The Science of Fear: How the Culture of Fear Manipulates Your Brain

by Daniel Gardner

Even subtle changes in language can have considerable impact. Paul Slovic and his team gave forensic psychiatrists—men and women trained in math and science—what they were told was another clinician’s assessment of a mental patient confined to an institution. Based on this assessment, the psychiatrists were asked, would you release this patient? Half the assessments estimated that patients similar to Mr. Jones “have a 20 percent chance of committing an act of violence” after release. Of the psychiatrists who read this version, 21 percent said they would refuse to release the patient. The wording of the second version of the assessment was changed very slightly. It is estimated, the assessment said, that “20 out of every 100 patients similar to Mr. Jones” will be violent after release. Of course, “20 percent” and “20 out of every 100” mean the same thing. But 41 percent of the psychiatrists who read this second version said they would keep the patient confined, so an apparently trivial change in wording boosted the refusal rate by almost 100 percent. How is that possible? The explanation lies in the emotional content of the phrase “20 percent.” It’s hollow, abstract, a mere statistic. What’s a “percent”? Can I see a “percent”? Can I touch it? No. But “20 out of every 100 patients” is very concrete and real.