Cognitive Biases

What is a cognitive bias

A cognitive bias is a recurring tilt in judgment that shows up when we process information. Because no one can fully analyze every piece of information, we rely on quick decision rules. These rules are useful in many situations, but they sometimes distort our judgment.

Bias isn’t a problem only for people who don’t know better. Even smart people are swayed by the information they want to see, the explanations they’re used to, and the examples they heard most recently.

Common biases

Bias	Description	Example
Confirmation bias	Seeking only information you want to believe	Reading only articles that match your opinion
Availability heuristic	Overweighting examples that come to mind easily	Overestimating danger after seeing a recent accident in the news
Anchoring	Letting the first piece of information set your judgment	The first price you see becomes the reference point
Hindsight bias	Feeling like you “knew it all along” after seeing the outcome	Saying “I knew that would happen”
Loss aversion	Feeling a loss more strongly than an equivalent gain	Sticking with a bad choice because you hate losing

How to reduce bias

Bias is hard to eliminate completely, but building a process helps. Deliberately looking for counter-evidence, writing down your criteria before you decide, separating numbers from anecdotes, and explaining your reasoning to someone else all help.

For important decisions especially, the question “If I’m wrong, what would the reason be?” is effective — it weakens confirmation bias.

Example: making a purchase decision

If you read only the highest-rated reviews for a product, that’s confirmation bias at work. If one recent bad review feels disproportionately alarming, that’s the availability heuristic. In these cases, look at the total number of reviews, recurring complaints, and the conditions of use together.

Key takeaways

• A cognitive bias is a recurring tilt in judgment that appears during information processing.
• Bias can happen even to knowledgeable people, and it’s hard to remove entirely.
• Looking for counter-evidence and setting criteria in advance both help reduce bias.
• Separating anecdotes from numbers reduces exaggerated judgments.

Next chapter: how to evaluate the quality of evidence and the credibility of sources.