Cognitive Load

Cognitive load is the mental effort required to use your interface. When load exceeds capacity, users make mistakes, give up, or leave. Your job is to reduce unnecessary complexity while supporting users through necessary complexity.

Three types of load

Intrinsic load

The inherent complexity of the task itself. Filing taxes is complex. Creating a budget is moderately complex. Clicking a button is simple. You can’t eliminate intrinsic load — it’s part of what users came to do.

Extraneous load

Unnecessary complexity added by poor design. Confusing navigation, unclear labels, inconsistent patterns, hidden options — all of this is avoidable. Reducing extraneous load is the primary goal of good UX.

Germane load

Mental effort that helps users learn and build understanding. Well-designed onboarding, clear mental models, and meaningful feedback create germane load. This is the “good” kind of cognitive work.

Reducing extraneous load

Simplify

Remove unnecessary steps
Eliminate rarely-used options
Provide sensible defaults
Auto-detect what you can (location, language, device)

Chunk information

Break content into digestible pieces. Long forms become multi-step wizards. Dense text becomes scannable sections with headings. Long lists become grouped categories.

Progressive disclosure

Show only what’s needed for the current step. Advanced options hide behind “More settings.” Details expand on demand. Don’t front-load complexity.

Consistency

Use the same patterns throughout:

Same terminology for same concepts
Same placement for same functions
Same visual treatment for same element types

When everything works the same way, users transfer learning automatically.

Visual clarity

Clear hierarchy guides attention
Whitespace creates breathing room
Meaningful grouping shows relationships
Contrast distinguishes interactive from static

Supporting intrinsic load

When tasks are genuinely complex, help users through them:

Examples and templates

Show users what success looks like. Pre-filled examples, templates, and wizards reduce the “blank page” problem.

Preview and confirmation

Let users see the result before committing. “You’re about to send this to 47 people” is clearer than “Send.”

Inline help

Put help text where users need it — next to the relevant field or action, not in a separate help section they won’t find.

Clear error recovery

When users make mistakes, explain what went wrong and how to fix it. Don’t just say “Error” — say “Email address must include @”.

Measuring cognitive load

Task completion time: Longer = higher load
Error rates: More errors = higher load
Abandonment: People leave when overwhelmed
User feedback: “This is confusing” = high extraneous load

Recent Research (2024-2025)

Interface Optimization Based on Cognitive Load Theory

Research from 2024 demonstrates that optimization methods based on cognitive load theory can effectively reduce operators’ cognitive load and improve operation efficiency. Research on Information Interaction Interface Optimization Based on Cognitive Load shows strategic management of intrinsic, extraneous, and germane cognitive load in information services interfaces.

Mobile Applications and Elderly Users

A 2024 study using eye movement tests and subjective evaluation scales found that visual complexity of mobile news client interfaces significantly impacts cognitive load of elderly users. Research on the Influence of Interface Visual Design Features of Mobile News on Cognitive Load emphasizes the importance of reducing visual clutter for aging populations.

Serious Games and Interface Complexity

Recent research reveals that complex interfaces in serious games may impose additional cognitive load beyond the game mechanics themselves. A 2025 study on interface and load in MCI (Mild Cognitive Impairment) found that benefits depend on interface optimization that balances engagement with cognitive sustainability.

Measurement Methods

Studies suggest combining subjective assessments (like NASA-TLX) with objective physiological measurements including electrodermal activity, heart rate variability, electroencephalography, and electrocardiography. Research on mobile learning applications developed new subjective instruments specifically for measuring extraneous cognitive load caused by UI design.

Studies on multi-modal gaze and gesture interfaces found they can deliberately enhance cognitive load, indicating that exaggerated design is not recommended in educational systems and accessibility contexts.

These studies emphasize user-centered design approaches that minimize extraneous cognitive load through visual hierarchy, consistent design patterns, and adaptive interfaces tailored to specific user populations.

References

Foundational Work:

Sweller (1988) — Cognitive load during problem solving: https://doi.org/10.1016/0959-4752(88)90004-4
Mayer (2009) — Multimedia Learning (cognitive load in learning): https://www.cambridge.org/core/books/multimedia-learning/A74FCED632DD219B3F00487AA45F7ADB

Practical Resources:

NN/g — Minimize Cognitive Load: https://www.nngroup.com/articles/minimize-cognitive-load/