In the 1840s, many doctors carried out autopsies of women who had died of childbirth fever. The doctors sometimes became infected with bacteria without knowing it. When they delivered more babies, they transmitted the infection to more women, causing more to die. When it was suggested to the doctors that they might be unintentionally carrying harmful bacteria they felt insulted and reacted with angry denials. Fortunately, since then our profession has gone through a paradigm shift based on understanding the germ theory of disease. Initially, it was thought that doctors who deliver babies should never carry out autopsies, but methods of preventing and/or curing bacterial infection such as surgical gloves and hand washing have been shown to be effective.

We now face a similar situation. In 2008, many doctors allowed themselves to be exposed to drug promotion. These doctors may have become infected with bias without knowing it. When they treat patients their decisions are not as good as they could be. When it is suggested to the doctors that they might be unintentionally carrying harmful bias they feel insulted and react with angry denials. Our profession needs to go through a paradigm shift based on understanding theories of how decision-making can be biased, such as the Elaboration Likelihood Model and Cognitive–Experiential Self Theory.1 Unfortunately, at this time, we do not have any proven methods for detecting, let alone preventing or curing, bias.

Currently, many doctors deny that they are influenced by drug promotion, but are not so confident about their colleagues. This “illusion of unique invulnerability” is common and makes people overconfident and thus at higher risk of being misled.2 We …