The first time Jennifer Eberhardt presented her research at a law enforcement conference, she braced for a cold shoulder. How much would streetwise cops care what a social psychology professor had to say about the hidden reaches of racial bias?
Instead, she heard gasps, the loudest after she described an experiment that showed how quickly people link black faces with crime or danger at a subconscious level. In the experiment, students looking at a screen were exposed to a subliminal flurry of black or white faces. The subjects were then asked to identify blurry images as they came into focus frame by frame.
The makeup of the facial prompts had little effect on how quickly people recognized mundane items like staplers or books. But with images of weapons, the difference was stark—subjects who had unknowingly seen black faces needed far fewer frames to identify a gun or a knife than those who had been shown white faces. For a profession dealing in split-second decisions, the implications were powerful.