Language Evolution and Computation Bibliography

In recent years, laboratory studies of cultural evolution have become increasingly prevalent as a means of identifying and understanding the effects of cultural transmission on the form and functionality of transmitted material. The datasets generated by these studies may provide insights into the conditions encouraging, or inhibiting, high rates of innovation, as well as the effect that this has on measures of adaptive cultural change. Here we review recent experimental studies of cultural evolution with a view to elucidating the role of innovation in generating observed trends. We first consider how tasks are presented to participants, and how the corresponding conceptualization of task success is likely to influence the degree of intent underlying any deviations from perfect reproduction. We then consider the measures of interest used by the researchers to track the changes that occur as a result of transmission, and how these are likely to be affected by differing rates of retention. We conclude that considering studies of cultural evolution from the perspective of innovation provides us with valuable insights that help to clarify important differences in research designs, which have implications for the likely effects of variation in retention rates on measures of cultural adaptation.

Formal models of cultural evolution have illustrated circumstances under which behavioral traits that have no inherent advantage over others can undergo positive selection pressure. One situation in which this may occur is when the behavior functions as a social marker, and there is pressure to identify oneself as a member of a particular group. Our aim in the current study was to determine whether participants organized into subpopulations could effectively exploit variation in a completely novel behavior to advertise themselves as belonging to a particular subpopulation, such that discrimination between in-group and out-group members was possible and subpopulations exhibited increasing distinctiveness. Eighty participants took part, organized into four subpopulations, each composed of five four-member generations. They each completed a tower-building task, used in previous experimental studies of cultural evolution. An incentive payment structure was imposed with the aim of motivating participants to advertise themselves as belonging to a particular subpopulation and to distinguish in-group members from members of other subpopulations. The first generation were exposed to photographs of randomly assigned “seed” towers, and later generations were exposed to photographs of the towers built by the members of the previous generation of their own subpopulation. Participants were able to discriminate towers built by in-group members of the same generation, from towers built by out-group members. Over generations, tower designs evolved such that they were increasingly identifiable as belonging to a particular subpopulation. Arbitrary traits which had no prior advantage became associated with group membership, providing empirical support for theoretical models.

Christiansen & Chater's (C&C's) argument rests on an assumption that convergent cultural evolution can produce similar (complex) behaviours in isolated populations. In this commentary, I describe how experiments recently carried out by Caldwell and colleagues can contribute to the understanding of such phenomena.

Cumulative cultural evolution is the term given to a particular kind of social learning, which allows for the accumulation of modifications over time, involving a ratchet-like effect where successful modifications are maintained until they can be improved upon. There has been great interest in the topic of cumulative cultural evolution from researchers from a wide variety of disciplines, but until recently there were no experimental studies of this phenomenon. Here, we describe our motivations for developing experimental methods for studying cumulative cultural evolution and review the results we have obtained using these techniques. The results that we describe have provided insights into understanding the outcomes of cultural processes at the population level. Our experiments show that cumulative cultural evolution can result in adaptive complexity in behaviour and can also produce convergence in behaviour. These findings lend support to ideas that some behaviours commonly attributed to natural selection and innate tendencies could in fact be shaped by cultural processes.