Perception, Attention, and Memory in Interface Design

Interface performance depends on perceptual processing, attentional allocation, and memory limits of human users (George, 2025).

Sequential processing approximation

A useful approximation of response latency:

with perceptual, cognitive, and motor components.

Typical nominal values ($\approx100\,\mathrm{ms}$, $70\,\mathrm{ms}$, $70\,\mathrm{ms}$) imply a lower-bound reaction time near $240\,\mathrm{ms}$ for simple tasks, which helps explain the response-time thresholds summarized in speed of interactions.

Attention constraints

• top-down and bottom-up control interact,
• modality/resource overlap increases dual-task interference,
• working memory is capacity-limited and decay-prone.

These constraints directly affect error rate, completion time, and subjective workload.

Heuristic translation

Cognitive constraints motivate classic design heuristics:

• recognition over recall,
• consistent mappings,
• explicit state visibility,
• strong error prevention.

The objective is to externalize memory load into interface structure; at the UI level, decision cost and movement cost therefore need to be reasoned about together via Hick’s law and Fitts’s law.

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