New study discovers why American politics is so divided

In research that should come as no surprise to anyone familiar with the current political climate in the US, a new study discovered that supporters of either candidate in the last Presidential election were more likely to accept new data if it agreed with their desired outcome.

Writing in the Journal of Experimental Psychology: General, corresponding author Ben Tappin, a postgraduate researcher in the Royal Holloway, University of London psychology department, and his colleagues examined how supporters of both Donald Trump and Hillary Clinton changed their predictions regarding the election when presented with new information.

They recruited more than 800 individuals and had each indicate who they wanted to see win the 2016 Presidential election, as well as who they believed would win. Afterwards, each participant was presented with new information that was either consistent or inconsistent with their desired outcome, and again asked which candidate they believed would ultimately win the election.

What they found, the authors explained, is that the participants were more likely to update their predictions if the information was consistent with their desired outcome, and were less likely to change their beliefs if the data was inconsistent with their preferred result.

“The mechanisms by which people revise their beliefs about political matters are nuanced and complex,” Tappin said during an interview with PsyPost. “Our study provides evidence for this complexity: specifically, by showing that biases related to our prior beliefs and our desires are dissociable, and this may have implications for political belief revision.”

Desirability bias stronger than confirmation bias, study finds

At the heart of the research is the conflict between the two primary theories used to explain the revision of human beliefs: desirability bias (the tendency to place greater value on information he/she wants to believe) and confirmation bias (the tendency to favor information that confirms our beliefs and to be more dismissive of information that counters said beliefs).

Tappin and his colleagues explained that his team’s study revealed “a robust desirability bias” among supporters of both candidates, indicating that they were more likely to update what they believed would happen if the new information they received was consistent with their desired outcome – regardless of whether or not that information was consistent with their prior beliefs.

Conversely, they said, evidence of an independent confirmation bias was “limited.” Most Trump supporters who believed that their candidate would lose the election did not assign greater value to polls that seemed to confirm that belief, PsyPost explained. Likewise, Clinton supporters who believed that she would lose did not assign more weight to polls that seemed to prove them right, apparently suggesting that political polarization in the US is mainly due to desirability bias.

“Given the well-known polarization and disagreement that exist over certain issues in the realm of politics, we were interested in what factors cause people to revise their beliefs in the political domain,” Tappin told the website. “The aim of our study was to try and tease these two biases apart to get a clearer picture of what may be driving belief revision in the political domain.”

“Our study suggests that political belief polarization may emerge because of peoples’ conflicting desires, not their conflicting beliefs per se,” he and his co-authors added in a story published last month by the New York Times. “This is rather troubling, as it implies that even if we were to escape from our political echo chambers, it wouldn’t help much. Short of changing what people want to believe, we must find other ways to unify our perceptions of reality.”


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