🧠 Psychology of Design106 Cognitive Biases & Principles That Affect Your UX

Every time users interact with your product, they:

  1. 🙈 Filter the information
  2. 🔮 Seek the meaning of it
  3. ⏰ Act within a given time
  4. 💾 Store bits of the interaction in their memories

So to improve your user experience, you need to understand the biases & heuristics affecting those four decision-cycle steps.

Below is a list of cognitive biases and design principles (with examples and tips) for each category. Let’s dive right in.

PS: Don’t have time to read the whole list? Get the cheat sheet

🙈 Information

Users filter out a lot of the information that they receive, even when it could be important.

👀 Hick's Law

More options leads to harder decisions

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💼 Confirmation Bias

People look for evidence that confirms what they think

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👁 Priming

Previous stimuli influence users' decision

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🚛 Cognitive Load

Total amount of mental effort that is required to complete a task

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⚓️ Anchoring Bias

Users rely heavily on the first piece of information they see

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👉 Nudge

Subtle hints can affect users' decisions

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🍰 Progressive Disclosure

Users are less overwhelmed if they're exposed to complex features later

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🎯 Fitts's Law

Large and close elements are easier to interact with

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🕺 Decoy Effect

Create a new option that's easy to discard

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🖼 Framing

The way information is presented affects how users make decisions

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🐠 Attentional Bias

Users' thoughts filter what they pay attention to

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💔 Empathy Gap

People underestimate how much emotions influence user behaviors

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⛵️ Visual Anchors

Elements used to guide users' eyes

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🌶 Von Restorff Effect

People notice items that stand out more

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🎖 Visual Hierarchy

The order in which people perceive what they see

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🔭 Selective Attention

People filter out things from their environment when in focus

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✈️ Survivorship Bias

People neglect things that don't make it past a selection process

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🍒 Juxtaposition

Elements that are close and similar are perceived as a single unit

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🚦 Signifiers

Elements that communicate what they will do

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🎭 Contrast

Users' attention is drawn to higher visual weights

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🚨 External Trigger

When the information on what to do next is within the prompt itself

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🎪 Centre-Stage Effect

People tend to choose the middle option in a set of items

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🍣 Law of Proximity

Elements close to each other are usually considered related

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🍬 Tesler's Law

If you simplify too much, you'll transfer some complexity to the users

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🧨 Spark Effect

Users are more likely to take action when the effort is small

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🥏 Feedback Loop

When users take action, feedback communicates what happened

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😻 Expectations Bias

People tend to be influenced by their own expectations

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🚆 Aesthetic-Usability Effect

People perceive designs with great aesthetics as easier to use

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🔮 Meaning

When users try to give sense to information, they make stories and assumptions to fill the gaps.

👥 Social Proof

Users adapt their behaviors based on what others do

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🦄 Scarcity

People value things more when they're in limited supply

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💭 Curiosity Gap

Users have a desire to seek out missing information

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🖲 Mental Model

Users have a preconceived opinion of how things work

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👨‍👩‍👧‍👦 Familiarity Bias

People prefer familiar experiences

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🕹 Skeuomorphism

Users adapt more easily to things that look like real-world objects

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🎁 Reciprocity

People feel the need to reciprocate when they receive something

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🤝 Singularity Effect

Users care disproportionately about an individual as compared to a group

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🎰 Variable Reward

People especially enjoy unexpected rewards

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🎉 Aha! moment

When new users first realize the value of your product

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🥅 Goal Gradient Effect

Motivation increases as users get closer to their goal

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💈 Occam’s Razor

Simple solutions are often better than the more complex ones

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🎗 Noble Edge Effect

Users tend to prefer socially responsible companies

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🧿 Hawthorne Effect

Users change their behavior when they know they are being observed

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👼 Halo Effect

People judge things (or people) based on their feelings towards one trait

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☎️ Miller’s Law

Users can only keep 5±2 items in their working memory

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🍱 Unit Bias

One unit of something feels like the optimal amount

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🌊 Flow State

Being fully immersed and focused on a task

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👑 Authority Bias

Users attribute more importance to the opinion of an authority figure

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🏺 Pseudo-Set Framing

Tasks that are part of a group are more tempting to complete

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🎊 Group Attractiveness Effect

Individual items seem more attractive when presented in a group

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🚰 Curse of Knowledge

Not realizing that people don't have the same level of knowledge

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📮 Self-Initiated Triggers

Users are more likely to interact with prompts they setup for themselves

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✏️ Survey Bias

Users tend to skew survey answers towards what's socially acceptable

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🎭 Cognitive Dissonance

It's painful to hold two opposing ideas in our mind

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💫 Feedforward

When users know what to expect before they take action

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🏒 Hindsight Bias

People overestimate their ability to predict outcomes after the fact

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🎏 Law of Similarity

Users perceive a relationship between elements that look similar

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🌓 Law of Prägnanz

Users interpret ambiguous images in a simpler and more complete form

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🐘 Streisand Effect

When trying to censor information ends up increasing awareness of that information

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🔦 Spotlight Effect

People tend to believe they are being noticed more than they really are

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🗓 Fresh Start Effect

Users are more likely to take action if there's a feeling of new beginnings

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⏰ Time

Users are busy so they look for shortcuts and jump to conclusions quickly.

