So an interaction model, when well-defined, describes how a system is intended to function over time. It is comprised of the following elements:
- UX patterns: Repetitive structures and pathways that people will encounter and move through over and over again. Example: A news feed in Facebook would always scroll downward, containing endless objects that a user could act upon. This is important: A UX pattern describes where actions will take place, rarely a range of specific actions. That is reserved for…
- Feature clusters: The specific functionality that a system contains. The features should be organized in a manner that makes logical sense to the people who use it, and have a dynamic relationship with the UX patterns. Example: When using my Facebook news feed, I am able to act upon an object by commenting on it, liking it, sharing it, etc.
- System behaviour over time: The animation, transitions, and other ways that the system behaves in response to (or anticipating) user input. Example: I click on a field that says, “Write a comment…” in my news feed. It dynamically exposes a larger box with my photos, encouraging text input. If I click away, it snaps shut automatically.
- UX principles: A set of guidelines tailored by the designer that governs the elements above. Violating the UX principles can causes all the other elements to suffer in both usability and desirability for end users. Example: I’d imagine that Facebook wants the minimum number of interactions or clicks possible from scrolling a news feed to interacting with content—one or two at most. Any new functionality must try to preserve this principle.
David Sherwin: The metaphor of the system, Part 2