Confirmation Bias
Type: Information — Selection Also Known As: Myside bias, confirmatory bias
Definition
Seeking, interpreting, and remembering information in ways that confirm pre-existing beliefs while ignoring or dismissing contradictory evidence. We see what we expect to see.
“I knew the project would fail — look at all these problems I’m finding.”
Form
- A belief or hypothesis is formed
- Information is selectively sought that supports it
- Contradictory information is ignored or discounted
- Ambiguous information is interpreted as confirming
- Belief becomes stronger regardless of evidence
Examples
Example 1: Political Beliefs
A person convinced their preferred candidate is honest dismisses corruption allegations as “political attacks” while accepting unverified positive claims uncritically.
Problem: The same evidence standard applied differently based on bias.
Example 2: Medical Diagnosis
A doctor convinced a patient has anxiety interprets physical symptoms as psychosomatic, missing an underlying autoimmune condition.
Problem: The anxiety diagnosis created a confirmation trap.
Example 3: Investment Decisions
An investor bullish on crypto celebrates price increases as validation while explaining away drops as “temporary corrections.”
Problem: Contradictory data never actually registers as falsification.
Example 4: Relationship Judgments
“I knew they were selfish — look, they didn’t hold the door.” One action confirms a character judgment; previous helpful acts are forgotten.
Problem: Memory itself becomes selective to maintain the narrative.
Why It Happens
- Cognitive dissonance is uncomfortable
- Changing beliefs requires mental effort
- Ego protection — admitting error feels like failure
- We prefer coherent narratives over messy reality
- Evolution favored quick commitment over perpetual uncertainty
How to Counter
- Seek falsification: Actively look for disconfirming evidence
- Devil’s advocate: Seriously argue the opposite position
- Bayesian thinking: Update beliefs incrementally with evidence
- Premortem: Assume you’re wrong — what would explain it?
- Diverse inputs: Follow sources that challenge your views
When It’s NOT a Bias
Focusing on confirmatory evidence IS valid when:
- Testing requires specific positive results (scientific method)
- Practical constraints limit investigation scope
- The hypothesis has extremely high prior probability
- Seeking disconfirmation is dangerous or impossible
Related Concepts
- Anchoring Bias — First belief becomes the anchor
- Availability Heuristic — Confirming evidence is more available
- Hindsight Bias — We remember confirming our predictions
- Fundamental Attribution Error — Confirms our character judgments
References
- Nickerson, R.S. (1998). Confirmation bias: A ubiquitous phenomenon in many guises
- Klayman, J. & Ha, Y.W. (1987). Confirmation, disconfirmation, and information in hypothesis testing
- Lord, C.G. et al. (1979). Biased assimilation and attitude polarization
Part of the Convergence Protocol — Clear thinking for complex times.