The Arithmetic of Compassion: “One death is a tragedy; a million deaths is a statistic.”

And even 14 is much higher than necessary to desensitize us. In studies published last year in the journal PLOS One, one of us, Paul Slovic, and colleagues demonstrated that “compassion fade” can occur when an incident involving a single person expands to as few as two people.

Participants were asked, in both hypothetical and real situations, to make donations, and to report how they felt about donating, to either a single needy child or two needy children, each of whom was identified with a photograph, name and age. We found that people’s positive feelings about donating declined substantially when the group size was two, and that this decrease was related to lower levels of donation.

By SCOTT SLOVIC and PAUL SLOVIC