Modulating Action Duration to Establish Nonconventional Communication

January 1, 2018

Cordula Vesper, Laura Schmitz, Günther Knoblich

In many joint actions, knowledge about the precise task to be performed is distributed asymmetricallysuch that one person has information that another person lacks. In such situations, interpersonalcoordination can be achieved if the knowledgeable person modulates basic parameters of her goal-directed actions in a way that provides relevant information to the co-actor with incomplete taskknowledge. Whereas such sensorimotor communication has frequently been shown for spatial parameterslike movement amplitude, little is known about how co-actors use temporal parameters of their actionsto establish communication. The current study investigated whether systematic modulations of actionduration provide a sufficient basis for communication. The results of 3 experiments demonstrate thatknowledgeable actors spontaneously and systematically adjusted the duration of their actions to com-municate task-relevant information if the naïve co-actor could not access this information in other ways.The clearer the communicative signal was the higher was the benefit for the co-actor’s performance.Moreover, we provide evidence that knowledgeable actors have a preference to separate instrumentalfrom communicative aspects of their action. Together, our findings suggest that generating and perceiv-ing systematic deviations from the predicted duration of a goal-directed action can establish noncon-ventionalized forms of communication during joint action