Generalized identity matching in the pigeon: Role of extended observing- and choice-response requirements

Four experimentally naïve White Carneau pigeons matched three hues to each other in a variant of an identity matching-to-sample procedure with a fixed-ratio 20 on samples and a response-initiated fixed-interval 8 s on comparisons. The extent to which the pigeons were matching on the basis of identity was assessed by presenting, in extinction, test trials comprising novel stimuli serving as the sample and comparison stimuli. When the test trials were comprised only of novel stimuli, three out of the four pigeons demonstrated substantially above-chance levels of accuracy. These data suggest that the extended observing- and choice-response requirements facilitate the development of generalized identity matching performance.