Figure 2
From: Ancestral social environments plus nonlinear benefits can explain cooperation in human societies
Examples of a group of five individuals forming according to the rules of the three homophilic group-formation models: (a) leader driven, (b) members attract, and (c) members recruit. Current members sequentially recruit or attract new members (lines) who tend to be kin (same colour). The grey group in (b) represents attraction of nonkin to the group itself.
