Confirmation Bias

Activate when: user says 'we keep finding evidence that supports our view,' 'the team is all aligned on this,' 'I've done the research and it checks out,' or a decision moves forward with only supporting evidence cited. Do NOT activate when: context is explicit advocacy (legal brief, pitch deck) where one-sided argument is the design; or stakes are too low to justify structured disconfirmation.

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"

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

Coaching Novices (Adaptive Front Door)

• Engine mode: user has a concrete case → run The Process directly.
• Coach mode: user is unfamiliar or has no concrete case → guide step by step.

In Coach mode, respond one step at a time. Each [WAIT] is a hard stop — output only that step's question, then stop.

1. One-liner: before trusting evidence that supports your view, ask what would have changed your mind — and whether you actually looked for it.
2. Check fit against When to Use / When NOT to use.
3. Elicit the specific claim and evidence cited.

[WAIT — do not advance until user responds]

4. One question at a time: what would falsify this? Did you look for that? What's the strongest counter-evidence? How did you treat it?

[WAIT — do not advance until user responds]

5. Close: name the falsification test + structural countermeasure (Devil's advocate, red team, blind evaluation).

[WAIT — do not advance until user responds]

The Process

Step 1 — State claim: Claim / Evidence cited / Confidence level.

Step 2 — Construct falsification: What observation would falsify this? What would you expect if wrong? Has anyone looked for that? (If you can't articulate falsification, you have a description, not a hypothesis.)

Step 3 — Audit evidence-seeking: Sources consulted — belief-aligned? Strongest case against sought? Evidence encountered and dismissed?

Step 4 — Re-evaluate ambiguous evidence: Of evidence cited, how much is unambiguous vs. ambiguous-read-as-supporting? Does the opposite reading fit equally? (If yes, it's interpretation, not evidence.)

Step 5 — Install structural countermeasure: Devil's advocate (rotated, mandatory) · Red team · Pre-mortem (Klein 2007) · Blind evaluation · Falsification-first design (three refuting cases before one confirming).

Step 6 — Establish update conditions: What would convince me I'm wrong? When will I formally re-examine? Who is empowered to push back?

Output Template

text

Claim: / Evidence: / Confidence:
Falsification: what would falsify it / has it been tested:
Evidence audit: sources (aligned vs counter) / counter-evidence treatment:
Ambiguous evidence: amount / does opposite reading fit:
Countermeasure: [type] / Owner:
Update conditions: trigger / re-examination date:

→ Method in Action: Peter Wason's 2-4-6 Task, 1960

Pack: Confirmation Bias Patterns

Domain	Common manifestation	Countermeasure
Product	Building features based on early-adopter feedback only	Cohort retention; non-user interviews
Investment	Reading only the bull case for a held position	Pre-commit short thesis; quarterly "kill the position"
Hiring	Post-hoc rationalization of intuitive hire	Structured rubric; reference checks before offer
Debugging	Looking only where you think the bug is	Bisect elimination; alternative-hypothesis tests

→ Primary sources: references/sources.md

Common Rationalizations

[D] = designed upfront | [O] = observed in real use. [O] entries are more valuable.

Fake move	Reality
[D] "I've been doing this for years; I know"	Experience compounds confirmation bias if not paired with deliberate disconfirmation.
[D] "I have an open mind"	Self-report correlates poorly with measured open-mindedness. When did you last change your mind on counter-evidence?
[D] "I considered the alternative"	Considering ≠ stress-testing. Did you actively seek evidence the alternative is correct?
[D] "The evidence overwhelmingly supports my view"	Overwhelming-feeling evidence is exactly what confirmation bias produces.
[D] "I'm a critical thinker / scientist / analyst"	Wason's PhD subjects had the same bias. Structural countermeasures work; personal vigilance does not.
→ Add [O] entries here after each real use — paste the actual failure pattern	What went wrong and why

Red Flags

• Team converged quickly on a single answer; evidence cited is belief-aligned
• No one tasked with finding flaws; disconfirming evidence dismissed as "biased"
• Hypothesis not stated in falsifiable form; hypothesis-former is also the tester

Verification

• Claim stated in falsifiable form; specific falsifying observation named
• Counter-evidence actively sought (not just acknowledged)
• Ambiguous evidence re-evaluated against the opposite hypothesis
• Structural countermeasure installed (not just personal vigilance)
• Update conditions and re-examination point specified

---

Part of deciqAI Knowledge Skills — open-source thinking skills that make rigor executable for AI agents. Built by deciqAI · https://deciqai.com · Contributions welcome — see the template at the repo root.