Learning is a relatively permanent change in behavior or knowledge that results from experience. It is the process that allows organisms to adapt to the regularities of their environment.

Psychologists distinguish several forms. Classical conditioning links stimuli that occur together. Operant conditioning links actions with their consequences. Observational learning allows individuals to acquire new behaviors by watching others. Cognitive forms of learning include the formation of cognitive maps, insight, and the acquisition of concepts and rules. Not every change in behavior counts as learning; maturation, fatigue, and temporary shifts in motivation are excluded by the requirement of relative permanence and experiential origin.

Learning can be measured by improvement in performance, by the ability to transfer skill to new situations, and by changes in the nervous system that accompany the behavioral change. It occurs throughout the lifespan, though plasticity is greater in early development for certain skills. The study of learning connects psychology to neuroscience, education, and artificial intelligence.

Experience leaves a mark. When that mark changes what an organism does or knows, learning has occurred.