STUDY: Social psychological factors of interest in lay personality theories: why is ABO blood-typing popular?

JOURNAL: Shinrigaku Kenkyu 2000 Dec;71(5):361-369

AUTHORS: Nagata Y.

ABSTRACT: We hypothesized that one of the reasons that not a few Japanese are interested in lay personality theories of ABO blood-typing and similar unsupported beliefs on human nature, was unsatisfied needs of having clear collective and personal identities. To test the hypothesis, we asked 149 married women, 34 to 62 years of age, to describe themselves as in self introduction to strangers, and then separately indicate the degree of interest in lay personality theories. We then counted the number of references to personal/private aspects (an index of personal identity) and the number to social groups whose membership was known to be exclusive and limited (an index of collective one). Results showed that those who were high on both indices were less interested in lay theories than those low on one or both of personal and collective indices.

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COMMENTARY: As anyone who has read my books can determine, I am not much of a fan of the belief seen in certain societies, such as Japan, that there is a well-defined 'blood type personality.' However, there is considerable evidence that ABO blood group does have some influence on major neurochemical mediators, such as platelet MAO, dopamine and cortisol.

However, this article makes such basic assumption about the nature of personality theory as to render itself useless. First, it assumes that people interested in personality theory are 'unsatisified' with their identity; and to prove that the study focuses on married women, which (I can only hypothesize) the author feels are a prime group for such analysis. No structuring as to IQ, socio-economic group or education level are made. The measures of 'collective identity' (participation in social groups known to be limited and exclusive) or 'personal identity' (comments on personal/ private life) are ruefully simplistic.

We need well-designed studies, looking at neuro-psychiatric parameters that can be scientifically measured, not fuzzy groupings based on characterizations of the believing public.