While I have some differences from Mesoudi, compared to Laor and Jablonka, Mesoudi and I are very much singing from the same hymn sheet. So, a few replies. Laor and Jablonka ask?
Like cultural behaviors, institutions such as hospitals or churches, are not included in Mesoudi'sdefinition of culture. He suggests that they, like behaviors, are the “phenotypes” of a “cultural genotype” stored in people's brains as neural networks (for example, 3, 213). But since the neural network is a product of social learning that occurs during human development, in what sense is it a genotype? Are “phenotypes” and “genotypes” embodied within an individual or distributed among members of a collective? It seems to us that adherence to notions of genotype and phenotype in the cultural realm, where heredity is an aspect of development and requires an active process of reconstruction, is misplaced (it is, in fact, in need of qualification even in the biological realm!).There's a neat resolution of this issue: genotypes are composed of heritable information, phenotypes are the things that are influenced by them. This idea applies equally to DNA genes and to memes. The concepts often imply the notion of an individual - and so we have to say what a cultural individual is - but that isn't an insurmountable problem.
As Mesoudi confesses, his outline of a cultural-evolution synthesis inherits the problems of the twentieth century MS, in that it lacks a developmental perspective. We agree with Mesoudi that what development means in the cultural multi-generational context is not entirely clear. However, Jablonka and Lamb have argued that this lack of clarity is part of the solution, not the problem: it is inherent in the fact that the notions of heredity and development in the cultural realm are far less distinct than they are in the biological case.Genetics and memetics don't involve the study of development. Development is treated by these theories as a black box - containing arbitrary transformations which map from genotypes to phenotypes. Certainly development influences evolutionary trajectories. However, meteorite strikes, earthquakes, and fashion also influence evolutionary trajectories - we can't include everything under the umbrella of evolutionary theory. Development is a pretty different subject. Yes, there's evolutionary ontology, which applies evolutionary concepts to development - but it is OK to study development separately. As for the supposed "lack of clarity", the concept of "development" is best taken to refer to mappings from genotypes to phenotypes. It applies equally well to the organic and cultural realms. Maybe there's disagreement about the topic, but it seems easy enough to make it into a clear concept.
We believe that the major difference between the approach promoted by Mesoudi and that adopted by most social scientists is that the latter treat culture as a system. Cultural systems are not super-organisms, but they are also not an assembly of individuals, institutions and traits. They are – to differing extents and in different levels and ways – functionally integrated entities, and they occupy a middle-ground between a super-organism and an aggregate, a locus that is difficult to conceptualize if one is wedded to a traditional population-genetics-based metaphor. Social scientists endorsing the systems view do not reject approaches that focus on distinct and isolatable elements of culture, but they do treat the results of such analyses with caution, regarding them as limited and preliminary forays into the analysis of culture.There are two issues here. The first is that cultures are, overwhelmingly, assemblies of individuals, institutions and traits. Analysis of culture in those terms is highly productive. Entire cultures don't have intelligent designers making them. They are cobbled together by cultural evolution. Analysing culture in terms of its parts follows the scientific practice of reductionism, of breaking down a complex whole into its component parts in order to understand it. This has been a tremendously productive approach in practically all branches of science. However, the application of frequency analysis - and other such techniques - to cultural variation doesn't presuppose the lack of high-level system characters. Their existence, or rather in most cases their lack of existence, is a separate empirical issue.