Cultural Selection Drives the Evolution of Human Communication Systems
Human communication systems evolve culturally, but the evolutionary mechanisms that drive this evolution are not well understood. Against a baseline that communication variants spread in a population following neutral evolutionary dynamics (also known as Drift models), we tested the role of two cultural selection models: Coordination-biased and Content-biased. We constructed a parameterized mixed probabilistic model of the spread of communicative variants in four 8-person laboratory micro-societies engaged in a simple communication game. We found that selectionist models, working in combination, explain the majority of the empirical data. The best-fitting parameter setting includes an egocentric bias and a content bias, suggesting that participants retained their own previously used communicative variants unless they encountered a superior (content-biased) variant, in which case it was adopted. This novel pattern of results suggests that 1) a theory of the cultural evolution of human communication systems must integrate selectionist models and that 2) human communication systems are functionally adaptive complex systems.