N170 face specificity and face memory depend on hometown size

Effects of expectation on face perception and its association with expertise

Perceptual decisions are derived from the combination of priors and sensorial input. While priors are broadly understood to reflect experience/expertise developed over one's lifetime, the role of perceptual expertise at the individual level has seldom been directly explored. Here, we manipulate probabilistic information associated with a high and low expertise category (faces and cars respectively), while assessing individual level of expertise with each category. 67 participants learned the probabilistic association between a color cue and each target category (face/car) in a behavioural categorization task. Neural activity (EEG) was then recorded in a similar paradigm in the same participants featuring the previously learned contingencies without the explicit task. Behaviourally, perception of the higher expertise category (faces) was modulated by expectation. Specifically, we observed facilitatory and interference effects when targets were correctly or incorrectly expected, which were also associated with independently measured individual levels of face expertise. Multivariate pattern analysis of the EEG signal revealed clear effects of expectation from 100 ms post stimulus, with significant decoding of the neural response to expected vs. not stimuli, when viewing identical images. Latency of peak decoding when participants saw faces was directly associated with individual level facilitation effects in the behavioural task. The current results not only provide time sensitive evidence of expectation effects on early perception but highlight the role of higher-level expertise on forming priors.

The Expansion of House Mouse Major Urinary Protein Genes Likely Did Not Facilitate Commensalism with Humans

Mouse wild-derived strains (WDSs) combine the advantages of classical laboratory stocks and wild animals, and thus appear to be promising tools for diverse biomedical and evolutionary studies. We employed 18 WDSs representing three non-synanthropic species (Mus spretus, Mus spicilegus, and M. macedonicus) and three house mouse subspecies (Mus musculus musculus, M. m. domesticus, M. m. castaneus), which are all important human commensals to explore whether the number of major urinary protein (MUP) genes and their final protein levels in urine are correlated with the level of commensalism. Contrary to expectations, the MUP copy number (CN) and protein excretion in the strains derived from M. m. castaneus, which is supposed to be the strongest commensal, were not significantly different from the non-commensal species. Regardless of an overall tendency for higher MUP amounts in taxa with a higher CN, there was no significant correlation at the strain level. Our study thus suggests that expansion of the Mup cluster, which appeared before the house mouse diversification, is unlikely to facilitate commensalism with humans in three house mouse subspecies. Finally, we found considerable variation among con(sub)specific WDSs, warning against generalisations of results based on a few strains.

Literacy acquisition facilitates inversion effects for faces with full-, low-, and high-spatial frequency: evidence from illiterate and literate adults

Previous studies have found that literacy acquisition modulates configural face processing (i.e., holistic and second-order configural processing). However, it remains unclear how literacy acquisition impacts the configural processing indexed by the inversion effect of normal or filtered faces. We asked Chinese illiterate and literate adults to judge whether two sequentially-presented stimuli, including faces, houses (experiment 1), and high- or low-pass filtered faces (experiment 2) were identical. Literate adults outperformed illiterate controls in the upright face and house conditions (experiment 1) and the upright high- and low-pass filtered conditions (experiment 2) but not in the inverted conditions. Notably, the size of an inversion effect (i.e., subtracting inverted accuracy from upright accuracy) was greater among literate adults than that among illiterate adults in both experiments. These findings support that literacy acquisition promotes configural face processing.

Unfamiliar face matching ability predicts the slope of face learning

We provide the first examination of individual differences in the efficiency of face learning. Investigating individual differences in face learning can illuminate potential mechanisms and provide greater understanding of why certain individuals might be more efficient face learners. Participants completed two unfamiliar face matching tasks and a learning task in which learning was assessed after viewing 1, 3, 6, and 9 images of to-be-learned identities. Individual differences in the slope of face learning (i.e., increases in sensitivity to identity) were predicted by the ability to discriminate between matched (same-identity) vs. mismatched (different-identity) pairs of wholly unfamiliar faces. A Dual Process Signal Detection model showed that three parameters increased with learning: Familiarity (an unconscious type of memory that varies in strength), recollection-old (conscious recognition of a learned identity), and recollection-new (conscious/confident rejection of novel identities). Good (vs. poor) matchers had higher Recollection-Old scores throughout learning and showed a steeper increase in Recollection-New. We conclude that good matchers are better able to capitalize on exposure to within-person variability in appearance, an effect that is attributable to their conscious memory for both learned and novel faces. These results have applied implications and will inform contemporary and traditional models of face identification.

