100 Things Every Designer Needs to Know About People

Why do people click, buy, read, and decide the way they do? And why do they often miss what’s right in front of them or make choices that seem irrational? In 100 Things Every Designer Needs to Know About People, psychologist Susan Weinschenk invites you into one fascinating truth: every design decision is about human behavior. Whether you’re creating a website, a medical device, or a marketing campaign, you’re working with—never around—the quirks, limits, and motivations of the human brain.

Weinschenk argues that design isn’t only about aesthetics or usability; it’s about psychology. Our eyes don’t see everything, our brains filter reality, we pay attention selectively, and we make most decisions unconsciously. Understanding these patterns lets designers build experiences that feel intuitive and irresistible because they align with how people actually perceive, think, and act—not how they should.

The Brain as a Biased Interpreter

If you assume people observe and process the world objectively, you’re doomed as a designer. Weinschenk cites studies such as the Invisible Gorilla experiment (Chabris & Simons, 2010), which proves how easily we miss obvious changes when our attention is fixed elsewhere. Our perception is constantly filtered by expectations, emotions, and biases. We literally construct the world we think we see. That’s why slight changes in color, location, or movement can dramatically alter meaning and response.

How We See, Read, and Remember

You don’t just design for the eye—you design for the brain behind the eye. Peripheral vision often decides what a webpage is about before the person consciously reads anything. Colors carry cultural meaning; patterns help the brain organize chaos. When reading, people recognize word shapes and anticipate upcoming letters. Memory, meanwhile, is maddeningly fragile. People remember only about four items at once (Nelson Cowan, 2001), reconstruct memories differently each time, and forget most information unless they use it immediately. Design that aids recall—through repetition, visual cues, chunking, and storytelling—aligns with how memory naturally works.

Attention and Emotion Drive Action

Attention is fleeting—about 10 minutes before it fades (Weinschenk notes this applies even in conversations and videos). Emotional cues like faces, stories, and movement hijack our focus because they tie directly to evolutionary survival mechanisms. Danger, food, sex, and faces all light up the old brain, which means your design should honor the fact that people follow instincts, not logic. Our old brain constantly asks, “Can I eat it? Can I have sex with it? Will it kill me?” Great design satisfies or safely simulates these primal needs.

Motivation, Reward, and Habit

Design succeeds when it taps into motivation cycles. Dopamine fuels the desire to seek—not satisfaction, but anticipation. Whether it’s refreshing email or chasing variable rewards in social media, unpredictable feedback loops keep users hooked. The key isn’t bribery with extrinsic rewards (money or badges), but nurturing intrinsic ones like mastery, autonomy, and connection. People are happiest when they feel progress toward a goal (the goal-gradient effect) and when they can act freely. It also takes about 66 days to form a habit, so repetition and small steps matter more than novelty.

Social and Emotional Design

Humans are social animals. Mirror neurons make us mimic others automatically, creating empathy and trust. Smiles, laughter, and shared rituals foster cooperation. Video works better than static photos because it captures real emotion. Even online, people apply social rules—they expect politeness, reciprocity, and recognition. Break those rules (ask for personal data too soon, for example), and you lose trust immediately. Pastoral scenes soothe our stressed brains, familiar brands comfort us when we’re anxious, and music or scent can activate dopamine and memory directly.

How People Decide (Mostly Unconsciously)

By the time your rational mind thinks it’s decided, your unconscious already has. We make decisions guided by fear of loss, social proof, reciprocity, and identity. Weinschenk’s examples—from lottery ratings to product reviews—show how quickly we defer to others when uncertain. More choices don’t mean more satisfaction; they often cause paralysis. And once we perceive a choice as control, we cling to it fiercely. Even false progress (like two stamps already filled on a coffee card) makes us chase completion faster.

Ultimately, Weinschenk’s book is a roadmap for designing with empathy and realism. It reminds you that humans aren’t malfunctioning computers but emotional, distracted, story-driven creatures. Design that acknowledges these 100 truths becomes not only beautiful—it becomes humane.

