In contrast to traditional differences, cumulative cultural change is restricted to OL for a narrow range of environmental conditions. In Fig. 2 b we show average levels of cumulative cultural increases in energy intake. Statistically significant cumulative cultural change is only generated for OL and only for H=10 (Fig. 2 b, solid triangles, Wilcoxon signed rank test with continuity correction and a Bonferroni corrected α level of 0.0125 to maintain a familywise error rate of 0.05). Note that foragers in groups with LE or SE are not viable at H=10  and are excluded.