Understanding racial bias through electroencephalography

Research on racial bias in social and cognitive psychology has focused on automatic cognitive processes such as categorisation or stereotyping. Neuroimaging has revealed differences in the neural circuit when processing social information about one's own or another's ethnicity. This review investigates the influence of racial bias on human behaviour by reviewing studies that examined changes in neural circuitry (i.e. ERP responses) during automatic and controlled processes elicited by specific tasks. This systematic analysis of specific ERP components across different studies provides a greater understanding of how social contexts are perceived and become associated with specific stereotypes and behavioural predictions. Therefore, investigating these related cognitive and neurobiological functions can further our understanding of how racial bias affects our cognition more generally and guide more effective programs and policies aimed at its mitigation.

Stable individual differences in unfamiliar face identification: Evidence from simultaneous and sequential matching tasks

Matching identity in images of unfamiliar faces is difficult: Images of the same person can look different and images of different people can look similar. Recent studies have capitalized on individual differences in the ability to distinguish match (same ID) vs. mismatch (different IDs) face pairs to inform models of face recognition. We addressed two significant gaps in the literature by examining the stability of individual differences in both sensitivity to identity and response bias. In Study 1, 210 participants completed a battery of four tasks in each of two sessions separated by one week. Tasks varied in protocol (same/different, lineup, sorting) and stimulus characteristics (low vs. high within-person variability in appearance). In Study 2, 148 participants completed a battery of three tasks in a single session. Stimuli were presented simultaneously on some trials and sequentially on others, introducing short-term memory demands. Principal components analysis revealed two components that were stable across time and tasks: sensitivity to identity and bias. Analyses of response times suggest that individual differences in bias reflect decision-making processes. We discuss the implications of our findings in applied settings and for models of face recognition.

Face recognition ability is manifest in early dynamic decoding of face-orientation selectivity-Evidence from multi-variate pattern analysis of the neural response

Although humans are considered to be face experts, there is a well-established reliable variation in the degree to which neurotypical individuals are able to learn and recognise faces. While many behavioural studies have characterised these differences, studies that seek to relate the neuronal response to standardised behavioural measures of ability remain relatively scarce, particularly so for the time-resolved approaches and the early response to face stimuli. In the present study we make use of a relatively recent methodological advance, multi-variate pattern analysis (MVPA), to decode the time course of the neural response to faces compared to other object categories (inverted faces, objects). Importantly, for the first time, we directly relate metrics of this decoding assessed at the individual level to gold-standard measures of behavioural face processing ability assessed in an independent task. Thirty-nine participants completed the behavioural Cambridge Face Memory Test (CFMT), then viewed images of faces and houses (presented upright and inverted) while their neural activity was measured via electroencephalography. Significant decoding of both face orientation and face category were observed in all individual participants. Decoding of face orientation, a marker of more advanced face processing, was earlier and stronger in participants with higher levels of face expertise, while decoding of face category information was earlier but not stronger for individuals with greater face expertise. Taken together these results provide a marker of significant differences in the early neuronal response to faces from around 100 ms post stimulus as a function of behavioural expertise with faces.

Stratifying the autistic phenotype using electrophysiological indices of social perception

Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by difficulties in social communication, but also great heterogeneity. To offer individualized medicine approaches, we need to better target interventions by stratifying autistic people into subgroups with different biological profiles and/or prognoses. We sought to validate neural responses to faces as a potential stratification factor in ASD by measuring neural (electroencephalography) responses to faces (critical in social interaction) in N = 436 children and adults with and without ASD. The speed of early-stage face processing (N170 latency) was on average slower in ASD than in age-matched controls. In addition, N170 latency was associated with responses to faces in the fusiform gyrus, measured with functional magnetic resonance imaging, and polygenic scores for ASD. Within the ASD group, N170 latency predicted change in adaptive socialization skills over an 18-month follow-up period; data-driven clustering identified a subgroup with slower brain responses and poor social prognosis. Use of a distributional data-driven cutoff was associated with predicted improvements of power in simulated clinical trials targeting social functioning. Together, the data provide converging evidence for the utility of the N170 as a stratification factor to identify biologically and prognostically defined subgroups in ASD.

