Forming Facial Expressions Influences Assessment of Others' Dominance but Not Trustworthiness

Sensorimotor regulation of facial expression - An untouched frontier

Facial expression is a critical form of nonverbal social communication which promotes emotional exchange and affiliation among humans. Facial expressions are generated via precise contraction of the facial muscles, guided by sensory feedback. While the neural pathways underlying facial motor control are well characterized in humans and primates, it remains unknown how tactile and proprioceptive information reaches these pathways to guide facial muscle contraction. Thus, despite the importance of facial expressions for social functioning, little is known about how they are generated as a unique sensorimotor behavior. In this review, we highlight current knowledge about sensory feedback from the face and how it is distinct from other body regions. We describe connectivity between the facial sensory and motor brain systems, and call attention to the other brain systems which influence facial expression behavior, including vision, gustation, emotion, and interoception. Finally, we petition for more research on the sensory basis of facial expressions, asserting that incomplete understanding of sensorimotor mechanisms is a barrier to addressing atypical facial expressivity in clinical populations.

Should I trust you? Investigating trustworthiness judgements of painful facial expressions

Past research indicates that patients' reports of pain are often met with skepticism and that observers tend to underestimate patients' pain. The mechanisms behind these biases are not yet fully understood. One relevant domain of inquiry is the interaction between the emotional valence of a stranger's expression and the onlooker's trustworthiness judgment. The emotion overgeneralization hypothesis posits that when facial cues of valence are clear, individuals displaying negative expressions (e.g., disgust) are perceived as less trustworthy than those showing positive facial expressions (e.g., happiness). Accordingly, we hypothesized that facial expressions of pain (like disgust) would be judged more untrustworthy than facial expressions of happiness. In two separate studies, we measured trustworthiness judgments of four different facial expressions (i.e., neutral, happiness, pain, and disgust), displayed by both computer-generated and real faces, via both explicit self-reported ratings (Study 1) and implicit motor trajectories in a trustworthiness categorization task (Study 2). Ratings and categorization findings partly support our hypotheses. Our results reveal for the first time that when judging strangers' facial expressions, both negative expressions were perceived as more untrustworthy than happy expressions. They also indicate that facial expressions of pain are perceived as untrustworthy as disgust expressions, at least for computer-generated faces. These findings are relevant to the clinical setting because they highlight how overgeneralization of emotional facial expressions may subtend an early perceptual bias exerted by the patient's emotional facial cues onto the clinician's cognitive appraisal process.

Facial feedback effect on the sense of body ownership during the rubber hand illusion

The sense of body ownership, a feeling that one’s body belongs to the self, is an essential aspect of self-consciousness. Studies have focused on emotions and bodily states that could influence multisensory integration for the sense of body ownership. Based on the Facial Feedback Hypothesis, the purpose of this study was to examine whether displaying specific facial expressions affects the rubber hand illusion. We hypothesized that the expression of a smiling face changes the emotional experience and facilitates the formation of a sense of body ownership. In the experiment, participants (n = 30) were asked to hold a wooden chopstick in their mouths to simulate smile, neutral, and disgusted facial expressions during the induction of the rubber hand illusion. The results did not support the hypothesis, showing that proprioceptive drift (an index of illusory experience) was enhanced when the subjects displayed a disgusted facial expression, while the subjective reports of the illusion were not affected. These results, together with the previous studies regarding the effect of positive emotions, suggest that bodily affective information, regardless of its valence, facilitates multisensory integration and could influence the conscious representation of the bodily self.

The effects of facial expressions on judgments of others when observing two-person confrontation scenes from a third person perspective

When building personal relationships, it is important to select optimal partners, even based on the first meeting. This study was inspired by the idea that people who smile are considered more trustworthy and attractive. However, this may not always be true in daily life. Previous studies have used a relatively simple method of judging others by presenting a photograph of one person’s face. To move beyond this approach and examine more complex situations, we presented the faces of two people confronted with each other to participants and asked them to judge them from a third-person perspective. Through three experiments, participants were asked to judge which of the two persons was more appropriate for forming alliances, more trustworthy, or more attractive, respectively. In all experiments, images were shown for a short (500 ms) or a long time (5 s). In all three experiments, the results showed that participants were more likely to choose persons with happy faces than those with neutral, sad, or angry faces when the image presentation was short. Contrarily, the facial expressions did not affect those judgments when the image presentation was long. Instead, judgments were correlated with personality estimated from the model’s neutral face in a single-person presentation. These results suggest that although facial expressions can affect the judgments of others when observing two-person confrontations from a third-person perspective, when participants have more time to elaborate their judgments, they go beyond expressions.

The role of fragrance and self-esteem in perception of body odors and impressions of others

Human sweat odor serves as social communication signal for a person’s traits and emotional states. This study explored whether body odors can also communicate information about one’s self-esteem, and the role of applied fragrance in this relationship. Female participants were asked to rate self-esteem and attractiveness of different male contestants of a dating show, while being exposed to male participant’s body odors differing in self-esteem. High self-esteem sweat was rated more pleasant and less intense than low self-esteem sweat. However, there was no difference in perceived self-esteem and attractiveness of male contestants in videos, hence explicit differences in body odor did not transfer to judgments of related person characteristics. When the body odor was fragranced using a fragranced body spray, male contestants were rated as having higher self-esteem and being more attractive. The finding that body odors from male participants differing in self-esteem are rated differently and can be discriminated suggests self-esteem has distinct perceivable olfactory features, but the remaining findings imply that only fragrance affect the psychological impression someone makes. These findings are discussed in the context of the role of body odor and fragrance in human perception and social communication.

The nonverbal expression of power, status, and dominance

This paper reviews the nonverbal display of power, status, and dominance (PSDom). While PSDom are theoretically and often practically separate constructs, in the domain of nonverbal behaviors (NVBs) they are more often expressed similarly. Experimental research and field observations on adult humans were harvested for this review. The goals of this review were to: (1) summarize the list of reliable NVBs of PSDom (with associated references), (2) separately report those behaviors we think are associated with PSDom from those actually associated with PSDom, (3) describe the few existing distinctions between how power, status, and dominance each display NVBs and describe new reports on NVB associated with SES, social network size, and confidence, (4) address the quandary of whether the nonverbal expression of PSDom are universal across gender and culture and (5) provide a resource for researchers wishing to code nonverbal behaviors associated with PSDom.

The Role of the Face Itself in the Face Effect: Sensitivity, Expressiveness, and Anticipated Feedback in Individual Compliance

Face-to-face interactions are central to many individual choices and decision-making issues, such as customer services, sales, promotions, and negotiations. While the face effect, that is, face-to-face interactions are more effective in inducing compliance than other forms of interactions, has been noted in the literature, its mechanism has rarely been explored. This research helps to fill the theoretical void and provides new insights into the face effect with two lab experiments and one field experiment. Study 1, a field experiment conducted in a beauty salon, and Study 2, a lab experiment, show that the face effect is largely attributable to anticipated facial feedback and that the face effect is stronger when individuals are sensitive to face and when the requester's face is expressive. Study 3, using video-simulated face-to-face interactions, demonstrates that anticipated facial feedback, not necessarily actual feedback, is enough to drive the face effect. In so doing, this research furthers our understanding of factors that affect individual compliance in face-to-face interactions in both the "sending" and "receiving" stages. We discuss the theoretical and empirical implications, limitations, and future avenues of research.