Random copying and cultural evolution.
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Behavior↗
Biomedical subjects
R Alexander Bentley
Publications and source records attributed to R Alexander Bentley.
Random drift and large shifts in popularity of dog breeds.
A simple model of random copying among individuals, similar to the population genetic model of random drift, can predict the variability in the popularity of cultural variants. Here, we show that random drift also explains a biologically relevant cultural phenomenon--changes in the distributions of popularity of dog breeds in the United States in each of the past 50 years. There are, however, interesting deviations from the model that involve large changes in the popularity of certain breeds. By identifying meaningful departures from our null model, we show how it can serve as a foundation for studying culture change quantitatively, using the tools of population genetics.
Animals↗
Random drift and culture change.
We show that the frequency distributions of cultural variants, in three different real-world examples--first names, archaeological pottery and applications for technology patents--follow power laws that can be explained by a simple model of random drift. We conclude that cultural and economic choices often reflect a decision process that is value-neutral; this result has far-reaching testable implications for social-science research.
Computer Simulation↗
Drift as a mechanism for cultural change: an example from baby names.
In the social sciences, there is currently no consensus on the mechanism by which cultural elements come and go in human society. For elements that are value-neutral, an appropriate null model may be one of random copying between individuals in the population. We show that the frequency distributions of baby names used in the United States in each decade of the twentieth century, for both males and females, obey a power law that is maintained over 100 years even though the population is growing, names are being introduced and lost every decade and large changes in the frequencies of specific names are common. We show that these distributions are satisfactorily explained by a simple process in which individuals randomly copy names from each other, a process that is analogous to the infinite-allele model of population genetics with random genetic drift. By its simplicity, this model provides a powerful null hypothesis for cultural change. It further explains why a few elements inevitably become highly popular, even if they have no intrinsic superiority over alternatives. Random copying could potentially explain power law distributions in other cultural realms, including the links on the World Wide Web.
Culture↗