 This is the not the end of the problem, however. Some philosophers have argued that not all traits that are culturally transmitted or learnt can be properly understood using adaptationist methods, because many of these traits are not heritable even in this weaker sense, and hence cannot be adaptations (Driscoll, 2009; Driscoll and Stich, 2008; Kitcher, 1990). Worse, such traits could appear highly adaptive on evolutionary models. For example, traits which are subject to highly adaptive individual learning or adaptive social transmission processes in populations (Henrich and Boyd, 1998; Henrich and Gil-White, 2001) are nevertheless not adaptations because they are not shaped by natural  selection[8].  This is because in many of these cases, the features of the environment that make the trait appear adaptive may not actually have featured as selection conditions in the causal history of the trait (or perhaps as causes in any sense). In such cases, evolutionary methods popular in sociobiology and the current evolutionary social sciences (such as optimality modeling) will make traits appear to be adaptations to those conditions when they are not. For a more detailed discussion of dual inheritance theory, gene culture co-evolution and the associated theory, see the entry on  cultural evolution.