One Death is a Tragedy, One Million is a Statistic

Dave Collins of the Associated Press has covered a grim story (Emphasis mine):

Middletown police say 21-year-old city resident Tony Moreno confessed to throwing his son, Aaden, off the bridge July 5 and then jumping himself amid a custody dispute with Aaden’s mother.

After the 7-month-old boy was thrown to his death from a bridge last month, local officials have been considering safety improvements for the 90-foot-high span over the Connecticut River that has been known for decades as a destination for suicidal people.

Why is it so often the case that a social problem persists for a long period and then one dramatic instance of the problem galvanizes the previously somnolent into action? The answer, according to the great Daniel Kahneman, is rooted not in politics but in the limits of human cognition.

In a series of studies, researchers asked subjects to react to a particular vivid prototype, for example a photo of one bird struggling to escape an oil spill. After being asked how much they would donate to save the bird, the subjects are then asked how much they would donate to save countless birds from all of the world’s oil spills. Surprisingly, the two answers tend to be similar. That is, people who will donate $10 to save a particular prototypic bird in distress in one location will only donate $10 to save an unspecified number of birds in distress in many unspecified locations. It’s a stunning finding in that the subjects’ responses are logically equivalent to saying that birds in general are worthless but one particular bird has significant value. Kahnemann’s interprets such results to mean that human beings often react strongly to prototypes but are insensitive to quantity.

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This phenomenon has been understood by many activists over the years. Rosa Parks was one of a huge number of African-Americans to be asked to give up her bus seat to a white person, but civil rights activists chose her rather than a statistics chart to make their case. They had a pool of people to pick from and chose Parks because she was so unquestionably a remarkable and decent person (Other candidates for the role were set aside because of real or rumored problems in their lives that might have ruined the desired narrative).

Even though it had a happy result in the case of Rosa Parks and desegregation, there are great hazards when this shortcoming in our brain meets the political process. Sometimes the one, vivid example we all rally around is so unpresentative that we then create policy that doesn’t work. Kimberely Bergalis, who apparently was infected with HIV/AIDS by her dentist, was a vivid prototype which impressed upon Congress and the country a misdiagnosis of the real problem. As my colleague Doug Owens eventually showed, the risk of becoming infected with HIV in health care interactions comes mainly from patient to care provider transmission rather than the other way around.

[Cross-posted at The Reality-Based Community]

Keith Humphreys

Keith Humphreys is a professor of psychiatry at Stanford University. He served as a senior policy advisor at the White House Office of National Drug Control Policy from 2009 to 2010.