On the same wavelength: face-to-face communication increases interpersonal neural synchronization.

Editor's Note: These short, critical reviews of recent papers in the Journal, written exclusively by graduate students or postdoctoral fellows, are intended to summarize the important findings of the paper and provide additional insight and commentary. For more information on the format and purpose of the Journal Club, please see Review of Jiang et al. Understanding neural mechanisms of social interaction is important for understanding human social nature and for developing treatments for social deficits related to disorders such as autism. However, conventional cognitive and behavioral neurosci-ence has concentrated on developing novel experimental paradigms and investigating human– computer interactions, rather than studying interpersonal interaction per se. To fully understand neural mechanisms of human interpersonal interaction, we will likely have to investigate human behavior and neural processes in face-to-face social interaction rather than human– computer interaction. Recently, simultaneous EEG or functional near-infrared spectros-copy (fNIRS) has been used to record brain activity of two participants in a face-to-face setting (i.e., hyperscanning) to investigate human social interaction in a more natural-istic context (Jiang et al., 2012; Yun et al., 2012). In a recent article published in The Journal of Neuroscience, Jiang et al. (2012) investigated interbrain neural synchronization during face-to-face communication using fNIRS hyperscanning. fNIRS measures changes in the regional cerebral blood flow by quantifying the changes in oxyhemoglo-bin concentration. Given that the left hemisphere is dominant for language function and that the left inferior frontal cortex and inferior parietal cortex have been known to be closely related to action understanding and imitation, i.e., mirror neuron system, fNIRS was placed only on the left hemisphere. The inferior frontal cortex has been particularly associated with empathy and social cognition (Farrow et al., 2001). Jiang and colleagues found a significant increase in cross-correlation between changes in activity of two participants' left inferior frontal cortices only during a dialog in which subjects faced each other (face-to-face), but none during other communication conditions , including dialog in which subjects faced away from each other (back-to-back), monologue with subjects facing each other, and monologue with subjects facing away from each other. Moreover, quality of communication in each condition was assessed by self-report, and face-to-face dialog represented a higher quality of communication than back-to-back dialog. These results suggest that face-to-face conversation has special features that other types of communication lack and that interbrain correlated activity may be an underlying neural process of successful face-to-face communication. In this Journal Club …