The presence of adjacent others facilitates interpersonal neural synchronization in the left prefrontal cortex during a simple addition task

Abstract

The hyperscanning technique, that is, simultaneous measurement of neural signals in more than one person, is a powerful research tool for understanding humans’ social interactions. In recent years, many studies have investigated interpersonal neural synchronization during various types of communication processes. However, there has been little focus on the impact of the presence of others without explicit social interaction, despite the mere presence of others having been suggested as influencing behavior. In this study, we clarify whether neural signals during a self-paced, repeated, addition task are synchronized when another individual is adjacent without direct interaction. Twenty pairs of participants were measured using a hyperscanning approach with near-infrared spectroscopy. The results show that interpersonal neural synchronization of the task-related signal in the left forehead region was enhanced under the condition of being adjacent to another participant. By contrast, a significant decrease in neural synchronization in the center of the forehead region, where increased neural synchronization is often reported in explicit communication, was observed. Thus, the results indicate that the adjacency of others modulates interpersonal neural synchronization in the task-related signal, and the effect on cognitive processing is different from that of explicit social interaction.

参与式社会互动中脑间同步的自我-他人重叠机制

“…然而, 观察式范式与实时互动的情 境有着本质的不同, 两种情境下个体对社会刺激的反 应也不尽相同 [23] . 例如, 当察觉到现场有他人存在时, 即使两人任务节奏不同, 也会出现显著的脑间同步现 象 [24] . 考虑到观察式实验范式的局限, 有研究提倡参与 式的研究范式, 即让个体与他人实时互动或让个体相 信自己正与他人实时互动 [4,5] .…”

Unraveling dyadic psycho-physiology of social presence between strangers during an audio drama – a signal-analysis approach

“…Shifting one's gaze to the eyes of the other person might indicate a social action, for instance, a confirmation of joint attention, or a search for a confirmation of a joint affective response (Hamilton, 2016). If the other person is a stranger, eye-contact may also have an important role in establishing a non-verbal agreement of mutual co-presence in the shared space (Miura and Noguchi, 2022). The human skill to recognize and make judgments of an unfamiliar person relies to a great extent on unconscious neural processing of dynamic features of the new face (George, 2016).…”

“…The human skill to recognize and make judgments of an unfamiliar person relies to a great extent on unconscious neural processing of dynamic features of the new face (George, 2016). The presence of another person can be expected to change the properties of the physiological signals of an individual in a complex manner (Chib et al, 2018;Miura and Noguchi, 2022; see Hamilton, 2016;Stephenson et al, 2021, for reviews).…”