tools-only Bias Encyclopedia
A comprehensive reference for cognitive biases that affect decision-making.
Core Decision Biases
FOMO (Fear of Missing Out)
Definition: Anxiety that others are having rewarding experiences you're absent from.
In Decisions: Creates urgency where none exists. Makes opportunities seem more unique than they are.
Counter-questions:
- What evidence suggests this is truly one-of-a-kind?
- Will similar opportunities exist in the future?
- What's the actual cost of waiting?
Signs you have it:
- Feeling rushed to decide
- Imagining others succeeding without you
- Focusing on what you'll miss, not what you'll gain
Sunk Cost Fallacy
Definition: Continuing a behavior due to previously invested resources (time, money, effort).
In Decisions: Makes you factor past investment into future choices, even when it's irrelevant.
Counter-questions:
- If I hadn't invested anything yet, would I start now?
- Is my past investment recoverable by continuing?
- Am I deciding based on future value or past cost?
Signs you have it:
- "I've already put in so much..."
- Difficulty abandoning projects you've invested in
- Feeling guilty about "wasted" past effort
Authority Bias
Definition: Attributing greater accuracy to opinions of authority figures.
In Decisions: Deferring to credentials, status, or famous investors without independent evaluation.
Counter-questions:
- Would I trust this advice from someone unknown?
- Does their authority apply to this specific domain?
- What's their actual track record in this area?
Signs you have it:
- Mentioning credentials as justification
- Feeling reassured by who's involved, not what's being done
- Not questioning expert opinions
Social Proof
Definition: Assuming actions are correct because others are doing them.
In Decisions: Following the crowd without evaluating fit for your specific situation.
Counter-questions:
- Do these "others" have the same context as me?
- What's the base rate of success for people who did this?
- Would I do this if no one else was?
Signs you have it:
- "Everyone is doing it..."
- Drawing confidence from popularity
- Not knowing why it works, just that others say it does
Commitment and Consistency Bias
Definition: Desire to appear consistent with what you've already done or said.
In Decisions: Feeling obligated by past statements or actions to continue on a path.
Counter-questions:
- Has new information emerged since my commitment?
- What would a stranger advise given current facts?
- Is consistency more important than correctness?
Signs you have it:
- "But I already said I would..."
- Discomfort with changing your mind
- Feeling like changing course is "breaking a promise"
Optimism Bias
Definition: Believing you're less likely to experience negative events than others.
In Decisions: Assuming problems will resolve, risks won't materialize, or you're somehow exempt.
Counter-questions:
- What's the base rate of this going wrong?
- Why would I be luckier than average?
- What if the problems don't just "work out"?
Signs you have it:
- "It'll probably be fine..."
- Dismissing warning signs
- Expecting best-case scenarios without evidence
Recency Bias
Definition: Giving more weight to recent events than older ones.
In Decisions: Overweighting the last meeting, latest data point, or most recent experience.
Counter-questions:
- Does my opinion change based on the order I received information?
- What does the full timeline show?
- Is the recent event representative or anomalous?
Signs you have it:
- Strong reaction to latest news
- Forgetting earlier patterns
- "But just last week..."
Confirmation Bias
Definition: Seeking information that confirms existing beliefs; avoiding contradicting evidence.
In Decisions: Cherry-picking data that supports what you already want to do.
Counter-questions:
- What information would make me change my mind?
- Have I actively sought disconfirming evidence?
- Am I interpreting neutral data as supportive?
Signs you have it:
- Only reading positive reviews
- Dismissing critics as "not understanding"
- Feeling annoyed by contrary information
Shiny Object Syndrome
Definition: Being attracted to new ideas, tools, or opportunities over current commitments.
In Decisions: Novelty masquerading as value. Abandoning proven paths for unproven new ones.
Counter-questions:
- Is this genuinely better, or just newer?
- Would I pursue this if it had been available all along?
- Am I running toward something or away from something?
Signs you have it:
- Excitement about starting, less about finishing
- History of pivoting to "the next thing"
- Current projects feel boring in comparison
Loss Aversion
Definition: Preferring avoiding losses over acquiring equivalent gains.
In Decisions: Overweighting what you might lose; underweighting what you might gain.
Counter-questions:
- Am I equally weighing gains and losses?
- What's the actual probability of loss?
- What's the opportunity cost of avoiding loss?
Signs you have it:
- Focus on downside scenarios
- Feeling protective of current position
- "I can't afford to lose..."
Secondary Biases
Anchoring
Definition: Relying heavily on the first piece of information encountered.
In Decisions: First number or offer unduly influences subsequent judgments.
Counter: Generate your own estimate before seeing any anchors.
Availability Heuristic
Definition: Judging likelihood by how easily examples come to mind.
In Decisions: Overestimating risks/opportunities that are memorable or recent.
Counter: Look up actual statistics; don't rely on memory.
Bandwagon Effect
Definition: Probability of adoption increases with prevalence.
In Decisions: Following trends without independent evaluation.
Counter: Ask "Would I do this if no one else was?"
Dunning-Kruger Effect
Definition: Overestimating competence in areas of ignorance.
In Decisions: Underestimating difficulty or risk due to inexperience.
Counter: Seek opinions from genuine experts in the domain.
Endowment Effect
Definition: Overvaluing things you already possess.
In Decisions: Overweighting current situation; undervaluing alternatives.
Counter: Imagine you're advising a stranger starting fresh.
Halo Effect
Definition: Overall impression influences evaluation of specific traits.
In Decisions: One positive attribute colors entire assessment.
Counter: Evaluate each dimension independently.
Hindsight Bias
Definition: After learning outcome, believing you "knew it all along."
In Decisions: Overconfidence in predicting future based on explained past.
Counter: Document predictions before outcomes are known.
Planning Fallacy
Definition: Underestimating time, costs, and risks of future actions.
In Decisions: Overly optimistic timelines and resource estimates.
Counter: Use reference class forecasting; multiply estimates by 1.5-2x.
Status Quo Bias
Definition: Preference for the current state of affairs.
In Decisions: Inaction feels safer even when action is better.
Counter: Evaluate "do nothing" as actively as "do something."
Survivorship Bias
Definition: Focusing on winners; ignoring failures.
In Decisions: Learning only from success stories; underestimating failure rates.
Counter: Actively seek information about failures.
Using This Encyclopedia
- Before deciding: Scan list for biases you might be experiencing
- When uncertain: Check counter-questions for your suspected biases
- After deciding: Review for biases that might have influenced you
- In groups: Use as discussion prompt to surface diverse perspectives
Quick Reference Card
| Bias | One-Line Description | Quick Counter |
|---|---|---|
| FOMO | Fear others are succeeding without you | Will similar opportunities exist later? |
| Sunk Cost | Continuing because of past investment | Would I start this today from scratch? |
| Authority | Trusting credentials over evidence | Does their expertise apply here? |
| Social Proof | Following the crowd | Would I do this alone? |
| Commitment | Sticking to past statements | Has new info emerged? |
| Optimism | Assuming problems will resolve | What's the base rate of failure? |
| Recency | Overweighting recent events | What does the full history show? |
| Confirmation | Seeking validating info | What would change my mind? |
| Shiny Object | Attracted to novelty | Is this better or just newer? |
| Loss Aversion | Overweighting potential losses | Am I equally weighing gains? |