Different blood types, really different personalities?

Japanese Takeji Furukawa first proposed the relationship between ABO blood type and personality. In 1927, he proposed that "people have different temperaments due to different blood types; The same blood type, the same temperament ". Between the two world wars, when the Sino-Japanese War was defeated in 1895, the Qing Dynasty ceded Taiwan Province Province to Japan with a treaty of shimonoseki for more than 30 years. Furukawa's hypothesis actually served the Japanese colonial rule in Taiwan Province Province. According to Furukawa's theory, the proportion of type O blood in Taiwan Province province is as high as 4 1.2%, which is much higher than that of Japanese population. People with type O blood are "bold, aggressive, like directing others, confident, strong-willed and enterprising", so people with type O blood are more aggressive. In contrast, the Ainu people living in the northeast of Japan have only 23.8% type O blood, while Ainu people are more gentle and obedient than people in Taiwan Province province. Furukawa used this to explain why the people of Taiwan Province Province were constantly resisting Japanese rule. On this basis, he also suggested that the authorities should promote consanguineous marriage among people in Taiwan Province province, so as to reduce the proportion of people with type O blood in Taiwan Province province.

We can see how absurd his theory is from Furukawa's proposal. These bizarre studies are not uncommon in countries under fascist rule. Scientists in Nazi Germany investigated the blood types of different races and found that the blood types of different races were different, and on this basis, they came to the absurd conclusion that "the blood of Germanic races is more noble". The crazy experiment of trying to prove racial superiority with blood type came to an end after World War II, and the relationship between blood type and personality began to enter scientists' field of vision as a pure scientific topic.

However, it is not so easy to understand the relationship between blood type and personality. Different blood types can be easily distinguished by blood tests. How to distinguish different personalities?

Personality refers to people's consistent and stable psychological characteristics, thinking and behavior. It is not easy to quantify these subjective characteristics by scientific methods. The most commonly used methods of scientists are various questionnaires, and the personality of the subjects is analyzed through the results of the questionnaires. These questionnaires are made by professional psychologists or psychiatrists, and can objectively reflect the personality characteristics of the subjects after repeated calibration and revision. Commonly used questionnaires include Minnesota Multiphasic Personality Test, Eysenck Personality Test, Cattell 16 Personality Factor Questionnaire, Yadabi-guildford Personality Test, etc. The results of these tests usually analyze people's personality from different angles, and the high or low scores obtained by the subjects from a certain angle represent completely opposite personality characteristics respectively. For example, the 16PF test divides a person's personality into 16 angles (so-called "dimensions"). People who score low in one dimension of "n: sophisticated" are frank, straightforward and naive, while those who score high are very smart, capable and sophisticated. On the other hand, people who score low in the dimension of "H: Dare to do something" are timid and lack self-confidence, while those who score high are adventurous and have no scruples. By analyzing the performance of subjects in these "dimensions" one by one, researchers can roughly outline the whole picture of their personality.