The purpose of this study is to provide an in-depth discussion of the developmental process of the understanding of mind-body relationships, by focusing on aging phenomena that are influenced by this relationship. The results indicate that one’s ability to estimate the strength of influence on aging exerted by the correlation between factors within the physical domain and cognitive domain (e.g., a balanced diet reduces the decline in physical function; engaging in brain-training tasks prevents memory loss) reaches the level of a university student when or before the person is in the first year of elementary school. In contrast, the ability to estimate the strength of the influence exerted by the correlation between factors of different domains ( physical , cognitive, emotional/social) and factors within the emotional/social domain (e.g., psychologically relaxing reduces the decline in openness) reaches the level of a university student when or after the person is in middle childhood.