The Baldwin effect and genetic assimilation: contrasting explanatory foci and gene concepts in two approaches to an evolutionary process

has discussed the relationship between social learning and the family of postulated evolutionary processes that includes 'organic selection', 'coincident selection', 'autonomisation', 'the Baldwin effect' and 'genetic assimilation'. In all these processes a trait which initially develops in the members of a population as a result of some interaction with the environment comes to develop without that interaction in their descendants. It is uncontroversial that the development of an identical phenotypic trait might depend on an interaction with the environment in one population and not in another. For example, some species of passerine songbirds require exposure to species-typical songs in order to reproduce those songs whilst others do not. Hence we can envisage a species beginning with one type of developmental pathway and evolving the other type. If, however, the successive evolution of these two developmental pathways were a mere coincidence, selection first favoring the ability to acquire the trait and later, quite independently, favoring the ability to develop it autonomously, then this would not be a distinctive kind of evolutionary process, but merely two standard instances of natural selection. George Gaylord Simpson pointed this out in the paper that gave us the term 'Baldwin effect' (Simpson, 1953). The real interest of the Baldwin effect and its relatives lies in the mechanisms which might link the evolution of the two developmental pathways, so that acquiring the trait through interaction with the environment makes it more likely that later generations will evolve the ability to acquire the same trait without that interaction. Papineau focuses on the way in which social learning can facilitate such Baldwin-like links. His basic idea is that the genes which accelerate the social learning of some complex behaviour might become advantageous only if that behaviour is already being passed on by learning in an 'animal culture'.. In this scenario the relevant genes would be selected once the population is socially transmitting the behaviour, but not otherwise, thus yielding a scenario that