🧠 Psychological Cognitive Biases & Principles That Affect Your UX

With every new technological advancement, new constraints and possibilities are introduced.
This article is a collection of best practices that designers can consider when building user interfaces.
Sharing meaningful experiences will provide more support for psychological knowledge and contribute to making the world a better place.
An understanding of psychology-specifically the psychology behind how users behave and interact with digital interfaces-is perhaps the single most valuable non-design skill a designer can have.
Every time users interact with your product, they are:

🙈 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.

🙈 Filter the information

	Name	One-Liner	Category
1	👀 Hick's Law	More options leads to harder decisions	Information
2	💼 Confirmation Bias	People look for evidence that confirms what they think	Information
3	👁 Priming	Previous stimuli influence users' decision	Information
4	🚛 Cognitive Load	Total amount of mental effort that is required to complete a task	Information
5	⚓️ Anchoring Bias	Users rely heavily on the first piece of information they see	Information
6	👉 Nudge	Subtle hints can affect users' decisions	Information
7	🍰 Progressive Disclosure	Users are less overwhelmed if they're exposed to complex features later	Information
8	🎯 Fitts's Law	Large and close elements are easier to interact with	Information
9	🐠 Attentional Bias	Users' thoughts filter what they pay attention to	Information
10	🤝 Empathy Gap	People underestimate how much emotions influence user behaviors	Information
11	⛵️ Visual Anchors	Elements used to guide users' eyes	Information
12	🌶 Von Restorff Effect	People notice items that stand out more	Information
13	🥇 Inverted Pyramid	Users prefer receiving the most important information first, followed by details	Information
14	🎖 Visual Hierarchy	The order in which people perceive what they see	Information
15	🔭 Selective Attention	People filter out things from their environment when in focus	Information
16	🕶 Banner Blindness	Users tune out the stuff they get repeatedly exposed to	Information
17	🍒 Juxtaposition	Elements that are close and similar are perceived as a single unit	Information
18	🚦 Signifiers	Elements that communicate what they will do	Information
19	🆚 Contrast	Users' attention is drawn to higher visual weights	Information
20	🚨 External Trigger	When the information on what to do next is within the prompt itself	Information
21	🕺 Decoy Effect	Create a new option that's easy to discard	Information
22	🎪 Centre-Stage Effect	People tend to choose the middle option in a set of items	Information
23	🖼 Framing	The way information is presented affects how users make decisions	Information
24	🍣 Law of Proximity	Elements close to each other are usually considered related	Information
25	🍬 Tesler's Law	If you simplify too much, you'll transfer some complexity to the users	Information
26	🧨 Spark Effect	Users are more likely to take action when the effort is small	Information
27	🥏 Feedback Loop	When users take action, feedback communicates what happened	Information
28	😻 Expectations Bias	People tend to be influenced by their own expectations	Information
29	🚆 Aesthetic-Usability Effect	People perceive designs with great aesthetics as easier to use	Information
30	✈️ Survivorship Bias	People neglect things that don't make it past a selection process	Information
31	⛰️ Interference Effect	When multiple pieces of information compete, it can hinder memory retention	Information
32	💡 Pygmalion Effect	Higher expectations lead to improved performance, while lower expectations result in poorer outcomes	Information
33	⬛️ common-fate	Users perceive elements that move in the same direction as being related or part of a group	Information
34	🔗 Uniform Connectedness	Users perceive elements that are visually connected as being more related than those that are not	Information
35	🎨 Figure-Ground	Users instinctively separate elements into the foreground (figure) and background (ground)	Information
36	➡️ Continuation	Users follow lines or patterns naturally, assuming they continue in a consistent direction	Information
37	🛤️ Desire Line	Users tend to follow the path of least resistance or the route that naturally aligns with their goals	Information

🔮 Seek the meaning of it

	Name	One-Liner	Category
1	👥 Social Proof	Users adapt their behaviors based on what others do	Meaning
2	🦄 Scarcity	People value things more when they're in limited supply	Meaning
3	💭 Curiosity Gap	Users have a desire to seek out missing information	Meaning
4	🖲 Mental Model	Users have a preconceived opinion of how things work	Meaning
5	🌟 Familiarity Bias	People prefer familiar experiences	Meaning
6	⚖️ Flexibility Tradeoffs	People often overestimate how much flexibility they can have without sacrificing consistency or efficiency	Meaning
7	👼 Halo Effect	People judge things (or people) based on their feelings towards one trait	Meaning
8	☎️ Miller's Law	Users can only keep 5±2 items in their working memory	Meaning
9	🍱 Unit Bias	One unit of something feels like the optimal amount	Meaning
10	🕹 Skeuomorphism	Users adapt more easily to things that look like real-world objects	Meaning
11	🤝 Singularity Effect	Users care disproportionately about an individual as compared to a group	Meaning
12	🎁 Reciprocity	People feel the need to reciprocate when they receive something	Meaning
13	👑 Authority Bias	Users attribute more importance to the opinion of an authority figure	Meaning
14	🏺 Pseudo-Set Framing	Tasks that are part of a group are more tempting to complete	Meaning
15	🎰 Variable Reward	People especially enjoy unexpected rewards	Meaning
16	🎊 Group Attractiveness Effect	Individual items seem more attractive when presented in a group	Meaning
17	🚰 Curse of Knowledge	Not realizing that people don't have the same level of knowledge	Meaning
18	🎉 Aha! moment	When new users first realize the value of your product	Meaning
19	📮 Self-Initiated Triggers	Users are more likely to interact with prompts they setup for themselves	Meaning
20	✏️ Survey Bias	Users tend to skew survey answers towards what's socially acceptable	Meaning
21	🎭 Cognitive Dissonance	It's painful to hold two opposing ideas in our mind	Meaning
22	🥅 Goal Gradient Effect	Motivation increases as users get closer to their goal	Meaning
23	💫 Feedforward	When users know what to expect before they take action	Meaning
24	🪒 Occam’s Razor	Simple solutions are often better than the more complex ones	Meaning
25	🎗 Noble Edge Effect	Users tend to prefer socially responsible companies	Meaning
26	🧿 Hawthorne Effect	Users change their behavior when they know they are being observed	Meaning
27	🏒 Hindsight Bias	People overestimate their ability to predict outcomes after the fact	Meaning
28	🎏 Law of Similarity	Users perceive a relationship between elements that look similar	Meaning
29	🌓 Law of Prägnanz	Users interpret ambiguous images in a simpler and more complete form	Meaning
30	🐘 Streisand Effect	When trying to censor information ends up increasing awareness of that information	Meaning
31	🔦 Spotlight Effect	People tend to believe they are being noticed more than they really are	Meaning
32	🌊 Flow State	Being fully immersed and focused on a task	Meaning
33	👁️ Mere Exposure Effect	Repeated exposure to something makes users more likely to develop a preference for it	Meaning

