What is 100 Things Every Designer Needs to Know About People about?

Susan Weinschenk is a behavioral scientist and UX consultant, and this book is her translation of cognitive science research into practical guidance for designers. The premise is direct: people behave in predictable ways because of how their perceptual and cognitive systems work, and designers who understand those systems make better decisions than designers who work from intuition alone. Each of the 100 entries is short — one to four pages — covering a specific finding from psychology or neuroscience with a "What to do with this information" section attached.

The topics are organized into thematic chapters: how people see, how people read, how people remember, how people think, how people focus, how people feel, how people decide, how people make mistakes, and how people behave socially. The coverage is broad enough to touch most areas that matter to visual and interaction designers, from the mechanics of pre-attentive processing (why certain visual attributes grab attention before conscious thought) to the cognitive load effects of different navigation architectures to the emotional influence of color and sound.

Some of the most consistently applicable chapters address attention and perception. Weinschenk explains why human vision is essentially peripheral, how motion captures attention regardless of other content, and how the Gestalt principles — proximity, similarity, closure, continuity — are not aesthetic preferences but descriptions of how the visual cortex groups elements. For designers who learned these principles as style rules, understanding the neural basis changes how to apply them: they are perceptual facts, not taste.

The memory chapters are similarly practically useful. Working memory holds roughly four items (not seven, as older models suggested), and chunking is the technique for managing that limitation. Prospective memory — remembering to do something in the future — is fragile and context-dependent, which has direct implications for reminder systems and notification design. Long-term memory is reconstructive, not reproductive, which is why users misremember interfaces differently from how they actually worked.

The book's limitations are real. The entries are deliberately short, which means nuance and conflicting evidence often get compressed. Some findings cited have not replicated well in subsequent meta-analyses. The "what to do" sections occasionally feel formulaic. But as an introductory survey of the psychological literature most relevant to design, it remains one of the better single-volume resources, and the brevity is a practical virtue for readers without time for full textbooks.