What you think people see isn’t always what their brains register. Weinschenk opens with illusions like the Kanizsa triangle, where your mind sees shapes that don’t exist. This simple test reveals the brain’s constant guessing game—it interprets fragments, fills gaps, and builds meaning where there may be none. As designer, you need to know: vision is an act of interpretation, not passive reception.

How Vision Takes Shortcuts

Our brains process millions of signals every second through rules of thumb learned over eons. The visual cortex breaks inputs into separate tracks—color, motion, shape, edges—and stitches them together using experience. We see triangles or rectangles in partial patterns because the brain loves order. Weinschenk’s discussion of how cones and rods handle light explains why night vision works better when we look slightly off-center, not straight ahead.

Faces Always Win Attention

Nancy Kanwisher’s discovery of the fusiform face area shows that faces get VIP processing. When a website includes a human face—especially one looking directly at you—your attention spikes, emotions engage, and trust deepens. A face gazing toward a product will make people look there too. The reason? The FFA and amygdala collaborate: one recognizes, the other feels. That’s why faces outperform objects in every attention competition. (Interestingly, people with autism use nonface pathways, which explains differences in perception.)

Peripheral Vision Matters More Than You Think

Peripheral vision doesn’t just notice movement—it defines context. Research by Adam Larson and Lester Loschky shows that people recognize scenes faster from peripheral cues than from central detail. This means layout edges—often ignored—set the emotional and semantic tone. A blinking ad or animation in a sidebar can hijack attention, even if users find it annoying. The takeaway: respect the periphery. It’s the compass the brain uses to understand where it is.

Designers should therefore control where people look, by leveraging proximity (group related items close together), patterns, and expected positions. What people perceive on-screen isn’t just the pixels—it’s the story their brain constructs in milliseconds from fragments, colors, and cues.

Memory feels dependable—you recall names, events, numbers—but research proves it’s astonishingly unreliable. Weinschenk dismantles this myth with examples like the flashbulb memories of 9/11 and the Challenger explosion. People swear by vivid details that later prove false. The reason: every time you remember something, you rewrite it.

Working Versus Long-Term Memory

The brain can juggle only three to four items at once. Working memory, managed by the prefrontal cortex, is tied to focused attention. Stress degrades it dramatically—fMRI scans show low activity under pressure (Lupien, 2007). That’s why multitasking ruins recall and why people forget information between screens or steps in a form. Long-term memory, by contrast, depends on repetition and schemas. Expert chess players remember more because they chunk information into familiar patterns—a technique anyone can borrow through organized design and repetition cues.

How Forgetting Protects Us

Ebbinghaus’s Forgetting Curve reveals that memory loss isn’t always bad—it’s selective housekeeping. Humans forget so we can function without overload. Designers should assume forgetfulness and build “memory aids”: visible instructions, persistent data, or confirmation messages. If it’s critical, don’t rely on recall—make information available when needed.

Why Sleep and Emotion Shape Memory

Rats dreaming in mazes led Matthew Wilson and Daoyun Ji to discover that dreaming consolidates memory. Humans do the same. Sleep reorganizes experiences, deciding what deserves storage. Emotional inputs—joy, fear, regret—also tag memories via the amygdala. This is why stories and sensory cues (like smell or music) dramatically enhance retention. The takeaway for designers and communicators: associate your content with emotion and rhythm; rhymes, melodies, and visual hooks trigger durable recall.

Design informed by cognitive psychology therefore acknowledges the limits: minimize cognitive load, chunk information, repeat key data, and use emotion and structure to make ideas stick.

Every day, 40 billion sensory signals strike your brain—but only about forty reach conscious awareness. Attention is a bottleneck and a filter, not an open gate. Weinschenk illustrates this by explaining selective attention, the cocktail party effect, and the famous gorilla video. If people focus on counting basketball passes, they miss the gorilla dancing across the screen. As a designer, that means what seems obvious to you might be invisible to your users.

Selective and Sustained Focus

Attention lasts about 7–10 minutes before it fades; longer exposure demands novelty or breaks. Instructions tightly tuned to a task help users filter distractions—but the unconscious still monitors threats, names, and social signals. Weinschenk notes that faces, movement, and stories dominate attention because they connect to primal survival instincts. Loud noises surprise us; danger cues trigger the reptilian brain’s “fight or flight.” Intriguingly, half conversations we overhear (“halfalogues”) consume more mental effort than full dialogues because unpredictability demands processing power.

