Anomalous patterns of response learning and transfer in decorticate rats

Behavioural flexibility in decorticate rats was examined by testing response transfer in an obstructed alleyway. In the first experiment, rats were trained to push a ball out of a cylindrical alleyway in order to gain access to the goal box. When this 'push' habit was prevented by blocking forward movement of the ball, decorticate rats were much quicker than sham-operated rats in successfully developing the novel clearance response of pulling the ball into the start box. Both groups were subsequently able to reverse effectively between responses. In a second experiment, sham-operated and decorticate rats were first shaped to pull the ball clear from the alleyway, and then required to adopt a push-type clearance response when movement of the ball towards the start box was prevented. Here, the decorticates showed difficulty both in learning to pull the ball out of the alley and in transferring to a push-type clearance response, but having transferred they coped well with subsequent reversals. This asymmetrical pattern of transfer results is not readily attributed to response preference and raises the possibility that, in some situations at least, decorticated animals may show greater behavioural flexibility than had previously been supposed.