Thermal facial reactivity patterns predict social categorization bias triggered by unconscious and conscious emotional stimuli.

Members of highly social species decode, interpret, and react to the emotion of a conspecific depending on whether the other belongs to the same (ingroup) or different (outgroup) social group. While studies indicate that consciously perceived emotional stimuli drive social categorization, information about how implicit emotional stimuli and specific physiological signatures affect social categorization is lacking. We addressed this issue by exploring whether subliminal and supraliminal affective priming can influence the categorization of neutral faces as ingroup versus outgroup. Functional infrared thermal imaging was used to investigate whether the effect of affective priming on the categorization decision was moderated by the activation of the sympathetic nervous system (SNS). During the subliminal condition, we found that stronger SNS activation after positive or negative affective primes induced ingroup and outgroup face categorization, respectively. The exact opposite pattern (i.e. outgroup after positive and ingroup after negative primes) was observed in the supraliminal condition. We also found that misattribution effects were stronger in people with low emotional awareness, suggesting that this trait moderates how one recognizes SNS signals and employs them for unrelated decisions. Our results allow the remarkable implication that low-level affective reactions coupled with sympathetic activation may bias social categorization.

Embodying Others in Immersive Virtual Reality: Electro-Cortical Signatures of Monitoring the Errors in the Actions of an Avatar Seen from a First-Person Perspective.

Brain monitoring of errors in one's own and other's actions is crucial for a variety of processes, ranging from the fine-tuning of motor skill learning to important social functions, such as reading out and anticipating the intentions of others. Here, we combined immersive virtual reality and EEG recording to explore whether embodying the errors of an avatar by seeing it from a first-person perspective may activate the error monitoring system in the brain of an onlooker. We asked healthy participants to observe, from a first- or third-person perspective, an avatar performing a correct or an incorrect reach-to-grasp movement toward one of two virtual mugs placed on a table. At the end of each trial, participants reported verbally how much they embodied the avatar's arm. Ratings were maximal in first-person perspective, indicating that immersive virtual reality can be a powerful tool to induce embodiment of an artificial agent, even through mere visual perception and in the absence of any cross-modal boosting. Observation of erroneous grasping from a first-person perspective enhanced error-related negativity and medial-frontal theta power in the trials where human onlookers embodied the virtual character, hinting at the tight link between early, automatic coding of error detection and sense of embodiment. Error positivity was similar in 1PP and 3PP, suggesting that conscious coding of errors is similar for self and other. Thus, embodiment plays an important role in activating specific components of the action monitoring system when others' errors are coded as if they are one's own errors. SIGNIFICANCE STATEMENT: Detecting errors in other's actions is crucial for social functions, such as reading out and anticipating the intentions of others. Using immersive virtual reality and EEG recording, we explored how the brain of an onlooker reacted to the errors of an avatar seen from a first-person perspective. We found that mere observation of erroneous actions enhances electrocortical markers of error detection in the trials where human onlookers embodied the virtual character. Thus, the cerebral system for action monitoring is maximally activated when others' errors are coded as if they are one's own errors. The results have important implications for understanding how the brain can control the external world and thus creating new brain-computer interfaces.

"Neural efficiency" of experts' brain during judgment of actions: a high-resolution EEG study in elite and amateur karate athletes.

Here we tested two working hypotheses on spatially selective cortical activation ("neural efficiency") in experts: (i) compared to non-athletes, elite karate athletes are characterized by a reduced cortical activation during the judgment of karate actions; (ii) compared to non-athletes and elite karate athletes, amateur karate athletes are characterized by an intermediate cortical activation during the judgment of karate actions. Electroencephalographic (EEG) data were recorded in 16 elite karate athletes, 15 amateur athletes and 17 non-athletes. They observed a series of 120 karate videos. At the end of each video, the subjects had to judge the technical/athletic level of the exercise by a scale from 0 to 10. The mismatch between their judgment and that of the coach indexed the degree of action judgment. The EEG cortical sources were estimated by sLORETA. With reference to a pre-stimulus period, the power decrease of alpha (8-12 Hz) rhythms during the video indexed the cortical activation (event-related desynchronization, ERD). Regarding the hypothesis of reduced activity in elite karate athletes, low- and high-frequency alpha ERD was less pronounced in dorsal and "mirror" pathways in the elite karate athletes than in the non-athletes. Regarding the hypothesis of intermediate cortical activity in amateur karate athletes, low- and high-frequency alpha ERD was less pronounced in dorsal pathways across the non-athletes, the amateur karate athletes, and the elite karate athletes. In conclusion, athletes' judgment of observed sporting actions is related to less pronounced alpha ERD, as a possible index of "neural efficiency" in experts engaged in social cognition.