Introspective equilibrium for coordination games with changing group size

Abstract: In the laboratory, minimum-effort coordination games routinely reach low levels for larger group sizes. Weber (2006 American Economic Review) showed that by simply starting with a small group and adding players that are exposed to the group’s history over time, one can “grow” larger groups with high effort levels. Adapting the concept of introspective equilibrium, I create a model to replicate the findings of minimum-effort games with growing player counts. While remaining simple and flexible for further extensions it manages to explain almost all findings of previous growth experiments.