Cognitive Load & Usability

The extent to which a system places a load on working memory has a decisive influence on its usability. Cognitive Load Theory provides a useful framework model for this.

Definition: Cognitive Load & Usability

Cognitive load describes the mental effort required to process information and perform tasks - especially in working memory.

Three Types of Cognitive Load

The Cognitive Load Theory (CLT) according to Sweller distinguishes between three types of mental stress:

1. Intrinsic load This results from the complexity of the content itself. A simple form for changing an address generates a low intrinsic load - a complex control module, on the other hand, generates a high intrinsic load. UX design cannot reduce it, but it can support it through good structuring.

2. Extrinsic load This is caused by poor design. Illogical navigation, unnecessary pop-ups or incomprehensible wording lead to unnecessary mental effort. UX goal: minimize this burden.

3. Load conducive to learning It arises when information is prepared in such a way that it promotes deeper understanding - for example through interactive assistance or clear visual structures. UX goal: activate this in a targeted manner.

Design Goal

Good interfaces reduce extrinsic stress - without devaluing the cognitive content.

Principles for cognitively relieved UX design

A usable design helps users to use their cognitive energy efficiently. Here are some key strategies:

Chunking: Organize complex content into meaningful sections - for example by creating groups in forms.
Progressive Disclosure: Only show the information that is currently relevant, e.g. through step-by-step navigation or accordions.
Consistency: Recognizable symbols, layouts and interactions promote quick comprehension.
Visual feedback: After an input, for example, a button should react so that no uncertainty arises.
Use white space in a targeted manner: It improves visual legibility and reduces sensory overload.
Limited choices: Fewer options lead to faster decisions (→ Hick’s Law).

Practical Example: Form Design

An insurance form with 20 mandatory fields on one page seems overwhelming.
Better: It is divided into three manageable sections, each of which is supplemented by a progress bar. Help texts appear depending on the context - only when they are needed. This significantly reduces extrinsic stress.

Measurement of Cognitive Load

UX research can capture cognitive load using various methods:

Subjective methods such as NASA-TLX questionnaires
behavioral data such as time-on-task or error frequency
Physiological methods such as pupillometry or eye tracking

These indicators help to identify critical points in the interface - and to make targeted improvements.

Conclusion

A good UX design is not just visually appealing or functional. It also takes into account the __MARKBOLD_cognitive resources of the user.
Design decisions that consciously control cognitive load enable more effective use, more satisfaction - and ultimately better usability.

Take Home Message

Good usability takes the pressure off thinking - not the users.

Frequently asked questions (FAQ)

What does cognitive load mean in the UX context?

Cognitive load describes the mental effort required to process information and perform tasks - especially in working memory.

What types of cognitive load are there?

Cognitive load theory distinguishes three types: intrinsic load (inherent complexity of the task), extrinsic load (caused by poor design) and learning-enhancing load (supports deep understanding).

Why is extrinsic load problematic?

It is caused by unnecessarily complicated interfaces, unclear navigation or superfluous information. It increases mental stress and worsens usability.

How can UX design reduce cognitive load?

Through strategies such as chunking, progressive disclosure, consistent design, visual feedback, targeted white space and limited choices.

How can cognitive load be measured?

Using subjective methods (e.g. NASA-TLX), behavioral data (errors, time-on-task) or physiological methods such as pupillometry and eye tracking.

What is the goal in UX design?

Minimize extrinsic stress, structure intrinsic stress sensibly and activate stress that promotes learning in a targeted manner - for efficient and pleasant use.

Last modified: 2 November 2025