Donating blood and organs 1 Running head: Donating blood and organs Donating blood and organs: Using an extended Theory of Planned Behavior perspective to identify similarities and differences in individual motivations to donate

Due to the critical shortage and continued need of blood and organ donations, research exploring similarities and differences in the motivational determinants of these behaviors is needed. In a sample of 258 university students, we used a cross-sectional design to test the utility of an extended theory of planned behavior (TPB) including moral norm, self-identity, and in-group altruism (family/close friends, ethnic group), to predict people’s blood and organ donation intentions. Overall, the extended TPB explained 77.0% and 74.6% of variance in blood and organ donation intentions, respectively. In regression analyses, common contributors to intentions across donation contexts were attitude, self-efficacy, and self-identity. Normative influences varied with subjective norm as a significant related to organ donation intentions but not blood donation intentions at the final step of regression analyses. Moral norm did not contribute significantly to blood or organ donation intentions. In-group altruism (family/close friends) was significantly related to organ donation intentions only in regressions. Future donation strategies should increase confidence to donate, foster a perception of self as the type of person who donates blood and/or organs, and address preferences to donate organs to in-group members only.