🧗‍♂️ Labor Illusion

People value things more when they see the work behind them

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🚶‍♂️ Default Bias

Users tend not to change an established behavior

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🏦 Investment Loops

When users invest themselves, they're more likely to come back

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🕯 Loss Aversion

People prefer to avoid losses more than earning equivalent gains

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👞 Commitment & Consistency

Users tend to be consistent with their previous actions

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🏝 Sunk Cost Effect

Users are reluctant to pull out of something they're invested in.

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🌋 Reactance

Users are less likely to adopt a behavior when they feel forced

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🔨 Law of the Instrument

If all you have is a hammer, everything looks like a nail

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🍭 Temptation Bundling

Hard tasks are less scary when coupled with something users desire

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🎩 Dunning-Kruger Effect

People tend to overestimate their skills when they don't know much

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🔍 Discoverability

The ease with which users can discover your features

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🐍 Second-Order Effect

The consequences of the consequences of actions

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🌛 Decision Fatigue

Making a lot of decisions lowers users' ability to make rational ones

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🥽 Observer-Expectancy Effect

When researchers' biases influence the participants of an experiment

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🌱 Weber's Law

Users adapt better to small incremental changes

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🎈 Parkinson’s Law

The time required to complete a task will take as much time as allowed

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🌤 Affect Heuristic

People's current emotions cloud and influence their judgment

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📉 Hyperbolic Discounting

People tend to prioritize immediate benefits over bigger future gains

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⌚️ Chronoception

People's perception of time is subjective

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💳 Cashless Effect

People spend more when they can't actually see the money

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🌚 Self-serving bias

People take credits for positive events and blame others if negative

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🥬 Pareto Principle

Roughly 80% of the effects come from 20% of the causes

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🔫 Backfire Effect

When people's convictions are challenged, their beliefs get stronger

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🌈 False Consensus Effect

People overestimate how much other people agree with them

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🚋 Bandwagon Effect

Users tend to adopt beliefs in proportion of others who have already done so

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🧙‍♂️ Barnum-Forer Effect

When you believe generic personality descriptions apply specifically to you.

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🛋 IKEA Effect

When user partially create something, they value it way more

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🧚‍♂️ Planning Fallacy

People tend to underestimate how much time a task will take

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💾 Memory

Users try to remember what's most important, but their brain prefers some elements over others.

🏕 Provide Exit Points

Invite users to leave your app at the right moment

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🎢 Peak-End Rule

People judge an experience by its peak and how it ends.

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👅 Sensory Appeal

Users engage more with things appealing to multiple senses

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🧩 Zeigarnik Effect

People remember incomplete tasks better than completed ones

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🧤 Endowment Effect

Users value something more if they feel it's theirs

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🛍 Chunking

People remember grouped information better

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💚 Delighters

People remember more unexpected and playful pleasures

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💛 Internal Trigger

When users are prompted to take action based on a memory

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📸 Picture Superiority Effect

People remember pictures better than words

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📌 Method of Loci

People remember things more when they're associated with a location

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🧭 Shaping

Incrementally reinforcing actions to get closer to a target behavior

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💾 Recognition Over Recall

It's easier to recognize things than recall them from memory

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🏰 Storytelling Effect

People remember stories better than facts alone

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👹 Negativity Bias

Users recall negative events more than positive ones

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Availability Heuristic

Users favor recent and available information over past information

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🌌 Spacing Effect

People learn more effectively when study sessions are spaced out

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🏁 Serial Position Effect

It's easier for users to recall the first and last items of a list

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Product Psychology Resources

If you want to learn more about behavioral psychology and mental models, we recommend these resources:

📓 Cognitive Biases Codex

The four categories of our list come from Buster Benson's work

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📘 Super Thinking

The big book of mental models and cognitive biases (Gabriel Weinberg)

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📙 Hooked

How to build habit-forming products (Nir Eyal)

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📕 Influence

The psychology of persuasion (Robert Cialdini)

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📔 Predictably Irrational

The hidden forces that shape our decisions (Dan Ariely)

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Cognitive Biases Cheat sheet

We took the time to summarize each principle in one line.

They are all in a free cheat sheet of cognitive biases principles.

You can download this cheatsheet as a PDF here.

Use it as a user empathy reminder while you build a feature.

Nir Eyal
We all have a responsibility to build ethically-designed products and services to improve people’s lives. Growth.Design’s list of cognitive biases and psychological principles is a great reference for any team committed to improving their customers’ user experience. Dan & Louis-Xavier’s comic book case studies show you how.Nir Eyal, bestselling author of Hooked and Indistractable

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Are there missing elements we should add to the list?

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