Spillovers of prosocial motivation are crucial for the formation of social capital. They facilitate interactions among individuals and create social multipliers that amplify the effects of policy interventions. We conducted a large-scale intervention study among dyads of blood donors to investigate whether social ties lead to motivational spillovers in the decision to donate. The intervention i...

This week, my school hosted a blood drive. Gay men were not allowed to donate. I was so repulsed by this that I, a female friend, refused to donate just on principle. Is there some reason why gay men are still excluded from blood drives? Are they still so much more likely to be HIV positive than heterosexuals? Is this a policy from a time before blood screening was required? Someone said it was...

This week, my school hosted a blood drive. Gay men were not allowed to donate. I was so repulsed by this that I, a female friend, refused to donate just on principle. Is there some reason why gay men are still excluded from blood drives? Are they still so much more likely to be HIV positive than heterosexuals? Is this a policy from a time before blood screening was required? Someone said it was...