๐Ÿง  Psychology of Design106 Cognitive Biases & Principles That Affect Your UX

Every time users interact with your product, they:

  1. ๐Ÿ™ˆ Filter the information
  2. ๐Ÿ”ฎ Seek the meaning of it
  3. โฐ Act within a given time
  4. ๐Ÿ’พ 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. Letโ€™s dive right in.

PS: Donโ€™t have time to read the whole list?ย Get the cheat sheet

๐Ÿ™ˆ Information

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

๐Ÿ‘€ Hick's Law

More options leads to harder decisions

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๐Ÿ’ผ Confirmation Bias

People look for evidence that confirms what they think

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๐Ÿ‘ Priming

Previous stimuli influence users' decision

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๐Ÿš› Cognitive Load

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

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โš“๏ธ Anchoring Bias

Users rely heavily on the first piece of information they see

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๐Ÿ‘‰ Nudge

Subtle hints can affect users' decisions

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๐Ÿฐ Progressive Disclosure

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

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๐ŸŽฏ Fitts's Law

Large and close elements are easier to interact with

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๐Ÿ•บ Decoy Effect

Create a new option that's easy to discard

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๐Ÿ–ผ Framing

The way information is presented affects how users make decisions

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๐Ÿ  Attentional Bias

Users' thoughts filter what they pay attention to

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๐Ÿ’” Empathy Gap

People underestimate how much emotions influence user behaviors

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โ›ต๏ธ Visual Anchors

Elements used to guide users' eyes

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๐ŸŒถ Von Restorff Effect

People notice items that stand out more

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๐ŸŽ– Visual Hierarchy

The order in which people perceive what they see

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๐Ÿ”ญ Selective Attention

People filter out things from their environment when in focus

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โœˆ๏ธ Survivorship Bias

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

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๐Ÿ’ Juxtaposition

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

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๐Ÿšฆ Signifiers

Elements that communicate what they will do

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๐ŸŽญ Contrast

Users' attention is drawn to higher visual weights

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๐Ÿšจ External Trigger

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

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๐ŸŽช Centre-Stage Effect

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

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๐Ÿฃ Law of Proximity

Elements close to each other are usually considered related

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๐Ÿฌ Tesler's Law

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

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๐Ÿงจ Spark Effect

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

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๐Ÿฅ Feedback Loop

When users take action, feedback communicates what happened

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๐Ÿ˜ป Expectations Bias

People tend to be influenced by their own expectations

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๐Ÿš† Aesthetic-Usability Effect

People perceive designs with great aesthetics as easier to use

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๐Ÿ”ฎ Meaning

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

๐Ÿ‘ฅ Social Proof

Users adapt their behaviors based on what others do

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๐Ÿฆ„ Scarcity

People value things more when they're in limited supply

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๐Ÿ’ญ Curiosity Gap

Users have a desire to seek out missing information

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๐Ÿ–ฒ Mental Model

Users have a preconceived opinion of how things work

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๐Ÿ‘จโ€๐Ÿ‘ฉโ€๐Ÿ‘งโ€๐Ÿ‘ฆ Familiarity Bias

People prefer familiar experiences

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๐Ÿ•น Skeuomorphism

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

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๐ŸŽ Reciprocity

People feel the need to reciprocate when they receive something

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๐Ÿค Singularity Effect

Users care disproportionately about an individual as compared to a group

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๐ŸŽฐ Variable Reward

People especially enjoy unexpected rewards

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๐ŸŽ‰ Aha! moment

When new users first realize the value of your product

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๐Ÿฅ… Goal Gradient Effect

Motivation increases as users get closer to their goal

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๐Ÿ’ˆ Occamโ€™s Razor

Simple solutions are often better than the more complex ones

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๐ŸŽ— Noble Edge Effect

Users tend to prefer socially responsible companies

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๐Ÿงฟ Hawthorne Effect

Users change their behavior when they know they are being observed

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๐Ÿ‘ผ Halo Effect

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

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โ˜Ž๏ธ Millerโ€™s Law

Users can only keep 7ยฑ2 items in their working memory

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๐Ÿฑ Unit Bias

One unit of something feels like the optimal amount

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๐ŸŒŠ Flow State

Being fully immersed and focused on a task

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๐Ÿ‘‘ Authority Bias

Users attribute more importance to the opinion of an authority figure

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๐Ÿบ Pseudo-Set Framing

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

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๐ŸŽŠ Group Attractiveness Effect

Individual items seem more attractive when presented in a group

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๐Ÿšฐ Curse of Knowledge

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

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๐Ÿ“ฎ Self-Initiated Triggers

