1 LOCAL EXTINCTIONS AND REGIONAL CULTURAL DIVERSIFICATION IN TIME- AVERAGED ASSEMBLAGES Galen Miller-Atkins and L.S. Premo Department of Anthropology Washington State University The Upper Paleolithic has been characterized as a “cultural revolution,” marked by an increase in innovation, the appearance of regional “cultures,” and the use of symbols, that resulted from changes in cognition. Recent empirical work has raised a number of other potential explanations. Although increased cognitive power, population size, and a decrease in local extinction rates have been proposed for the emergence of so-called behavioral modernity, it remains unknown where, when, or how humans became behaviorally modern. In this paper, we explore the relationship between local extinction rates and the spatial scale of cultural similarity in a neutral cultural trait within time-averaged assemblages. The model presented here includes groups of social learners, who learn a cultural variant through unbiased transmission and then deposit the variant into cell-specific assemblages. We apply local indicators of spatial association to the simulated data in order to investigate how local extinctions affect the spatial scale of a proxy for cultural “traditions.” The model shows that local extinctions can have a positive effect on the spatial scale of cultural similarity in time-averaged assemblages under unbiased transmission. The results have implications for interpreting the regional-scale cultural diversity in Paleolithic material culture. Keywords: Behavioral Modernity Cultural Transmission Agent-Based Modeling Spatial Statistics