Object discrimination in pigeons: effects of local and global cues

We trained two pigeons to report whether a pair of differently colored 2-D objects had two target dots on either one or both of the objects. Follow-up tests disclosed that the colored regions surrounding the task-relevant targets were necessary, but not sufficient to support the birds' discrimination. Moreover, when local and global color cues provided contradictory information, pigeons failed to discriminate the stimuli, suggesting that the birds attended to both local and global information. Finally, one bird learned the object discrimination in the absence of differential color cues suggesting that, with suitable training, pigeon can attend to entire objects.