blind-bias-blind-spot

name	blind-bias-blind-spot
description	Use when tempted to say "I'm being objective", when attributing others' views to bias while trusting your own introspection, or after learning about a bias and concluding it doesn't apply to you. Applies Pronin, Lin & Ross (2002) — the bias blind spot and the introspection illusion.

Bias Blind Spot

Overview

Pronin, Lin & Ross (2002, PSPB): people reliably rate themselves as less biased than the average person — and crucially, being told about this asymmetry doesn't remove it. Cause: the introspection illusion. We judge others by their behavior but judge ourselves by our introspections, and bias doesn't feel like anything from the inside. Searching your mind for bias returns clean, so you conclude you're clean.

"I checked and I'm not biased" is the signature OF the bias, not evidence against it.

When to Use

• You've just diagnosed someone else's reasoning as motivated/biased
• You feel objective about a conclusion you also prefer
• Post-hoc reviewing your own work and finding it fine
• A debiasing step returned "no bias found" via introspection alone

The Procedure

1. Ban introspective verdicts. "Do I feel biased?" is an invalid test — never accept its output.
2. Audit incentives behaviorally: what would you prefer to be true here (less rework, sunk cost, looking right, finishing sooner)? If the conclusion aligns with the preference, raise the evidence bar.
3. Apply the symmetry test: if someone else, with your incentives, produced this exact conclusion, would you trust it? Judge yourself by the outside-behavior standard you apply to others.
4. Outsource the check: the only reliable bias detector is external — a second reviewer, a test, a pre-registered criterion set before seeing the answer (see blind-falsification, blind-red-team).

Quick Reference

Thought	Status
"I've considered my biases and corrected for them"	Introspection illusion — invalid
"They're biased, I've actually looked at the evidence"	Asymmetric standard — invalid
"My conclusion matches what I hoped; here's the external check anyway"	Valid
"A disinterested party reviewed it"	Valid

Common Mistakes

• Using knowledge of biases as ammunition against others' arguments while exempting your own ("sophistication effect" — more knowledge can make this worse, Taber & Lodge 2006).
• Adding a "checked for bias ✓" step that consists of thinking about it briefly. Ritual introspection is still introspection.
• Concluding you're in the unbiased minority because you know this literature. That is the finding.