In cognitive psychology, cognitive load is the effort being used in the working memory. According to work conducted in the field of instructional design and pedagogy, broadly, there are three types of cognitive load:

However, over the years, the additivity of these types of cognitive load has been investigated and questioned. Now it is believed that they circularly influence each other.

Cognitive load theory was developed in the late 1980s out of a study of problem solving by John Sweller. Sweller argued that instructional design can be used to reduce cognitive load in learners. Much later, other researchers developed a way to measure perceived mental effort which is indicative of cognitive load. Task-invoked pupillary response is a reliable and sensitive measurement of cognitive load that is directly related to working memory. Information may only be stored in long-term memory after first being attended to, and processed by, working memory.^{[citation needed]} Working memory, however, is extremely limited in both capacity and duration. These limitations will, under some conditions, impede learning.^{[citation needed]} Heavy cognitive load can have negative effects on task completion, and the experience of cognitive load is not the same in everyone.^{[citation needed]} The elderly, students, and children experience different, and more often higher, amounts of cognitive load.^{[citation needed]}

The fundamental tenet of cognitive load theory is that the quality of instructional design will be raised if greater consideration is given to the role and limitations of working memory. With increased distractions, particularly from cell phone use, students are more prone to experiencing high cognitive load which can reduce academic success.

In the late 1980s, educational psychologist John Sweller developed cognitive load theory out of a study of problem solving, in order "to provide guidelines intended to assist in the presentation of information in a manner that encourages learner activities that optimize intellectual performance". Sweller's theory employs aspects of information processing theory to emphasize the inherent limitations of concurrent working memory load on learning during instruction.^{[citation needed]} It makes use of the schema as primary unit of analysis for the design of instructional materials.^{[citation needed]}

The history of cognitive load theory can be traced to the beginning of cognitive science in the 1950s and the work of G. A. Miller. In his classic paper, Miller was perhaps the first to suggest our working memory capacity has inherent limits. His experimental results suggested that humans are generally able to hold only seven plus or minus two units of information in short-term memory.

In 1973 Simon and Chase were the first to use the term chunk to describe how people might organize information in short-term memory. This chunking of memory components has also been described as schema construction.

In the late 1980s Sweller developed cognitive load theory (CLT) while studying problem solving. Studying learners as they solved problems, he and his associates found that learners often use a problem-solving strategy called means–ends analysis. He suggests problem solving by means–ends analysis requires a relatively large amount of cognitive processing capacity, which may not be devoted to schema construction. Sweller suggested that instructional designers should prevent this unnecessary cognitive load by designing instructional materials which do not involve problem solving. Examples of alternative instructional materials include what are known as worked examples and goal-free problems.^{[citation needed]}