Interaction Design

Interaction design specifies the conversation between a person and an interactive system. The person forms an intent, notices an available action, acts, receives feedback, and interprets the result. The system moves from one state to another throughout that exchange. A screen layout matters, but the interaction also includes timing, language, input method, rules, errors, and recovery.

The central design object is behavior over time. A static mockup can show a button and a form. An interaction model states when the button is enabled, what happens after activation, how progress is communicated, what invalid input does, whether work can be undone, and what remains true after a failure.

The interaction loop

A useful interaction loop has six parts:

Intent: The person has a goal in a real context.
Opportunity: The interface makes a relevant action perceivable.
Action: The person uses a supported input method.
State change: The system accepts, rejects, or continues the operation.
Feedback: The interface communicates what happened in time to guide the next decision.
Interpretation: The person compares the result with the goal and continues, recovers, or stops.

Breaks can occur at every boundary. A control without a clear label hides the opportunity. A pointer-only gesture excludes keyboard use. Delayed or absent feedback makes a completed action look ignored. An error message that describes the system rather than the remedy prevents recovery.

Interaction Design

The interaction loop

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