---
name: Cognitive load
slug: cognitive-load
category: accessibility
status: published
created: 2026-08-21T00:00:00.000Z
modified: 2026-08-21T00:00:00.000Z
definition: The mental effort an interface demands, split between the work the
  task really needs and the work the design added by way of clutter, jargon, and
  avoidable steps.
aliases:
  - name: memory load
    source: community
  - name: extraneous load
    source: community
  - name: working memory demand
    source: community
  - name: mental effort
    source: community
tags:
  - perception
relations:
  contrastWith:
    - plain-language
    - chunking
  variantOf: []
  partOf: []
  seeAlso:
    - progressive-disclosure
implementations: []
sources:
  - title: "W3C WAI: Cognitive Accessibility at W3C"
    url: https://www.w3.org/WAI/cognitive/
  - title: "W3C: Avoid Too Much Content"
    url: https://www.w3.org/WAI/WCAG2/supplemental/patterns/o5p03-manageable-quantity
demo: inline
exhibit: false
useWhen: a screen is correct but exhausting to use
---

The useful split, borrowed from cognitive load theory, is between the load a task carries
inherently and the load the design added on top. Choosing a delivery date is intrinsic: the
decision exists whether or not anyone designs a screen for it. Nine ungrouped options with
names taken from a file format specification, no answer filled in, and a paragraph of
qualifying copy above them are extraneous, and extraneous load is the only kind a redesign
can actually remove. That distinction is what keeps the term from collapsing into "this
feels busy", because it names which of the busyness was avoidable.

Working memory is the resource being spent, and it is small and short. The classic figure
of seven items has been revised downward for years, and the practical reading is that
anything a reader has to carry from one screen to the next is expensive: a code from an
email, a total from a previous step, the meaning of an abbreviation defined earlier. The
cheapest fixes are the boring ones. Group the choices so the eye reads three clusters
instead of nine items. Write the labels in the words the reader already has. Answer what
you can already answer, since a [smart default](/smart-defaults) turns a decision into a
confirmation. Hide the rare controls behind
[progressive disclosure](/progressive-disclosure) rather than ranking everything at once.
Keep the earlier answers on screen, which is the whole argument for a
[check answers](/check-answers) page.

This matters most for the people the accessibility literature calls cognitively disabled,
which is a very wide group: readers with a learning disability, an attention or memory
condition, aphasia, a brain injury, or simply the ordinary decline of processing speed
with age. It also covers a much larger temporary population, since anyone doing this on a
phone, on a bus, tired, in a second language, or in the middle of something else is
running with less working memory than they would in a usability lab. Cognitive
accessibility guidance largely reads as good design advice for everybody, and that is not
a coincidence.

Be honest about measurement. Load is not read off a screen: it is inferred from proxies
such as task completion time, error rate, backtracking, pupil dilation, or a self-report
scale like NASA-TLX, all of which measure something adjacent to the thing. A design
review can still be rigorous without a number. Count the decisions the screen asks for,
count the ones it could have answered itself, count the words the reader would have to
look up, and count what they are being asked to remember from a previous screen. Those
four counts are arguable in a way that "it feels cluttered" is not.