Insight in pigeons: absence of means-end processing in displacement tests

The understanding of functional relations between action and consequence is a critical component of intelligence. To examine this linkage in pigeons, we investigated their understanding of the relations of the elements tested in an extension of Kohler's box stacking task to this species. In the experiments, the pigeons had to move a spatially displaced box under an out-of-reach target. Experiment 1 successfully replicated and extended the previous finding showing that when separately trained to move a box and stand on it to peck the target, pigeons can synthesize these behaviors to solve the single-box displacement problem quickly on their first attempt. Experiment 2 tested whether pigeons, when given a simultaneous choice between two boxes with identical reinforcement histories, would selectively choose the box with the correct functional affordance (i.e., permitting standing) to solve the problem rather than a non-functional one. Their extensive, equivalent, and undirected behavior in moving both boxes during these tests suggests the pigeons did not possess a means-end understanding of the functional properties of the boxes. Instead, their results were consistent with an analysis of their earlier synthetic behavior as being due to the temporal and spatial relations of the physical elements in the task and their prior learned behaviors.