Why users click, scroll, and abandon. The psychology behind every decision.
Why do users click, scroll, and abandon? The answers lie in cognitive psychology. This part reveals the mental models and decision-making patterns behind every user action—from attention and memory limits to perception biases. Master these 27 principles and you'll predict user behavior before you design, not after you ship.
Key Concepts:
Key Concepts:
How these principles validate your work—whether you use Figma, Cursor, or V0
Stop defending designs with "it feels right." When a stakeholder challenges your layout, reference Miller's Law on cognitive load. When explaining navigation depth, cite Hick's Law. These 27 principles give you peer-reviewed ammunition for every design review.
Bad UX decisions become expensive technical debt. Understanding why users abandon forms or miss CTAs helps you push back on specs that will fail. Build interfaces that align with how brains actually work—not how PMs assume they work.
"Users don't like it" isn't actionable feedback. These principles translate vague complaints into specific fixes: "Users abandon because choice overload triggers decision paralysis (Hick's Law)." Turn opinion battles into evidence-based roadmap decisions.
32 principles organized into 2 chapters
17 principles
10 principles
Validation paths tailored for different experience levels
From Subjective to Scientific
Start with Chunking and Cognitive Load —you'll use these in every project. Then tackle Gestalt principles to understand why some layouts "just work." Within a week, you'll spot cognitive violations in every app you use.
From Guesswork to Guidelines
You know the basics work; now learn why. Study the research citations behind each principle so you can defend decisions in stakeholder meetings. Focus on behavioral psychology—understanding decision paralysis and flow states separates good designers from great ones.
From Features to Outcomes
Combine principles strategically. When Hick's Law conflicts with Fitts's Law, which wins? Learn to balance competing cognitive demands and predict where principles intersect. Use this knowledge to mentor juniors and lead design reviews.
Validate your AI output with these principles in your daily workflow
Apply these principles to fix your highest-friction screens today:
Build these into your design system and review process:
Apply what you learned with these exercises
Identify where your interface overwhelms users with too much information at once
Break down a complex form into logical groups and measure completion rates
Document which visual grouping principles your current design uses (or violates)
Predict where users look first on your key pages, then validate with testing
Ask 5 users how they expect your navigation to work—compare to reality
Recommended knowledge before starting
This is the foundational part. No prior experience needed to begin.