Ask people what is 'moral', and you get a variety of answers: being fair, being chaste, following religious teachings, etc. Studies have found that people of some societies are especially likely to endorse 'group-binding' morals such as loyalty to the country, obedience to authority, and bodily or spiritual purity. In recently published work,
Florian van Leeuwen
have shown that people living in world regions with higher pathogen prevalence are more likely to emphasize such group-binding morals. This finding sheds new light on the origins of differences in values between people of different cultures, suggesting that cross-cultural differences in values may be part of an evolved disease-avoidance strategy.
Van Leeuwen, F., Park, J. H., Koenig, B. L., & Graham, J. (in press). Regional variation in pathogen prevalence predicts endorsement of group-focused moral concerns. Evolution and Human Behavior. (DOI: 10.1016/j.evolhumbehav.2011.12.005)