Copying you copying me:Interpersonal motor co-ordination influences automatic imitation

Moving in a co-ordinated fashion with another individual changes our behaviour towards them; we tend to like them more, find them more attractive, and are more willing to co-operate with them. It is generally assumed that this effect on behaviour results from alterations in representations of self and others. Specifically, through neurophysiological perception-action matching mechanisms, interpersonal motor co-ordination (IMC) is believed to forge a neural coupling between actor and observer, which serves to blur boundaries in conceptual self-other representations and causes positive views of the self to be projected onto others. An investigation into this potential neural mechanism is lacking, however. Moreover, the specific components of IMC that might influence this mechanism have not yet been specified. In the present study we exploited a robust behavioural phenomenon - automatic imitation - to assess the degree to which IMC influences neural action observation-execution matching mechanisms. This revealed that automatic imitation is reduced when the actions of another individual are perceived to be synchronised in time, but are spatially incongruent, with our own. We interpret our findings as evidence that IMC does indeed exert an effect on neural perception-action matching mechanisms, but this serves to promote better self-other distinction. Our findings demonstrate that further investigation is required to understand the complex relationship between neural perception-action coupling, conceptual self-other representations, and social behaviour

Estimates of mediatory effect of perceived synchronicity.

<p>Estimate values after 1000 bootstrapped resamples.</p><p> = The Asynch condition served as the reference group;</p><p>SE = standard error; CI<i>_lower</i> and CI<i>_upper</i> = 95% lower- and upper-level confidence interval, respectively.</p

Primary results.

<p>(<i>A</i> and <i>B</i>) Results of Mann-Whitney tests, revealing a greater willingness to co-operate and enhanced likeability ratings in participants who provided higher ratings of PS; * = p<.05. (<i>C</i>) Results of one-way ANOVA, illustrating reduced AI in the Temp compared with the Asynch condition. Error bars present standard error; * = p<.05. (<i>D</i>) Results of the regression analysis, illustrating that AI decreases as a function of increasing subjective ratings of synchronicity. Regression line: <i>AI</i> = −1.05 <i>PS</i>+74.49.</p

Visual stimuli.

<p>(<i>A</i>) Snapshots of the stimuli presented during the four hand-waving blocks of the IMC phase. Two instances of dots are presented (top and bottom frames) to illustrate that the dot-counting task demanded attention towards the actor’s actions. (<i>B</i>) Stimuli comprising the AI phase. Each trial began with the warning stimulus (<i>top</i>), after which the imperative stimulus (coloured dot) was presented, superimposed over congruent (<i>middle</i>) or incongruent (<i>bottom</i>) actions. NB: The actor has provided written informed consent, as outlined in the PLOS consent form, for the publication of this image. Although her identity is concealed in this figure, her eyes were visible throughout all experimental stimuli.</p