Implicit negative attitudes towards other races are important in certain kinds of prejudicial social behaviour. However, little is known about the neurobiological processes which might mediate implicit, negative racial biases.
In a pioneering project, and working with healthy volunteers, our group showed that a β-adrenoceptor antagonist, propranolol, compared to placebo, significantly lowered heart rate and abolished implicit racial bias (as measured using the racial implicit association test), without affecting the measure of explicit racial prejudice. These results indicated that β-adrenoceptors play a role in the expression of implicit racial attitudes, suggesting that noradrenaline-related emotional mechanisms may mediate negative racial bias.
Ranked #1 as the most widely discussed/mentioned neuroscience paper published in neuroscience in 2012 (Springer Ldt.), the article is the result of a collaboration between Phil Cowen and Sarah McTavish (Department of Psychiatry), Guy Kahane and Julian Savulescu (Department of Philosophy), and Miles Hewstone (Department of Experimental Psychology).
Mean response times in the racial implicit association task
for the propranolol and placebo groups
We are now exploring the neural basis for this pharmacologically-induced changes using functional MRI, conducted at OCMR. Lead by Sylvia Terbeck, our hypothesis is that propranolol will be assiciated with reduced activity in the amygdala, a part of the brain which plays a key role in the early non-conscious appraisal of threat.
fMRI images of the amygdala in a healthy human brain