Definition: In HCI, psychology and design of interacting systems refers to the application of psychological principles—such as perception, memory, attention, learning, emotion, and human behavior—to the design of interfaces and technologies that people use.
It focuses on understanding how humans think, behave, and interact, and applying this knowledge to create systems that are usable, efficient, intuitive, and enjoyable.
In short:
Good system design depends on understanding how people work.
Humans are not machines. They have limited memory, selective attention, emotions, biases, and variations in abilities. Psychology helps designers create systems that fit these human characteristics.
Without psychological principles, systems may be
Understanding how users see, hear, and interpret information.
Design implications:
Users can only focus on limited things at once.
Design implications:
Users have limited short-term memory (7 ± 2 items).
Design implications:
People learn systems through repetition, patterns, and feedback.
Design implications:
Definition: A mental model is the user’s internal understanding of how a system works.
If the system matches the user’s mental model:
Design implication:
User emotions influence satisfaction, performance, and engagement.
Design implications:
People vary by:
Design implications:
Definition: Clues that indicate how something should be used. Example: a button that looks “pressable.”
Definition: The system’s response to user actions. Example: clicking sound, animation, message.
Good feedback reduces confusion.
Definition: Design limits that prevent incorrect actions. Example: grayed-out menu options.
Definition: Important functions should be easy to find. “Out of sight = out of mind.”
Consistent controls and layouts help learning and reduce cognitive load.
Definition: The relationship between controls and their effects. Example: volume slider → up increases, down decreases.
| Concept | Definition | Role in Design |
|---|---|---|
| Perception | How users interpret sensory information | Create clear visuals and sound cues |
| Attention | Limited focus capacity | Reduce clutter; highlight important elements |
| Memory | Storing and recalling info | Minimize cognitive load; use recognition |
| Learning | Process of acquiring skills | Consistency, feedback, tutorials |
| Mental Models | User’s understanding of system | Match design to user expectations |
| Emotion | Feelings affecting behavior | Make interfaces pleasant and motivating |
| Individual Differences | Variation in users | Design accessible and adaptable systems |
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