Diet traditions and cumulative cultural processes as side-effects of grouping

Social learning and cognitive sophistication are often assumed to be prerequisites for the origins of culture. In contrast, we studied to what extent the most simple social influences on individual learning can support cultural inheritance. We did this using a spatial individual-based model where group foragers have to learn what to eat in a diverse patchy environment, and used simple population dynamics to investigate the potential of ‘merely living in groups’ to allow for inheritance of diet traditions. Our results show that grouping by itself is a sufficient social influence on individual learning for supporting the inheritance of diet traditions. Unexpectedly, we find that grouping is also sufficient to generate cumulative group-level learning through which groups increase diet quality over the generations. Whether ‘traditions’ or ‘progressive change’ dominates depends on foraging selectivity. We show that these cultural phenomena can arise as side-effects of grouping and therefore independently of their adaptive consequences. This suggests that cultural phenomena could be quite general and shows that cumulative cultural processes already occur even for the most simple social influences on learning.