Individual differences in trust evaluations are shaped mostly by environments, not genes.

People evaluate a stranger's trustworthiness from their facial features in a fraction of a second, despite common advice "not to judge a book by its cover." Evaluations of trustworthiness have critical and widespread social impact, predicting financial lending, mate selection, and even criminal justice outcomes. Consequently, understanding how people perceive trustworthiness from faces has been a major focus of scientific inquiry, and detailed models explain how consensus impressions of trustworthiness are driven by facial attributes. However, facial impression models do not consider variation between observers. Here, we develop a sensitive test of trustworthiness evaluation and use it to document substantial, stable individual differences in trustworthiness impressions. Via a twin study, we show that these individual differences are largely shaped by variation in personal experience, rather than genes or shared environments. Finally, using multivariate twin modeling, we show that variation in trustworthiness evaluation is specific, dissociating from other key facial evaluations of dominance and attractiveness. Our finding that variation in facial trustworthiness evaluation is driven mostly by personal experience represents a rare example of a core social perceptual capacity being predominantly shaped by a person's unique environment. Notably, it stands in sharp contrast to variation in facial recognition ability, which is driven mostly by genes. Our study provides insights into the development of the social brain, offers a different perspective on disagreement in trust in wider society, and motivates new research into the origins and potential malleability of face evaluation, a critical aspect of human social cognition.

Trustworthiness perception is mandatory: Task instructions do not modulate fast periodic visual stimulation trustworthiness responses.

Although it is often assumed that humans spontaneously respond to the trustworthiness of others' faces, it is still unclear whether responses to facial trust are mandatory or can be modulated by instructions. Considerable scientific interest lies in understanding whether trust processing is mandatory, given the societal consequences of biased trusting behavior. We tested whether neural responses indexing trustworthiness discrimination depended on whether the task involved focusing on facial trustworthiness or not, using a fast periodic visual stimulation electroencephalography oddball paradigm with a neural marker of trustworthiness discrimination at 1 Hz. Participants judged faces on size without any reference to trust, explicitly formed impressions of facial trust, or were given a financial lending context that primed trust, without explicit trust judgement instructions. Significant trustworthiness discrimination responses at 1 Hz were found in all three conditions, demonstrating the robust nature of trustworthiness discrimination at the neural level. Moreover, no effect of task instruction was observed, with Bayesian analyses providing moderate to decisive evidence that task instruction did not affect trustworthiness discrimination. Our finding that visual trustworthiness discrimination is mandatory points to the remarkable spontaneity of trustworthiness processing, providing clues regarding why these often unreliable impressions are ubiquitous.

Associations between hypomania proneness and attentional bias to happy, but not angry or fearful, faces in emerging adults.

Mania, the core feature of bipolar disorder, is associated with heightened and positive emotion responding. Yet, little is known about the underlying cognitive processes that may contribute to heightened positive emotionality observed. Additionally, while previous research has investigated positive emotion biases in non-clinical samples, few if any, account for subthreshold clinical symptoms or traits, which have reliably assessed psychopathological risk. The present study compared continuous scores on a widely used self-report measure of hypomania proneness (HPS-48) with a dot-probe task to investigate attentional biases for happy, angry, fearful, and neutral faces among 66 college student participants. Results suggested that hypomania proneness was positively associated with attentional bias towards happy, but not angry or fearful faces. Results remained robust when controlling for positive affect and did not appear to be affected by negative affect or current symptoms of depression, anxiety, and stress. Findings provide insight into potential behavioural markers that co-occur with heightened positive emotional responding and hypomania in emerging adults.

Can People Accurately Estimate the Calories in Food Images? An Optimised Set of Low- and High- Calorie Images from the food-pics database.

