A contrast effect between the concurrent production and perception of movement directions

With three experiments, we explored the nature of specific interference between the concurrent production and perception of movements. Participants were asked to move one of their hands in a certain direction while simultaneously trying to identify the direction of an independent and non-biological stimulus motion. Perceived direction of the stimulus was assessed with either above/below judgements (Experiment 1), same/different judgements (Experiment 2), or the adjustment of a line (Experiment 3). The results revealed a form of contrast effect: Perceived directions were repulsed by produced directions. Moreover, the size of the effect was comparable across the three experiments, which points to its robustness and allowed us to control for potential confounds associated with some of the perceptual measures. These results alleviate concerns regarding the interpretation of related findings and demonstrate that effects of this type are not tied to the processing of biological motion, as previously proposed.