Laterality effects on motor awareness

The ability to perceive self-produced movements and to correctly attribute an action to its proper agent is a natural task and a basic requirement to human social communication. Recent experiments suggest that this apparently simple phenomenon is related to the mechanisms of motor production, raising the question whether recognition of self-produced movement is affected by asymmetries similar to those present in motor skills. In this study. right- and left-handed subjects decided whether a moving hand presented on a screen was the image of their own hand or of that of another person. Two experimental conditions were tested: either subjects saw their own moving hand (subject condition) or they were shown the experimenter's hand pantomiming their movement (experimenter condition); a glove masked morphological differences between the two hands. Verbal responses and response times were analysed. Results showed that all subjects were more accurate in recognising their preferred hand with respect to their non-preferred hand. Right-handers responded faster than left-handers did, the latter group being especially slowed down in the experimenter condition. On the contrary, in the right-handers group, response times did not differ among conditions. The present data indicate that the ability to recognise self-generated movements is affected by motor dominance, thus suggesting that conscious knowledge of self-produced movements is closely related to the motor system. (C) 2002 Elsevier Science Ltd. All rights reserved.