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

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โœ๏ธ Survey Bias

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

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๐ŸŽญ Cognitive Dissonance

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

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๐Ÿ’ซ Feedforward

When users know what to expect before they take action

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๐Ÿ’ Hindsight Bias

People overestimate their ability to predict outcomes after the fact

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๐ŸŽ Law of Similarity

Users perceive a relationship between elements that look similar

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๐ŸŒ“ Law of Prรคgnanz

Users interpret ambiguous images in a simpler and more complete form

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๐Ÿ˜ Streisand Effect

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

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๐Ÿ”ฆ Spotlight Effect

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

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๐Ÿ—“ Fresh Start Effect

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

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โฐ Time

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

๐Ÿง—โ€โ™‚๏ธ Labor Illusion

People value things more when they see the work behind them

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๐Ÿšถโ€โ™‚๏ธ Default Bias

Users tend not to change an established behavior

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๐Ÿฆ Investment Loops

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

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๐Ÿ•ฏ Loss Aversion

People prefer to avoid losses more than earning equivalent gains

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๐Ÿ‘ž Commitment & Consistency

Users tend to be consistent with their previous actions

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๐Ÿ Sunk Cost Effect

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

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๐ŸŒ‹ Reactance

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

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๐Ÿ”จ Law of the Instrument

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

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๐Ÿญ Temptation Bundling

Hard tasks are less scary when coupled with something users desire

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๐ŸŽฉ Dunning-Kruger Effect

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

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๐Ÿ” Discoverability

The ease with which users can discover your features

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๐Ÿ Second-Order Effect

The consequences of the consequences of actions

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๐ŸŒ› Decision Fatigue

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

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๐Ÿฅฝ Observer-Expectancy Effect

When researchers' biases influence the participants of an experiment

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๐ŸŒฑ Weber's Law

Users adapt better to small incremental changes

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๐ŸŽˆ Parkinsonโ€™s Law

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

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๐ŸŒค Affect Heuristic

People's current emotions cloud and influence their judgment

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๐Ÿ“‰ Hyperbolic Discounting

People tend to prioritize immediate benefits over bigger future gains

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โŒš๏ธ Chronoception

People's perception of time is subjective

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๐Ÿ’ณ Cashless Effect

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

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๐ŸŒš Self-serving bias

People take credits for positive events and blame others if negative

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๐Ÿฅฌ Pareto Principle

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

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๐Ÿ”ซ Backfire Effect

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

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๐ŸŒˆ False Consensus Effect

People overestimate how much other people agree with them

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๐Ÿš‹ Bandwagon Effect

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

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๐Ÿง™โ€โ™‚๏ธ Barnum-Forer Effect

When you believe generic personality descriptions apply specifically to you.

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๐Ÿ›‹ IKEA Effect

When user partially create something, they value it way more

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๐Ÿงšโ€โ™‚๏ธ Planning Fallacy

People tend to underestimate how much time a task will take

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๐Ÿ’พ Memory

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

๐Ÿ• Provide Exit Points

Invite users to leave your app at the right moment

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๐ŸŽข Peak-End Rule

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

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๐Ÿ‘… Sensory Appeal

Users engage more with things appealing to multiple senses

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๐Ÿงฉ Zeigarnik Effect

People remember incomplete tasks better than completed ones

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๐Ÿงค Endowment Effect

Users value something more if they feel it's theirs

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๐Ÿ› Chunking

People remember grouped information better

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๐Ÿ’š Delighters

People remember more unexpected and playful pleasures

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๐Ÿ’› Internal Trigger

When users are prompted to take action based on a memory

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๐Ÿ“ธ Picture Superiority Effect

People remember pictures better than words

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๐Ÿ“Œ Method of Loci

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

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๐Ÿงญ Shaping

Incrementally reinforcing actions to get closer to a target behavior

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๐Ÿ’พ Recognition Over Recall

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

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๐Ÿฐ Storytelling Effect

People remember stories better than facts alone

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๐Ÿ‘น Negativity Bias

Users recall negative events more than positive ones

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โฐ Availability Heuristic

Users favor recent and available information over past information

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๐ŸŒŒ Spacing Effect

People learn more effectively when study sessions are spaced out

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๐Ÿ 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:

๐Ÿ““ Cognitive Biases Codex

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

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๐Ÿ“˜ Super Thinking

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

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๐Ÿ“™ Hooked

How to build habit-forming products (Nir Eyal)

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๐Ÿ“• Influence

The psychology of persuasion (Robert Cialdini)

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๐Ÿ“” 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 canย download this cheatsheet as a PDF here.

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

Nir Eyal
โ€œWe all have a responsibility to build ethically-designed products and services to improve peopleโ€™s lives. Growth.Designโ€™s list of cognitive biases and psychological principles is a great reference for any team committed to improving their customersโ€™ user experience. Dan & Louis-Xavierโ€™s comic book case studies show you how.โ€โ€” Nir Eyal, bestselling author of Hooked and Indistractable

Now Itโ€™s Your Turn

So which principle are you going to try next?

Are there missing elements we should add to the list?

You can reach us at team@growth.design, we reply to everyone!

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