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Morin Olivier | Fellow Postdoctoral
2013-11-01 - 2015-06-30 | Research area: Cognition and Sociality
Biological Generations in Cultural Evolution
Personal webpage: Does the succession of biological generations structure cultural change — and if so, how? This research project will investigate the consequences of demographic turn over on the diffusion and mutations of traditions. Two reasons invite us to expect cultural change to be driven by demography. The first reason is the existence of sensitive periods for cultural acquisition: critical «windows» where grammatical parameters (for speakers of a given language) artistic styles (for painters) or theoretical options (for scientists) tend to get fixated, more or less irreversibly. The second reason is the slow pace of some changes: they appear to be constrained by the supply of young learners (which in most populations is a more or less constant quantity) rather than determined by the number of models (which can grow exponentially). In spite of this, finding generational dynamics in cultural evolution is not easy. Identifying sensitive periods is a matter of some controversy. The cultural inputs that people are exposed to are changing with time, making the respective contributions of sensitive periods, cognitive maturation and changing environments difficult to tease apart. The pace and rhythm of cultural change may also differ depending on the subpopulation that one is observing: the adoption of evolutionary theory does not look the same if one looks at it among members of the Royal Society, French zoologists, or American clergymen. These difficulties partly explain why we still lack precise concepts and instruments to estimate, let alone predict, how important generational change will be for a given cultural change. This investigation will use a simple statistical tool to tackle the issue. The method uses the fact that any individual’s birthdate is equal to the date at which he is observed, minus his age. For any cultural change (given two of these parameters for every data point), this method allows us to know whether the change is driven by generational turn over, by an event that is external to the population, or by a series of individual maturations. Several data sets will be explored using this method, with the aim of developing a general framework for cultural demography. This framework should predict the importance of generational turn over for various cultural changes, based on their time scale and on the cognitive mechanisms they recruit. Personal webpage: