Constructive criticism: An evaluation of Buller and Hardcastle's genetic and neuroscientific arguments against Evolutionary Psychology

Abstract

David Buller and Valerie Hardcastle have argued that various discoveries about the genetics and nature of brain development show that most “central” psychological mechanisms cannot be adaptations because the nature of the contribution from the environment on which they are based shows they are not heritable. Some philosophers and scientists have argued that a strong role for the environment is compatible with high heritability as long as the environment is highly stable down lineages. In this paper I support this view by arguing that the discoveries Buller and Hardcastle refer to either do not show as strong a role for the environment as they suggest, or these discoveries show that the brain's developmental process depends in many cases on input from the environment that is highly stable across generations.

Keywords::

• Brain Development
• Evolutionary Psychology
• Neuroscience
• Philosophy of Cognitive Science

Notes

^[1] Please note that in Buller's book Adapting minds (Buller, 2005a), the chapter in which he addresses these arguments is labeled as co-authored by Hardcastle, so I will also describe arguments in this chapter as “Buller and Hardcastle's” arguments.

^[2] Interestingly, as Sterelny (2007) suggests, broad sense heritability is not needed for natural selection to act so long as environments themselves are transmitted reliably across generations (e.g., by powerful niche construction). Technically, the Evolutionary Psychologists could avoid Buller and Hardcastle's argument if there was good reason to think most psychological mechanisms were transmitted across generations in this way; however, I won't rely on this idea at all in this paper.

^[3] Some adaptations are, of course, designed to vary in response to standard changes in the developmental environment (they are facultative or plastic adaptations); the kinds of variation Buller and Hardcastle have in mind here go beyond variation that is part of the adaptation.

^[4] Technically, a proper demonstration of the degree of heritability of human psychological mechanisms would require a statistical analysis of how much variation in such mechanisms is due to genetic and environmental variation in human populations. Buller and Hardcastle aren't claiming to have done this, and doing so would be extraordinarily difficult. Instead, they take their evidence to tell against the high heritability of human psychological mechanisms in the weaker sense described here.

Additional information

Notes on contributors

Catherine Driscoll

Catherine Driscoll is Associate Professor of Philosophy at North Carolina State University