Calorie intake plays an important role in maintaining a healthy weight. As such, researchers often use the calorie content of food as a distinction when investigating appetite related brain processes and eating behaviour. This distinction assumes that observers accurately perceive caloric content. However, there is evidence suggesting this is not always the case. The current study examined how accurately observers could estimate the caloric content of food images from the widely used "Food-pics" database. Eight hundred and forty psychology undergraduate students (aged 16-60, 64% female) estimated the caloric value of 178 high and 182 low calorie foods. Calorie content of food from both categories was significantly overestimated. Additionally, 7.7% of low calorie images were misperceived as being high calorie images and 35% of high calorie images were misperceived as being low calorie foods. Neither participants' gender, nor the recognisability and likability of the food images, influenced calorie estimation. Our findings show that most people are unable to accurately estimate caloric content of most food. Despite this, a selection of food images were judged accurately, and we advocate the use of these in research where it is important to have low- and high-calorie food images. Specifically, we propose an optimised stimulus set of 25 high and 25 low calorie food images that are accurately judged by adult participants. In addition, we provide the open source dataset of our ratings of Food-pics images which, when added to the existing Food-pics attributes, creates an enhanced tool for researchers selecting food stimuli.

Evidence for a perceptual mechanism relating body size misperception and eating disorder symptoms.

PURPOSE: There are known and serious health risks associated with extreme body weights, including the development of eating disorders. Body size misperceptions are particularly evident in individuals with eating disorders, compared to healthy controls. The present research investigated whether serial dependence, a recently discovered bias in body size judgement, is associated with eating disorder symptomatology. We additionally examined whether this bias operates on holistic body representations or whether it works by distorting specific visual features. METHODS: A correlational analysis was used to examine the association between serial dependence and eating disorder symptomatology. We used a within-subjects experimental design to investigate the holistic nature of this misperception. Participants were 63 young women, who judged the size of upright and inverted female body images using a visual analogue scale and then completed the Eating Disorder Examination-Questionnaire (EDE-Q) to assess eating disorder symptoms. RESULTS: Our findings provide the first evidence of an association between serial dependence and eating disorder symptoms, with significant and positive correlations between body size misperception owing to serial dependence and EDE-Q scores, when controlling for Body Mass Index. Furthermore, we reveal that serial dependence is consistent with distortion of local visual features. CONCLUSIONS: Findings are discussed in relation to the broader theories of central coherence, cognitive inflexibility, and multisensory integration difficulties, and as providing a candidate mechanism for body size misperception in an eating disorder population. LEVEL OF EVIDENCE: Level 1, experimental study.

Ensemble coding of faces occurs in children and develops dissociably from coding of individual faces.

Ensemble coding allows adults to access useful information about average properties of groups, sometimes even in the absence of detailed representations of individual group members. This form of coding may emerge early in development with initial reports of ensemble coding for simple properties (size, numerosity) in young children and even infants. Here we demonstrate that ensemble coding of faces, which provides information about average properties of social groups, is already present in 6-8-year-old children. This access to average information increases with age from 6 to 18 years and its development is dissociable from age-related improvements in the coding of individual face identities. This dissociation provides the first direct evidence that distinct processes underlie ensemble and individual coding of face identity, evidence that has been lacking from adult studies. More generally, our results add to the emerging evidence for impressively mature sensitivity to statistical properties of the visual environment in children. They indicate that children have access to gist information about social groups that may facilitate adaptive social behaviour.

Disrupted Face Processing in Frontotemporal Dementia: A Review of the Clinical and Neuroanatomical Evidence.

Faces play an integral role in day-to-day functioning, particularly for social interactions where dynamic and rapid processing of information is vital. Analysis of faces allows an individual to ascertain a wide range of information including deciphering mood and identity, with these assessments directing an individual's subsequent response and behaviours. The prominent social and emotional deficits observed in frontotemporal dementia (FTD), a younger-onset dementia syndrome, may in part reflect a breakdown of the face processing network. Different subtypes of FTD present with divergent patterns of atrophy, although damage is predominantly confined to the frontal and temporal lobes. Specific predictions regarding the role of frontal and temporal regions in face processing have been proposed in the model outlined by Haxby et al. Trends in Cognitive Sciences, 4(6), 223-233 (2000). This model presents a parsimonious method by which to understand face processing in FTD while concurrently allowing assessment of the predictive value and applicability of such a model. By applying the Haxby model to the existing FTD literature, this review presents both direct and indirect evidence of a breakdown in key elements of the face processing network. The type and degree of breakdown appears to differ as a function of FTD subtype and associated brain atrophy. The evidence presented in this review and its relationship with predictions of the Haxby model provides impetus and direction for future research investigating face processing in FTD.

Perceived emotion genuineness: normative ratings for popular facial expression stimuli and the development of perceived-as-genuine and perceived-as-fake sets.