Children's ability to recognize their parent's face improves with age

Adults are experts at recognizing familiar faces across images that incorporate natural within-person variability in appearance (i.e., ambient images). Little is known about children's ability to do so. In the current study, we investigated whether 4- to 7-year-olds (n = 56) could recognize images of their own parent-a person with whom children have had abundant exposure in a variety of different contexts. Children were asked to identify images of their parent that were intermixed with images of other people. We included images of each parent taken both before and after their child was born to manipulate how close the images were to the child's own experience. When viewing before-birth images, 4- and 5-year-olds were less sensitive to identity than were older children; sensitivity did not differ when viewing images taken after the child was born. These findings suggest that with even the most familiar face, 4- and 5-year-olds have difficulty recognizing instances that go beyond their direct experience. We discuss two factors that may contribute to the prolonged development of familiar face recognition.

Early lifetime experience of urban living predicts social attention in real world crowds

More than half of the world's population is currently living in cities, with more and more people moving to densely populated areas. The experience of growing up and living in crowded environments might influence the way we explore our social environment, mainly how we attend to others. Yet, we know little about how urbanicity affects this vital function of our social life. In two studies, we use mobile eye-tracking to measure participants' social attention, while walking through a shopping mall. Results show that social density of participants' native place impacts how frequently they look at passing strangers. People who experienced more city living from birth to early adolescence, attend more to strangers' faces than their rural counterparts. Our findings demonstrate that the early experience of urban upbringing configures social attention in adulthood. The urbanicity-related bias towards social gazing might reflect a more efficient processing of social information in urban natives.

The development of visual attention in infancy: A cascade approach

Visual attention develops rapidly and significantly during the first postnatal years. At birth, infants have poor visual acuity, poor head and neck control, and as a result have little autonomy over where and how long they look. Across the first year, the neural systems that support alerting, orienting, and endogenous attention develop, allowing infants to more effectively focus their attention on information in the environment important for processing. However, visual attention is a system that develops in the context of the whole child, and fully understanding this development requires understanding how attentional systems interact and how these systems interact with other systems across wide domains. By adopting a cascades framework we can better position the development of visual attention in the context of the whole developing child. Specifically, development builds, with previous achievements setting the stage for current development, and current development having cascading consequences on future development. In addition, development reflects changes in multiple domains, and those domains influence each other across development. Finally, development reflects and produces changes in the input that the visual system receives; understanding the changing input is key to fully understand the development of visual attention. The development of visual attention is described in this context.

Is human face recognition lateralized to the right hemisphere due to neural competition with left-lateralized visual word recognition? A critical review

The right hemispheric lateralization of face recognition, which is well documented and appears to be specific to the human species, remains a scientific mystery. According to a long-standing view, the evolution of language, which is typically substantiated in the left hemisphere, competes with the cortical space in that hemisphere available for visuospatial processes, including face recognition. Over the last decade, a specific hypothesis derived from this view according to which neural competition in the left ventral occipito-temporal cortex with selective representations of letter strings causes right hemispheric lateralization of face recognition, has generated considerable interest and research in the scientific community. Here, a systematic review of studies performed in various populations (infants, children, literate and illiterate adults, left-handed adults) and methodologies (behavior, lesion studies, (intra)electroencephalography, neuroimaging) offers little if any support for this reading lateralized neural competition hypothesis. Specifically, right-lateralized face-selective neural activity already emerges at a few months of age, well before reading acquisition. Moreover, consistent evidence of face recognition performance and its right hemispheric lateralization being modulated by literacy level during development or at adulthood is lacking. Given the absence of solid alternative hypotheses and the key role of neural competition in the sensory-motor cortices for selectivity of representations, learning, and plasticity, a revised language-related neural competition hypothesis for the right hemispheric lateralization of face recognition should be further explored in future research, albeit with substantial conceptual clarification and advances in methodological rigor.

