Applied behavior analysis (ABA) is a science that involves using modern behavioral learning theory

Behaviorism

Behaviorism , also called the learning perspective , is a philosophy of psychology based on the proposition that all things that organisms do—including acting, thinking, and feeling—can and should be regarded as behaviors, and that psychological disorders are best treated by altering behavior...

 to modify behaviors. Behavior analysts reject the use of hypothetical constructs and focus on the observable relationship of behavior to the environment. By functionally assessing the relationship between a targeted behavior and the environment, the methods of ABA can be used to change that behavior. Research in applied behavior analysis ranges from behavioral intervention methods to basic research which investigates the rules by which humans adapt and maintain behavior.

ABA-based interventions are best known for treating people with developmental disabilities, most notably autism spectrum disorders.