Figure 5

Average cooperation (a) and fusion (b) as a function of the rate of execution error \(e_x\). Average cooperation (c) and fusion (d) as a function of the rate of perception error \(e_p\). Ostracism of type 1, 2, or 3 is performed by each agent i with a probability equal to the agent’s fusion level \(f_i\). Perception error \(e_p\) is defined as the probability of the individual’s contribution to the group being replaced by a random number in the range [0,1]. Execution error \(e_x\) is defined as the probability for an agent not to perform ostracism when it should. Agents interact randomly with the other fused individuals within their in-group with a probability equal to their own fusion levels (\(S_i = f_i\)). The in-group of an agent i is defined as the subset of agents having at least same level of fusion as i (i.e., \(f_i\) or greater). Agents interact randomly with the whole population with a probability equal to 1 − \(S_i\). Results are averaged over five randomly seeded runs, each conducted for 50,000 generations. Parameter settings are consistent with Fig. 1.