| Abstract: | Pigeons with hyperstriatal lesions and unoperated controls were given minimal or extended side-key pretraining prior to acquisition of a position discrimination. Operated birds were impaired following extended, but not minimal, pretraining. The birds then acquired a simultaneous color discrimination with posiversals of the color discrimination, operated birds were impaired, and this was primarily due to an exaggeration of perseverative responding to the former positive stimulus. Analysis of choice latencies found no tendency towards an exaggerated "Mahut effect" in hyperstriatals and indicated that operated subjects used the same solution strategies as normals. These findings directly contradict the response-shift account of hyperstriatal function and indicate a return to the response-inhibition hypothesis. |
