The bias library

Over 100 cognitive biases and principles, each explaining how to apply them and the study that backs them.
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dataset
Decision Making
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Paradox of Choice

Too many options reduce satisfaction.
neurology
Perception and Cognition
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Peak-End Rule

Judging experiences by peak moments and the end.
dataset
Decision Making
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Scarcity Principle

Assigning greater value to limited resources.
dataset
Decision Making
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Framing Effect

Decisions shaped by how information is presented.
dataset
Decision Making
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Anchoring Bias

Relying heavily on the first info seen.
diversity_1
Social and Emotional Influence
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Social Proof

Following others' actions in uncertainty.
dataset
Decision Making
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Endowment Effect

Overvaluing items because they are owned.
diversity_1
Social and Emotional Influence
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Loss Aversion

Fearing losses more than valuing gains.
dataset
Decision Making
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Status Quo Bias

Preferring existing situations over change.
dataset
Decision Making
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Decoy Effect

An irrelevant option alters preferences.
dataset
Decision Making
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Sunk Cost Fallacy

Continuing due to past investment.
dataset
Decision Making
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Choice Architecture

Structuring options to influence decisions.
dataset
Decision Making
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Commitment Bias

Sticking to initial decisions or investments despite contradictory evidence.
touch_app
Usability and Interaction
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Overconfidence Effect

Excessive belief in personal accuracy.
touch_app
Usability and Interaction
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Cognitive Dissonance

Discomfort from conflicting thoughts or actions.
touch_app
Usability and Interaction
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Optimism Bias

Overestimating positive outcomes.
touch_app
Usability and Interaction
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Regret Aversion

Avoiding decisions to prevent future regret.
touch_app
Usability and Interaction
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Self-Serving Bias

Attributing success internally and failures externally.
neurology
Perception and Cognition
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Recency Effect

Prioritising the last information seen.
neurology
Perception and Cognition
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Primacy Effect

Prioritising the first information seen.
neurology
Perception and Cognition
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Serial Position Effect

Remembering the first and last items in a sequence.
touch_app
Usability and Interaction
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Hindsight Bias

Believing outcomes were predictable after the fact.
touch_app
Usability and Interaction
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Mere Exposure Effect

Familiarity breeds preference.
touch_app
Usability and Interaction
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Von Restorff Effect

People notice items that stand out more.
diversity_1
Social and Emotional Influence
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Barnum Effect

Believing vague statements are personal.
touch_app
Usability and Interaction
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Illusory Correlation

Perceiving relationships where none exist.
touch_app
Usability and Interaction
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Belief Perseverance

Holding onto beliefs despite contrary evidence.
diversity_1
Social and Emotional Influence
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The Bandwagon Effect

People adopt behaviours or beliefs because others do.
diversity_1
Social and Emotional Influence
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Authority Bias

Trusting authority figures more than others.
touch_app
Usability and Interaction
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Illusion of Control

Overestimating one's ability to influence outcomes.
diversity_1
Social and Emotional Influence
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False Consensus Effect

Overestimating agreement with personal views.
dataset
Decision Making
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Risk Compensation Effect

Increased risk-taking after safety improvements.
dataset
Decision Making
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Omission Bias

Preferring inaction over equivalent action.
touch_app
Usability and Interaction
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Fear of Missing Out (FOMO)

Anxiety from perceived missed opportunities.
diversity_1
Social and Emotional Influence
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Temporal Discounting

Preferring smaller immediate rewards over larger future ones.
touch_app
Usability and Interaction
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Dunning-Kruger Effect

Overconfidence in one's competence.
dataset
Decision Making
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Pseudocertainty Effect

Preferring certain outcomes over probabilistic ones.
diversity_1
Social and Emotional Influence
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Foot-in-the-Door Technique

Gaining compliance through small initial requests.
touch_app
Usability and Interaction
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Contrast Effect

Perceiving differences more sharply.
diversity_1
Social and Emotional Influence
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Reciprocity Principle

Feeling obligated to repay favours.
touch_app
Usability and Interaction
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Placebo Effect

Belief influencing outcomes.
touch_app
Usability and Interaction
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Effort Justification

Valuing outcomes based on effort invested.
diversity_1
Social and Emotional Influence
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Self-Fulfilling Prophecy

Beliefs shape actions, influencing outcomes.
touch_app
Usability and Interaction
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Survivorship Bias

Focusing on successes, ignoring failures.
touch_app
Usability and Interaction
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Backfire Effect

Reinforcing beliefs when challenged.
neurology
Perception and Cognition
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Nudge

Subtle hints can affect user decisions.
touch_app
Usability and Interaction
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Cognitive Load

Mental effort needed for tasks.
touch_app
Usability and Interaction
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Attentional Bias

Focusing on certain stimuli over others.
touch_app
Usability and Interaction
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Curse of Knowledge

Difficulty imagining others' lack of knowledge.
neurology
Perception and Cognition
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Choice-Supportive Bias

