A complete picture of shamanism's cultural evolution requires an understanding of how the professionalization of shamanism affects the distribution of knowledge within societies. We suggest that limiting knowledge to fewer people could impede the accumulation of functional knowledge within shamanism. On this basis, we make further predictions about how the domain of shamanism could change and collapse.

Spirituality and religiosity have a significant impact on one's well-being. Although previous studies have indicated that the neuropeptide hormone oxytocin is associated with spirituality/religiosity, existing findings remain inconsistent. Some studies have reported a positive relationship between oxytocin and spirituality/religiosity, while other studies have reported a negative association. Herein, we examined the association between endogenous oxytocin and spirituality/religiosity in 200 non-Abrahamic Japanese individuals by measuring the level of salivary oxytocin and spiritual/religious faith. We found that the level of salivary oxytocin was (...) negatively associated with spiritual/religious faith. Individuals with higher levels of salivary oxytocin tend to have more negative spiritual/religious faith compared with those with low oxytocin levels. Moreover, this tendency was only significant in individuals who were not interested in a specific religion. The uniqueness of spirituality/religiosity in Japan could help interpret the current findings. (shrink)