Why then do so many people give to Make-A-Wish, when there are more practical ways of using their charitable dollars? The answer lies, at least in part, in those above-mentioned emotions, which, as a growing body of psychological research shows, make the plight of a single identifiable individual much more salient to us than that of a large number of people we cannot identify.

In one study, people who had earned money for participating in an experiment were given the opportunity to donate some of it to Save the Children, an organization that helps children in poverty. One group was told things like: “Food shortages in Malawi are affecting more than three million children.” A second group was shown a photo of a 7-year-old African girl, told that her name was Rokia and urged that “her life will be changed for the better as a result of your financial gift.” The second group gave significantly more. It seems that seeing a photo of Rokia triggered an emotional desire to help, whereas learning facts about millions of people in need did not.

Similarly, the unknown and unknowable children who will be infected with malaria without bed nets just don’t grab our emotions like the kid with leukemia we can watch on TV. That is a flaw in our emotional make-up, one that developed over millions of years when we could help only people we could see in front of us. It is not justification for ignoring the needs of distant strangers.