10 principles
UX Psychology.
Design with human cognition.
Ten principles that explain why users behave the way they do — and how to design with human psychology, not against it.
Hick's Law
The time it takes to make a decision grows logarithmically with the number of choices available.
Fitts' Law
The time to acquire a target is a function of the distance to and size of the target.
Cognitive Load
The total amount of mental effort required to use and understand an interface at any moment.
Progressive Disclosure
Revealing information and options only when they are relevant to the user's current task.
Recognition vs Recall
Recognition (seeing an option and knowing it) requires less cognitive effort than recall (remembering from scratch).
Decision Fatigue
The degradation in quality of decisions after a user has made many choices in sequence.
Trust Signals
Design elements that increase user confidence in a product's reliability, security, and legitimacy.
Error Recovery
The design of pathways that help users understand, recover from, and prevent errors.
Empty States
The psychology of first-use moments and how designed empty states can drive user activation.
Onboarding Psychology
The psychological principles underlying successful user activation and habit formation.
Peak-End Rule
People judge an experience based almost entirely on its most intense moment and its final moment — not the average of all moments.
Serial Position Effect
People best remember items at the beginning and end of a sequence, and worst remember items in the middle.
Von Restorff Effect
An item that stands out from its peers is more memorable — also called the isolation effect.
Aesthetic-Usability Effect
Users perceive aesthetically pleasing designs as more usable and more trustworthy, even when they are not.
Zeigarnik Effect
People remember uncompleted or interrupted tasks better than completed ones — creating a cognitive pull to finish.
Anticipation
A preparatory motion or visual cue that signals what is about to happen, reducing surprise and making transitions feel intentional.
Feedback Loops
The psychological need for confirmation after actions — when a system does not acknowledge what the user did, anxiety fills the gap.
Motion as Emotion
The way animation speed, easing, and amplitude map directly to perceived brand personality — motion is a tone-of-voice decision, not a technical one.
Endowment Effect
People value things more once they feel ownership over them — UI that creates perceived ownership early increases engagement and reduces churn.