Applied behavior analysis (ABA), also called behavioral engineering, is a psychological intervention that applies empirical approaches based upon the principles of respondent and operant conditioning to change behavior of social significance. It is the applied form of behavior analysis; the other two forms are radical behaviorism (or the philosophy of the science) and the experimental analysis of behavior (or basic experimental laboratory research). The name applied behavior analysis has replaced behavior modification because the latter approach suggested attempting to change behavior without clarifying the relevant behavior-environment interactions. In contrast, ABA changes behavior by first assessing the functional relationship between a targeted behavior and the environment. Further, the approach often seeks to develop socially acceptable alternatives for aberrant behaviors. Although service delivery providers overwhelmingly specialize in utilizing structured and naturalistic early behavioral interventions for individuals with autism, ABA has also been utilized in a range of other areas. ABA is controversial, especially among members of the autism rights movement, for a number of reasons. There is a perception that ABA emphasizes indistinguishability instead of acceptance, and a history of, in some embodiments of ABA and its predecessors, the use of aversives, such as electric shocks. ABA is also controversial due to its relatively weak evidence base. Definition ABA is an applied science devoted to developing procedures which will produce observable changes in behavior. It is to be distinguished from the experimental analysis of behavior, which focuses on basic experimental laboratory research, but it uses principles developed by such research, in particular operant conditioning and classical conditioning. Behavior analysis adopts the viewpoint of radical behaviorism, treating thoughts, emotions, and other covert activity as behavior that is subject to the same rules as overt responses. This represents a shift away from methodological behaviorism, which restricts behavior-change procedures to behaviors that are overt, and was the conceptual underpinning of behavior modification. Behavior analysts also emphasize that the science of behavior must be a natural science as opposed to a social science. As such, behavior analysts focus on the observable relationship of behavior with the environment, including antecedents and consequences, without resort to "hypothetical constructs". History The beginnings of ABA can be traced back to Teodoro Ayllon and Jack Michael's study "The psychiatric nurse as a behavioral engineer" (1959) that they published in the Journal of the Experimental Analysis of Behavior (JEAB). Ayllon and Michael were training the staff at a psychiatric hospital how to