(p. 57) The comparative approach
We have already emphasized the way in which evolutionary theory provides us with a broad framework in which to situate questions of psychological interest. Given evolutionary continuity across species, it is obvious that these questions can and should be extended to other species besides ourselves; after all, humans did not drop into the Pleistocene fully formed, and our cognitive mechanisms and the behaviours they produce have a much longer evolutionary history than the last 10 000 years.
As an anthropocentric endeavour designed to shed light on how we came to be, studies of non-human primates have tended to take centre-stage in comparative studies of cognition, as befits their close evolutionary relationship to us. However, as Rendall et al. remind us, our anthropocentric assumptions may often be misplaced when we try to ‘homologize the mind’ in this way, at least partly because we fail to recognise the ‘bushiness’ of the evolutionary family tree, and the varying evolutionary paths that different species have taken. Assuming that other primate species will possess the precursors of human behaviour and cognition reflects an (often unrecognized) assumption that other species' abilities must be the evolutionary stepping stones by which our own cognitive abilities were gradually built up, as well as assuming that our selective environments have been fundamentally the same. Rendall et al. thus draw on some of the themes raised by Mameli and Laland in the previous section in order to place our views of ourselves, and other primate species, under close scrutiny.
These arguments obviously extend beyond the primates, and also raise the issue of whether, given our massively enlarged brains, primates, including humans, are as cognitively ‘special’ as we so often assume. The answer to this question obviously requires that we investigate the abilities of other, non-primate, species, and focus on identifying the kinds of evolutionary pressures that are associated with particular cognitive abilities. As Bshary et al. argue, this ‘ecological approach’ moves us beyond our rather narrow anthropocentric concerns, as well as enabling more controlled and detailed investigations of the links between behaviour and cognition through the use of ‘model’ species more amenable to study than ourselves. At the same time, we shouldn't lose sight of the real animal, acting in its natural environment, for without such data we would have little idea of what experiments to perform. Behavioural, ecological and evolutionary studies of animal behaviour can inform the field of comparative cognition in crucially important ways: we should not forget the intellectual sterility of radical behaviourism, and the importance of thinking outside of the (Skinner) box.
In some instances, an ecological approach may include anthropocentrically relevant elements, especially among highly social species where (p. 58) getting along with one's fellows is likely to have exerted a very strong selection pressure. The degree to which such social manoeuvring can be explained by ‘knowledge-based’ as opposed to ‘cue-based’ (i.e. associative) mechanisms is one of the key issues at stake in this respect, and Call argues that the weight of evidence lies with the former rather than the latter, at least among the Great Apes. Van Schaik adds weight to this conclusion in his discussion of the evolutionary relevance of ontogeny among these long-lived species, arguing that the ‘scaffolding’ of learning by other, more experienced, individuals over long periods of development may be the key to explaining the greater cultural capacities of the apes compared to other species. The social support of learning is, however, likely to differ from that shown by human mothers to their offspring in important respects: a lack of ‘other-regarding’ preferences among the Great Apes, as discussed by Silk, would seem to suggest that, whatever mechanisms underlie these social learning processes, an empathic concern for others is unlikely to be among them.