In everyday social interactions, people's facial expressions sometimes reflect genuine emotion (e.g., anger in response to a misbehaving child) and sometimes do not (e.g., smiling for a school photo). There is increasing theoretical interest in this distinction, but little is known about perceived emotion genuineness for existing facial expression databases. We present a new method for rating perceived genuineness using a neutral-midpoint scale (-7 = completely fake; 0 = don't know; +7 = completely genuine) that, unlike previous methods, provides data on both relative and absolute perceptions. Normative ratings from typically developing adults for five emotions (anger, disgust, fear, sadness, and happiness) provide three key contributions. First, the widely used Pictures of Facial Affect (PoFA; i.e., "the Ekman faces") and the Radboud Faces Database (RaFD) are typically perceived as not showing genuine emotion. Also, in the only published set for which the actual emotional states of the displayers are known (via self-report; the McLellan faces), percepts of emotion genuineness often do not match actual emotion genuineness. Second, we provide genuine/fake norms for 558 faces from several sources (PoFA, RaFD, KDEF, Gur, FacePlace, McLellan, News media), including a list of 143 stimuli that are event-elicited (rather than posed) and, congruently, perceived as reflecting genuine emotion. Third, using the norms we develop sets of perceived-as-genuine (from event-elicited sources) and perceived-as-fake (from posed sources) stimuli, matched on sex, viewpoint, eye-gaze direction, and rated intensity. We also outline the many types of research questions that these norms and stimulus sets could be used to answer.

Dynamic facial expressions are processed holistically, but not more holistically than static facial expressions.

There is evidence that facial expressions are perceived holistically and featurally. The composite task is a direct measure of holistic processing (although the absence of a composite effect implies the use of other types of processing). Most composite task studies have used static images, despite the fact that movement is an important aspect of facial expressions and there is some evidence that movement may facilitate recognition. We created static and dynamic composites, in which emotions were reliably identified from each half of the face. The magnitude of the composite effect was similar for static and dynamic expressions identified from the top half (anger, sadness and surprise) but was reduced in dynamic as compared to static expressions identified from the bottom half (fear, disgust and joy). Thus, any advantage in recognising dynamic over static expressions is not likely to stem from enhanced holistic processing, rather motion may emphasise or disambiguate diagnostic featural information.

Fearful faces drive gaze-cueing and threat bias effects in children on the lookout for danger.

Most developmental studies of face emotion processing show faces in isolation, in the absence of any broader context. Here we investigate two types of interactions between expression and threat contexts. First, in adults, following of another person's direction of social attention is increased when that person shows fear and the context requires vigilance for danger. We investigate whether this also occurs in children. Using a Posner-style eye-gaze cueing paradigm, we tested whether children would show greater gaze-cueing from fearful than happy expressions when the task was to be vigilant for possible dangerous animals. Testing across the 8-12-year-old age range, we found this fear priority effect was absent in the youngest children but developed to reach adult levels in the oldest children. However, even the oldest children were unable to sustain fear-prioritization when the onset of the target was delayed. Second, we addressed the development of 'threat bias' - namely faster identification of dangerous animals than safe animals - in the social context provided by expressive faces. In our non-anxious samples (i.e. with typical-population levels of anxiety), adults showed a threat bias regardless of the expression or looking direction of the just-seen cue face whereas 8-12-year-olds only showed a threat bias when the just-seen cue face displayed fear. Overall, the results argue that some, but not all, aspects of expression-context interactions are mature by 12 years of age.

Autistic traits are associated with differences in the perception of genuineness and approachability in emotional facial expressions, independently of alexithymia.

