Infants prefer a trustworthy person: An early sign of social cognition in infants

Age-group differences in trust-related decision-making and learning

Facial impressions contribute to evaluations of trustworthiness. Older adults are especially vulnerable to trust violations, incurring risks for deception and exploitation. Using the newly developed social Iowa Gambling Task (S-IGT), we examined age-group differences in the impact of facial trustworthiness on decision-making and learning. In the congruent condition (CS-IGT), advantageous decks were paired with trustworthy faces and disadvantageous decks with untrustworthy faces. In the incongruent condition (IS-IGT), this pairing was reversed. Younger (n = 143) and older (n = 129) participants completed either the standard Iowa Gambling Task (IGT), CS-IGT, or IS-IGT. Both age groups preferred trustworthy faces in their initial choices. Older adults performed worse than younger adults across all tasks over time. Further, compared to younger adults, older adults performed worse on the IS-IGT, suggesting that incongruent facial cues interfered with older adults' performance, which aligns with reduced sensitivity to negative social reputations in aging. Multilevel modeling also indicated that age-group differences were most pronounced across all tasks in the last 40 trials. Together these findings suggest that differences between younger and older adults in experience-dependent decision-making are magnified in social contexts that involve a "wolf in sheep's clothing," which may reflect age-related difficulties in integrating incongruent information.

Toddlers' sensitivity to dominance traits from faces

In adults, seeing individual faces is sufficient to trigger dominance evaluations, even when conflict is absent. From early on, infants represent dyadic dominance relations and they can infer conflict outcomes based on a variety of cues. To date, it is unclear if toddlers also make automatic dominance trait evaluations of individual faces. Here we asked if toddlers are sensitive to dominance traits from faces, and whether their sensitivity depends on their face experience. We employed a visual preference paradigm to study 18- and 24-month-old toddlers' sensitivity to dominance traits from three types of faces: artificial, male, female. When presented with artificial faces (Experiment 1), 18- and 24-month-olds attended longer to the non-dominant faces, but only when they were in upright orientation. For real male faces (Experiment 2), toddlers showed equivalent looking durations to the dominant and non-dominant upright faces. However, when looking at female faces (Experiment 3), toddlers displayed a visual preference for the upright non-dominant faces at 24 months. To our knowledge, this is the first study to show that toddlers already display sensitivity to facial cues of dominance from 18 months of age, at least for artificial face stimuli.

The role of the prefrontal cortex in social interactions of animal models and the implications for autism spectrum disorder

Social interaction is a complex behavior which requires the individual to integrate various internal processes, such as social motivation, social recognition, salience, reward, and emotional state, as well as external cues informing the individual of others' behavior, emotional state and social rank. This complex phenotype is susceptible to disruption in humans affected by neurodevelopmental and psychiatric disorders, including autism spectrum disorder (ASD). Multiple pieces of convergent evidence collected from studies of humans and rodents suggest that the prefrontal cortex (PFC) plays a pivotal role in social interactions, serving as a hub for motivation, affiliation, empathy, and social hierarchy. Indeed, disruption of the PFC circuitry results in social behavior deficits symptomatic of ASD. Here, we review this evidence and describe various ethologically relevant social behavior tasks which could be employed with rodent models to study the role of the PFC in social interactions. We also discuss the evidence linking the PFC to pathologies associated with ASD. Finally, we address specific questions regarding mechanisms employed by the PFC circuitry that may result in atypical social interactions in rodent models, which future studies should address.

We need to move beyond rating scales, white faces and adult perceivers: Invited Commentary on Sutherland & Young (2022), understanding trait impressions from faces

Sutherland and Young's perspective is a timely and rigorous examination of trait impressions based on facial cues. We propose three strtegies to further advance the field: incorporating natural language processing, including diverse facial stimuli, and re-interpreting developmental data.

Face-to-trait inferences in Japanese children and adults based on Caucasian faces

Recently, many studies have indicated that humans make social evaluations from facial appearances instantaneously and automatically. Furthermore, such judgments play an important role in several social contexts. However, the mechanisms involved in the ability to form impressions from faces are still unknown, as is the extent to which these can be regarded as universal in perceiving impressions. In the current study, computer-generated Caucasian faces were used to assess the universality or cultural differences in impression formation among Japanese children and adults. This study hypothesized that impressions of trustworthiness and dominance may be more fundamental and universal, whereas the impression of competence may be more complex and culture-dependent. In Experiment 1a, 42 children aged 3-6 years were presented with 10 pairs of face images and asked which image in each pair was more trustworthy, dominant, or competent. Overall, it was found that as age increased, the rate of agreement of Japanese participants with the judgment of American participants, obtained in a previous study, increased. However, the agreement rate for competence was relatively low. Experiment 1b, conducted with 46 children, was a replication of Experiment 1a, and the results showed the same tendency. In Experiment 2, 45 Japanese adults made impression judgments on 19 pairs of face images identical to those used in Experiment 1b. The results suggested that while dominance was a dimension not easily influenced by developmental changes or culture, trustworthiness could be influenced by cultural differences in facial expression recognition. Therefore, different judgment criteria are used for children and adults. For competence, the agreement rate with Americans was relatively stable and low among the different age groups. This suggests that depending on the dimension of the trait, certain judgments are influenced by cultural context and, therefore, change criteria, while others are based on more universal criteria.