Favouring past choices despite flaws.
diversity_1
Social and Emotional Influence
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Bystander Effect

Reduced action in the presence of others.
neurology
Perception and Cognition
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End-of-Day Effect

Recalling the last event more vividly.
dataset
Decision Making
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Category Size Bias

Assuming greater likelihood of success when associated with a larger category.
touch_app
Usability and Interaction
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Time Perception Bias

Perceiving time differently under varying contexts.
dataset
Decision Making
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The Ostrich Effect

Ignoring negative information to avoid discomfort.
diversity_1
Social and Emotional Influence
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The Just-World Hypothesis

Believing the world is inherently fair.
diversity_1
Social and Emotional Influence
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The Illusion of Asymmetric Insight

Believing you understand others better than they understand you.
touch_app
Usability and Interaction
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The Illusion of Validity

Overestimating the accuracy of our judgments.
touch_app
Usability and Interaction
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Egocentric Bias

Overestimating how much others share one’s views.
dataset
Decision Making
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Bikeshedding

Focusing on trivial tasks over more complex, significant ones.
diversity_1
Social and Emotional Influence
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Cultural Bias

Judging through the lens of one's culture.
neurology
Perception and Cognition
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False Memory

Recollections can be inaccurate or fabricated.
dataset
Decision Making
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Default Bias

Preference for pre-selected options.
touch_app
Usability and Interaction
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Cheerleader Effect

Groups appear more attractive than individuals.
neurology
Perception and Cognition
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Confirmation Bias

Seeking info that confirms beliefs.
neurology
Perception and Cognition
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Negativity Bias

Focusing on negative over positive information.
touch_app
Usability and Interaction
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IKEA Effect

Overvaluing self-created items.
dataset
Decision Making
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Planning Bias

Underestimating task time and complexity.
touch_app
Usability and Interaction
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Hedonic Adaptation

Adjusting to positive or negative changes.
neurology
Perception and Cognition
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Fitts's Law

Ease of interaction depends on size and distance.
neurology
Perception and Cognition
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Zeigarnik Effect

Remembering incomplete tasks better.
neurology
Perception and Cognition
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Progressive Disclosure

Presenting information gradually to avoid overwhelming users.
dataset
Decision Making
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Pareto Principle (80/20 Rule)

80% of outcomes stem from 20% of causes.
touch_app
Usability and Interaction
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Self-Consistency Bias

Believing past actions align with current beliefs.
diversity_1
Social and Emotional Influence
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Emotional Contagion

Sharing emotions through observation.
diversity_1
Social and Emotional Influence
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Bottom-Dollar Effect

Negative emotions tied to depleted resources transfer to purchases made at th...
diversity_1
Social and Emotional Influence
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Over-justification Effect

Rewards reducing intrinsic motivation.
touch_app
Usability and Interaction
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False Uniqueness Effect

Overestimating the uniqueness of one’s traits.
diversity_1
Social and Emotional Influence
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Groupthink

Conforming to group decisions for harmony.
neurology
Perception and Cognition
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Feedback Loop

When users take action, feedback communicates what happened.
neurology
Perception and Cognition
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Hick's Law

More options lead to harder decisions.
touch_app
Usability and Interaction
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Availability Heuristic

Judging likelihood by ease of recall.
diversity_1
Social and Emotional Influence
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The Ben Franklin Effect

Doing a favour for someone increases liking.
touch_app
Usability and Interaction
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Hot Hand Fallacy

Believing a streak will continue.
touch_app
Usability and Interaction
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Forer Effect

Believing vague statements are personal.
diversity_1
Social and Emotional Influence
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Empathy Gap

Difficulty predicting behaviour in different emotional states.
diversity_1
Social and Emotional Influence
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In-Group Bias

Favouring members of one's own group.
dataset
Decision Making
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Ambiguity Effect

Avoiding options with unknown outcomes.
dataset
Decision Making
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Action Bias

Preference for action over inaction.
touch_app
Usability and Interaction
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Halo Effect

Judging based on one positive attribute.
neurology
Perception and Cognition
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Affect Heuristic

Decisions based on current emotions rather than logic.
touch_app
Usability and Interaction
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Priming

Subconscious influence from prior exposure.
touch_app
Usability and Interaction
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Attentional Spotlight Effect

Overestimating how much others notice you.
dataset
Decision Making
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Outcome Bias

Judging decisions by their outcomes.
touch_app
Usability and Interaction
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Simpson's Paradox

Trends reversing when data is grouped.
diversity_1
Social and Emotional Influence
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Pygmalion Effect

High expectations improve performance.
touch_app
Usability and Interaction
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Proximity Principle

Grouping based on spatial closeness.
touch_app
Usability and Interaction
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Projection Bias

Assuming future preferences match current ones.
touch_app
Usability and Interaction
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Self-Handicapping Bias

Creating excuses to protect self-esteem.
touch_app
Usability and Interaction
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Base Rate Fallacy

Ignoring general probabilities for specifics.

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