100 Things Every Designer Needs to Know About People

Picture this: You're scrolling through a website, and within seconds, you've decided whether to stay or leave. You can't quite put your finger on why, but something about the colors, the layout, or the way information is presented either draws you in or pushes you away. This split-second decision isn't random—it's the result of deeply ingrained psychological patterns that influence how we perceive, process, and interact with design.

Every day, designers make countless decisions about fonts, colors, layouts, and interactions. Yet many of these choices are made without understanding the psychological principles that determine their effectiveness. The gap between intuitive design and psychologically-informed design can mean the difference between a product that merely functions and one that truly resonates with users. By understanding the fundamental ways humans see, think, remember, and feel, designers can create experiences that not only look beautiful but also work harmoniously with our natural mental processes.

The human visual system is far more complex and fascinating than we often realize. What we think we see isn't actually what our eyes capture—it's what our brain constructs from incomplete information, filled with shortcuts, assumptions, and evolutionary adaptations that have kept our species alive for millennia.

Consider the remarkable discovery that your brain creates shapes that aren't actually there. When you look at the famous Kanizsa triangle—three pac-man shapes positioned strategically—your mind automatically fills in the gaps and sees a complete white triangle floating above the background. This isn't a flaw in your vision; it's your brain working efficiently, using past experiences and expectations to make sense of the world around you. This same principle applies every time someone visits your website or uses your app.

The process becomes even more intriguing when we examine peripheral vision. Research from Kansas State University revealed that we use our peripheral vision more than our central vision to understand what type of scene we're looking at. When participants viewed photographs with either the center or edges obscured, they could still identify a kitchen or living room when the peripheral information was intact, but struggled when only the center remained visible. This discovery revolutionizes how we think about screen layout and information hierarchy.

Your visual system also contains specialized neural pathways that bypass normal processing channels. The fusiform face area in your brain is dedicated solely to recognizing faces, allowing them to capture attention faster than any other visual element. This is why faces in design are so powerful—they tap into an ancient survival mechanism that automatically draws our focus and creates emotional connection.

Understanding these visual processing patterns means recognizing that people scan screens based on cultural reading patterns and past experiences, avoid looking at screen edges, and can miss significant changes if they're focused elsewhere. The implications for design are profound: place important information where the visual system naturally expects to find it, use faces strategically to guide attention, and remember that what people see is always a collaboration between your design and their brain's interpretation of it.

Every person carries an invisible library in their mind—mental models that represent how they believe the world works. These internal frameworks, built from past experiences and cultural learning, determine how people approach new interfaces and predict what will happen when they interact with your design. The closer your design aligns with these existing mental models, the more intuitive and effortless the user experience becomes.

The concept of mental models emerged from cognitive science research showing that people don't start from scratch when encountering new systems. Instead, they immediately begin mapping new experiences onto familiar patterns. When someone first sees an iPad, they don't see a blank slate—they see something that might work like books they've read, computers they've used, or touch surfaces they've encountered. Their mental model begins forming before they even turn the device on.

Dr. Susan Carey's foundational research demonstrated how mental models shape our understanding: they represent our thought processes about how something works, built from incomplete facts, past experiences, and intuitive perceptions. These models aren't always accurate, but they powerfully influence what people pay attention to, how they approach problems, and what actions they expect to be possible. The designer's challenge is creating conceptual models—the actual interface people interact with—that harmonize with these mental expectations.

Consider how successful products leverage existing mental models. The desktop metaphor in computer interfaces worked because people already understood physical desktops with folders, files, and trash cans. Touch interfaces succeeded partly because humans naturally expect to manipulate objects by touching them. When there's a mismatch between mental models and interface design, people struggle, make errors, and often abandon the experience entirely.

The key to matching mental models lies in thorough user research and testing. You must understand not just who your users are demographically, but how they think about the domain you're designing for. What analogies do they use? What past experiences shape their expectations? By designing interfaces that feel familiar while introducing new capabilities gradually, you create experiences that feel both comfortable and empowering, allowing people to focus on their goals rather than figuring out how your system works.

Human attention is not a limitless resource waiting to be captured—it's a selective, fragile, and highly strategic system that has evolved to keep us alive in a world full of competing demands. Understanding how attention works, and what motivates people to sustain it, is crucial for creating designs that not only grab notice but maintain engagement over time.

