Dataset for: Measuring Mimicry: General Corticospinal Facilitation During Observation of Naturalistic Behaviour

Mimicry of others’ postures and behaviours forms an implicit yet indispensable component of social interactions. However, whereas numerous behavioural studies have investigated the occurrence of mimicry and its social sensitivity, the underlying neurocognitive mechanisms remain elusive. In this study, single pulse transcranial magnetic stimulation was used to measure corticospinal facilitation during a naturalistic behaviour observation task adapted from the behavioural mimicry literature. Motor evoked potentials (MEPs) in participants’ right hands were measured as they observed stimulus videos of a confederate describing photographs. MEPs were recorded while confederates were and were not carrying out hand and leg behaviours that also differed in spatial extent (i.e. large behaviours: face rubbing and leg crossing; small behaviours: finger tapping and foot bouncing). However, the cover task instructions did not refer to the confederate's behaviour but instead required participants to focus on the confederates’ photograph descriptions in order to later perform a recognition test. A general arousal effect was found, with higher MEPs during stimulus video observation than during a fixation-cross baseline, regardless of whether or not the confederate was carrying out a behaviour at the time of the pulse. When controlling for this general arousal effect, results showed that MEPs during observation of the larger two behaviours were significantly higher than the smaller two behaviours, irrespective of effector. Thus, by using a controlled yet naturalistic paradigm, this study suggests that general sensorimotor arousal during social interactions could play a role in implicit behavioural mimicry.

对他人姿势与行为的模仿，是社会互动中一种隐性却不可或缺的组成部分。然而，尽管已有大量行为学研究探讨了模仿现象的发生及其社会敏感性，其背后的神经认知机制仍尚不明确。本研究采用单脉冲经颅磁刺激（single pulse transcranial magnetic stimulation）技术，在一项改编自行为模仿相关研究文献的自然主义行为观察任务中测量皮层脊髓易化效应。研究者测量了被试观察实验同谋描述照片的刺激视频时，右手的运动诱发电位（motor evoked potentials, MEPs）。实验中，实验同谋会做出或不做出手部与腿部行为，且这些行为的空间幅度存在差异：大尺度行为包括揉脸与跷腿，小尺度行为包括敲击手指与足部抖动。但实验的掩饰任务指导语并未提及实验同谋的行为，而是要求被试专注于实验同谋对照片的描述，以便后续完成再认测试。研究发现了一般性唤醒效应：相较于十字注视基线条件，被试在观察刺激视频时的运动诱发电位更高，且无论脉冲发放时实验同谋是否正在做出行为。在控制该一般性唤醒效应后，结果显示，相较于两种小尺度行为，被试观察两种大尺度行为时的运动诱发电位显著更高，且不受效应器类型影响。因此，本研究通过采用兼具控制性与自然主义的实验范式，表明社会互动过程中的一般性感觉运动唤醒，可能在隐性行为模仿中发挥作用。