Sensorimotor communication in cooperative and competitive motor interactions

Introduction We cooperate or compete with others daily. During cooperation, two partners coordinate their actions to achieve a common goal; instead, during competition, two opponents compete to achieve two opposite and individual goals. Despite these differences, in both scenarios, nonverbal forms of communication (i.e., signaling) can play a key role1: any time there is an asymmetric information distribution between co-agents, the one with more information (the sender) can intentionally make her/his actions more (cooperation) or less (competition) predictable to convey/hide information to the other agent (receiver). However, how the sender’s movements change during competitive vs cooperative motor interactions remains unknown, as well as whether social cognition underlying its implementation. Methods Pairs played a motor interaction task in which they used a joystick to move a cursor (an “egg” or a “hand”) to one of four targets on the screen. In Cooperation, they had the common goal of synchronously reaching (i.e., minimizing asynchrony) the same target. In Competition, the Egg had to maximize the asynchrony in reaching the target while the Hand had to minimize it. Within each context, in different blocks, same or different information was provided to participants: in symmetric blocks, both knew the target to reach; in asymmetric blocks, only the Egg (sender) received the auditory instruction on which target to reach (thus, just here signaling is expected). Participants’ social skills were assessed through action prediction, implicit perspective-taking, and theory of mind tasks. Results Since signaling constitutes a deviation from an “optimal” trajectory performed with a communicative intent, we computed its index by calculating the distance between the participants’ performed trajectory and the linear trajectory linking the cursor’s starting position to the targets. We found higher values in the senders’ distances during both cooperative and competitive asymmetric interactions compared with symmetric ones, but with two opposite social intents. The speed profile also differentiated the asymmetric and symmetric conditions in opposite ways between the two contexts. Moreover, individual’s social skills modulate behavioral performance. Discussion Our preliminary results suggest that, during asymmetric cooperative motor interactions compared to symmetric ones, individuals with more information apply coordination smoothers2 to facilitate performance success, making their trajectory less ambiguous (i.e., dissimilating their actions from the alternative ones) and reducing the velocity of their movements. On the contrary, during asymmetric competitive motor interactions compared to symmetric ones, senders increase the ambiguity of their trajectory, making feints (i.e., assimilating their actions from the alternative ones) and increasing the velocity of their movements. Furthermore, individual social skills seem to carve the motor behavior during interpersonal interactions.