Figure 1.
Regions of parameter space in which conditional helping and approach are stable. (a) The range of values of s (the probability of switching state, here assumed equal for both states) and c (the cost to the recipient of harm, relative to the benefit of help) over which an equilibrium of the kind considered in the text proves stable, for three different values of e, the probability that harmful behaviour is observed: successively darker shading corresponds to successively lower values of e, 1, 0.75 and 0.5, respectively. In all cases, x2/x1=0.1 and y2/x1=0.05. (b) Equivalent regions of stability for three different values of x2/x1, the temptation to harm when in state 2 relative to that in state 1 successively darker shading corresponds to successively greater values of x2/x1, 0.05, 0.1 and 0.15, respectively. In all cases, e=0.75 and y2/x1=0.05.