The Formation of Confirmation Bias in the Brain , Nature - Neuroscience

A study published this week in Nature Neuroscience found that the posterior medial prefrontal cortex (PMFC) promotes confirmation bias in humans.specifically, PMFC is less sensitive to the power of others' opinions that do not confirm an individual's own beliefs.experimental examples | source: Kappes et al.this kind of confirmation bias has an important impact on everything from politics to science and education, but the mechanism behind the formation characteristics of this belief has been little known.Andreas Kappes and Tali sharot, from the Department of psychology, city college, University of London, UK, hypothesized that this process may occur in PMFC, which tracks decision information and signals when decisions should be changed.a group of 42 adults were asked to judge independently whether the listing price of the property was higher or lower than the displayed price.after that, participants made bets based on their confidence in their own judgment - ranging from 1-60 cents.next, each subject entered the MRI scanner, and the experimenters showed them the relevant real estate again and reminded them of their initial judgment and bet.subsequently, they saw their peers' judgments and bets on the same real estate and were asked to submit the final bet - showing their confidence in their initial judgment.the author found that when the peer's judgment confirmed a subject's initial judgment, the subject would increase the final bet, and the final bet was related to the partner's bet.the author also confirmed that PMFC regulated the effect of peer bets on the final bet, but only if their judgments were consistent.this indicates that PMFC is sensitive to the power of other people's opinions only when they agree with each other, but decreases when they disagree, which leads to confirmation bias.© natureNeuro |doi:10.1038/s41593-019-0549-2