Abstract
Inhibition of return (IOR) refers to the finding that longer reaction times (RTs) are observed for movements made to the same location as a previous event/response (Posner & Cohen, 1984). IOR has been shown to occur both when participants perform the task on their own (individual-IOR) and in joint action contexts (social-IOR) (Welsh et al., 2005). Typical social-IOR paradigms involve participants moving to targets to the left or right of a home position. Target locations are indicated by the onset of a visual stimulus and pairs of individuals take turns responding to the illuminated location. The longer RTs to targets presented at the same location as the partner’s previous response is characteristic of IOR and, as such, social-IOR has been suggested to be caused by an inhibitory mechanism enacted to bias visual search to new locations. In the present study, we sought to determine if the partner’s responses also bias the individual’s response selection. Pairs of participants (n=16) completed two social movement tasks in which they alternatively moved to one of two locations. In the forced-choice task, the onset of a light indicated the target for the trial. In the free-choice task, there was no light stimulus and participants were free to choose to move to either location. The analysis of the forced-choice task revealed that RTs for different targets were significantly shorter than those for repeated targets (social-IOR). Although there were no RT differences in the free-choice task, participants were significantly less likely to move to the same location that their partner just moved to (i.e., they were more likely to move to the opposite location). These results suggest that the inhibitory mechanisms underlying social-IOR can bias response selection and suggest that social-IOR is not due to attentional biases induced by peripheral visual events.
Meeting abstract presented at VSS 2012