Confirmation Bias

Overview

Confirmation bias is the systematic tendency to seek, interpret, remember, and weight evidence in ways that support existing beliefs — and to correspondingly miss disconfirming evidence. It is the most-replicated finding in cognitive psychology, documented across cultures, expertise levels, and IQ ranges.

The canonical proof: Wason's 1960 "2-4-6 task" showed ~80% of subjects (including PhD scientists) confidently announced a wrong rule after testing only sequences they expected to confirm — never proposing a sequence designed to refute the hypothesis.

Composes with critical-thinking, bayesian-reasoning, abductive-reasoning, and metacognition.

When to Use

• A team is converging on a single answer too quickly
• You feel confident about a claim and haven't looked for evidence against it
• Research or due diligence keeps "validating" existing beliefs
• Someone says "cherry-picking," "echo chamber," or "looking for what you want to see"
• A team is committing to an AI thesis (AI capex, AI valuations, or AI adoption) by citing confirming demos and adoption while discounting failed eval results

Not when: explicit advocacy context; very low-stakes decision; cost of disconfirmation exceeds value of decision.