The scientists were hoping to see which group became more altruistic, and they succeeded. The findings were an interesting mix. Those primed in an abstract way by general thoughts about dying were more generous than the dentist-imagining controls, but only when the need was high. This result suggests that the abstract thinkers were reaffirming the societal expectation that it is good to give to the needy—not exactly a sweeping personal epiphany.
Those who were vividly primed by thoughts of their own death in flames, however, were even more generous than those primed in a more subtle and abstract way. They were willing to give blood whether the need was high or low, suggesting they had undergone a fundamental reexamination of their values.
Why would this difference exist? One possibility, as the scientists write in the online version of the journal Psychological Science, is that our abstract existential system has no tolerance for the gory details of death; in fact, abstract thoughts of death generate an aversion to bodily fluids, including blood. Indeed, previous experiments have supported this idea: after being reminded of their mortality, people are more squeamish about physical trauma. In the current study this aversion to blood was not strong enough to trump the cultural expectation that we should help those in need—but it carefully meted out generosity to those truly in the most need.
People who have come close to perishing, on the other hand, see things differently. For them, blood is not something aversive at all—it is the stuff of life.