The potential role of robust face representations learned within families when searching for one's child in a crowd.

Own child's face is one of the most socially salient stimuli for parents, and a faster search for it than for other children's faces may help provide warmer and more sensitive care. However, it has not been experimentally examined whether parents find their child's face faster. In addition, although own child's face is specially processed, the search time for own child's face may be similar to that for other socially salient stimuli, such as own or spouse's faces. This study tested these possibilities using a visual search paradigm. Participants (parents) searched for their child's, own, spouse's, other child's, same-sex adult's, or opposite-sex adult's faces as search targets. Our findings indicate that both mothers and fathers identified their child's face more quickly than other children's faces. Similarly, parents found their own and spouse's faces more quickly than other adults' faces. Moreover, the search time for family members' faces increased with the number of faces on the search display, suggesting an attentional serial search. These results suggest that robust face representations learned within families and close relationships can support reduced search times for family members' faces.

Interpersonal physiological synchrony is associated with first person and third person subjective assessments of excitement during cooperative joint tasks.

Interpersonal physiological synchrony has been shown to play important roles in social activities. While most studies have shed light on the effects of physiological synchrony on recognition of the group state, such as cohesion or togetherness, the effect of physiological synchrony on the recognition of emotional experience has not been adequately researched. In this study, we examined how physiological synchrony is associated with first- and third-person emotion recognition during a joint task. Two participants played a cooperative block-stacking game (Jenga), alternating their roles as player and adviser, while their heart rates were recorded. The participants evaluated their own emotional experience for each turn. Bystanders watched the game to evaluate the players' emotions. Results showed that the players' subjective excitement increased not only with their own heart rate, but also with increased heart rate synchrony with their adviser. Heart rate synchrony between player and adviser also related to increased intensity in perceived excitement from the bystanders. Given that both first- and third-person emotion recognition can have cumulative impacts on a group, the relationship between physiological synchrony and emotion recognition observed in the present study will help deepen understanding of the psychophysiological mechanisms underlying larger group phenomena such as crowd excitement.

Your Face and Moves Seem Happier When I Smile.

In this experiment, we replicated the effect of muscle engagement on perception such that the recognition of another's facial expressions was biased by the observer's facial muscular activity (Blaesi & Wilson, 2010). We extended this replication to show that such a modulatory effect is also observed for the recognition of dynamic bodily expressions. Via a multilab and within-subjects approach, we investigated the emotion recognition of point-light biological walkers, along with that of morphed face stimuli, while subjects were or were not holding a pen in their teeth. Under the "pen-in-the-teeth" condition, participants tended to lower their threshold of perception of happy expressions in facial stimuli compared to the "no-pen" condition, thus replicating the experiment by Blaesi and Wilson (2010). A similar effect was found for the biological motion stimuli such that participants lowered their threshold to perceive happy walkers in the pen-in-the-teeth condition compared to the no-pen condition. This pattern of results was also found in a second experiment in which the no-pen condition was replaced by a situation in which participants held a pen in their lips ("pen-in-lips" condition). These results suggested that facial muscular activity alters the recognition of not only facial expressions but also bodily expressions.

Convergence of physiological responses to pain during face-to-face interaction.

Empathy with another's pain is an important social glue for maintaining interpersonal relationships. In most previous studies investigating the sharing of pain, a signal conveying a painful experience is presented by a target ("sender") as a stimulus to a participant ("receiver"), and the emotional/physiological responses of the participant are measured. However, this unilateral "sender-receiver" paradigm does not adequately address the possible bidirectional experience of shared pain accruing from interaction. Our aim was therefore to investigate the bidirectional effects of sharing pain in social settings. Thirty-six unfamiliar pairs were simultaneously and repeatedly exposed to the same pain-provoking (thermal) stimuli, either in a face-to-face or a "shielded" condition where a partition prevented the partner's responses from being fully observed. We recorded the blood volume pulse of each participant to measure the acute sympathetic response while a pair of participants experienced the stimuli simultaneously. The results revealed that participants with weaker reactions elevated their physiological reactivity to the stimulus in accordance with their partner's reactions in the face-to-face condition. The pair-level physiological similarity was also higher compared to the shielded condition. Such a low-to-high physiological convergence may underlie the collective elevation of pain expressions, which is often observed in interactive settings.

