Hand preferences in human adults: non-communicative actions versus communicative gestures.

Hand preferences for pointing gestures and bimanual manipulative activities were investigated in 127 adult participants. Pointing gestures were produced in two different conditions: a speech condition, in which the gestures were accompanied by speech, and a silent condition. Although the classification of participants as left- or right-handers, or ambidextrous, was consistent across the manipulation and pointing tasks for 85% of participants, results showed only moderate correlations between handedness scores for bimanual manipulation and pointing gestures. Moreover, results did not reveal any difference in the degree of hand preference between pointing gestures produced along with speech and gestures produced on their own. The implications of these findings are discussed in relation to the lateralization of non-communicative manual actions, communicative gestures and speech.