Pigeon transitive inference: Tests of simple accounts of a complex performance

This study addressed pigeons' abilities to form transitive inferences and the mechanism by which they do so. Subjects were trained on four operant discriminations in a 5-term series-A + B - , B + C - , C + D - and D + E - (where [ + ] denotes reward, and [ -] non-reward in choice). In unreinforced tests, choice of B over D is evidence of transitive inference formation. Training proceeded without the subjects being presented the training pairs in blocks. Results show that randomized training degrades the performance of pigeons, just as it does human subjects, but that some subjects can still respond transitively under these conditions. In addition, the results support reinforcement models of transitive inference performance.