What psychological concept does reinforcement primarily relate to?

Reinforcement primarily relates to behavior because it is a key concept in behaviorism, a branch of psychology that focuses on observable behaviors rather than internal mental processes. Reinforcement involves any consequence that strengthens or increases the likelihood of a behavior occurring in the future. This can happen through positive reinforcement, which adds a stimulus following the behavior, or negative reinforcement, which removes an aversive stimulus. By providing rewards or removing negative outcomes, reinforcement shapes how individuals act and interact with their environment. This focus on observable actions and the effects of external stimuli is fundamental to understanding behavior modification and learning processes in various contexts.