THE MECHANISMS OF IMITATION KEVIN N. LALAND PATRICK BATESON Sub- Department of Animal Behaviour, University of Cambridge, United Kingdom Imitation is a process by which individuals learn to perform a behavior pat- tern as a result of observing another animal performing a similar action. Despite a century of research and a great deal of interest, the processes under- lying imitation remain unknown. On the basis of neural network simulations, we put forward a hypothesis for the computational processes that underlie imitation. This analysis suggests that imitation may occur because the observational experience (which includes both the demonstrator’s perform- ance of the target behavior and contextual cues) is composed of stimuli that have features in common with cues associated with an individual’s past experience. This leads us to propose a stimulus generalization hypothesis for the mechanism underlying imitation. We suggest that a stimulus generalization explanation for imitation has been prematurely rejected, because the complexity and signi¢cance of this prior experience have not been fully appreciated. The hypothesis may be able to account for many reported cases of imitation in animals and humans. This analysis allows us to make a number of predictions which are accessible to empirical test. Imitation has been variously de¢ned as ``learning to do an act from see- ing it done’’ (Thorndike, 1898), ``purposeful, goal-directed copying of the behavior of one animal by another’’ (Galef, 1988), or ``the learning of a response-reinforcement contingency by observation’’ (Heyes & Dawson, 1990). Notwithstanding some promising recent developments (Heyes & Ray, 2000), when it comes to the process called ``imitation,’’ no satisfactory explanation exists (Galef, 1988). Cybernetics and Systems: An International Journal, 32 : 195±224, 2001 Copyright # 2001 Taylor & Francis 0196-9722/01 $12.00 + .00 Address correspondence to K. N. Laland, Sub-Department of Animal Behaviour, University of Cambridge, Madingley, Cambridge CB3 8AA, UK. E-mail: KNL11001@hermes.cam.ac.uk 195