User Interface Elements -
Devices
- Input devices: user providing input to system
- Output devices: system providing output to user
User Interface Elements -
Interaction techniques
Interaction techniques translate inputs from input devices, and possibly context sensors, into changes in the user interface.
User Interface Elements -
Representations
Representations determine how data, events, objects and actions appear to the user.
e.g. design and appearance of icons/menus
User Interface Elements -
Organization
The broader set of principles that organize the data environment in the user interface.
Design objectives -
Usability
Qualities of the user interface that help users achieve their goals enjoyably and efficiently.
Design objectives -
Accessibility
Equivalent levels of usability across user groups
Design objectives -
Efficiency
The speed-accuracy trade-off: performance
Design objectives -
Learnability
- Easy to learn
- Time to become proficient
- How to allow optimal performance
Design objectives -
Consistency
- Internal: similar features and aspects of the interface are used in similar ways
- External: compliance with standards, guidelines, and expectations
Nielsen’s heuristics -
Visibility of system status
The current state of the system should be visible to the user
Nielsen’s heuristics -
Match between system and the real world
The user interface should follow the language and any relevant conventions that users are already aware of
Nielsen’s heuristics -
User control and freedom
Users should be encouraged to explore different ways to achieve their goals in the user interface
Nielsen’s heuristics -
Consistency and standards
External consistency (standards) and internal consistency (similar labels for similar features)
Nielsen’s heuristics -
Error prevention
The user interface should be designed to prevent errors
e.g. display warning and require user confirmation before triggering a non-reversible action
Nielsen’s heuristics -
Recognition rather than recall
It is more difficult for users to recall from memory how to trigger an action than to recognize a trigger mechanism on the display
Nielsen’s heuristics -
Flexibility and efficiency of use
Since users inevitably vary in their proficiency of a user interface, it is often effective to provide interface features that tailor to different users
Nielsen’s heuristics -
Aesthetic and minimalist design
Ensure that the user interface focuses on content and information essential towards achieving user’s primary goals
Nielsen’s heuristics -
Help and documentation
If documentation is required, ensure that it is focused on aiding users and it is easy to access and search
Interaction techniques -
Examples
- Bubble cursor
- Pie menus
- Marking menus
- Text entry (gestures)
Why is naming things in user interfaces challenging?
- Vocabulary problem: different people may have different names for the same action
- Polysemy: same word may have multiple meanings
- Context important in the naming of commands
Minimizing errors on GUI
- Preempting errors
- Reversing outcomes
- Explaining outcomes and confirming actions
Direct manipulation - Principles
- Continuous representations of the objects and actions of interest with meaningful visual metaphors
- Physical actions or presses of labeled buttons, instead of complex syntax
- Rapid, reversible, incremental actions whose effects are immediately visible
Direct manipulation -
Benefits
- Distances the mental effort required to translate goals into actions and then evaluate their effects
- Engagement is the locus of user control within the system
- Supports visual recognition
Reality-based interaction
Reality-based interaction is a framework that provides aims for building interactive technology that better exploits and supports our capabilities (using awareness and skills).
