Nagasaki University
Cosy Muto and Masahiro Nagashima et al. (Nagasaki University) conducted a supplementary survey of Yamazaki and Sakamoto in 2011. They demonstrated that significant and the same difference in personalities between blood-types by using the same database as Samamoto and Yamazaki used. In the 1990s, the difference due to blood types was stabilized and variances became smaller. Then in the 2000s, the difference was statistically significant, too. However, the effect magnitude was extremely small, despite 'significance' in the statistical sense.