International Journal of Comparative Psychology

One particular concern of the 2010 Winter Conference on Animal Learning and Behaviour was the degree to which the behaviours of human and nonhuman animals might be interpreted as the result ofthe same cognitive mechanisms. Here, we examine three examples in rats (causal-reasoning, sensitivity to the absence of stimuli, and the relationship between effort and reward) where higher ordermental processes might be invoked as explanations of the observed behaviour. In each case we argue that alternative accounts, based on “lower” mental processes, are also consistent with the observed data. On the basis of the principle of parsimony, enshrined as a grounding assumption of comparative psychology in C. Lloyd Morgan’s Canon, the existence of such alternative accounts means that the available evidence does not licence the conclusion that non-human animals display evidence of human-like cognitive processes in these areas.