Levels of explanation in category learning

Multiple-system accounts of category learning are now entrenched in the cognitive neuroscience literature. This entrenchment sometimes seems impervious to behavioural evidence that contradicts or questions key assumptions of multiple-systems accounts. In this brief article, I consider relevant sources of evidence (behavioural, neuropsychological, neuro-imaging) and argue that the evidence from all sources is not as clear-cut as many multiple-system theorists often claim. More importantly, the review emphasises that one needs to be sensitive to the desired level of explanation of category learning (psychological, biological, mathematical) when considering the relevance of different types of data and the adequacy of proposed accounts.