The Myth of Multitasking

Eyal Ophir and Clifford Nass proved that “great multitaskers” are actually the worst at filtering distractions. Attention doesn’t divide—it toggles. Even walking while on a phone reduces awareness; Ira Hyman’s clown-on-a-unicycle study showed people missed obvious events. The implication for interface design is clear: avoid forcing multitasking. Simplify steps, reduce concurrent demands, and design forgiving error recovery.

Signal Detection and Saliency

Whether detecting planes on radar or errors on screens, perception relies on “signal detection theory.” Misses and false alarms carry different consequences, so signal strength should differ accordingly—bright colors for danger, subtle tones for routine info. Without clear saliency, users’ expectation models fail, as seen when airport screeners miss contraband they rarely encounter. Highlight what’s rare but critical.

Ultimately, attention isn’t something you control—it’s something you invite. Design that respects limited focus engages through emotion, clarity, and immediate relevance.

Design that ignores emotion fails. In Weinschenk’s section on feeling, she reveals the neurological and physical ties between mood and muscle, smell and memory, and even surprise and delight. Emotions aren’t side effects—they’re decision drivers.

Facial Feedback and Empathy

Research by Joshua Davis and David Havas showed that Botox dampens emotional experience: if you can’t frown, you can’t fully feel sadness. Muscle movement amplifies mood. On-screen design thus literally shapes emotion—small fonts cause squinting and frowning, reducing friendliness; smiling visuals promote happiness. Showing videos of smiling faces (activating mirror neurons) boosts positive association and engagement.

Smell and Multi-Sensory Branding

Smell bypasses rational filtering by traveling directly to the amygdala, evoking memories and emotions instantly. Hotels like Sheraton or Westin employ scent branding (fig and jasmine, white tea) to trigger comfort and loyalty. This direct emotional route underscores the power of sensory design—even digital products can benefit through metaphorical sensory triggers, imagery, and rhythm.

The Pleasure of Surprise

Gregory Berns’ fMRI studies show that unpredictability sparks dopamine release: we crave novelty because anticipation itself is exhilarating. A design that breaks patterns thoughtfully—through delightful microinteractions or discoveries—creates pleasure. But pleasant surprise differs from shock; Marina Belova’s research shows the brain processes positive and negative surprises separately in the amygdala.

Familiarity and Comfort

When sad or scared, people seek the familiar. Marieke De Vries found that mood dictates brand choice—fear pushes buyers toward known logos; happiness opens them to novelty. Design for emotion means matching tone to user state: familiar for stress, adventurous for joy.

Emotion connects physiology, expectation, and behavior. Designers influence feelings through every pixel, rhythm, and gesture—and in doing so, affect what people think and do.

Why do people click “refresh” endlessly or chase another level in a game? The answer lies in the interplay of dopamine, progress, and autonomy. Weinschenk synthesizes decades of behavioral research—from Skinner’s reinforcement schedules to Daniel Pink’s Drive—to explain how motivation truly works.

Dopamine and Variable Rewards

Dopamine isn’t a pleasure chemical—it’s a seeking chemical. It fuels curiosity and drives continual searching. Unpredictable rewards—like new notifications or tweets—stimulate dopamine far more than predictable ones. Skinner’s variable ratio reinforcement schedule (the slot machine principle) keeps us engaged. Break a habit loop by removing cues and unpredictability; build engagement by inserting them intentionally.

Intrinsic versus Extrinsic Rewards

Mark Lepper’s Good Drawing Certificate experiments show that expected rewards reduce motivation. When children drew for an unexpected reward, they kept drawing later; expected rewards killed joy. Daniel Pink connects this to modern work: algorithmic tasks respond to external incentives, but creative, heuristic tasks demand autonomy, mastery, and purpose. People crave progress and self-direction, not just prizes.

