Parsing the Mechanisms Underlying Ingroup Facial Resemblance

People prefer to form relationships with people like themselves—a tendency that extends even to facial appearance, resulting in groups whose members look alike. Here, we investigated the mechanisms underlying homophilic resemblance using facial photos of fraternity/sorority members from two time points: before joining the group and after belonging to the group for three years. Analyses of both subjective trait impressions and objective face-shape measurements revealed that not only did group members look alike, they resembled one another even before joining the group. Moreover, photos of potential fraternity recruits revealed that facial appearance predicted both the group that individuals sought to join and the group’s likelihood of accepting them. Individuals, therefore, seek to join groups consisting of people who look like them, and the groups preferentially accept new members who resemble those already in the group. This bidirectional preference for homophily likely perpetuates intragroup homogeneity, suggesting potential implications beyond appearance.

The Effect of the Intensity of Happy Expression on Social Perception of Chinese Faces

Numerous studies have shown that facial expressions influence trait impressions in the Western context. There are cultural differences in the perception and recognition rules of different intensities of happy expressions, and researchers have only explored the influence of the intensity of happy expressions on a few facial traits (warmth, trustworthiness, and competence). Therefore, we examined the effect of different intensities of Chinese happy expressions on the social perception of faces from 11 traits, namely trustworthiness, responsibility, attractiveness, sociability, confidence, intelligence, aggressiveness, dominance, competence, warmth, and tenacity. In this study, participants were asked to view a series of photographs of faces with high-intensity or low-intensity happy expressions and rate the 11 traits on a 7-point Likert scale (1 = “not very ××,” 7 = “very ××”). The results indicated that high-intensity happy expression had higher-rated scores for sociability and warmth but lower scores for dominance, aggressiveness, intelligence, and competence than the low-intensity happy expression; there was no significant difference in the rated scores for trustworthiness, attractiveness, responsibility, confidence, and tenacity between the high-intensity and low-intensity happy expressions. These results suggested that, compared to the low-intensity happy expression, the high-intensity happy expression will enhance the perceptual outcome of the traits related to approachability, reduce the perceptual outcome of traits related to capability, and have no significant effect on trustworthiness, attractiveness, responsibility, confidence, and tenacity.

Person perception across group boundaries: a dynamic model of perception across race and gender lines

People form impressions of others from their faces, inferring character traits (e.g., friendly) along two broad, influential dimensions: Warmth and Competence. Although these two dimensions are presumed to be independent, research has yet to examine the generalizability of this model to cross-group impressions, despite extant evidence that Warmth and Competence are not independent for outgroup targets. This thesis explores this possibility by testing models of person perception for own-group and other-group perceptions, implementing confirmatory factor analysis in a structural equation modeling framework, and analyzing the underlying trait space using representational similarity analysis. I fit 402,473 ratings of 873 unique faces from 5,040 participants on 14 trait impressions to own-group and other-group models, exploring whether perceptions across race and gender are more unidimensional. Results indicate that current models of face perception fit poorly and are not universal as presumed: the space of trait impressions varies depending on targets’ race and gender. Keywords: person perception, impression formation, face perception, intergroup processes, social cognition

Person perception across group boundaries: a dynamic model of perception across race and gender lines

People form impressions of others from their faces, inferring character traits (e.g., friendly) along two broad, influential dimensions: Warmth and Competence. Although these two dimensions are presumed to be independent, research has yet to examine the generalizability of this model to cross-group impressions, despite extant evidence that Warmth and Competence are not independent for outgroup targets. This thesis explores this possibility by testing models of person perception for own-group and other-group perceptions, implementing confirmatory factor analysis in a structural equation modeling framework, and analyzing the underlying trait space using representational similarity analysis. I fit 402,473 ratings of 873 unique faces from 5,040 participants on 14 trait impressions to own-group and other-group models, exploring whether perceptions across race and gender are more unidimensional. Results indicate that current models of face perception fit poorly and are not universal as presumed: the space of trait impressions varies depending on targets’ race and gender. Keywords: person perception, impression formation, face perception, intergroup processes, social cognition

Face masks reduce emotion-recognition accuracy and perceived closeness

Face masks became the symbol of the global fight against the coronavirus. While face masks’ medical benefits are clear, little is known about their psychological consequences. Drawing on theories of the social functions of emotions and rapid trait impressions, we tested hypotheses on face masks’ effects on emotion-recognition accuracy and social judgments (perceived trustworthiness, likability, and closeness). Our preregistered study with 191 German adults revealed that face masks diminish people’s ability to accurately categorize an emotion expression and make target persons appear less close. Exploratory analyses further revealed that face masks buffered the negative effect of negative (vs. non-negative) emotion expressions on perceptions of trustworthiness, likability, and closeness. Associating face masks with the coronavirus’ dangers predicted higher perceptions of closeness for masked but not for unmasked faces. By highlighting face masks’ effects on social functioning, our findings inform policymaking and point at contexts where alternatives to face masks are needed.

