Alexander Green and colleagues from Harvard Medical School tested whether doctors showed unconscious race bias and whether the scale of such bias predicted recommendations for medical intervention for black and white patients with acute coronary conditions.

The researchers used a web-based survey tool that randomly assigned doctors to look at a picture of a black or white patient presenting to the emergency room department, alongside a brief clinical history and symptoms suggestive of a myocardial infarction.

The doctors were then asked whether the chest pain was the result of coronary artery disease, whether they would give the patient thrombolysis and the strength of the recommendation on a scale of ‘1 – definitely’ to ‘5 - definitely not’. The researchers used computer-based Implicit Association Tests (IATs) to measure unconscious bias. The software asked doctors whether they preferred white or black Americans and also about their beliefs concerning patients’ cooperativeness in general and with regard to medical procedures in particular. Doctors’ conscious racial bias was also assessed by questionnaire.

Doctors who participated reported no conscious preference for white versus black patients and reported black and white patients to be equally cooperative with medical procedures. In contrast, IATs revealed an unconscious preference favouring white Americans, and unconscious stereotypes of black Americans as less cooperative with medical procedures and less cooperative generally.

Doctors’ self-reported attitudes towards patients and of stereotypes about cooperativeness by race did not influence their decision to give thrombolysis for black versus white patients. However, doctors’ unconscious biases strongly influenced whether or not they gave the patients thrombolysis. As doctors’ pro white unconscious bias increased, so did their likelihood of treating white patients and not treating black patients.; Source: Springer