From The New York Times:
Last year, a team of researchers at Harvard made headlines with an experiment testing unconscious bias at hospitals. Doctors were shown the picture of a 50-year-old man — sometimes black, sometimes white — and asked how they would treat him if he arrived at the emergency room with chest pains indicating a possible heart attack. Then the doctors took a computer test intended to reveal unconscious racial bias. The doctors who scored higher on the bias test were less likely than the other doctors to give clot-busting drugs to the black patients, according to the researchers, who suggested addressing the problem by encouraging doctors to test themselves for unconscious bias. The results were hailed by other psychologists as some of the strongest evidence that unconscious bias leads to harmful discrimination.
But then two other researchers, Neal Dawson and Hal Arkes, pointed out a curious pattern in the data. Even though most of the doctors registered some antiblack bias, as defined by the researchers, on the whole doctors ended up prescribing the clot-busting drugs to blacks just as often as to whites. The doctors scoring low on bias had a pronounced preference for giving the drugs to blacks, while high-scoring doctors had a relatively small preference for giving the drugs to whites — meaning that the more “biased” doctors actually treated blacks and whites more equally.