A Probabilistic Solution for the Mystery of Japanese Blood Type Prediction Accuracy


Hirose, Hideo


The Fifth Asian Conference on Psychology & the Behavioral Sciences (ACP2015), March 26-29, 2015, Osaka.

In Japan, a belief that there is a relationship between personality and ABO blood types seems to have subsided now. Statistical hypothesis test results deny that relationship for many times up to now. However, many people still like to talk about blood types in connection with personality. They believe in predicting the blood type of one person with accuracy over a probability of 0.25 which is the mean value in providing the correct answer under the condition that they select one of the blood types at random. Actually, the questionnaire results we took several times reveal us an intriguing phenomenon; in Japan, blood type A and O were more accurately predicted than the random selection probability of 0.25. In the questionnaires, personality questions were not included, and this approach is new. In this research, we focused on the human intuition ability in predicting the blood types. That is, we investigated whether the correct answer ratio of human intuition is superior to the probability of random selection. Based on the conditional probability and Bayes theories, we show that this kind of superficial result can be expected as a natural phenomenon. We have revealed that people implicitly use the underlying knowledge of relationship between personality and ABO blood types as imprinting, which shows us superficial human intuition ability.

Key Words
blood type, personality, new questionnaire, human intuition, Bayes theory, imprinting.



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