Human prosociality in altruism niche

Possible effects of external and internal factors affecting prosociality in Japanese undergraduates were investigated. We employed social support as an external factor and helping norms, self-consciousness, other-consciousness, self-esteem, and religious attitude as internal factors. Prosociality toward friends/acquaintances was significantly positively correlated with social support from siblings, social support from friends/acquaintances, self-sacrifice norms, and private self-consciousness, whereas prosociality toward strangers was significantly positively correlated with social support from mothers, private self-consciousness, and self-esteem but negatively correlated with social support from siblings. The results support claims of an altruism niche that rest on the assumption that prosociality can be maintained only in an environment or a society in which altruistic acts are rewarded. Among the internal factors, private self-consciousness was the only factor found to correlate with both aspects of prosociality. Higher scores on private selfconsciousness were related to irrational altruism, making people less susceptible to the features of particular situations and, consequently, producing reputational benefits.