Laws of UX: Using Psychology to Design Better Products & Services

Résumé de Laws of UX

1. 1

   When Design Meets Mind: The Invisible Forces Shaping Your Digital Life

   

   00:00

   00:00

   Have you ever wondered why scrolling through Instagram feels effortless while navigating your bank's website feels like solving a puzzle? The difference isn't random-it's psychology at work. Every tap, swipe, and click you make has been shaped by principles rooted in how your brain processes information. What began as Jon Yablonski's personal reference during a tough design project transformed into a framework now used by tech giants worldwide. The brilliance lies in translating abstract psychological concepts into tangible design rules, creating digital experiences that feel less like using technology and more like natural extensions of thought itself. Picture walking into a friend's new apartment. Without asking, you know where to look for light switches, how doors open, and where the kitchen probably is. This isn't psychic ability-it's your brain using mental shortcuts built from thousands of previous experiences. Digital interfaces work the same way. When you visit a website, you expect the logo in the top left, navigation at the top, and contact details at the bottom. This expectation is Jakob's Law: users prefer your site to work like all the others they already know. This principle recognizes something profound about human cognition-we develop mental models based on cumulative experiences and apply them to everything new we encounter. When designs violate these models, chaos ensues. Remember Snapchat's 2018 redesign disaster? Over 1.2 million people signed a petition demanding the old version back because the changes shattered their mental models. Contrast that with Google's approach: gradual transitions, optional previews, letting users adjust at their own pace. Even physical products leverage this-Mercedes-Benz shapes their seat controls like actual seats, creating intuitive connections between what you touch and what moves. The lesson isn't about creating identical products but respecting that people learn new things through the lens of what they already understand.

2. 2

   The Physical Laws of Digital Interaction

   Commencer l'écoute

   Ever missed a tiny button on your phone? That's Fitts's Law-a 1954 principle stating that selection time depends on target size and distance. This manifests everywhere: form labels that expand clickable areas, submit buttons placed near the last input field, navigation items spaced generously apart. Tesla's Model 3 dashboard exemplifies this-ample spacing between controls prevents accidental taps while driving. Research reveals people prefer the center of smartphone screens where accuracy peaks, not the upper left where desktop users typically start. Mobile interfaces are particularly vulnerable because limited screen space tempts designers to cram everything together. The solution isn't cramming-it's making interactive elements sufficiently large, properly spaced, and positioned where fingers naturally rest. Our digital experiences remain fundamentally physical, governed by the same laws of motion and distance that govern everything else we touch.

3. 3

   When Abundance Becomes Paralysis and the Art of Reduction

   Commencer l'écoute

   Stare at a restaurant menu with 200 items and watch yourself freeze. This is Hick's Law: decision time increases logarithmically with choice quantity and complexity. William Edmund Hick and Ray Hyman discovered in 1952 that each additional option adds disproportionate mental burden. Your brain has limited RAM-when information exceeds working memory capacity, you struggle and often abandon tasks entirely. TV remotes exemplify this perfectly. As features multiplied, remotes became Byzantine nightmares until "grandparent-friendly" versions emerged-people literally taped off unused buttons. Modern smart remotes now hide complexity in on-screen menus instead. Google Search demonstrates this brilliantly-filtering options appear only after initial results. Slack's onboarding hides everything except messaging initially, progressively revealing features as you gain confidence. Yet oversimplification creates problems too. Icons rarely mean the same thing across products. Adding text labels provides clarity without sacrificing elegance. The art of reduction-eliminating elements that don't serve user goals-becomes critical. The less users must think about reaching their goals, the more likely they'll actually get there.

4. Chapitre 4

   The Magic Number That Isn't Magic: Understanding Memory and Chunking

   George Miller's 1956 observation that young adults remember about seven items in short-term memory became design's most misunderstood concept. The real revelation wasn't the number-it was chunking, our ability to group familiar units into collections. Seven words stick in memory as easily as seven letters because we process them as single chunks. Phone numbers demonstrate this: 123-456-7890 versus 1234567890. The first version chunks information into digestible groups, dramatically improving recall. In content design, chunking transforms text walls into scannable sections through headings, bullets, and paragraph breaks. Bloomberg chunks market data into distinct modules. Amazon separates specifications, pricing, and reviews. Yet Miller's law gets misinterpreted as a strict seven-item interface limit, ignoring that visible information doesn't require memorization. Apple and Microsoft successfully implement extensive menus through careful categorization, proving well-organized information can exceed seven items while remaining user-friendly.

   Chapitre 5

   Flexibility in a Rigid World: Building Resilient Systems

   Jon Postel's internet protocol principle-"Be conservative in what you do, be liberal in what you accept from others"-means systems should strictly conform when sending data but graciously accept nonconformant input when receiving. This fault tolerance helped the early internet thrive and influenced how HTML and CSS handle errors loosely rather than catastrophically. Apple's Face ID exemplifies this by eliminating manual authentication entirely, handling complexity invisibly. Responsive web design embodies this philosophy by creating websites that fluidly adapt to any screen. Progressive enhancement ensures basic content accessibility while adding features as capabilities allow. Design resiliency acknowledges that user input varies wildly-English text can expand 300% when translated to Italian, and customizable font sizes improve accessibility but break poorly designed layouts. Amazon demonstrates resilience by intelligently reorganizing navigation as font size increases, prioritizing important links while removing less critical ones. Postel's law bridges the human-machine gap by creating systems that liberally accept variable human input while translating it into structured output, shifting burden away from users.

   Chapitre 6

   Why Endings Matter More Than Middles: The Peak-End Rule

   Your vacation memories focus on the best moment and final day, not every experience. This is the Peak-End Rule-people judge experiences by emotional peaks and conclusions. Daniel Kahneman's 1993 study showed participants preferred longer uncomfortable experiences when they ended less painfully. Mailchimp applies this by enhancing emotionally charged moments. When sending campaigns, their mascot Freddie nervously hovers over the button with animated sweat, then offers a congratulatory high-five. Uber redesigned Express POOL wait times using animations to reduce idleness aversion and show progress. Product failures-outages, vulnerabilities, design oversights-create negative peaks but become opportunities when handled properly. The common 404 error page represents a potential negative peak that companies transform through humor and brand personality, turning frustration into positive interaction. Users judge experiences not on complete duration but on peak emotional moments and endings-these critical moments determine whether users return or recommend your product.

   Chapitre 7

   Moving Forward: Design That Respects Humanity

   The psychological principles enabling intuitive products can also manipulate users. Techniques creating seamless experiences become addictive-intermittent rewards mimicking slot machines, infinite loops maximizing screen time, social affirmation delivering dopamine hits, dark patterns tricking users into unintended actions. Research reveals disturbing effects: smartphones reduce cognitive capacity even when off, social media correlates with increased depression, adolescent suicide rates are rising. Unintended consequences abound-Facebook's "like" button becoming addictive, Snapchat's filters driving cosmetic surgery demand, disappearing videos enabling harassment. Designers must support users' goals and well-being rather than exploit vulnerabilities for profit. Building ethical products requires integrating ethics into design-consider edge cases and vulnerable users first, diversify teams to avoid blind spots, look beyond quantitative data to understand why people use products. These principles aren't just tools for intuitive interfaces-they're responsibilities. Use them to build experiences that respect human psychology, enhance capabilities, and serve the people who depend on them. Great design isn't just about making things work better-it's about making life better.

   Continuer la lecture