Interaction Design, Prototyping, and Cognitive Ergonomics
How people perceive and act
Interaction design beyond visual layout
Interaction design focuses on the sequence of actions, feedback, constraints, and recoveries that shape a user's experience. Advanced interface work considers attention, memory, motor control, error prevention, and the cost of decision-making.
Human-factors concepts
Prototype to learn
A prototype is not a miniature finished product; it is a question made tangible.
Low vs. high-fidelity prototyping
Low-fidelity
- Fast and cheap
- Great for structure and flow
- Useful early in exploration
High-fidelity
- Closer to real implementation
- Useful for micro-interactions and realism
- Higher cost and more commitment
Which design principle most directly reduces cognitive load?
Chunking and reducing decision overhead help users process information more easily.
Correct answer: Chunking information and limiting unnecessary decisions
Why is feedback important in interaction design?
Feedback reduces uncertainty and prevents repeated or conflicting actions.
Correct answer: It tells users that the system received their action and helps them understand the resulting state.
Interaction patterns and behavioral flow
A prototyping workflow for complex interactions
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Step 1: Define the user goal and state transitions.
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Step 2: Sketch the interaction flow and edge cases.
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Step 3: Prototype the highest-risk interactions first.
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Step 4: Test with realistic tasks and capture failure modes.
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Step 5: Iterate on timing, feedback, and recoverability.
What is the main advantage of testing edge cases in prototypes?
Edge-case testing surfaces risky interaction breakdowns early.
Correct answer: It reveals failure modes before implementation is expensive
What is one reason high-fidelity prototypes are useful late in design?
High fidelity better approximates the final experience.
Correct answer: They let teams evaluate realism, motion, copy, and micro-interactions more accurately.