The whole is equal to the sum of its parts: Pigeons (Columba livia) and crows (Corvus macrorhynchos) do not perceive emergent configurations

Abstract

We previously demonstrated that chimpanzees, like humans, showed better accuracy and faster response time in discriminating visual patterns when the patterns were presented in redundant and uninformative contexts than when they were presented alone. In the present study, we examined the effect of redundant context on pattern discrimination in pigeons (Columba livia) and large-billed crows (Corvus macrorhynchos) using the same task and stimuli as those used in our previous study on chimpanzees. Birds were trained to search for an odd target among homogenous distractors. Each stimulus was presented in one of three ways: (1) alone, (2) with identical context that resulted in emergent configuration to chimpanzees (congruent context), or (3) with identical context that did not result in emergent configuration to chimpanzees (incongruent context). In contrast to the facilitative effect of congruent contexts we previously reported in chimpanzees, the same contexts disrupted target localization performance in both pigeons and crows. These results imply that birds, unlike chimpanzees, do not perceive emergent configurations.