⏰ Act within a given time

	Name	One-Liner	Category
1	🗓 Fresh Start Effect	Users are more likely to take action if there's a feeling of new beginnings	Time
2	⚒️ Labor Illusion	People value things more when they see the work behind them	Time
3	⚖️ Default Bias	Users tend not to change an established behavior	Time
4	🏦 Investment Loops	When users invest themselves, they're more likely to come back	Time
5	🕯 Loss Aversion	People prefer to avoid losses more than earning equivalent gains	Time
6	👞 Commitment & Consistency	Users tend to be consistent with their previous actions	Time
7	🏝 Sunk Cost Effect	Users are reluctant to pull out of something they're invested in	Time
8	🌛 Decision Fatigue	Making a lot of decisions lowers users' ability to make rational ones	Time
9	🌋 Reactance	Users are less likely to adopt a behavior when they feel forced	Time
10	🥽 Observer-Expectancy Effect	When researchers' biases influence the participants of an experiment	Time
11	🌱 Weber's Law	Users adapt better to small incremental changes	Time
12	🔨 Law of the Instrument	If all you have is a hammer, everything looks like a nail	Time
13	🍭 Temptation Bundling	Hard tasks are less scary when coupled with something users desire	Time
14	🎈 Parkinson’s Law	The time required to complete a task will take as much time as allowed	Time
15	🎩 Dunning-Kruger Effect	People tend to overestimate their skills when they don't know much	Time
16	🌤 Affect Heuristic	People's current emotions cloud and influence their judgment	Time
17	📉 Hyperbolic Discounting	People tend to prioritize immediate benefits over bigger future gains	Time
18	💳 Cashless Effect	People spend more when they can't actually see the money	Time
19	⌚️ Chronoception	People's perception of time is subjective	Time
20	🌚 Self-serving bias	People take credit for positive events and blame others if negative	Time
21	🥬 Pareto Principle	Roughly 80% of the effects come from 20% of the causes	Time
22	🧠 Doherty Threshold	Users feel more engaged when system responses are under 400ms	Time

💾 Store bits of the interaction in their memories

	Name	One-Liner	Category
1	🔍 Discoverability	The ease with which users can discover your features	Memory
2	🔫 Backfire Effect	When people's convictions are challenged, their beliefs get stronger	Memory
3	🌈 False Consensus Effect	People overestimate how much other people agree with them	Memory
4	🚋 Bandwagon Effect	Users tend to adopt beliefs in proportion to others who have already done so	Memory
5	📝 Barnum Effect	When you believe generic personality descriptions apply specifically to you	Memory
6	🐍 Second-Order Effect	The consequences of the consequences of actions	Memory
7	🛋 IKEA Effect	When users partially create something, they value it way more	Memory
8	📅 Planning Fallacy	People tend to underestimate how much time a task will take	Memory
9	🏕 Provide Exit Points	Invite users to leave your app at the right moment	Memory
10	🎢 Peak-End Rule	People judge an experience by its peak and how it ends	Memory
11	👅 Sensory Appeal	Users engage more with things appealing to multiple senses	Memory
12	🧩 Zeigarnik Effect	People remember incomplete tasks better than completed ones	Memory
13	🧤 Endowment Effect	Users value something more if they feel it's theirs	Memory
14	🛍 Chunking	People remember grouped information better	Memory
15	📸 Picture Superiority Effect	People remember pictures better than words	Memory
16	📌 Method of Loci	People remember things more when they're associated with a location	Memory
17	🧭 Shaping	Incrementally reinforcing actions to get closer to a target behavior	Memory
18	💚 Delighters	People remember more unexpected and playful pleasures	Memory
19	💛 Internal Trigger	When users are prompted to take action based on a memory	Memory
20	💾 Recognition Over Recall	It's easier to recognize things than recall them from memory	Memory
21	🏰 Storytelling Effect	People remember stories better than facts alone	Memory
22	👹 Negativity Bias	Users recall negative events more than positive ones	Memory
23	⏰ Availability Heuristic	Users favor recent and available information over past information	Memory
24	🌌 Spacing Effect	People learn more effectively when study sessions are spaced out	Memory
25	🏁 Serial Position Effect	It's easier for users to recall the first and last items of a list	Memory

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