This study examined the role of noradrenergic mechanisms in the generation of implicit racial attitudes and involved 36 healthy volunteers of White ethnic origin, who were randomised to receive a single oral 40 mg dose of the β-adrenoceptor antagonist, propranolol (n=18) or a placebo (n=18). Participants completed an explicit measure of prejudice and the racial implicit association test, 1–2 h after propranolol administration. Relative to placebo, propranolol significantly lowered heart rate and abolished implicit racial bias, without affecting the measure of explicit racial prejudice. Propranolol did not affect subjective mood.
