Prediction error induced motor contagions in human behaviors

Motor contagions refer to implicit effects on one's actions induced by observed actions. Motor contagions are believed to be induced simply by action observation and cause an observer's action to become similar to the action observed. In contrast, here we report a new motor contagion that is induced only when the observation is accompanied by prediction errors - differences between actions one observes and those he/she predicts or expects. In two experiments, one on whole-body baseball pitching and another on simple arm reaching, we show that the observation of the same action induces distinct motor contagions, depending on whether prediction errors are present or not. In the absence of prediction errors, as in previous reports, participants' actions changed to become similar to the observed action, while in the presence of prediction errors, their actions changed to diverge away from it, suggesting distinct effects of action observation and action prediction on human actions.

动作传染（Motor contagions）指由观察他人动作所引发的、对自身行为的内隐影响。过往研究认为，这类动作传染仅通过动作观察即可触发，并会使观察者的行为向所观察到的动作趋近。与之相对，本研究报道了一种全新的动作传染：它仅在动作观察伴随预测误差时触发——即观察到的动作与个体自身预期或预测的动作之间存在偏差。本研究通过两项实验（一项针对全身性棒球投球动作，另一项针对简单的手臂伸够动作）证实：针对同一动作的观察，会因是否存在预测误差而引发截然不同的动作传染效应。当不存在预测误差时（与过往研究结果一致），被试的行为会向所观察到的动作趋近；而当存在预测误差时，被试的行为反而会偏离所观察的动作，这表明动作观察与动作预测对人类行为的影响路径截然不同。