Design interaction around user-reasonable objects.
Structure the interface according to objects users can reason about.
Contents 3. Interaction Mechanics & Agency 1. Human-Interface Objects
What users act upon.
First, ask yourself
“Are all interactive objects in your system clearly defined, stable, and understandable?”
Mission statement
Ensure users can act on interface elements by making objects identifiable and operable.
Key heuristics Human-Interface Objects
- Interaction must be organized around objects users can reason about.
- Exposed objects must align with user understanding, not internal storage models.
- Each object must maintain a clear and singular conceptual identity.
- Meaningful objects must be visible or inspectable in interaction.
- Available actions must correspond to the object’s conceptual type.
- Distinct behaviors must be represented by distinct objects.
- Interaction patterns must consistently reinforce what an object represents.
- Established object behavior must remain stable over time.
Executive brief
The system must provide clear, stable human-interface objects that users can understand and act upon confidently.
Core questions Human-Interface Objects
“What objects does the system show? What does each mean?”
“Can users identify and understand each object clearly?”
Focus areas
Mental-model first
“What can users point to and recognize as a distinct ‘thing’?”
“What entities does the interface teach users to think with?”
Action-sensitive
“What actions belong to this object alone?”
“What changes when the user acts on it?”
Error-prevention
“Could objects be confused with one another?”
“Does any object behave inconsistently or ambiguously?”
AI-aware
“Is the object acting, or just being acted upon?”
“Does it suggest intelligence or agency it does not have?”
UX directives Human-Interface Objects
Model objects for user reasoning, not system storage.
Expose conceptual objects that align with user understanding rather than internal data structures.
Ensure each object has a clear and stable identity.
Do not assign multiple conflicting meanings to a single object.
Make meaningful objects visible or inspectable.
Avoid invisible entities in core interactions.
Align actions with object type.
Ensure available actions are consistent with the object’s conceptual identity.
Separate objects when behavior diverges.
Do not overload one object with incompatible interaction rules.
Ensure behavior reinforces object identity.
Use consistent interaction patterns to teach what an object represents.
Maintain predictable object behavior over time.
Do not alter interaction rules for established objects.
Executive summary
- Human-Interface Objects are conceptual entities for user reasoning, not reflections of internal data structures.
- They define what the user can act upon and how the system is understood.
- The system must model objects according to user-reasonable concepts, not storage logic.
- Each object must have a clear, stable identity with actions consistent with its type.
- Object visibility and inspectability are prerequisites of correct interaction.
- Human-Interface Objects succeed when behavior consistently reinforces what an object is and what can be done with it.
Success indicators
- Interface objects represent things users can easily understand.
- Each object has a clear and stable identity.
- Important objects are visible or easy to inspect.
- Available actions match what the object represents.
- Objects behave consistently across the system.
One-line summary
Before users can act with confidence, they must know what they are acting on.