What is Myside bias?
Myside bias is the tendency to evaluate evidence, generate arguments, and test hypotheses in ways that favor one’s own prior opinions, beliefs, or hypotheses. It is related to confirmation bias but emphasizes the self-serving direction of the distortion.
How it works
Stanovich et al. (2013) showed that myside bias is largely independent of intelligence: smart people are not less biased but are better at constructing arguments for their preferred position. This means that cognitive ability can actually amplify myside bias by making rationalizations more sophisticated. The bias appears across domains: political beliefs, personal decisions, scientific interpretations, and moral judgments.
Applied example
Asked to evaluate arguments for and against a policy they support, people rate supporting arguments as ‘strong and well-reasoned’ and opposing arguments as ‘weak and flawed,’ even when the arguments are of identical objective quality (as rated by blind reviewers).
Why it matters
Myside bias undermines the assumption that more education or intelligence leads to better reasoning: without active debiasing strategies, greater cognitive ability is used to build better cases for what the person already believes.
