The Japanese Journal of Psychology
Online ISSN : 1884-1082
Print ISSN : 0021-5236
ISSN-L : 0021-5236
Original Articles
No relationship between blood type and personality: Evidence from large-scale surveys in Japan and the US
Kengo Nawata
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2014 Volume 85 Issue 2 Pages 148-156


Despite the widespread popular belief in Japan about a relationship between personality and ABO blood type, this association has not been empirically substantiated. This study provides more robust evidence that there is no relationship between blood type and personality, through a secondary analysis of large-scale survey data. Recent data (after 2000) were collected using large-scale random sampling from over 10,000 people in total from both Japan and the US. Effect sizes were calculated. Japanese datasets from 2004 (N = 2,878–2,938), and 2,005 (N = 3,618–3,692) as well as one dataset from the US in 2004 (N = 3,037–3,092) were used. In all the datasets, 65 of 68 items yielded non-significant differences between blood groups. Effect sizes (η2) were less than .003. This means that blood type explained less than 0.3% of the total variance in personality. These results show the non-relevance of blood type for personality.

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© 2014 The Japanese Psychological Association
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