People’s ability to think logically suffers when they are faced with arguments that go against their political belief systems, a study has found.
The research, published in the journal Social Psychological and Personality Science, also shows that when confronted with the unsound reasoning of opposing groups, people become better able to identify flawed logic.
The researchers from the University of Virginia and University of California, Irvine in the US studied ideological belief bias among 924 American liberals and conservatives from a website YourMorals.org.
Visitors to the site evaluated the logical soundness of classically structured logical syllogisms supporting liberal or conservative beliefs. Of 16 syllogisms, half were structured as sound arguments, and half unsound.
On average, participants correctly judged 73 per cent of the syllogisms. However, their ability to judge correctly depended on their political views.
“Liberals were better at identifying flawed arguments supporting conservative beliefs and conservatives were better at identifying flawed arguments supporting liberal beliefs,” said Anup Gampa from the University of Virginia.
The researchers also observed ideological belief bias effects among 1,489 participants from ProjectImplicit.org. The participants in this study were trained in logical reasoning before evaluating political syllogisms using language similar to what they might encounter in popular media.
Even with the training, the ability to analyse arguments fell into the same patterns. They found similar patterns of bias in a nationally representative sample containing 1,109 liberals and conservatives.
In the era of fake news, these logical fallacies can be even more potent.
“When two sides don’t share a common view of even seemingly objective facts, these differences become embedded in our collective reasoning ability,” said Sean Wojcik from the University of California, Irvine.
“Our biases drive us apart not only in our disagreements about political and ideological worldviews, but also in our understanding of logic itself,” said Wojcik.
Researchers said not that in our political world, we might not be as vigilant as we think about the logical grounding of our own beliefs and “we might be unreasonably harsh about the logical grounding of the belief of those we disagree with.”
Despite this, being able to hear the other side can open us to our own flawed arguments, they said.