Reconciling and Reassessing the Accumulated Copying Error Model's Population-Level Predictions for Continuous Cultural Traits

Abstract

The accumulated copying error (ACE) model exploits the fact that limits to human visual perception introduce proportional copying errors during cultural transmission of a continuous trait, such as the length of a tool. Archaeologists have used ACE to infer the mechanisms of cultural transmission employed in the past. But ACE's predictions apply only under “idealized” conditions in which the population contains infinitely many vertical transmission chains and the continuous trait can take any positive value. Here, I relax each assumption to show: (1) the mean and variance of a vertically transmitted continuous trait are functions of population size and number of transmission events, and (2) functional constraints weaken the cumulative effects of proportional copying error. Incorporating the effects of population size and functional constraints in future work will reduce Type I errors (falsely rejecting a true null) when inferring the cultural transmission mechanisms responsible for population-level variation in continuous traits. [cultural evolution, cultural transmission, finite population size, functional constraints, Paleolithic, simulation, social learning].