Transitive inference in animals: Reasoning or conditioned associations?

It is widely accepted that many species of non-human animals appear to engage in transitive inference, producing appropriate responses to novel pairings of non-adjacent members of an ordered series without previous experience of these pairings. Some researchers have taken this capability as providing direct evidence that these animals reason. Others resist such declarations, favouring instead explanations in terms of associative conditioning. Associative accounts of transitive inference have been refined in application to a simple five-element learning task that is the main paradigm for laboratory investigations of the phenomenon, but it remains unclear how well those accounts generalize to more informationrich environments such as primate social hierarchies, which may contain scores of individuals. The case of transitive inference is an example of a more general dispute between proponents of associative accounts and advocates of more cognitive accounts of animal behaviour. Examination of the specific details of transitive inference suggests some lessons for the wider debate. 7.1 Transitive inference Transitive relationships are frequently important to animals, especially those living in social groups. Some of these relationships are manifest in perception: if A is larger than B, and B is larger than C, then simple inspection of A next to C will reveal that A is larger; no reasoning is required. But it is also possible to draw the inference that A is larger than C without having to see A and C side by side. Most adult humans have the capacity for such reasoning, demonstrating their understanding of the transitivity of the larger-than relationship. Other transitive relationships are not directly manifest in perception. If A is a faster runner than B and B is a faster runner than C, it will not always be able to tell just by looking at them. But once these relationships are known, 07-Hurley-Chap07.qxd 23/7/05 11:19 AM Page 175