Matteo Mameli

Cultural traits are those phenotypic traits whose development depends on social learning. These include practices, skills, beliefs, desires, values, and artefacts. The distribution of cultural traits in the human species changes over time. But this is not enough to show that culture evolves. That depends on the mechanisms of change. In the cultural realm, one can often observe something similar to biology’s ‘descent with modification’: cultural traits are sometimes modified, their modifications are sometimes retained and passed on to others through social learning, until new modifications are added. In this way, new modifications are piled on top of old modifications, generating cumulative change. But, again, this is not enough to show that culture evolves. For culture to evolve, cumulative change must be the result of hidden-hand mechanisms similar to those that explain cumulative biological change. If cumulative cultural change cannot be explained in these terms, the analogy between cultural change and biological evolution is unhelpful. The best known biological mechanism is natural selection. There are reasons to think that cultural change is at least sometimes due to natural-selection-like mechanisms. The adaptive fit often found between cultural traits and the environment has in many cases been built gradually and in a way that involves natural selection operating at the cultural level. The parallel with morphological adaptation is compelling. No complete and universally accepted account of natural-selectionlike processes operating at the cultural level exists at this stage. But at least three kinds of processes seem possible.

According to the received view of evolution, only genes are inherited. From this view it follows that only genetically-caused phenotypic variation is selectable and, thereby, that all selection is at bottom genetic selection. This paper argues that the received view is wrong. In many species, there are intergenerationally-stable phenotypic differences due to environmental differences. Natural selection can act on these nongenetically-caused phenotypic differences in the same way it acts on genetically-caused phenotypic differences. Some selection is at bottom nongenetic selection. The argument against the received view involves a reformulation of the concepts of inheritance and heritability. Inherited factors are all those developmental factors responsible for parent–offspring similarity; some inherited factors are genetic and some are not. Heritable variation is intergenerationally-stable phenotypic variation; some such variation is genetically-caused and some is not. The received view and its critics The possibility of nongenetic selection (the lucky butterfly) The reality of nongenetic selection 3.1 Imprinting mechanisms 3.2 Other learning mechanisms 3.3 Other nongenetic mechanisms Genetic and nongenetic inheritance mechanisms Genetic and nongenetic inherited factors Genetic and nongenetic heritability Conclusions + Current address: Dr Matteo Mameli, Research Fellow, King's College, Cambridge, CB2 1ST, United Kingdom, matteo.mameli{at}kings.cam.ac.uk' + u + '@' + d + ''//-->.

I present and apply some powerful tools for studying human evolution and the impact of cultural resources on it. The tools in question are a theory of niche construction and a theory about the evolutionary significance of extragenetic (and, in particular, of psychological and social) inheritance. These tools are used to show how culturally transmitted resources can be recruited by development and become generatively entrenched. The case study is constituted by those culturally transmitted items that social psychologists call ‘expectancies’. Expectancy effects are mindshaping effects of our mindreading dispositions. I show how expectancies may have been recruited by important human developmental processes (like those involved in language acquisition and those responsible for gender differences) and how they may have become entrenched. If the hypothesis is correct, the relation between mindreading and human evolution is more intricate than usually thought

The concept of innateness is a part of folk wisdom but is also used by biologists and cognitive scientists. This concept has a legitimate role to play in science only if the colloquial usage relates to a coherent body of evidence. We examine many different candidates for the post of scientific successor of the folk concept of innateness. We argue that none of these candidates is entirely satisfactory. Some of the candidates are more interesting and useful than others, but the interesting candidates are not equivalent to each other and the empirical and evidential relations between them are far from clear. Researchers have treated the various scientific notions that capture some aspect of the folk concept of innateness as equivalent to each other or at least as tracking properties that are strongly correlated with each other. But whether these correlations exist is an empirical issue. This empirical issue has not been thoroughly investigated because in the attempt to create a bridge between the folk view and their theories, researchers have often assumed that the properties must somehow cluster. Rather than making further attempts to import the folk concept of innateness into the sciences, efforts should now be made to focus on the empirical questions raised by the debates and pave the way to a better way of studying the development of living organisms. Such empirical questions must be answered before it can be decided whether a good scientific successor – in the form of a concept that refers to a collection of biologically significant properties that tend to co-occur – can be identified or whether the concept of innateness deserves no place in science.

Since the discovery of the double helical structure of DNA, the standard account of the inheritance of features has been in terms of DNA-copying and DNA-transmission. This theory is just a version of the old theory according to which the inheritance of features is explained by the transfer at conception of some developmentally privileged material from parents to offspring. This paper does the following things: (1) it explains what the inheritance of features is; (2) it explains how the DNA-centric theory emerged; (3) it clarifies the relation between the DNA-centric theory and the ‘unfolding’ theory of development; (4) it argues that (given what we now know about developmental processes and genetic activity) the DNA-centric theory should be abandoned in favour of a pluralistic (but not holistic) theory of the inheritance of features. According to this pluralistic theory, the reliable reoccurrence of phenotypes must be explained by appealing not only to processes responsible for the reliable reoccurrence of genetic developmental factors but also to processes responsible for the reliable reoccurrence (or persistence) of nongenetic developmental factors.