Richard Lewontin's (1970) early work on the units of selection initiated the conceptual and theoretical investigations that have led to the hierarchical perspective on selection that has reached near consensus status today. This paper explores other aspects of his work, work on what he termed continuity and quasi-independence, that connect to contemporary explorations of modularity in development and evolution. I characterize such modules and argue that they are the true units of selection in that they are what evolution by natural (...) selection individuates, selects among, and transforms. (shrink)

Kim Sterelny and Paul Griffiths (Sterelny 1992, Sterelny and Griffiths 1999) have argued that sociobiology is unworkable because it requires that human behaviors can be adaptations; however, behaviors produced by a functionalist psychology do not meet Lewontin's quasi-independence criterion and therefore cannot be adaptations. Consequently, an evolutionary psychology which regards psychological mechanisms as adaptations should replace sociobiology. I address two interpretations of their argument. I argue that the strong interpretation fails because functionalist psychology need not prevent behaviors from evolving independently, (...) and it relies on too strong an interpretation of the quasi-independence criterion. The weaker interpretation does not undermine sociobiology, and evolutionary psychology would be vulnerable to the same criticism. Finally, I offer reasons to think that both mental mechanisms and behaviors can be adaptations. (shrink)