What drives collective versus individualistic behaviors?

Talheim et al. offer a strikingly simple explanation for why collective versus individualistic behaviors may arise in a given cultural group. Rather than the usual comparison of Western and Asian cultures as a whole, they look at large-scale psychological differences with China, and find that they correlate with the different behavioral requirements of rice versus wheat agriculture:

Cross-cultural psychologists have mostly contrasted East Asia with the West. However, this study shows that there are major psychological differences within China. We propose that a history of farming rice makes cultures more interdependent, whereas farming wheat makes cultures more independent, and these agricultural legacies continue to affect people in the modern world. We tested 1162 Han Chinese participants in six sites and found that rice-growing southern China is more interdependent and holistic-thinking than the wheat-growing north. To control for confounds like climate, we tested people from neighboring counties along the rice-wheat border and found differences that were just as large. We also find that modernization and pathogen prevalence theories do not fit the data.

From Henrich's description of their methods:

To investigate the individualism and analytical thinking in participants from different agricultural regions in China, Talhelm et al. used three tests. They measured analytical thinking with a series of triads. Participants were given a target object, such as a rabbit, and asked which of two other objects it goes with. Analytic thinkers tend to match on categories, so rabbits and dogs go together. Holistic thinkers tend to match on relationships, so rabbits eat carrots. The authors also measured individualism in two ways. First, they asked participants to draw a sociogram, with labeled circles representing themselves and their friends. In this test, individualism is measured implicitly by how much bigger the “self” circle is relative to the average “friends” circle. Second, they assessed the nepotism (in-group loyalty) of participants by asking them about hypothetical scenarios in which they could reward or punish friends and strangers for helpful or harmful action.