Other instances of moral failure are furthered by a simple lack of arithmetical skills. Many people are more likely to make charitable contributions, for example, when the outcome of their contributions can be characterized as largely positive, even when an outcome that is likely to be more negatively characterized does much more good. Thus, they're more likely to contribute to a project that promises to save 90 percent of 100 lives than to one that's likely to save only 10 percent of 5,000 lives, despite the fact that the latter intervention would save 410 more lives.
Or what about an almost cost-free intervention, such as the bombing of a few train lines during World War II that might have saved "only" 1 percent of those who died in concentration camps? (Of course, a reluctance to look at the numbers and a readiness to be swayed by marginally relevant personal stories is pervasive and extends far beyond the issue of genocide.)
Another study by Slovic (together with Loewenstein and Small) demonstrates the power of individual pictures. Researchers gave people the opportunity to contribute up to $5 to Save the Children and showed a group of them a picture of a starving African girl with text describing her dire conditions. The researchers showed a second group of people a set of general statistics about starving children in Africa, and they showed a third group both the picture and facts of an identifiable life as well as a statistical description of the general conditions.
The first group contributed the most money, the second and third groups substantially less. Astonishingly, adding the statistical description to the picture and personal information actually decreased the amount contributed.
One inference from this work is that for most people a compelling picture of an individual is worth a thousand statistics. The thought occurs that this might be an opportunity for some paparazzi to redeem themselves. Forget celebrities' rehab centers; go to Darfur's refugee camps.
John Allen Paulos, a professor of mathematics at Temple University, has written such best-sellers as "Innumeracy" and "A Mathematician Plays the Stock Market." His "Who's Counting?" column on ABCNEWS.com appears the first weekend of every month.