Blood Type and Blood Donation Behavior

We empirically investigated how voluntary helping behavior is influenced by the number of its potential recipients by using a nationwide survey in Japan (N = 1,333) and examining the relationship between blood type and blood donation behavior. It is generally known in Japan that type O blood can be medically transfused to individuals of all blood groups; therefore, the potential transfusion recipients’ number of the type O blood is the largest among the four blood groups. Our empirical analysis revealed that people with type O blood were more likely to have donated blood in the past than those with the other blood types. This association was stronger in a subsample of individuals who had knowledge relating to the above-mentioned widespread utility of type O blood. In addition, our empirical analysis arrested the concern that potential blood-type differences in altruistic attitudes might explain their differences in blood donation behavior, by confirming that type O blood was not significantly related to other altruistic behaviors (i.e., registration for bone-marrow donation, intention to donate organs, and making monetary donations) or attitudes (i.e., general trust, altruism, reciprocity, and agreeableness). After conducting further analyses, we concluded that the vast number of potential recipients of type O blood causes different patterns of Japanese people’s blood donation behavior across the four blood groups. This study added to the literature the real-world evidence concerning how having many potential recipients affect people’s behavior of providing common goods.