Neural target selection as a marker of real-world familiarity during search for perceptually distinct objects

Prior studies have shown that behavioral performance is better when detecting specific familiar items based on real-world experience (e.g., an own-age face, a specific bird for bird experts), compared to less familiar items (e.g., an other-age face). These biases emerge from exposure to and interactions with initially less familiar items, which allow for better discrimination and search (e.g., finding an other-age face in a crowd). However, many broad categories in the natural environment (e.g., vintage objects, exotic fruit) contain perceptually distinct items that people can accurately search for individually, even if the objects are not as familiar. How might real-world familiarity impact search in these cases? Recent studies suggest that the N2pc event-related potential (ERP, neural marker of target selection) may be more sensitive than behavioral performance in reflecting prior knowledge, and perhaps familiarity, during visual search. In two experiments, the present study investigated the behavioral effects (Experiment 1) and N2pc effects (Experiment 2) of searching for distinct familiar (modern) versus less familiar (vintage) objects in younger adults. Experiment 1 also included a sample of older adults, who were familiar with both types of objects. Overall, the behavioral results did not reveal robust differences in searching for modern versus vintage objects. However, the N2pc in younger adults was present when searching for modern objects, but not for vintage objects. The N2pc results suggest that this neural marker may be more sensitive than behavioral measures in reflecting familiarity from real-world experiences with object categories.

Social categorization modulates own-age bias in face recognition and ERP correlates of face processing

The aim of the present study was to further understanding of how social categorization influences face recognition. According to the categorization-individuation model, face recognition can either be biased toward categorization or individuation. We hypothesized that the face recognition bias associated with a social category (e.g., the own-age bias) would be larger when faces were initially categorized according to that category. To examine this hypothesis, young adults (N = 63) completed a face recognition task after either making age or sex judgments while encoding child and adult faces. Young adults showed the own-age and own-sex biases in face recognition. Consistent with our hypothesis, the magnitude of the own-age bias in face recognition was larger when individuals made age, rather than sex, judgments at encoding. To probe the mechanisms underlying this effect, we examined ERP responses to child and adult faces across the social categorization conditions. Neither the P1 nor the N170 ERP components were modulated by the social categorization task or the social category membership of the face. However, the P2, which is associated with second-order configural processing, was larger to adult faces than child faces only in the age categorization condition. The N250, which is associated with individuation, was larger (i.e., more negative) to adult than child faces and during age categorization than sex categorization. These results are interpreted within the context of the categorization-individuation model and current research on biases in face recognition.

The characteristics of face configural effect in illiterates and literates

Literacy acquisition can modulate the way we process visual words and language. However, little is known about its function in reshaping how we process non-linguistic materials, like faces. In this study, we explored this question by comparing the facial recognition skills of illiterate and literate adults in China. Our results showed that illiterates were less sensitive to changes in spatial configuration among key features in upright faces when stimuli were presented simultaneously. The differences in sensitivity of spatial configuration between the literates and illiterates were also observed in house processing. These results thus provide evidence that literacy acquisition during childhood could reshape configural processing.

Gender and hometown population density interact to predict face recognition ability

Several studies have found that individuals from small hometowns show diminished face recognition ability as compared with individuals from larger hometowns. We further this line of research by relating six measures of face recognition ability to hometown density. We predicted that the three face recognition ability measures which included a learning component would relate to hometown density whereas the three measures which did not include such a learning component would not. Instead, we found that none of the six measures related to hometown density. Interestingly, we found interactions between gender and hometown population density on many of these measures and on a general index of face recognition, with females from small hometowns outperforming males from small hometowns but no such differences in the large hometown group. In a follow-up re-analysis of a previous study, we found a similar interaction in one of two face recognition ability measures. Together, these results reveal a pattern of gender differences modulated by hometown population density. If indeed experience with faces in one's hometown influences face recognition ability, understanding these effects may require more than a quantification of the environment. Men and women growing up in the same environment likely have different experiences, which likely modulates effects on visual abilities.