People with autism and higher levels of autistic traits often have difficulty interpreting facial emotion. Research has commonly investigated the association between autistic traits and expression labeling ability. Here, we investigated the association between two relatively understudied abilities, namely, judging whether expressions reflect genuine emotion, and using expressions to make social approach judgements, in a nonclinical sample of undergraduates at an Australian university (N = 149; data collected during 2018). Autistic traits were associated with more difficulty discriminating genuineness and less typical social approach judgements. Importantly, we also investigated whether these associations could be explained by the co-occurring personality trait alexithymia, which describes a difficulty interpreting one's own emotions. Alexithymia is hypothesized to be the source of many emotional difficulties experienced by autistic people and often accounts for expression labeling difficulties associated with autism and autistic traits. In contrast, the current results provided no evidence that alexithymia is associated with differences in genuineness discrimination and social approach judgements. Rather, differences varied as a function of individual differences in specific domains of autistic traits. More autistic-like social skills and communication predicted greater difficulty in genuineness discrimination, and more autistic-like social skills and attention to details and patterns predicted differences in approach judgements. These findings suggest that difficulties in these areas are likely to be better understood as features of the autism phenotype than of alexithymia. Finally, results highlight the importance of considering the authenticity of emotional expressions, with associations between differences in approach judgements being more pronounced for genuine emotional expressions. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Face recognition's practical relevance: Social bonds, not social butterflies.

Research on individual differences in face recognition has provided important foundational insights: their broad range, cognitive specificity, strong heritability, and resilience to change. Elusive, however, has been the key issue of practical relevance: do these individual differences correlate with aspects of life that go beyond the recognition of faces, per se? Though often assumed, especially in social realms, such correlates remain largely theoretical, without empirical support. Here, we investigate an array of potential social correlates of face recognition. We establish social relationship quality as a reproducible correlate. This link generalises across face recognition tasks and across independent samples. In contrast, we detect no robust association with the sheer quantity of social connections, whether measured directly via number of social contacts or indirectly via extraversion-related personality indices. These findings document the existence of a key social correlate of face recognition and provide some of the first evidence to support its practical relevance. At the same time, they challenge the naive assumption that face recognition relates equally to all social outcomes. In contrast, they suggest a focused link of face recognition to the quality, not quantity, of one's social connections.

What is overt and what is covert in congenital prosopagnosia?

The term covert recognition refers to recognition without awareness. In the context of face recognition, it refers to the fact that some individuals show behavioural, electrophysiological or autonomic indices of recognition in the absence of overt, conscious recognition. Originally described in cases of people that have lost their ability to overtly recognize faces (acquired prosopagnosia, AP), covert face recognition has more recently also been described in cases of congenital prosopagnosia (CP), who never develop typical overt face recognition skills. The presence of covert processing in a developmental disorder such as CP is a particularly intriguing phenomenon, and its investigation is relevant for a variety of reasons. From a theoretical point of view, it is useful to help shed light on the cognitive and neural underpinnings of face recognition deficits. From a clinical point of view, it has the potential to aid the design of rehabilitation protocols aimed at improving face recognition skills in this population. In the current review we selectively summarize the recent literature on covert face recognition in CP, highlight its main findings, and provide a theoretical interpretation for them.

Eye Gaze in Autism Spectrum Disorder: A Review of Neural Evidence for the Eye Avoidance Hypothesis.

Reduced eye contact early in life may play a role in the developmental pathways that culminate in a diagnosis of autism spectrum disorder. However, there are contradictory theories regarding the neural mechanisms involved. According to the amygdala theory of autism, reduced eye contact results from a hypoactive amygdala that fails to flag eyes as salient. However, the eye avoidance hypothesis proposes the opposite-that amygdala hyperactivity causes eye avoidance. This review evaluated studies that measured the relationship between eye gaze and activity in the 'social brain' when viewing facial stimuli. Of the reviewed studies, eight of eleven supported the eye avoidance hypothesis. These results suggest eye avoidance may be used to reduce amygdala-related hyperarousal among people on the autism spectrum.

Face perception and facial emotional expression recognition ability: Both unique predictors of the broader autism phenotype.

Autism spectrum disorder (ASD) and the broader autistic phenotype (BAP) have been suggested to be associated with perceptual-cognitive difficulties processing human faces. However, the empirical results are mixed, arguably, in part due to inadequate samples and analyses. Consequently, we administered the Cambridge Face Perception Test (CFPT), the Reading the Mind in the Eyes Test (RMET), a vocabulary test, and the Autism Quotient (AQ) to a sample of 318 adults in the general community. Based on a disattenuated path analytic modelling strategy, we found that both face perception ability (ß = -.21) and facial emotional expression recognition ability (ß = -.27) predicted uniquely and significantly the Communication dimension of AQ. Vocabulary failed to yield a significant, direct effect onto the Communication dimension of the AQ. We conclude that difficulties perceiving information from the faces of others may contribute to difficulties in nonverbal communication, as conceptualised and measured within the context of BAP.