Vasopressin enhances human preemptive strike in both males and females.

The neuropeptide arginine vasopressin (AVP), which is known to modulate a wide range of social behaviors in animals, has been identified as a modulator of various negative responses to social stimuli in humans. However, behavioral evidence directly supporting its involvement in human defensive aggression has been rare. We investigated the effect of intranasal AVP on defensive aggression in a laboratory experiment, using an incentivized economic game called the "preemptive strike game" (PSG). Participants played PSG individually (1 on 1) as well as in pairs (2 on 2) under either AVP or saline. We observed that exogenous but not basal AVP modulated the attack rate in PSG for both male and female participants. A model-based analysis of the aggregation of individual attack preferences into pair decisions revealed that the AVP effect on defensive aggression occurred mainly at the individual level and was not amplified at the pair level. Overall, these results present the first evidence that intranasal AVP promotes human defensive aggression for both males and females in a bilateral situation where each party can potentially damage the resources of the other party. These findings also parallel accumulating evidence from non-human animals concerning AVP's involvement in territorial defense against potential intruders.

Gaze-Cueing With Crossed Eyes: Asymmetry Between Nasal and Temporal Shifts.

A person's direction of gaze (and visual attention) can be inferred from the direction of the parallel shift of the eyes. However, the direction of gaze is ambiguous when there is a misalignment between the eyes. The use of schematic drawings of faces in a previous study demonstrated that gaze-cueing was equally effective, even when one eye looked straight and the other eye was averted. In the current study, we used more realistic computer-generated face models to re-examine if the diverging direction of the eyes affected gaze-cueing. The condition where one eye was averted nasally while the other looked straight produced a significantly smaller gaze-cueing effect in comparison with when both eyes were averted in parallel or one eye was averted temporally. The difference in the gaze-cueing effect disappeared when the position of one eye was occluded with a rectangular surface or an eye-patch. These results highlight the possibility that the gaze-cueing effect might be weakened when a direct gaze exists between the cueing eye (i.e., nasally oriented eye) and the target and the effect magnitude might depend on which type of face stimulus are used as a cue.

Spontaneous Facial Mimicry Is Enhanced by the Goal of Inferring Emotional States: Evidence for Moderation of "Automatic" Mimicry by Higher Cognitive Processes.

A number of studies have shown that individuals often spontaneously mimic the facial expressions of others, a tendency known as facial mimicry. This tendency has generally been considered a reflex-like "automatic" response, but several recent studies have shown that the degree of mimicry may be moderated by contextual information. However, the cognitive and motivational factors underlying the contextual moderation of facial mimicry require further empirical investigation. In this study, we present evidence that the degree to which participants spontaneously mimic a target's facial expressions depends on whether participants are motivated to infer the target's emotional state. In the first study we show that facial mimicry, assessed by facial electromyography, occurs more frequently when participants are specifically instructed to infer a target's emotional state than when given no instruction. In the second study, we replicate this effect using the Facial Action Coding System to show that participants are more likely to mimic facial expressions of emotion when they are asked to infer the target's emotional state, rather than make inferences about a physical trait unrelated to emotion. These results provide convergent evidence that the explicit goal of understanding a target's emotional state affects the degree of facial mimicry shown by the perceiver, suggesting moderation of reflex-like motor activities by higher cognitive processes.

Empathizing with a dissimilar other: the role of self-other distinction in sympathetic responding.

Can we empathize effectively with someone who has a different sensitivity to physical events from ours? Or, are we susceptible to an egocentric bias in overprojection, which may lead us to under- or overreact in such cases? In this study, participants with normal visual and auditory capacity observed a video clip in which a sighted or blind target was exposed to a strong flash or high-frequency sound, while their physiological arousals during the observation were recorded. On average, participants displayed a differential arousal pattern to the aversive stimuli, according to the target's ability to perceive them. Degrees of arousal control were also correlated with dispositional differences in empathy. Participants who scored higher on the Empathic Concern subscale of Davis's Interpersonal Reactivity Index were better at controlling arousals in accordance with the Target × Stimulus interaction. The authors' findings have important implications for helping disabled people while respecting their inherent dignity and individual autonomy.