Preferential looking studies of trustworthiness detection confound structural and expressive cues to facial trustworthiness

On encountering a stranger, we spontaneously attribute to them character traits (e.g., trustworthiness, intelligence) based on their facial appearance. Participants can base impressions on structural face cues-the stable aspects of facial appearance that support identity recognition-or expression cues, such as the presence of a smile. It has been reported that 6- to 8-month-old infants attend to faces that adults judge to be trustworthy in preference to faces judged untrustworthy. These results are striking because the face stimuli employed were ostensibly emotion neutral. Consequently, these preferential looking effects have been taken as evidence for innate sensitivity to structural face cues to trustworthiness. However, scrutiny of the emotion rating procedure used with adults suggests that the face stimuli employed may have been judged emotion neutral only when interleaved with more obvious examples of facial affect. This means that the faces may vary in emotional expression when compared to each other. Here, we report new evidence obtained from adult raters that the stimuli used in these studies confound trustworthiness and untrustworthiness with the presence of happiness and anger, respectively. These findings suggest that the preferential looking effects described in infants are compatible with a preference for positive facial affect and may not reflect early sensitivity to structural face cues to trustworthiness.

Sensitivity to trustworthiness cues in own- and other-race faces: The role of spatial frequency information

Research has shown that adults are better at processing faces of the most represented ethnic group in their social environment compared to faces from other ethnicities, and that they rely more on holistic/configural information for identity discrimination in own-race than other-race faces. Here, we applied a spatial filtering approach to the investigation of trustworthiness perception to explore whether the information on which trustworthiness judgments are based differs according to face race. European participants (N = 165) performed an online-delivered pairwise preference task in which they were asked to select the face they would trust more within pairs randomly selected from validated White and Asian broad spectrum, low-pass filter and high-pass filter trustworthiness continua. Results confirmed earlier demonstrations that trustworthiness perception generalizes across face ethnicity, but discrimination of trustworthiness intensity relied more heavily on the LSF content of the images for own-race faces compared to other-race faces. Results are discussed in light of previous work on emotion discrimination and the hypothesis of overlapping perceptual mechanisms subtending social perception of faces.

The cultural learning account of first impressions

Humans spontaneously attribute character traits to strangers based on their facial appearance. Although these 'first impressions' typically have no basis in reality, some authors have assumed that they have an innate origin. By contrast, the Trait Inference Mapping (TIM) account proposes that first impressions are products of culturally acquired associative mappings that allow activation to spread from representations of facial appearance to representations of trait profiles. According to TIM, cultural instruments, including propaganda, illustrated storybooks, art and iconography, ritual, film, and TV, expose many individuals within a community to common sources of correlated face-trait experience, yielding first impressions that are shared by many, but typically inaccurate. Here, we review emerging empirical findings, many of which accord with TIM, and argue that future work must distinguish first impressions based on invariant facial features (e.g., shape) from those based on facial behaviours (e.g., expressions).

Identifying criminals: No biasing effect of criminal context on recalled threat

To date, it is still unclear whether there is a systematic pattern in the errors made in eyewitness recall and whether certain features of a person are more likely to lead to false identification. Moreover, we also do not know the extent of systematic errors impacting identification of a person from their body rather than solely their face. To address this, based on the contextual model of eyewitness identification (CMEI; Osborne & Davies, 2014, Applied Cognitive Psychology, 28[3], 392-402), we hypothesized that having framed a target as a perpetrator of a violent crime, participants would recall that target person as appearing more like a stereotypical criminal (i.e., more threatening). In three separate experiments, participants were first presented with either no frame, a neutral frame, or a criminal frame (perpetrators of a violent crime) accompanying a target (either a face or body). Participants were then asked to identify the original target from a selection of people that varied in facial threat or body musculature. Contrary to our hypotheses, we found no evidence of bias. However, identification accuracy was highest for the most threatening target bodies high in musculature, as well as bodies paired with detailed neutral contextual information. Overall, these findings suggest that while no systematic bias exists in the recall of criminal bodies, the nature of the body itself and the context in which it is presented can significantly impact identification accuracy.

Neural sensitivity to trustworthiness cues from realistic face images is associated with temperament: An electrophysiological study with 6-month-old infants

Discriminating facial cues to trustworthiness is a fundamental social skill whose developmental origins are still debated. Prior investigations used computer-generated faces, which might fail to reflect infants' face processing expertise. Here, Event-Related Potentials (ERPs) were recorded in Caucasian adults (N = 20, 7 males, M age = 25.25 years) and 6-month-old infants (N = 21, 10 males) in response to variations in trustworthiness intensity expressed by morphed images of realistic female faces associated with explicit trustworthiness judgments (Study 1). Preferential looking behavior in response to the same faces was also investigated in infants (N = 27, 11 males) (Study 2). ERP results showed that both age groups distinguished subtle stimulus differences, and that interindividual variability in neural sensitivity to these differences were associated with infants' temperament. No signs of stimulus differentiation emerged from infants' looking behavior. These findings contribute to the understanding of the developmental origins of human sensitivity to social cues from faces by extending prior evidence to more ecological stimuli and by unraveling the mediating role of temperament.

Parents reinforce the formation of first impressions in conversation with their children

The tendency to form first impressions from facial appearance emerges early in development. One route through which these impressions may be learned is parent-child interaction. In Study 1, 24 parent-child dyads (children aged 5–6 years, 50% male, 83% White British) were given four computer generated faces and asked to talk about each of the characters shown. Study 2 (children aged 5–6 years, 50% male, 92% White British) followed a similar procedure using images of real faces. Across both studies, around 13% of conversation related to the perceived traits of the individuals depicted. Furthermore, parents actively reinforced their children’s face-trait mappings, agreeing with the opinions they voiced on approximately 40% of occasions across both studies. Interestingly, although parents often encouraged face-trait mappings in their children, their responses to questionnaire items suggested they typically did not approve of judging others based on their appearance.

Culturally learned first impressions occur rapidly and automatically and emerge early in development

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 ms (Study 3). Finally, we show that 6-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.