Children show neural sensitivity to facial trustworthiness as measured by fast periodic visual stimulation.

Adults exhibit neural responses over the visual occipito-temporal area in response to faces that vary in how trustworthy they appear. However, it is not yet known when a mature pattern of neural sensitivity can be seen in children. Using a fast periodic visual stimulation (FPVS) paradigm, face images were presented to 8-to-9-year-old children (an age group which shows development of trust impressions; N = 31) and adult (N = 33) participants at a rate of 6 Hz (6 face images per second). Within this sequence, an 'oddball' face differing in the level of facial trustworthiness compared to the other faces, was presented at a rate of 1 Hz (once per second). Children were sensitive to variations in facial trustworthiness, showing reliable and significant neural responses at 1 Hz in the absence of instructions to respond to facial trustworthiness. Additionally, the magnitude of children's and adults' neural responses was similar, with strong Bayesian evidence that implicit neural responses to facial trustworthiness did not differ across the groups, and therefore, that visual sensitivity to differences in facial trustworthiness can show mature patterns by this age. Thus, nine or less years of social experience, perceptual and/or cognitive development may be sufficient for adult-like neural sensitivity to facial trustworthiness to emerge. We also validate the use of the FPVS methodology to examine children's implicit face-based trust processing for the first time, which is especially valuable in developmental research because this paradigm requires no explicit instructions or responses from participants.

Autistic Traits are Associated with Less Precise Perceptual Integration of Face Identity.

Face recognition difficulties are common in autism and could be a consequence of perceptual atypicalities that disrupt the ability to integrate current and prior information. We tested this theory by measuring the strength of serial dependence for faces (i.e. how likely is it that current perception of a face is biased towards a previously seen face) across the broader autism phenotype. Though serial dependence was not weaker in individuals with more autistic traits, more autistic traits were associated with greater integration of less similar faces. These results suggest that serial dependence is less specialised, and may not operate optimally, in individuals with more autistic traits and could therefore be a contributing factor to autism-linked face recognition difficulties.

Children's dynamic use of face- and behavior-based cues in an economic trust game.

Who do children trust? We investigated the extent to which children use face-based versus behavior-based cues when deciding whom to trust in a multiturn economic trust game. Children's (N = 42; aged 8 to 10 years; 31 females; predominantly White) trust decisions were informed by an interaction between face-based and behavior-based cues to trustworthiness, similarly to those of adults (N = 41; aged 17 to 48 years; 23 females; predominantly White). Facial trustworthiness guided children's investment decisions initially, such that they invested highly with trustworthy-looking partners and less with untrustworthy-looking partners. However, by the end of the trust game, after children had experienced game partners' fair or unfair return behavior, they overcame this bias and instead used partners' previous behavior to guide their trust decisions. Using partners' return behavior to guide decisions was the most rational strategy, because partners' facial trustworthiness was not an accurate cue to their actual trustworthiness. This dynamic use of different cues to trustworthiness suggests sophisticated levels of social cognition in children, which may reflect the social importance of trust impressions. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Serial dependence of facial identity for own- and other-race faces.

It is well established that individuals are better at recognising faces of their own-race compared with other-races; however, there is ongoing debate regarding the perceptual mechanisms that may be involved and therefore sensitive to face-race. Here, we ask whether serial dependence of facial identity, a bias where the perception of a face's identity is biased towards a previously presented face, shows an other-race effect. Serial dependence is associated with face recognition ability and appears to operate on high-level, face-selective representations, like other candidate mechanisms (e.g., holistic processing). We therefore expected to find an other-race effect for serial dependence for our Caucasian and Asian participants. While participants showed robust effects of serial dependence for all faces, only Caucasian participants showed stronger serial dependence for own-race faces. Intriguingly, we found that individual variation in own-race, but not other-race, serial dependence was significantly associated with face recognition abilities. Preliminary evidence also suggested that other-race contact is associated with other-race serial dependence. In conclusion, though we did not find an overall difference in serial dependence for own- versus other-race faces in both participant groups, our results highlight that this bias may be functionally different for own- versus other-race faces and sensitive to racial experience.