Cultural evolution of arbitrary communicative conventions in experimental microsocieties
Previous studies have shown that iconic graphical signs can evolve into symbols through repeated usage within dyads and interacting communities. We investigated the evolution of graphical signs over chains of participants. In these chains (or “replacement microsocieties”), membership of an interacting group changed repeatedly such that the most experienced members were continually replaced by naïve participants. Signs rapidly became symbolic, such that they were mutually incomprehensible across experienced members of different chains, and new entrants needed to learn conventionalised meanings. Objective measurement of graphical complexity confirmed that the signs were becoming progressively simplified. A learning-like effect (involving increased efficiency over successive attempts) was therefore observed, in spite of the fact that different individuals were making each of these attempts. In this respect, these findings were similar to those from our other studies involving the microsociety method. However, in contrast to our previous research (which used simple building tasks) there was also strong evidence of relatively stable and distinctive traditions within the chains, reminiscent of patterns of cultural variation in the real world.