🧠 The Psychology of Design106 Cognitive Biases & Principles That Affect Your UX
Every time users interact with your product, they:
- 🙈 Filter the information
- 🔮 Seek the meaning of it
- ⏰ Act within a given time
- 💾 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
💼 Confirmation Bias
People look for evidence that confirms what they think
👁 Priming
Previous stimuli influence users' decision
🚛 Cognitive Load
Total amount of mental effort that is required to complete a task
⚓️ Anchoring Bias
Users rely heavily on the first piece of information they see
👉 Nudge
Subtle hints can affect users' decisions
🍰 Progressive Disclosure
Users are less overwhelmed if they're exposed to complex features later
🎯 Fitts's Law
Large and close elements are easier to interact with
🕶 Banner Blindness
Users tune out the stuff they get repeatedly exposed to
🕺 Decoy Effect
Create a new option that's easy to discard
🖼 Framing
The way information is presented affects how users make decisions
🐠 Attentional Bias
Users' thoughts filter what they pay attention to
💔 Empathy Gap
People underestimate how much emotions influence user behaviors
⛵️ Visual Anchors
Elements used to guide users' eyes
🌶 Von Restorff Effect
People notice items that stand out more
🎖 Visual Hierarchy
The order in which people perceive what they see
🔭 Selective Attention
People filter out things from their environment when in focus
✈️ Survivorship Bias
People neglect things that don't make it past a selection process
🍒 Juxtaposition
Elements that are close and similar are perceived as a single unit
🚦 Signifiers
Elements that communicate what they will do
🎭 Contrast
Users' attention is drawn to higher visual weights
🚨 External Trigger
When the information on what to do next is within the prompt itself
🎪 Centre-Stage Effect
People tend to choose the middle option in a set of items
🍣 Law of Proximity
Elements close to each other are usually considered related
🍬 Tesler's Law
If you simplify too much, you'll transfer some complexity to the users
🧨 Spark Effect
Users are more likely to take action when the effort is small
🥏 Feedback Loop
When users take action, feedback communicates what happened
😻 Expectations Bias
People tend to be influenced by their own expectations
🚆 Aesthetic-Usability Effect
People perceive designs with great aesthetics as easier to use
🔮 Meaning
When users try to give sense to information, they make stories and assumptions to fill the gaps.
🦄 Scarcity
People value things more when they're in limited supply
💭 Curiosity Gap
Users have a desire to seek out missing information
🖲 Mental Model
Users have a preconceived opinion of how things work
👨👩👧👦 Familiarity Bias
People prefer familiar experiences
🕹 Skeuomorphism
Users adapt more easily to things that look like real-world objects
🎁 Reciprocity
People feel the need to reciprocate when they receive something
🤝 Singularity Effect
Users care disproportionately about an individual as compared to a group
🎰 Variable Reward
People especially enjoy unexpected rewards
🎉 Aha! moment
When new users first realize the value of your product
🥅 Goal Gradient Effect
Motivation increases as users get closer to their goal
💈 Occam’s Razor
Simple solutions are often better than the more complex ones
🎗 Noble Edge Effect
Users tend to prefer socially responsible companies
🧿 Hawthorne Effect
Users change their behavior when they know they are being observed
👼 Halo Effect
People judge things (or people) based on their feelings towards one trait
☎️ Miller’s Law
Users can only keep 7±2 items in their working memory
🍱 Unit Bias
One unit of something feels like the optimal amount
🌊 Flow State
Being fully immersed and focused on a task
👑 Authority Bias
Users attribute more importance to the opinion of an authority figure
🏺 Pseudo-Set Framing
Tasks that are part of a group are more tempting to complete
🎊 Group Attractiveness Effect
Individual items seem more attractive when presented in a group
🚰 Curse of Knowledge
Not realizing that people don't have the same level of knowledge
📮 Self-Initiated Triggers
Users are more likely to interact with prompts they setup for themselves
✏️ Survey Bias
Users tend to skew survey answers towards what's socially acceptable
🎭 Cognitive Dissonance
It's painful to hold two opposing ideas in our mind
💫 Feedforward
When users know what to expect before they take action
🏒 Hindsight Bias
People overestimate their ability to predict outcomes after the fact
🎏 Law of Similarity
Users perceive a relationship between elements that look similar
🌓 Law of Prägnanz
Users interpret ambiguous images in a simpler and more complete form
🐘 Streisand Effect
When trying to censor information ends up increasing awareness of that information
🔦 Spotlight Effect
People tend to believe they are being noticed more than they really are
🗓 Fresh Start Effect
Users are more likely to take action if there's a feeling of new beginnings
⏰ 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
🚶♂️ Default Bias
Users tend not to change an established behavior
🏦 Investment Loops
When users invest themselves, they're more likely to come back
🕯 Loss Aversion
People prefer to avoid losses more than earning equivalent gains
👞 Commitment & Consistency
Users tend to be consistent with their previous actions
🏝 Sunk Cost Effect
Users are reluctant to pull out of something they're invested in.