Face perception: A brief journey through recent discoveries and current directions

Faces are a rich source of information about the people around us. Identity, state of mind, emotions, intentions, age, gender, ethnic background, attractiveness and a host of other attributes about an individual can be gleaned from a face. When face perception fails, dramatic psycho-social consequences can follow at the individual level, as in the case of prosopagnosic parents who are unable to recognize their children at school pick-up. At the species level, social interaction patterns are shaped by human face perception abilities. The computational feat of recognizing faces and facial attributes, and the challenges overcome by the human brain to achieve this feat, have fascinated generations of vision researchers. In this paper, we present a brief overview of some of the milestones of discovery as well as outline a selected set of current directions and open questions on this topic.

How faces (and cars) may become special

Recent reports have shown that individuals from small hometowns show relatively poor face recognition ability as measured by the Cambridge Face Memory Test or CFMT (Balas & Saville, 2015, 2017), suggesting that the number of faces present in an individual's visual environment relates to that individual's face recognition ability. We replicate this finding in a sample from a different region (Nebraska) and with more variable age distribution. We extend the study by using another test of face recognition ability that does not require learning over trials, and with non-face object recognition tests that share the learning format with the CFMT. We find no hometown effect in these other tests, although more power would be required to show the CFMT effect is significantly larger. We use the same dataset to explore whether experience with more faces and cars in larger hometowns leads to specialization of these abilities. We find strong and substantial support for the hypothesis that the recognition abilities for faces and for cars are more independent from general object recognition in people from larger hometowns. This suggests that experience may be critical to the specialization of these abilities.

Beauty-related perceptual bias: Who captures the mind of the beholder?

INTRODUCTION

To explore the beauty-related perceptual bias and answers the question: Who can capture the mind of the beholder? Many studies have explored the specificity of human faces through ERP or other ways, and the materials they used are general human faces and other objects. Therefore, we want to further explore the difference between attractive faces and beautiful objects such as flowers.

METHODS

We recorded the eye movement of 22 male observers and 23 female observers using a standard two-alternative forced choice.

RESULTS

(1) The attractive faces were looked at longer and more often in comparison with the beautiful flowers; (2) fixation counts of female participants are more than male participants; and (3) the participants watched the beautiful flowers first, followed by the attractive faces, but there was no significant difference on the first fixation duration between the beautiful flowers and the attractive faces.

CONCLUSIONS

The data in this study may suggest that people prefer attractive faces to beautiful flowers.

Memory and Perception-based Facial Image Reconstruction

Visual memory for faces has been extensively researched, especially regarding the main factors that influence face memorability. However, what we remember exactly about a face, namely, the pictorial content of visual memory, remains largely unclear. The current work aims to elucidate this issue by reconstructing face images from both perceptual and memory-based behavioural data. Specifically, our work builds upon and further validates the hypothesis that visual memory and perception share a common representational basis underlying facial identity recognition. To this end, we derived facial features directly from perceptual data and then used such features for image reconstruction separately from perception and memory data. Successful levels of reconstruction were achieved in both cases for newly-learned faces as well as for familiar faces retrieved from long-term memory. Theoretically, this work provides insights into the content of memory-based representations while, practically, it may open the path to novel applications, such as computer-based 'sketch artists'.

Scanning of own- versus other-race faces in infants from racially diverse or homogenous communities

We examined the role of community face experience on 6- and 8-month-old Caucasian infants' scanning of own- and other-race face scanning. We measured infants' proportional fixation time and scan path amplitudes as indices of face processing. Proportional fixation time to informationally rich face regions varied as a function of age and face race for infants living in a racially homogeneous community, whereas scan path amplitudes varied as a function of age and face race for infants living in a racially diverse community. In both communities 6-month-old infants did not show different responding to own- and other-race faces, whereas 8-month-old infants responded differently to own- and other-race faces. However, 8-month-old infants from the two communities showed different patterns of cross-race face scanning. Therefore, experience in the community beyond the home appears to contribute to the development of differential scanning of own- versus other-race faces between 6 and 8 months of age.

