The use of a shared task representation to select and plan movements during a sequential joint action task


One cognitive theoretical approach to the study of joint action holds that co-actors form shared task representations that contain a shared goal and information related to the completion of the goal.  The study of sequential joint actions (where one co-actors movement is the precursor for their partner’s movement) provides insight into how shared task representations could be used during joint actions.  If co-actors use  shared task representations to plan their movements, then the initial movement in a sequential joint action should be influenced by some feature of their co-actors subsequent movement. The purpose of the present study was to determine if co-actors plan their movements to accommodate the difficulty of their partners’ action.  Further, we investigated whether motor experience influences response selection in a joint action task. To these ends, partners performed an aiming task that was divided between them. The participants were told to place a dowel on a line between two potential targets and that their partner would have to make a movement with the dowel to one of the targets from wherever they placed it on the line. The targets varied in relative size throughout the session and the targets were randomly chosen on each trial. Participants completed the partner task before and after completing an individual task.  Consistent with the prediction, that co-actors take the difficulty of their partners’ actions into account, the dowel was placed closer to the smaller target of a pair. Further, in support of the prediction that motor experience influences dowel placement, there was a shift in dowel placement following the individual task.  These results support the hypothesis that co-actors plan their movements based on features of their co-actors movements and that motor experience provides information that allows people to better plan movements for their partners. 

Acknowledgments: NSERC and the Ontario Ministry of Innovation and Research