 Perovic &amp; Radenovic (2011) point out that this claim about the causal structure of development in a particular, late developmental stage is entirely compatible with the strongly interactionist view of how genes and environment build the brain favoured by developmental systems theorists. They suggest that neo-nativism is primarily concerned to show that how organisms respond to their environments depends strongly on cognitive structure that is in place before the organism encounters that environment. Conversely, anti-nativists are primarily concerned to show that environments often play a specific, instructive role in the development of cognitive structures. Since the two schools do such different research, the latter primarily focused on human development post-partum and well into childhood, and the former on early development, often in animal models for reasons of ethical and experimental tractability, there is considerable scope for accounts of psychological development that draw on both perspectives at different stages of development. So, once again, on this account disputes about nativism are fundamentally a reflection of scientists different explanatory interests.