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Cognition: theories of mind in animals and humans

Nature volume 459, page 506 (28 May 2009) | Download Citation



I believe that Johan Bolhuis and Clive Wynne, in their Essay 'Can evolution explain how minds work?' (Nature 458, 832–833; 2009), profoundly misrepresent the burgeoning interdisciplinary field of comparative cognition research as being rife with anthropomorphism and ignorance of evolutionary principles.

Darwinism in animal cognition is represented, not by the naive anthropomorphism practised by Darwin and his contemporaries, but by Darwin's claim that humans differ mentally from other species “in degree but not in kind”. There is evidence from behavioural studies that many of humans' mental powers are shared by other animals, including simple forms of learning, memory and categorization, and the elements of social, spatial and numerical cognition.

Only against this background does it make sense to propose, as some have, that there is a distinct small set of mental powers that is unique to humans, including theory of mind (see, for example, D. C. Penn et al. Behav. Brain Sci. 31, 109–130; 2008). Contrary to what Bolhuis and Wynne are suggesting, careful analysis of the behaviours taken as evidence for theory of mind in species from chimpanzees to dogs to birds has led to a rethink of claims that were initially anthropomorphic.

The authors suggest that relatedness among species is emphasized at the expense of convergently evolved cognitive similarities. On the contrary: apparently similar performances of distantly related species — as in tool-using, social cognition and teaching-like behaviour — are now increasingly being studied precisely because convergence is a recognized test-bed for functional hypotheses. For example, the proposal that monkeys and apes have evolved exceptional social skills to navigate a particular kind of social group is tested with non-primate species that have complex social organization, such as hyenas, some birds and even fish. Comparison of the cognitive mechanisms underlying such functionally similar behaviours is an active area of research.

Bolhuis and Wynne end with the proposal that we should “study animal and human minds empirically” — as if that is not already being done (for an overview, see S. J. Shettleworth Behav. Processes 80, 210–217; 2009). As they point out, evolution cannot explain how minds work (any more than it can explain precisely how nerves or genes work), and our own psychology can be an obstacle to understanding that of other species.

Nevertheless, studying minds in their phylogenetic and functional context can provide an indication of what they were selected to do. And, as in the other biological sciences, it can offer a theoretical framework for meaningful comparative research into mechanisms.

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  1. Department of Psychology, University of Toronto, 100 St George Street, Toronto, Ontario M5S 3G3, Canada

    • Sara J Shettleworth


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