In Blink, author Gladwell relates the experience of some orchestra whose cadre of grayback decision-makers conducted a blind audition and unanimously found the best wind player to be a woman, much to their surprise. They knew that women weren't strong enough to do winds. They'd never had this truth contradicted when they did visible auditions, i.e., their eyes saw more than their ears heard. The author himself was surprised to discover he possessed a certain bias against blacks having taken an internet test for that propensity--his mother is black.