Action observation causes implicit transfer of learning in task-sharing.

The aim of the present study was to investigate whether the implicit transfer of learning found in task-sharing situations occurs when one of the two participants observes the other. To this aim, two experiments using the social transfer of learning paradigm (Milanese et al., 2010) were conducted in which one of the participants observed the other performing a practice task. Then, both participants performed a joint Simon task. Results showed a modulation of the joint performance (i.e., the social Simon task), indicative of implicit transfer of learning, in both the agent and the observer. Thus, transfer of learning occurs even if the practice task is not actually performed hence indicating that both the agent and the observer co-represent the task as involving two co-acting partners. On the whole, these results suggest that shared representations are based on motor parameters.