Impaired Mirror-Image Imitation in Asperger and High-Functioning Autistic Subjects

S. Avikainen, A. Wohlsclager, S. Liuhanen, R. Hanninen and R. Hari, Current Biology, Volume 13, February 2003, Pages 339 - 341.

Imitation is crucial for proper development of social and communicative skills. Here, we argue that, based on an error analysis of a behavioural imitation task, adult Asperger and high-functioning autistic subjects suffer from intriguing deficit of imitation: they lack the natural preference for imitation in a mirror-image fashion. The imitation task consisted of a simple movement sequence of putting a pen with the left or right hand into a green or blue using one of two possible grips. The subjects were asked to imitate the experimenter's hand movements either using the crossed hand (e.g. the subjects right hand corresponding to the experimenter's right hand) for imitation or to imitate as if looking in a mirror (e.g. the subjects left hand corresponding to the experimenter's right hand). When people normally view other people's face-to-face, they prefer to imitate as in a mirror and observation of mirror-image-like movements speeds up performance in nominated tasks. However, our autistic subjects, defective in social cognition, did not profit from mirror-image movements of others. These results provide a new insight into the difficulties that autistic subjects face in viewing and understanding actions of others.