The attention system operates on multiple levels simultaneously. At the unconscious level, our brains constantly scan for danger, food, sex, movement, faces, and stories—the elements that historically determined survival and reproduction. This is why these elements still command attention in modern interfaces. A photo of a person looking directly at the viewer will capture attention faster than abstract graphics, and movement or blinking elements will pull focus even when people are trying to concentrate elsewhere.

Research by psychologist John Darley demonstrated how powerfully context affects attention and motivation. In his famous "Good Samaritan" study, seminary students preparing talks on helping others were given different time pressures to reach their destination. When told they were running late, only 10 percent stopped to help a person in distress, compared to 63 percent who stopped when they had plenty of time. The lesson for designers is profound: people's mental state and perceived time pressure dramatically affect what they notice and how they behave.

Sustained attention follows predictable patterns, typically lasting only seven to ten minutes before beginning to wane. This creates opportunities for strategic intervention—introducing novel elements, providing breaks, or transitioning to new phases of an experience. The goal-gradient effect shows that people become more motivated as they approach completion, suggesting that progress indicators and milestone celebrations can maintain engagement even through challenging tasks.

The most sophisticated understanding of motivation comes from recognizing that people are driven more by intrinsic rewards than external ones. Research by Mark Lepper revealed that children who expected rewards for drawing spent less time drawing when rewards weren't present, while those who received unexpected rewards maintained their intrinsic interest. This suggests that the best designed experiences provide inherent satisfaction—through mastery, autonomy, progress, and connection—rather than relying solely on external incentives to maintain engagement.

Humans are fundamentally social beings, and every interaction with a designed system carries the weight of social expectations and emotional responses. Even seemingly impersonal interfaces like government websites or software applications are processed by our brains as social interactions, complete with expectations about politeness, helpfulness, and trustworthiness.

The research of Robert Provine on laughter reveals the deeply social nature of human experience. Laughter occurs thirty times more often when people are with others than when alone, and it rarely follows jokes—instead, it follows mundane statements that serve to bond people together socially. This insight extends to digital experiences: people respond positively to interfaces that feel socially connected and emotionally intelligent, even when interacting with machines.

Elizabeth Sillence's research on health website trust uncovered a fascinating pattern: people make initial trust decisions based almost entirely on visual design factors like layout, color, and navigation. Eighty-three percent of comments about rejected websites focused on design elements, while credibility and content only mattered after a site passed the initial visual trust test. This means that building trust starts with visual design that signals competence and care, not just with accurate information.

The power of social validation cannot be overstated. When people are uncertain—which is often the case with new products or services—they look to others for guidance about what to do. Testimonials, ratings, reviews, and even simple indicators of what other people are choosing can dramatically influence behavior. The key is making these social cues feel authentic and relevant rather than manipulative.

Perhaps most importantly, emotional connection drives deeper engagement than rational argument alone. Research consistently shows that anecdotes and stories persuade more effectively than statistics and data, because stories activate empathy and emotional processing alongside logical analysis. When people feel emotionally connected to a design—through beautiful visuals, compelling narratives, or experiences that acknowledge their feelings—they become more forgiving of minor flaws and more likely to recommend the experience to others.

The intersection of psychology and design reveals a profound truth: the most successful products and experiences aren't just aesthetically pleasing or functionally efficient—they work in harmony with the fundamental patterns of human perception, cognition, and emotion. By understanding how people see, think, remember, feel, and connect, designers gain the power to create experiences that feel effortless, engaging, and deeply satisfying.

The research presented throughout these insights demonstrates that good design is never just about following trends or personal preferences. It's about recognizing that every color choice affects mood, every layout decision influences comprehension, every interaction pattern either supports or fights against deeply ingrained mental models. As the authors remind us, "People will do a task rather than be idle, but the task has to be seen as worthwhile." This principle extends beyond individual tasks to entire design philosophies: people will engage with experiences that respect their psychology and reward their investment of attention and effort.

Take one concrete step today: choose a design you're currently working on and identify one psychological principle you can apply immediately. Whether it's using faces to direct attention, providing progress indicators to maintain motivation, or simplifying choices to prevent decision paralysis, begin incorporating these evidence-based insights into your design practice. The goal isn't to manipulate users, but to create experiences that work with human nature rather than against it, ultimately serving people better while achieving your design objectives.