Progress and Mastery

Weinschenk illustrates progress visualization through examples like LinkedIn’s profile bar and Dropbox’s goal meters. Even illusionary progress (such as pre-stamped coffee cards) accelerates engagement. Mastery, like an asymptote, can never be fully reached but keeps us striving. Visual feedback loops sustain motivation far better than static success screens.

Autonomy and Habit Formation

Autonomy satisfies our primal need for control. Google’s App Inventor empowers users through self-service, invoking the old brain’s love of power over environment. Philippa Lally’s research reveals habits form in roughly 66 days through consistent repetition and small commitments—micro-steps that reshape identity and behavior.

Designing with these truths means blending intrinsic motivation, visible progress, and freedom. People are wired for mastery and autonomy—your job is to make their path to progress irresistible.

Every click, post, or purchase is social. Weinschenk shows that our brains synchronize with others, imitate gestures, and judge sincerity by facial micro-cues. Understanding how empathy and trust form online transforms sterile interfaces into human connections.

Mirror Neurons and Interaction

When you see someone smile, your premotor cortex fires as though you smiled. That neurological mirroring creates empathy and emotional resonance. Tanya Chartrand’s research proves people like you more when you subtly mimic their body language. In digital design, showing someone performing an action—clicking, learning, laughing—encourages viewers to do the same.

Social Media and the Brain

Fenna Krienen demonstrated that the medial prefrontal cortex activates for friends and family but not for strangers, explaining why Facebook feels personal while Twitter feels distant (Jonah Lehrer comments on this difference). Social tools work best when they mirror real-world kinship—intimacy breeds loyalty.

How People Judge Trust

Elizabeth Sillence’s research found that 83% of users dismiss health websites for poor design—long before reading content. Clean layout, color, and navigation determine trust faster than credentials. Once past that rejection stage, expert authority and relatable writing cement credibility. Trust shapes everything—Eric Weiner’s happiness studies even show national trust predicts well-being more than wealth.

Online Etiquette and Empathy

People expect websites to act like humans—responsive, polite, remembering past interactions. Asking for an email before delivering value feels socially rude, equivalent to demanding personal info on first meeting. Even laughter bonds people; Robert Provine showed how contagious and universal laughter creates instant social glue.

Design for the social brain by simulating eye contact, rhythm, reciprocity, and respect. The result? Interfaces people trust and relationships that persist.

Despite feeling rational, most decisions run on autopilot. Weinschenk’s final chapters merge neuroscience and behavioral economics to prove that the unconscious decides first. From impulse buys to moral choices, instincts dominate long before logic justifies them.

Unconscious Triggers

Antoine Bechara’s gambling experiment revealed participants’ skin conductance responses warned them of “bad decks” seconds before they consciously realized danger. The old brain spots threat or opportunity early. Similarly, consumers act on scarcity (“only 3 items left”) or reciprocity (“free gift”) before rationalizing the choice. You design for the gut, then support it with logic.

Choice Equals Control

Sheena Iyengar’s numerous experiments—from rats preferring branched paths to infants crying when control strings are removed—show people equate choice with autonomy. Removing options triggers frustration, even when fewer choices streamline success. Offer two paths, not one, and users feel empowered.

The Paradox of Too Much Choice

Iyengar and Lepper’s jam study proves that twenty-four options attract attention but kill conversion—only 3% purchased vs. 31% when six options were shown. Abundance paralyzes, because working memory can hold only about four choices. Limit options, or layer them progressively.

Social Validation and Influence

When people are uncertain, they follow others. Latane and Darley’s smoke-room experiment and Yi-Fen Chen’s review studies illustrate conformity: testimonials and ratings vastly influence online behavior. The “third-person effect” (John Bargh’s priming research) explains why we think others are influenced by ads but we’re not—self-deception preserves our illusion of control.

Feeling Over Thinking

Marieke De Vries found mood changes decision strategy—happy moods boost intuitive choices and perceived value; sad moods favor deliberation. Cassie Mogilner’s lemonade experiments show people value experiences invoked by “time” messaging over “money.” Emotion sets worth; logic follows.

If you design for unconscious decision-making, you design ethically and effectively: create positive emotional triggers, give choice without overload, and guide intuition toward meaningful outcomes.