Self-Construal Priming Modulates Ensemble Perception of Multiple-Face Identities

Oxytocin Modulates Neural Individuation/Categorization Processing of Faces in Early Face-Selective Areas

Oxytocin (OT) is known as a neuropeptide that promotes social adaptation. Individuating racial in-group members and viewing racial out-groups in categories is an adaptive strategy that evolved to aid effective social interaction. Nevertheless, whether OT modulates the neural individuation/categorization processing of racial in-group and out-group faces remain unknown. After intranasal OT or placebo administration, 46 male participants (OT: 24, placebo: 22) were presented with face pairs with the same or different identities or races in rapid succession. The neural repetition suppression (RS) effects to identity and race were measured using functional magnetic resonance imaging (fMRI) as indices of individuation/categorization face-processing. The results showed that while OT increased the RS effect to race, it decreased the RS effect to identity in the right fusiform face area. As for the left occipital face area, OT enlarged the differential RS effects to identities of in-group and out-group faces. Additionally, OT modulated the association of interdependence self-construal and the RS effects on identity and race. These findings bring to light preliminary evidence that OT can regulate neuronal specificity of identity and race in early face-selective regions and benefit adaptive individuation/categorization face-processing.

Emotion matters: Face ensemble perception is affected by emotional states

Ensemble coding is the ability of the visual system to extract a summary statistic from a set of stimuli. For example, observers often spontaneously extract an average face identity from a set of faces. Ensemble coding is known to operate in the frame of a distributed/global attention model. Because both attention and holistic processing are modulated by emotion - where positive emotions broaden the scope of attention and facilitate global processing, whereas negative emotions narrow the scope of attention and promote local processing - the current research explored whether emotional states could affect visual averaging of multiple face identities. Participants completed an ensemble-coding task before and after their emotion was induced via film clips. In the ensemble-coding task, a set of four face identities was shown briefly, followed by a probe face. Participants judged whether the probe face was presented in the preceding set. Evidence for ensemble coding was indexed by responses that treated an average face of the preceding set as a member of that set. The results showed that the tendency to choose this average was modulated by emotional states. Visual averaging increased after seeing positive film clips, but decreased after seeing negative film clips. These results support Frederickson's broaden-and-built theory, and extended its application to ensemble perception.

Self-Construal Priming Modulates Ensemble Perception of Multiple-Face Identities

This study explored the modulatory role of independent/interdependent self-construal on ensemble perception. Two experiments were conducted to study the effect of self-construal on ensemble coding of multiple-face identities (Experiment 1) and dot size (Experiment 2) separately. Before the implicit ensemble perception task, participants in both experiments were either primed with independent or interdependent self-construal via a well-validated pronoun circle task, in which they were exposed to either singular ("I," "me," and "my") or plural ("We," "us," and "our") pronouns in essays. The results showed that interdependent self-construal (vs. independent self-construal) featured as global processing and emphasizing interconnectedness with others enhanced the ensemble coding of high-level features (e.g., identity in Experiment 1) but not of low-level features (e.g., size in Experiment 2). To the best of our knowledge, this study was the first to investigate the role of self-construal on ensemble representations. In sum, the results of the current study supported the domain-specific mechanism of ensemble perception on one hand, and extended the effect of self-construal on single face recognition to multiple face recognition on the other hand.