Facial trustworthiness predicts ingroup inclusion decisions

Facial basis of stereotypes: Judgements of warmth and competence based on cross-group typicality/distinctiveness of faces

Human migration is an increasingly common phenomenon and migrants are at risk of disadvantageous treatment. We reasoned that migrants may receive differential treatment by locals based on the closeness of their facial features to the host average. Residents of Türkiye, the country with the largest number of refugees currently, served as participants. Because many of these refugees are of Arabic origin, we created target facial stimuli varying along the axis connecting Turkish and Arabic morphological prototypes (excluding skin colour) computed using geometric morphometrics and available databases. Participants made judgements of two universal dimensions of social perception-warmth and competence-on these faces. We predicted that participants judging faces manipulated towards the Turkish average would provide higher warmth and competence ratings compared to judging the same faces manipulated towards the Arabic average. Bayesian statistical tools were employed to estimate parameter values in multilevel models with intercorrelated varying effects. The findings did not support the prediction and revealed raters (as well as target faces) to be an important source of variation in social judgements. In the absence of simple cues (e.g. skin colour, group labels), the effect of facial morphology on social judgements may be much more complex than previously assumed.

Intergroup evaluative bias in facial representations of immigrants and citizens in the United States

We used a reverse-correlation image-classification paradigm to visualize facial representations of immigrants and citizens in the United States. Visualizations of immigrants' faces were judged by independent raters as less trustworthy and less competent and were more likely to be categorized as a non-White race/ethnicity than were visualizations of citizens' faces. Additionally, image generators' personal characteristics (e.g., implicit and explicit evaluations of immigrants, nativity status) did not reliably track with independent judges' ratings of image generators' representations of immigrants. These findings suggest that anti-immigrant sentiment and racial/ethnic assumptions characterize facial representations of immigrants in the United States, even among people who harbor positivity toward immigrants.

Preliminary evidence for neck musculature in shaping functional stereotypes of men's relationship motives

Neck musculature is reliably diagnostic of men's formidability and central to several inferences of their physical prowess. These inferences facilitate stereotypes of men's social value from which perceivers estimate their abilities to satisfy reproductive goals related to mate acquisition and parental care. Participants evaluated men's interest in various mating and parenting strategies, wherein men varied in the size of visible neck musculature through trapezii and sternocleidomastoids for perceivers to identify potential reproductive interests and goals. Large trapezii elicited perceptions of men as more effective at protecting offspring, albeit at the expense of nurturance and interest in long-term pair bonds. Results extend previous findings implicating formidability as central to relationship decisions by considering a novel modality.

Perceiver and target partisanship shift facial trustworthiness effects on likability

The affective polarization characteristic of the United States' political climate contributes to pervasive intergroup tension. This tension polarizes basic aspects of person perception, such as face impressions. For instance, face impressions are polarized by partisanship disclosure such that people form positive and negative impressions of, respectively, shared and opposing partisan faces. How partisanship interacts with other facial cues affecting impressions remains unclear. Building on work showing that facial trustworthiness, a core dimension of face perception, is especially salient for ingroup members, we reasoned that shared and opposing partisanship may also affect the relation between facial trustworthiness characteristics and subsequent likability impressions. A stronger positive relation emerged for shared versus opposing partisan faces across more conservative and liberal perceivers (Experiments 1 and 2). Exploratory analyses showed that this difference links to perceived partisan threat (Experiment 1) and that experimentally manipulating inter-party threat strengthened opposing partisan derogation and shared partisan enhancement patterns (Experiment 2). These findings suggest that partisanship extends from affecting overall face impressions of partisans to affecting the relation between a core dimension of face perception and subsequent impressions. These findings highlight the prevalence of partisanship effects in basic aspects of person perception and have implications for intergroup behavior.

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.