Cognitive load theory was developed by John Sweller in the late 1980s. It suggests that our working memory has a limited capacity, and when that capacity is exceeded, learning and task performance suffer significantly.

In the context of user experience and interface design, cognitive load represents the mental resources required for a user to interact with a system. High cognitive load can lead to user frustration, errors, and abandonment of tasks.

There are three types of cognitive load: intrinsic (inherent difficulty of the task), extraneous (how information is presented), and germane (effort put into creating permanent knowledge). Good design minimizes extraneous load while optimizing germane load.

Designers can reduce cognitive load through techniques such as progressive disclosure, chunking information, using familiar patterns, providing clear visual hierarchies, and eliminating unnecessary elements from the interface.