Both right- and left-handers show a bias to attend others' right arm

The common-coding hypothesis suggests that the more similar an observed action is to the way the observer would perform it, the stronger is the ensuing activation of motor representations. Therefore, producing actions could prime perception so that observers would be particularly responsive to (i.e. biased to perceive) actions that are related to, and share features with, their own actions. If this similarity principle also applies to handedness, right- and left-handers should be more likely to perceive actions as performed with their dominant rather than non-dominant hand. In two experiments, participants were required to indicate the perceived orientation (front or back view) of pictures of ambiguous human silhouettes performing one-handed manual actions. Experiment 1, in which 300 right-handers and 60 left-handers reported the orientation of a single silhouette seen for as much as they wished, showed that participants perceived the figures more frequently in an orientation congruent with a movement performed with the right rather than the left hand. Experiment 2, in which 12 right-handers and 12 left-handers reported the orientation of 52 silhouettes seen for 300 ms, showed similar results when multiple responses per participant were collected rather than only one. Contrary to our expectations, no difference was observed between right- and left-handers, which might suggest an attentional bias towards the right arm of human bodies in both groups. Moreover, participants were more likely to perceive the figure as front-facing than as back-facing, possibly due to the greater adaptive relevance of approaching compared to receding individuals.