15 UX Principles that help you hijack people's brains

Hello, founders, product leads and designers! At North Coast Code, we’ve built web and mobile apps that users rave about, and the secret isn’t chasing trends—it’s mastering timeless UX principles rooted in human psychology. We see users as heroes on a journey, with your app as their guide to a seamless, engaging experience. Whether you’re launching a startup or refining a product, these 15 UX principles will help you avoid pitfalls and create interfaces that keep users hooked. Let’s dive into detailed, standalone explanations with real-world examples to bring each one to life.

1. Jacob’s Law: Stick to What Users Know

Users bring expectations from platforms like Amazon or Google, where familiar patterns—like a top-right cart icon—make navigation effortless. Deviate, such as hiding the search bar in a footer, and users get confused, leading to drop-offs. For example, e-commerce apps mimicking Amazon’s checkout flow reduce friction because users already know the drill. By aligning with these familiar standards, you boost retention and make adoption feel like second nature, keeping users engaged from the first tap.

2. Fitts’s Law: Make Taps Easy

The time to hit a target depends on its size and distance, so prioritize large, accessible buttons for key actions. Tiny or far-off elements frustrate users, especially on mobile where thumbs dominate. Uber’s oversized “Book Ride” button, centrally placed, makes tapping effortless, reducing errors. Design CTAs like form submits or nav icons to be thumb-friendly and reachable. This creates a fluid experience, encouraging repeated interactions and minimizing user frustration.

3. Hick’s Law: Keep Choices Simple

Too many options trigger analysis-paralysis, where users freeze or abandon the process due to decision overload. Guide them with curated choices or examples, like Netflix’s personalized content rows that simplify browsing instead of dumping an endless grid. In practice, streamline signup forms to essential fields or offer default selections to nudge decisions. Reducing cognitive load keeps users moving smoothly, increasing engagement and completion rates.

4. Miller’s Law: Chunk Information

Human short-term memory holds about 7 (plus or minus 2) items, so overloading interfaces causes confusion and disengagement. Break content into digestible chunks, like dashboards grouping sales, traffic, and engagement stats into small sets, similar to hyphenated phone numbers for easy recall. This clarity helps users process information without mental strain, enhancing navigation and comprehension for a more approachable UX.

5. Peak-End Rule: Shine at Peaks and Endings

Users judge experiences by their emotional peaks and how they end, not the entire journey. Create memorable highs, like a rewarding animation for completing a task, and end with a positive note, such as Airbnb’s cheerful “Booking Confirmed” screen. Smooth pain points, like clear error messages, to avoid lows. This approach builds lasting positive impressions, encouraging users to return and advocate for your app.

6. Von Restorff Effect: Highlight Key Actions

Distinct elements grab attention in a uniform design, so use contrast strategically for CTAs without cluttering the UI. A bold “Sign Up” button in a neutral palette stands out, but too many highlights create noise. Instagram’s story icons pop against feeds, guiding clicks effectively. Apply this to focus users on critical paths, improving usability and boosting conversions with clear, intentional design.

7. Pareto Principle: Prioritize the Vital Few

80% of your app’s value comes from 20% of its features, so focus on what delivers the most impact, like search and checkout in e-commerce apps. Todoist nails this by perfecting task management over adding secondary features. By auditing user data, you can prioritize core functionalities, delivering a lean, high-value product faster. This keeps development efficient and users satisfied with what matters most.

8. Serial Position Effect: Leverage Commitment

Users are more likely to share personal details after investing time in a process, driven by the sunk-cost fallacy—once they’re committed, they’re less likely to abandon. Booking.com lets users pick hotels and customize bookings before asking for payment info, ensuring they’re “in” before sensitive steps. E-stores do this by finalizing carts before checkout details. Position low-commitment steps early and save data requests for the end to reduce drop-offs and boost completions.

9. Law of Prägnanz: Simplify Visuals

Humans interpret complex visuals as their simplest form, so designs must minimize ambiguity to avoid confusion. Instead of intricate icons, use clear, universal symbols—like a minimalist “play” triangle for video controls in a streaming app, instantly recognizable across contexts. Slack’s clean channel layouts avoid visual clutter, letting users focus. Audit your UI to strip unnecessary details, creating an elegant, intuitive interface that reduces cognitive effort and feels professional.

10. Zeigarnik Effect: Nudge Completion

Incomplete tasks linger in users’ minds, driving them to finish for closure. Progress bars, like LinkedIn’s profile completion meter, subtly urge users to keep going by showing how close they are to done. In multi-step forms or onboarding, this creates urgency without pressure, turning partial engagements into completions. Use this to increase conversion rates in critical flows like signups or purchases.

11. Postel’s Law: Forgive Errors, Stay Sharp

Accept varied user inputs, like typos or formatting errors, but deliver polished outputs. Search bars that auto-correct misspellings or forms that validate emails flexibly, as Google does with queries, prevent frustration. This builds trust by accommodating real-world behavior while keeping results clean. Implement forgiving input systems in data entry to lower barriers and enhance user confidence.

12. Doherty Threshold: Keep It Snappy

Interactions slower than 400ms break user flow, causing impatience and drop-offs. Optimize for near-instant feedback, like Spotify’s real-time search that updates as you type. Test load times across devices, especially mobile, to maintain engagement. Fast UX keeps users immersed, reducing abandonment and ensuring a seamless experience that feels responsive and reliable.

13. Gestalt Continuity: Guide the Flow

People naturally follow aligned elements like lines or curves, so use these to direct attention smoothly. Apple’s onboarding screens with flowing transitions make navigation feel instinctive. Avoid abrupt layout shifts by maintaining visual paths in menus or wizards. This enhances usability in complex flows, like feeds or forms, guiding users effortlessly to their next step.

14. Mental Model Mapping: Match Real Life

Design interfaces that reflect how users understand the world to make interactions intuitive. Beyond simple icons like a trash bin for delete, consider e-commerce apps that mimic physical shopping with drag-and-drop carts, quantity sliders resembling weight, or folder-based file explorers that echo desktop organization. Note-taking apps like Notion, styled like physical notebooks with pages and tabs, reduce the learning curve by leveraging familiar mental models, ensuring users feel at home instantly.

15. Aesthetic-Usability Effect: Beauty Sparks Action

Visually appealing designs are perceived as more usable, tapping into emotions to drive engagement. Your app, website, or e-store should immerse users in a crafted fantasy where images, icons, fonts, colors, and animations—like Stripe’s sleek, animated checkout—create an emotional pull that motivates action over logic. Users want the experience first, then rationalize their choice later. A polished aesthetic, with cohesive visuals and subtle micro-interactions, builds trust and makes your app feel reliable, encouraging conversions and loyalty.

Ignoring these principles can tank your app’s success. You might drive traffic but see no conversions, suffer low click-through rates on ads, or watch sales demos fall flat due to clunky UX, confusing layouts, or uninspiring visuals. Poor design frustrates users, erodes trust, and sends them running to competitors. At North Coast Code, we’re your partner in diagnosing these issues—whether it’s sluggish performance, choice overload, or lackluster aesthetics—and crafting solutions that turn clicks into loyal users. Our team specializes in pixel-perfect, user-focused designs that align with these principles to maximize engagement and growth.

Got a UX challenge holding you back? We here in North Coast Code are in the business of designing, building, transforming apps - users can’t resist. Let’s build something unforgettable.

Posted by Mihkel, Founder at North Coast Code