Background environment modulates motor contagions in humans

Motor contagions refer to implicit effects in one’s actions induced by the observation of actions made by others. A plethora of studies over the last two decades have exhibited that observed, as well as predicted, actions can induce various kinds of motor contagions in a human observer. However, motor contagion has always been investigated in regard to different features of an observed action and it remains unclear whether the environment, in which an observed action takes place, modulates motor contagions as well. Here we investigated the effect of the observed environment on motor contagions using an empirical hand steering task in which the participants were required to move a cursor through visual channels of different shapes. We observed the movement time of observers to be influenced by both the movement of the cursor they observed, as well as the background (channel shape) in which the cursor movement was observed. Observers consistently made faster movements after observing steering movements in a ‘narrowing’ channel compared to a ‘widening’ channel. These results show a distinct effect of the environment, in which an observed action occurs, on one’s own movement.