🌋 Reactance
Users are less likely to adopt a behavior when they feel forced
🔨 Law of the Instrument
If all you have is a hammer, everything looks like a nail
🍭 Temptation Bundling
Hard tasks are less scary when coupled with something users desire
🎩 Dunning-Kruger Effect
People tend to overestimate their skills when they don't know much
🔍 Discoverability
The ease with which users can discover your features
🐍 Second-Order Effect
The consequences of the consequences of actions
🌛 Decision Fatigue
Making a lot of decisions lowers users' ability to make rational ones
🥽 Observer-Expectancy Effect
When researchers' biases influence the participants of an experiment
🌱 Weber's Law
Users adapt better to small incremental changes
🎈 Parkinson’s Law
The time required to complete a task will take as much time as allowed
🌤 Affect Heuristic
People's current emotions cloud and influence their judgment
📉 Hyperbolic Discounting
People tend to prioritize immediate benefits over bigger future gains
⌚️ Chronoception
People's perception of time is subjective
💳 Cashless Effect
People spend more when they can't actually see the money
🌚 Self-serving bias
People take credits for positive events and blame others if negative
🥬 Pareto Principle
Roughly 80% of the effects come from 20% of the causes
🔫 Backfire Effect
When people's convictions are challenged, their beliefs get stronger
🌈 False Consensus Effect
People overestimate how much other people agree with them
🚋 Bandwagon Effect
Users tend to adopt beliefs in proportion of others who have already done so
🧙♂️ Barnum-Forer Effect
When you believe generic personality descriptions apply specifically to you.
🛋 IKEA Effect
When user partially create something, they value it way more
🧚♂️ Planning Fallacy
People tend to underestimate how much time a task will take
💾 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
🎢 Peak-End Rule
People judge an experience by its peak and how it ends.
👅 Sensory Appeal
Users engage more with things appealing to multiple senses
🧩 Zeigarnik Effect
People remember incomplete tasks better than completed ones
🧤 Endowment Effect
Users value something more if they feel it's theirs
🛍 Chunking
People remember grouped information better
💚 Delighters
People remember more unexpected and playful pleasures
💛 Internal Trigger
When users are prompted to take action based on a memory
📸 Picture Superiority Effect
People remember pictures better than words
📌 Method of Loci
People remember things more when they're associated with a location
🧭 Shaping
Incrementally reinforcing actions to get closer to a target behavior
💾 Recognition Over Recall
It's easier to recognize things than recall them from memory
🏰 Storytelling Effect
People remember stories better than facts alone
👹 Negativity Bias
Users recall negative events more than positive ones
⏰ Availability Heuristic
Users favor recent and available information over past information
🌌 Spacing Effect
People learn more effectively when study sessions are spaced out
🏁 Serial Position Effect
It's easier for users to recall the first and last items of a list
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
📘 Super Thinking
The big book of mental models and cognitive biases (Gabriel Weinberg)
📙 Hooked
How to build habit-forming products (Nir Eyal)
📕 Influence
The psychology of persuasion (Robert Cialdini)
📔 Predictably Irrational
The hidden forces that shape our decisions (Dan Ariely)
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.
“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
Now It’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!
👥 Social Proof
Users adapt their behaviors based on what others do