Hometown size affects the processing of naturalistic face variability

Face exposure during development determines adults' abilities to recognize faces and the information they use to process them. Individual differences in the face categories represented in the visual environment can lead to category-specific deficits for recognizing faces that are atypical of observer's experience (e.g. the other-race effect). But what happens when observers have limited opportunities to learn about faces in general? In previous work, we found that observers from depopulated areas have poorer face recognition performance than observers from larger communities, suggesting that impoverished face experience limits face processing broadly. Here, we further investigate this phenomenon by examining how hometown size impacts the ability to assess appearance variability in natural images of faces and bodies. We asked individuals from small and large communities to complete (1) an unconstrained card-sorting task designed to test observers' ability to categorize within-person and between-person appearance variability properly, and (2) the Cambridge Face Memory Test. For both tasks, we examined the direct comparison between groups as well as the relationship between CFMT scores and sorting performance as a function of face experience. We find that small-town observers perform more poorly on the CFMT, but exhibit both better and worse performance than large-town observers on different aspects of the card-sorting task. Further, we also examine the relationship between CFMT performance and card-sorting errors. Our results suggest that individual differences in lifetime face exposure induce important variation in face processing abilities.

The Effects of Face Inversion and Face Race on the P100 ERP

Research about the neural basis of face recognition has investigated the timing and anatomical substrates of different stages of face processing. Scalp-recorded ERP studies of face processing have focused on the N170, an ERP with a peak latency of ∼170 msec that has long been associated with the initial structural encoding of faces. However, several studies have reported earlier ERP differences related to faces, suggesting that face-specific processes might occur before N170. Here, we examined the influence of face inversion and face race on the timing of face-sensitive scalp-recorded ERPs by examining neural responses to upright and inverted line-drawn and luminance-matched white and black faces in a sample of white participants. We found that the P100 ERP evoked by inverted faces was significantly larger than that evoked by upright faces. Although this inversion effect was statistically significant at 100 msec, the inverted-upright ERP difference peaked at 138 msec, suggesting that it might represent an activity in neural sources that overlap with P100. Inverse modeling of the inversion effect difference waveform suggested possible neural sources in pericalcarine extrastriate visual cortex and lateral occipito-temporal cortex. We also found that the inversion effect difference wave was larger for white faces. These results are consistent with behavioral evidence that individuals process the faces of their own races more configurally than faces of other races. Taken together, the inversion and race effects observed in the current study suggest that configuration influences face processing by at least 100 msec.

Eyeglasses elicit effects similar to face-like perceptual expertise: evidence from the N170 response

Studies of event-related potentials show that the specific N170 response has become a stable electrophysiological hallmark of objects related to expertise in early perceptual processing. In the present study, we investigated whether eyeglasses can elicit N170 effects similar to those elicited by objects of expertise. Our results showed that the N170 response elicited by eyeglasses was larger than the response elicited by objects that do not generate perceptual expertise (e.g., houses). Importantly, we found that eyeglasses could produce a within-category N170 adaptation effect, similar to that produced in response to objects of expertise (e.g., faces). Our results have revealed for the first time that with a large amount of experience, eyeglasses could evoke the face-like N170 response, which suggested that eyeglasses may become an object of perceptual expertise to some human observers.

The Faces in Infant-Perspective Scenes Change over the First Year of Life

Mature face perception has its origins in the face experiences of infants. However, little is known about the basic statistics of faces in early visual environments. We used head cameras to capture and analyze over 72,000 infant-perspective scenes from 22 infants aged 1-11 months as they engaged in daily activities. The frequency of faces in these scenes declined markedly with age: for the youngest infants, faces were present 15 minutes in every waking hour but only 5 minutes for the oldest infants. In general, the available faces were well characterized by three properties: (1) they belonged to relatively few individuals; (2) they were close and visually large; and (3) they presented views showing both eyes. These three properties most strongly characterized the face corpora of our youngest infants and constitute environmental constraints on the early development of the visual system.