What is Cognitive Load?
The total amount of mental effort being used in working memory at any given moment. Originally developed by John Sweller for educational design, the concept applies broadly: every interface, process, or decision adds load. When load exceeds capacity, performance collapses: people make errors, give up, or default to heuristics.
My perspective
In practice
An underrated design principle. Reducing cognitive load is behind every great UX decision: progressive disclosure (show only what's needed now), consistent patterns (don't make users relearn), sensible defaults (decide for them when you can), and clear hierarchy (guide attention). In team contexts, it explains why simple processes beat comprehensive ones: a process nobody can remember is a process nobody follows.