Reading "User Experience. Design und Sustainability” & "Thinking-aloud in user interface design: A method promoting cognitive ergonomics.”

They follow Yablonski’s lead—design is not art. It’s behavior. And behavior is governed by laws.

Each law they present is grounded in human psychology, but filtered through a designer’s lens:

• Jakob’s Law (Familiarity): Users don’t want to learn your interface. They want to use it. The best design borrows from what’s already known—patterns, flows, mental models. Creativity isn’t about reinventing the wheel. It’s about making the ride smoother.
• Hick’s Law (Cognitive Load): Every new option adds weight. Don’t drown users in choices. Guide them. Highlight what matters. Simplify until it sings—but not until it’s silent.
• Tesler’s Law (Complexity): Some complexity can’t be removed—only shifted. Your job isn’t to eliminate it, but to absorb it on behalf of the user. Through defaults. Through smart grouping. Through gentle repetition.
• Postel’s Law (Flexibility): Be strict with output, generous with input. Anticipate mistakes. Forgive them. Interpret what the user meant, not just what they typed.
• Fitts’s Law (Precision): Big buttons win. Especially on touch. Don’t bury actions in pixel-tight clusters. Let people tap confidently. Design for thumbs—not mice.
• Miller’s Law (Memory): The brain can juggle ~7 items—on a good day. Chunk info. Group by relevance. Build hierarchies, not clutter.
• Peak-End Rule: What people remember? The peak and the ending. So design your product’s climax and exit as intentionally as its entry.
• von Restorff Effect: What stands out gets remembered. But don’t highlight everything. Use contrast sparingly. Make the right thing pop.
• Doherty Threshold: Interactions under 400ms keep users in flow. Go over that? Use loading animations, skeleton screens, micro-feedback. Perceived speed is emotional speed.
• Aesthetic–Usability Effect: Beautiful things feel easier. First impressions are split-second judgments. Style isn’t a luxury. It’s a cognitive shortcut.

Then comes the reminder: With power comes responsibility.

Design isn’t neutral. When you understand psychology, you wield influence. And that influence can manipulate just as easily as it can empower. So they call for ethical UX: respecting edge cases, diversity, motivations—not just metrics.

They close with a framework:

• Set clear principles.

• Link them to cognitive laws.

• Build rules that teams can apply.

  Not just vibes. Structure.