The Face of Social Networks: Naive Observers’ Accurate Assessment of Others’ Social Network Positions From Faces

We examined whether, even at zero acquaintance, observers accurately infer others’ social network positions—specifically, the number and patterning of social ties (e.g., brokerage—the extent to which a person bridges disconnected people) and the trait impressions that support this accuracy. We paired social network data ( n = 272 professional school students), with naive observers’ ( n = 301 undergraduates) judgments of facial images of each person within the network. Results revealed that observers’ judgments of targets’ number of friends were predicted by the actual number of people who considered the target a friend (in-degree centrality) and that perceived brokerage was significantly predicted by targets’ actual brokerage. Lens models revealed that targets’ perceived attractiveness, dominance, warmth, competence, and trustworthiness supported this accuracy, with attractiveness and warmth most associated with perceptions of popularity and brokerage. Overall, we demonstrate accuracy in naive observers’ judgments of social network position and the trait impressions supporting these inferences.

EXPRESS: The interplay between gaze cueing and facial trait impressions

The gaze cueing effect involves the rapid orientation of attention to follow the gaze direction of another person. Previous studies reported reciprocal influences between social variables and the gaze cueing effect, with modulation of gaze cueing by social features of face stimuli and modulation of the observer’s social judgments from the validity of the gaze cues themselves. However, it remains unclear which social dimensions can affect - and be affected by - gaze cues. We used computer-averaged prototype face-like images with high and low levels of perceived trustworthiness and dominance to investigate the impact of these two fundamental social impression dimensions on the gaze cueing effect. Moreover, by varying the proportions of valid and invalid gaze cues across three experiments, we assessed whether gaze cueing influences observers' impressions of dominance and trustworthiness through incidental learning. Bayesian statistical analyses provided clear evidence that the gaze cueing effect was not modulated by facial social trait impressions (Experiments 1-3). On the other hand, there was uncertain evidence of incidental learning of social evaluations following the gaze cueing task. A decrease in perceived trustworthiness for non-cooperative low dominance faces (Experiment 2) and an increase in dominance ratings for faces whose gaze behaviour contradicted expectations (Experiment 3) appeared, but further research is needed to clarify these effects. Thus, this study confirms that attentional shifts triggered by gaze direction involve a robust and relatively automatic process, which could nonetheless influence social impressions depending on perceived traits and the gaze behaviour of faces providing the cues.

Understanding the role of faces in person perception: Increased reliance on facial appearance when judging sociability

Faces play a central role in person perception. People spontaneously judge others’ personality based on their facial appearance and these impressions guide many consequential decisions. Under what conditions do people rely on facial appearance? Here, we test whether reliance on facial appearance depends on the goal of impression formation (i.e., on which trait dimension targets are evaluated). Trait impressions are, to a large extent, based on the resemblance of facial cues to emotion expressions. As emotional expressiveness is a central component of sociability, we hypothesized that people would more readily perceive sociability in faces. Across three preregistered studies (N = 1,436), we find that facial appearance is indeed seen as more indicative of a person’s sociability than their morality or competence. We find the same pattern when examining the influence of facial cues on judgment and decision-making. People are more confident in the accuracy of their trait impressions when judging sociability (vs. morality or competence; Study 1, n = 527), they value information on the facial appearance of job candidates more when looking for a sociable (vs. moral or competent) employee (Study 2, n = 390), and they view reliance on facial appearance when making hiring decisions as more appropriate and more effective when looking for a sociable (vs. moral or competent) employee (Study 3, n = 519). Together, our results provide converging evidence that people view facial appearance as especially relevant for judging a person’s sociability.

Face masks reduce emotion-recognition accuracy and perceived closeness

Face masks became the symbol of the global fight against the coronavirus. While face masks’ medical benefits are clear, little is known about their psychological consequences. Drawing on theories of the social functions of emotions and rapid trait impressions, we tested hypotheses on face masks’ effects on emotion-recognition accuracy and social judgments (perceived trustworthiness, likability, and closeness). Our preregistered study with 191 German adults revealed that face masks diminish people’s ability to accurately categorize an emotion expression and make target persons appear less close. Exploratory analyses further revealed that face masks buffered the negative effect of negative (vs. non-negative) emotion expressions on perceptions of trustworthiness, likability, and closeness. Associating face masks with the coronavirus’ dangers predicted higher perceptions of closeness for masked but not for unmasked faces. By highlighting face masks’ effects on social functioning, our findings inform policymaking and point at contexts where alternatives to face masks are needed.

Expectations about pain and analgesic treatment depend on medical providers’ facial appearances

There is a robust link between patients’ expectations and clinical outcomes, as evidenced by the placebo effect. These expectations are shaped by the context surrounding treatment, including the patient-provider interaction. Prior work indicates that the provider’s behavior and characteristics, including warmth and competence, can shape patient outcomes. Yet humans rapidly form trait impressions of others prior to any in-person interaction. Here, we tested whether trait-impressions of hypothetical medical providers, based purely on facial images, influence participants’ choice of medical providers and expectations about their health following hypothetical medical procedures performed by those providers in a series of vignettes. Across five studies, participants selected providers who appeared more competent, based on facial visual information alone. Further, providers’ apparent competence predicted participants’ expectations about post-procedural pain and medication use. Participants’ perception of their similarity to providers also shaped expectations about pain and treatment outcomes. Our results suggest that humans develop expectations about their health outcomes prior to even setting foot in the clinic, based exclusively on first impressions. These findings have strong implications for health care, as individuals increasingly rely on digital services to choose healthcare providers, schedule appointments, and even receive treatment and care, a trend which is exacerbated as the world embraces telemedicine.