condition ... more Traditionally, developmental prosopagnosia (DP) has been thought of as an apperceptive condition that hinders individuals' ability to encode face structure. However, several authors have recently raised the possibility that many DPs may be able to form accurate percepts, but be unable to maintain those percepts over time. The present study sought to distinguish these possibilities. In our first experiment 16 DPs and 22 typical controls completed a delayed match-to-sample task with face and car stimuli, with a retention interval of 1-second (low demand) or 6-seconds (high demand). As expected, the participants with DP were worse than the controls at face matching, and were disproportionately impaired at matching faces relative to cars. However, the relative degree of impairment seen in the DPs did not interact with retention interval; they exhibited similar levels of impairment when matching faces with 1-and 6-second delays. Next, we compared the performance of 72 DPs and 54 typical controls on the Cambridge Face Perception Test (CFPT), a task that measures face perception ability in a way that minimises the memory demands. As expected, we found that the DPs were impaired at the group level. This difference was not attributable to a few individuals with an apperceptive profile; rather we found evidence that the distribution of CFPT scores seen in the DP sample was shifted relative to that of typical controls. Some heterogeneity is likely in any neurodevelopmental population, and DP is no different.
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