 Important differences exist between sociocultural evolution and biological evolution (Claidière &amp; André 2012) [see the entry on  cultural evolution].  For example, Dawkins (1976) admits that he is on shaky ground when it comes to the high-fidelity copying required of replicators. Memes seem to get changed much more frequently than genes (see Sterelny (2006) for a review). In general, however, it is fair to say that the standards used to evaluate sociocultural transmission are not on par with those used to evaluate biological transmission. An overly idealized view of Mendelian genetics is contrasted with a much more realistic view of cultural change. So the criticism goes, one problem with memes is that they do not have discrete boundaries, do not all come in the same size, and, in their functioning, are strongly influenced by their environments. Genes, so the critics claim, have sharp boundaries, are all of the same size, and are immune to environmental influences. If sociocultural evolution is to be evaluated fairly, the same level of criticism must be applied to all putative examples of selection, from gene-based selection in biological evolution and the reaction of the immune system to antigens to the development of the central nervous system and social learning (Hull et al. 2001). The collection of articles in Aunger (2000) present the arguments for and against a memetic approach to culture, and a more recent discussion is available in Lewens (2015).