The blood type personality theory[1] is a pseudoscientific belief prevalent in Japan which states that a person's blood group system is predictive of a person's personality, temperament, and compatibility with others.[2] The theory is generally considered a superstition by the scientific community.
One of the reasons Japan developed the blood type personality indicator theory was in reaction to a claim from German scientist Emil von Dungern, that Blood type B people were inferior.[3][better source needed] The popular belief originates with publications by Masahiko Nomi in the 1970s.
Although some medical hypotheses have been proposed in support of blood type personality theory,[4] the scientific community generally dismisses blood type personality theories as superstition or pseudoscience because of lack of evidence or testable criteria.[2][5][6] Although research into the causal link between blood type and personality is limited, the majority of modern studies do not demonstrate any statistically significant association between the two.[7][8][9][10] Some studies suggest that there is a statistically significant relationship between blood type and personality, although it is unclear if this is simply due to a self-fulfilling prophecy.[11][12][13]
^Takeji Furukawa (1927), 血液型と気質 Blood Type and Temperament - in Europe, type A was more common than type B, while in Asia type B was more prevalent. Von Dungren claimed A people are superior to B people. Because Asia had more B people than some parts of Europe, the inference was that Asia was inferior (along with European B's) A Japanese scholar, Takeji Furukawa opposed that idea and asserted that B persons were active while A persons were passive.
^Cramer, K. M., & Imaike, E. (2002). Personality, blood type, and the five-factor model. Personality and individual differences, 32(4), 621–626.
^Rogers, M., & Glendon, A. I. (2003). Blood type and personality. Personality and individual differences, 34(7), 1099–1112.
^Wu, K., Lindsted, K. D., & Lee, J. W. (2005). Blood type and the five factors of personality in Asia. Personality and individual differences, 38(4), 797–808.
^Yamazaki, K., & Sakamoto, A. (1992), 血液型ステレオタイプによる自己成就現象II-全国調査の時系列分析- The self-fulfillment phenomenon generated by blood-typical personality stereotypes: time-series analysis of nation-wide survey II, Paper presented at the 33rd annual convention of the Japanese society of social psychology. Tokyo (pp. 342–345).