Evolutionary pressures promoting complexity in navigation and communication

This article presents results from simulations studying the hypothesis that mechanisms for landmark-based navigation could have served as preadaptations for compositional language. It is argued that sharing directions would significantly have helped bridge the gap between general and language-specific cognitive faculties. A number of different levels of navigational and communicative abilities are considered, resulting in a range of possible evolutionary paths. The selective pressures for, resp. against, increased complexity in either faculty are then evaluated for a range of environments. The study aims specifically to identify whether there is a viable evolutionary path leading to compositional language, and if so, under what circumstances. The results show that environmental conditions can render a step towards more complex communication either desirable or harmul, and suggest that very specific initial conditions and changes in the environment, resp. the ecological niche occupied, would have been needed to select for compositional language. Subject to these conditions, a language using order, but no hierarchical structure could evolve. This represents a middle ground, which brings closer hypotheses about syntax that have so far appeared difficult to reconcile.