ABO blood group system During the 1930s, connecting blood groups to personality types became popular in Japan and other areas of the world. Studies of this association have yet to confirm its existence definitively. Other popular but unsupported ideas include the use of a blood type diet, claims that group A causes severe hangovers, group O is associated with perfect teeth, and those with blood group A2 have the highest IQs. Scientific evidence in support of these concepts is nonexistent. ABO blood group system The ABO blood group system is used to denote the presence of one, both, or neither of the A and
Blood type personality theory Dr LAURENT: "4groupes sanguins, 4 personnalités" Marco Pietteur ed. 2007/2014. Belgium. (In French) Blood type personality theory A pseudoscientific belief exists in some East Asian countries, that a person's ABO blood type is predictive of a person's personality, temperament, and compatibility with others. This superstition is similar to how astrological signs are perceived as influencing factors in a person's life in other countries. One of the reasons Japan developed the blood type personality indicator theory was in reaction against ethnic stereotypes coming from Europe. The popular belief originates with publications by Masahiko Nomi in the 1970s. The scientific community generally