Limits of Symmetry Conceptualization in Pigeons

Three experiments investigated the discrimination of artificial patterns on the basis of an underlying symmetry rule by pigeons. In Experiment 1, two groups were trained to discriminate between different types of bilaterally symmetric and asymmetric “chequerboard” patterns. In the second experiment, we tested the ability of pigeons to generalize to novel patterns. Successful transfer was confined to patterns similar to those used for training in Experiment 1. Experiment 3 was designed to investigate the positive results obtained by Delius and Nowak (1982). Naive pigeons were trained on tasks either involving copies of their training patterns, or employing their training procedure, or both. The behaviour of these pigeons was similar to that found in Experiments 1 and 2 but different from that obtained by Delius and Nowak (1982). The results of these experiments indicate that the use of symmetry as an abstract concept: (a) depends on the type of stimuli used, and (b) is not an easy task for pigeons.