Fig. 2

Energy levels and exploration rates. a Average evolved energy levels in environments with varying task difficulty (H). b Average evolved energy levels in environments with varying rates of change (EC). c Difference in evolved energy levels between solitary (SOL) and other conditions in environments with varying task difficulty (H): i.e. all other lines minus the dashed line in top left graph. d Difference in evolved energy levels between solitary (SOL) and other conditions in environments with varying rates of change (EC): i.e. all other lines minus the dashed line in top right graph. SOL = solitary; G _LE = groups with only local enhancement; G _SE = groups with stimulus enhancement; G _OL = groups with observational learning; Each point (energy level) is the average energy of the whole population between year 950 and 1000 from 10 full evolutionary simulations