Cognitive Biases

Predictable errors in thinking and how to counter them.

Why Biases Exist

Our brains evolved for a different environment. Mental shortcuts (heuristics) that helped us survive on the savanna cause systematic errors in modern contexts.

The good news: Biases are predictable. Knowing them allows you to compensate.

The Most Dangerous Biases

Confirmation Bias

What it is: Seeking, interpreting, and remembering information that confirms what you already believe.

Example: You think a coworker is lazy. You notice every time they leave early, but not when they stay late.

Counter-measures:

• Actively seek disconfirming evidence
• Ask "What would change my mind?"
• Assign someone to argue the opposite position
• Read sources you disagree with

Sunk Cost Fallacy

What it is: Continuing a course of action because of past investment, regardless of future value.

Example: Staying in a bad relationship because you've already invested 5 years.

Counter-measures:

• Ask "If I were starting fresh, would I choose this?"
• Set kill criteria in advance
• Focus on future costs and benefits, not past
• The money/time is already gone. It's irrelevant

Availability Heuristic

What it is: Judging probability by how easily examples come to mind.

Example: After seeing news coverage, believing plane crashes are more common than car crashes.

Counter-measures:

• Look up actual statistics
• Ask "Is this memorable because it's common or because it's rare?"
• Recognize that vivid events distort perception

Anchoring

What it is: Over-relying on the first piece of information encountered.

Example: A high initial price makes a "discounted" price seem reasonable, even if it's still overpriced.

Counter-measures:

• Research independently before seeing their number
• Ignore arbitrary anchors
• Generate your own anchor from first principles
• Ask "What would I estimate without this information?"

Overconfidence Bias

What it is: Believing you're more right, more skilled, or more in control than you are.

Example: 93% of American drivers think they're above average.

Counter-measures:

• Track your predictions and review accuracy
• Assign probabilities, not certainties
• Ask "What's the base rate for people in my situation?"
• Seek feedback from others

Social Biases

Groupthink

What it is: Conforming to group consensus, suppressing dissent.

Counter-measures:

• Assign a devil's advocate role
• Anonymous voting on decisions
• Leader speaks last
• Encourage criticism explicitly

Authority Bias

What it is: Trusting someone because of their position, not their reasoning.

Counter-measures:

• Evaluate the argument, not the arguer
• Ask "Would this reasoning convince me from a random person?"
• Recognize that experts are often wrong outside their domain

Bandwagon Effect

What it is: Adopting beliefs or behaviors because others do.

Counter-measures:

• Form your view before seeing others'
• Ask "What would I think if I were the first to consider this?"
• Value independent thinking over consensus

In-Group Bias

What it is: Favoring people in your group, disfavoring outsiders.

Counter-measures:

• Actively consider opposing viewpoints
• Seek information from outside your group
• Evaluate ideas without knowing who proposed them

Memory and Perception Biases

Hindsight Bias

What it is: Believing, after the fact, that you "knew it all along."

Example: "I knew that startup would fail" (after it failed).

Counter-measures:

• Record predictions before outcomes
• Review decision journals
• Ask "What did I actually predict?"

Recency Bias

What it is: Weighting recent events more heavily than older ones.

Example: A manager rates an employee based on the last month, not the whole year.

Counter-measures:

• Keep logs and records
• Force yourself to consider full timeframes
• Create checklists for balanced evaluation

Peak-End Rule

What it is: Judging experiences by their peak intensity and end, not their average.

Counter-measures:

• Evaluate experiences systematically
• Don't let endings disproportionately color judgments
• Consider the whole experience

Decision-Making Biases

Status Quo Bias

What it is: Preferring the current state of affairs over change.

Example: Staying with a bad insurance policy because switching is effort.

Counter-measures:

• Ask "If I were starting fresh, would I choose this?"
• Quantify the cost of not changing
• Set calendar reminders to review recurring decisions

Loss Aversion

What it is: Losses hurt more than equivalent gains feel good (~2x).

Example: Refusing a bet with 50% chance to win $150 and 50% chance to lose $100.

Counter-measures:

• Frame decisions in terms of net expectation
• Consider portfolio of decisions, not single bets
• Ask "If I had neither, which would I choose?"

Endowment Effect

What it is: Valuing things more simply because you own them.

Example: Demanding more to sell something than you'd pay to buy it.

Counter-measures:

• Ask "What would I pay for this if I didn't own it?"
• Pretend you're advising a friend
• Focus on utility, not ownership

Choice-Supportive Bias

What it is: Remembering your choices as better than they were.

Counter-measures:

• Record decisions and reasoning at the time
• Review outcomes honestly
• Seek external feedback

Information Processing Biases

Dunning-Kruger Effect

What it is: Incompetent people overestimate their ability; experts underestimate theirs.

Counter-measures:

• For beginners: Assume you know less than you think
• For experts: Trust your expertise more
• Seek calibrated feedback

Survivorship Bias

What it is: Focusing on successes, ignoring failures that aren't visible.

Example: Studying successful entrepreneurs without considering the 90% who failed.

Counter-measures:

• Ask "What's the failure rate for this approach?"
• Seek out failure stories
• Consider the full population, not just visible examples

Narrative Fallacy

What it is: Creating stories to explain random events; seeing patterns in noise.

Counter-measures:

• Ask "Could this be random?"
• Look at large sample sizes
• Be skeptical of coherent explanations

Fundamental Attribution Error

What it is: Attributing others' behavior to character, your own to circumstances.

Example: "He's late because he's irresponsible" vs. "I'm late because of traffic."

Counter-measures:

• Consider situational factors for others
• Ask "What circumstances might explain this?"

Emotion-Related Biases

Affect Heuristic

What it is: Letting current emotional state influence judgment.

Example: Making important decisions when angry, excited, or tired.

Counter-measures:

• Delay big decisions when emotional
• Use 10/10/10 to get distance
• Create decision-making rituals that interrupt emotion

Optimism/Pessimism Bias

What it is: Systematically over- or under-estimating positive outcomes.

Counter-measures:

• Use base rates and outside view
• Track your predictions over time
• Adjust based on your historical tendency

Present Bias

What it is: Overvaluing immediate rewards vs. future rewards.

Example: Eating cake now vs. being healthy later.

Counter-measures:

• Pre-commit to future actions
• Make future rewards more salient
• Create environments that support good choices

Practical Application

Before Making a Decision

Ask yourself:

1. What biases am I most prone to?
2. What bias is most likely affecting this decision?
3. What would I think if I had opposite biases?
4. Who can give me an unbiased perspective?

Create Debiasing Habits

The Humility Check

You will still fall for biases. The goal isn't perfection, it's:

1. Recognizing when biases are likely
2. Taking steps to mitigate them
3. Making better decisions on average
4. Learning from mistakes