What's the News: Researchers have found that whether people stick with advice they were given, even when their own experience contradicts it, is linked to their genes, according to a new study published online in the Journal of Neuroscience. These findings suggest a possible genetic component of confirmation bias, the tendency to focus on new information that agrees with what you already know, and ignore information that contradicts your views. How the Heck:
The researchers gathered saliva samples from more than 70 participants. They then analyzed each person's genotype, focusing on two genes that impact the activity of the neurotransmitter dopamine, known to play an important role in learning, in one of two regions of the brain: the prefrontal cortex or the striatum. The prefrontal cortex stores and processes explicit instructions (e.g., "Always wear sunscreen"), while the striatum helps us glean lessons from our experience (e.g., "When I forget my sunscreen, I often get burned").
Each participant then played a game in which they would see two symbols (taken from the Japanese hiragana alphabet, unfamiliar to most English speakers) on a screen and have to choose the "correct" symbol; they'd then get feedback so they could learn to recognize the correct ones. For some of the symbol pairs, the participants were given advice about the symbols, but sometimes the advice was wrong.
Different versions of the COMT gene, which impacts how dopamine works in the prefrontal cortex, were linked to how much a person stuck with misleading advice. When their experience told them the advice was wrong, participants with one version of the gene ignored the bad advice nearly 70% of the time, while participants with the other version of the gene did so only 50% of the time.
One variation of the DARPP-32 gene, which affects how the striatum responds to dopamine, helped people learn from their experience particularly quickly when no one had given them advice---but they stuck with bad advice about 65% of the time, while people with the other version of the gene heeded misleading advice about 40% of the time.
These findings suggest that genes may predict how much someone emphasizes certain experiences processed by their striatum to fall in line with the instructions in their prefrontal cortex. In other words, "People will distort what they experience to be perceived as more consistent with what they thought already,” Brown University neuroscientist Michael Frank, an author of the study, said in a prepared statement.
What's the Context:
Confirmation bias happens in a wide variety of situations: in politics, where each side is sure the evidence supports them; in astrology, where people interpret their experiences as supporting the vague predictions of a horoscope or tarot deck; and even in science, where researchers pay more attention to data that fits their hypothesis.
There are times it's beneficial to stick with advice, and not rely on your own experience, the researchers point out, like when a parent tells a child not to jump off a tall building. But ways of thinking that are adaptive in some cases are often maladaptive in others---such as leaving your umbrella at home when the weatherman says it will be sunny, even when you see storms clouds overhead.
Not So Fast:
Showing that a gene variant is associated with a behavior doesn't mean it causes that behavior.
Additionally, the gene variants don't make people either mindless followers or free-thinking individualists---people with all the variants followed bad advice much of, but not all of, the time.
Reference: Bradley B. Doll, Kent E. Hutchison, and Michael J. Frank. "Dopaminergic Genes Predict Individual Differences in Susceptibility to Confirmation Bias." Journal of Neuroscience online, April 20, 2011. DOI: 10.1523/JNEUROSCI.6486-10.2011