National Differences in Personality as Related to ABO Blood Group Polymorphism

Abstract

Blood group polymorphisms of the ABO system are related to personality differences, AB being more frequent among introverts, and the ratio A/B being higher among stable subjects. In view of the fact that Japanese are more introverted and more neurotic than British samples, it was predicted that Japanese, as compared with British, would have a higher proportion of AB carriers and a lower A/B ratio. Both predictions were confirmed by study of the established frequencies for blood groups in the two countries.