Myside Bias

Myside bias is the tendency to search for, weight, and recall evidence in ways that favor your own position. What makes it distinctive is that it does not target people who think of themselves as closed-minded or ideologically rigid — it affects, measurably, people who see themselves as open and critical thinkers. Keith StanovichCanadian cognitive psychologist. He coined "Active Open-Minded Thinking" — the readiness to actively test your own assumptions.Learn more (opens in a new tab) reveals a striking gap between self-image and actual behavior.

How it works

When someone holds a belief with strong emotional investment — a political stance, a judgment about a person, a view on a contested topic — their thinking begins protecting that belief at three levels.

Searching: When looking something up, attention tends to follow trails that promise confirmation. Contrary sources exist, but they are not steered toward automatically. The result is a research diet weighted toward what is already believed.

Weighting: When arguments appear on both sides, the one supporting the held position gets evaluated generously: the methodology seems sound, the sample adequate, the conclusion plausible. The counterargument activates skepticism — the study's limitations become salient, the sample size questionable, possible funding conflicts worth noting. This is not deliberate; it is the standard toolkit of critical thinking deployed selectively.

Recalling: What gets retrieved later is not a neutral record of what was encountered. Arguments that supported the held position are remembered more vividly. Contrary evidence fades faster.

These three mechanisms form a stable feedback loop: a belief feels increasingly well-supported, because the material that feeds it is being unconsciously curated. Research on Keith StanovichCanadian cognitive psychologist. He coined "Active Open-Minded Thinking" — the readiness to actively test your own assumptions.Learn more (opens in a new tab) calls this "myside thinking" — reasoning that privileges one's own side without feeling like bias.

How to spot it

Myside bias is hard to see because it does not feel like distortion. It feels like normal thinking.

In conversation: Someone makes an argument against a firmly held belief. The first impulse is not curiosity — it is looking for the catch: Where does the source come from? How large was the study? Is this generalisable? These are in principle good questions. But do people ask them with the same intensity when a study supports their view?

When reading: An article gets shared because it "shows exactly what you already thought" — not because it was scrutinised carefully. The feeling of confirmation substitutes for the checking.

In a debate: Arguments for one's own side come readily. Counterarguments can be named — but typically in forms already considered refutable. When was the last time someone articulated a counterargument they themselves thought was strong?

In hindsight: People remember the key points of a discussion selectively. What gets noted down or repeated rarely reflects a neutral record of both sides — it tends to match what the person already believed.

What the research shows — and where the limits are

The finding: robust, replicated across many labs

Myside bias is among the best-replicated effects in cognitive and social psychology. It appears in argument-generation tasks, in the evaluation of scientific papers, in the assessment of policy arguments, in probability judgments, and in memory. It is not restricted to particular topics or groups.

The core surprise: the AOT decoupling

The most counterintuitive finding comes from over 25 years of research by Keith StanovichCanadian cognitive psychologist. He coined "Active Open-Minded Thinking" — the readiness to actively test your own assumptions.Learn more (opens in a new tab) and colleagues: the disposition toward (AOT) — the readiness to examine your own assumptions and take counter-evidence seriously — shows virtually no correlation with actually avoiding myside bias in behavior.

Stanovich and Toplak wrote in 2023 directly: AOT scales are strong predictors of performance on heuristics and biases tasks, yet "they do not predict the avoidance of myside thinking, even though it is virtually the quintessence of the AOT concept." Keith StanovichCanadian cognitive psychologist. He coined "Active Open-Minded Thinking" — the readiness to actively test your own assumptions.Learn more (opens in a new tab)

This means: people who score high on questionnaires measuring openness to new evidence show, in the lab, no less myside bias than others. The gap between self-image and behavior is measurable.

Multiple independent research groups converge on the same finding: AOT scores correlate with partisan identity, but not with the avoidance of myside bias in concrete argument evaluation tasks.

Resistant to intelligence and education

A second surprising finding: myside bias is largely independent of intelligence and level of education. Research shows that highly educated, cognitively capable people do not systematically display less myside bias — intelligence and educational status are not a protective factor.

This sounds discouraging — but it is precise. Intelligence helps people research better, argue more fluently, and spot inconsistencies. What it does not automatically do is break the selective deployment of those same abilities in favor of one's own side.

Where the finding's limits lie

Two qualifications need honest mention.

First — domain non-generality: Current research suggests myside bias shows limited generalisability across topics. Someone strongly biased on one contested issue is not necessarily strongly biased on a different one. Stanovich (2021) proposes that it may not be people who vary in their degree of myside bias so much as beliefs that vary in how strongly they resist contrary evidence. This is an important nuance: the effect is robust on average, but individual variance is high.

Second — normativity: Myside bias is not inherently irrational. If someone's prior evidence is strong and they reason from it, that is cognitive economy, not pathology. Research also shows that some forms of myside thinking can be defended as rational under certain epistemic models. The critical point is not that any preference for one's own side is bad, but that the degree of this preference frequently exceeds what the quality of available evidence would justify.

Connection to the Skeptic thinking style

The thinking style we call the Skeptic is most vulnerable precisely where it feels most secure. The Skeptic is defined by scrutiny: not simply accepting, asking for sources, evaluating studies, pausing before committing. That is a genuine strength.

The AOT decoupling shows, however, that this disposition toward openness and the actual application of that openness when strongly-held, personally significant beliefs are at stake come apart. Those who most identify as critical and evidence-based are at particular risk of missing this blind spot — because their self-image provides no occasion for distrust of their own evaluative practice.

This is not an accusation. It is a structural feature of the effect. Myside bias takes hold most strongly where beliefs carry emotional investment and identity proximity — a pattern the research finds consistently across all groups and thinking styles.