Experimental visual agnosia in the pigeon.

Recent research on animal cognitive ability has clarified that cognitive ability spreads to several species besides humans. Such studies make it possible to compare brain mechanisms of animal cognition and human cognition. Experimental lesions of the ectostriatum in pigeons caused deficits in the artificial pattern recognition, arbitrary classification of natural objects, conspecific individual recognition and discrimination of two different avian species. The lesions did not result in deficits in natural concept, such as food or conspecific. These results suggest that the ectostriatal lesions selectively disrupt visual cognition acquired through discriminative training.