Free, 9 biases, sorted by who has them
Cognitive biases in UX
Most lists of biases are alphabetical. This one is sorted by who has the bias, because that decides what you do about it. Your own biases you check with research. Your users’ biases you design with, and the only question is whether you do it in their interest.
New to the idea? Start with Types of Cognitive Bias for UX Designers and Marketers.
Part 1 Biases in your own judgement
These bend the research and the decisions before anything ships. You cannot switch them off, but you can check for them, and that checking is most of what user research is for.
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Confirmation bias
You notice the interview quote that agrees with you and skim past the three that do not.
Practise it: Lesson 3, turning assumptions into questions you can test.
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False consensus effect
You assume users think the way you do, so the persona ends up describing you.
Practise it: Lesson 4, building a persona from real behaviour instead of your own habits.
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Selection bias
Your data only holds the people who stayed long enough to be counted, and it reads as everyone.
Practise it: Lesson 6, checking who your data leaves out before you trust it.
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Bandwagon effect
A pattern gets chosen because every competitor uses it, not because your users need it.
Practise it: Lesson 2, moving design decisions from opinion to evidence.
Part 2 Biases in the people using your product
These shape how people read a screen and make a choice. Design works with them whether it means to or not, so the question is whether it does so in the user’s interest.
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Anchoring bias
The first number a person sees sets the scale for every number after it, which is why pricing pages lead with the big plan.
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Framing effect
The same fact, put as a gain or as a loss, gets a different answer.
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Conformity bias
People follow what others around them appear to do, so "most teams choose this" moves more clicks than a feature list.
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Aesthetic-usability effect
Attractive screens are judged easier to use, and forgiven for problems a plain one would be blamed for.
Practise it: Lesson 2, letting aesthetics support user goals instead of overriding them.
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Cognitive dissonance
Holding two conflicting beliefs is uncomfortable, and people change a belief or a choice to end the discomfort.
Practise the first part
Knowing a bias exists does not stop it. Checking for it does. The free UX Foundation Course is six short lessons, and four of them are where these checks happen: evidence over opinion, testable assumptions, personas from real behaviour, and data that shows who it leaves out.
Start lesson 1Frequently asked questions
What is a cognitive bias in UX?
A cognitive bias is a predictable shortcut in how people judge and decide. In UX it matters twice: designers carry biases into their research and decisions, and users carry biases into how they read a screen and make a choice.
Which cognitive biases matter most for UX research?
Confirmation bias, the false consensus effect and selection bias. They make research agree with what you already believed, make the persona describe you, and make the people who answered look like everyone.
Is it ethical to design with cognitive biases?
It depends on whose interest it serves. Using anchoring to show a fair price in context helps people decide. Using it to make a bad deal look good is a dark pattern. The bias is the same; the intent is what differs.
Where can I practise avoiding these biases?
In the free UX Foundation Course. Lesson 3 turns assumptions into testable questions, lesson 4 builds a persona from real behaviour, and lesson 6 checks who your data leaves out.
Coming later
The advanced course
The six free lessons give you the foundations. The advanced course will go further, with more practice on real products. Leave your email and you will get one message when it opens. Nothing else.