Psychology and design of interactive systems

Notes

Study Notes

HCI Notes: Memory, Thinking, and Emotion

Cognitive Processes in HCI

Understanding Memory, Thinking, and Emotion to design effective interfaces.

1. Human Memory

Human memory is not a single store but a complex system categorized into three main stages based on duration and capacity. Understanding these stages is critical for determining how information should be presented.

Sensory Memory

  • **Duration:** Very brief (milliseconds).
  • **Capacity:** High (registers everything).
  • **Role:** Filters and holds sensory inputs until they are processed or decay.

Short-Term/Working Memory (STM/WM)

  • **Duration:** Seconds (around 15-30s).
  • **Capacity:** Limited. The classic figure is $7 \pm 2$ "chunks" of information.
  • **HCI Implication:** Interfaces should minimize information that must be recalled (e.g., provide labels, avoid long sequences).

Long-Term Memory (LTM)

  • **Duration:** Infinite.
  • **Capacity:** Essentially unlimited.
  • **Types:** **Episodic** (events) and **Semantic** (facts/concepts, crucial for understanding interface metaphors).

Memory Retrieval

Retrieving information from LTM is easier when the interface supports **recognition** over **recall**.

  • **Recall (Difficult):** Generating information from memory (e.g., typing a file path). Requires high cognitive load.
  • **Recognition (Easy):** Identifying information when presented (e.g., selecting a file from a list). This is why GUIs are generally preferred over CLIs.

2. Thinking and Problem Solving

Cognitive Processes

Cognition involves the mental processes that transform sensory input into meaningful action.

A. Decision Making & Problem Solving

Humans often use **Heuristics** (rules of thumb) rather than exhaustive **Algorithms** (guaranteed steps) to solve problems, especially under pressure.

  • **Goal-Based Action:** HCI designs follow the **Gulfs of Execution and Evaluation** (Norman), requiring the user's goals to be mapped successfully to system actions and vice versa.

B. Errors and Mistakes

Errors are inevitable. Interfaces must be designed to minimize their occurrence and mitigate their effects.

  • **Slips:** Errors resulting from automatic behavior (e.g., mis-typing a familiar command). Addressed by constraints and feedback.
  • **Mistakes:** Errors resulting from a faulty intention or incorrect understanding of the goal (e.g., saving a file incorrectly because the save dialog was confusing). Addressed by better conceptual models.

3. Emotion and Affect

Affective Computing

Emotion (Affect) significantly influences user experience, attention, and decision-making. Don Norman highlights three levels of emotional processing:

Visceral Level

**"First Impression."** Governs immediate aesthetic reactions (e.g., colors, typography, initial look and feel).

Behavioral Level

**"Usefulness/Usability."** Focused on the joy or frustration derived from task performance and efficiency.

Reflective Level

**"Meaning/Memory."** Concerned with self-image, cultural meaning, and the memory of the interaction (e.g., telling others about a product).

Designing for Emotion

  • **Pleasure & Engagement:** Emotional interfaces (e.g., adding sound effects, delightful micro-animations) can increase user tolerance for minor usability flaws.
  • **Frustration Management:** Good interface design uses appropriate feedback and non-judgmental error messages to prevent negative affective states.
  • **Trust:** Reflective design fosters long-term trust and loyalty.

Navigation

Human memory, T... Back to Module Text entry devi...