Applied Behavior Analysis (ABA) is a scientific discipline that focuses on understanding and improving human behavior by applying principles of learning. The question of who created this therapy does not have a single, simple answer, as its origins involve both a theoretical foundation and a systematic clinical application. The framework for ABA was established by one influential figure, while its first widely recognized application for developmental disorders was pioneered by another. The history of ABA is a story of a scientific theory translated into a structured, real-world intervention that continues to evolve.
The Theoretical Roots in Behaviorism
The scientific foundation for Applied Behavior Analysis is rooted in the work of psychologist B.F. Skinner, the most influential figure in behaviorism. Skinner did not create the therapy known as ABA, but his research into how consequences affect behavior provided the governing principles ABA uses today. His key contribution was the concept of operant conditioning, which explains how behaviors are strengthened or weakened by the events that follow them.
Skinner’s experiments demonstrated that behavior is a function of its consequences. He defined the roles of reinforcement, which increases the future likelihood of a behavior, and punishment, which decreases it. He differentiated between positive reinforcement (adding a desirable consequence) and negative reinforcement (removing an undesirable one), both of which strengthen behavior. This work established the experimental analysis of behavior, a data-driven approach focusing only on observable actions and environmental variables.
O. Ivar Lovaas and the Clinical Application
While Skinner provided the theory, the first systematic, large-scale application of behavioral principles to treat individuals with autism was conducted by psychologist O. Ivar Lovaas. Working at the University of California, Los Angeles (UCLA) in the 1960s, Lovaas translated operant conditioning into a structured clinical methodology. His work with the UCLA Young Autism Project (YAP) is widely recognized as the birth of the first recognizable version of ABA therapy.
Lovaas’s model was characterized by its intensity, later termed Early Intensive Behavioral Intervention (EIBI), which called for up to 40 hours per week of one-to-one instruction for young children. The primary teaching method he employed was Discrete Trial Training (DTT), which systematically breaks down complex skills into small steps. In this approach, a therapist presents an instruction, the child responds, and a consequence—typically positive reinforcement—is delivered. Lovaas’s landmark 1987 study showed that this intensive intervention could lead to significant developmental gains for some children with autism.
Defining Modern Applied Behavior Analysis
The field of Applied Behavior Analysis has evolved significantly beyond the initial, highly structured methods developed by Lovaas. Today, ABA is a broad, flexible, and person-centered discipline, no longer defined by a single set of techniques like Discrete Trial Training. Contemporary ABA focuses heavily on individualization, tailoring interventions to a person’s specific needs, preferences, and cultural context.
A central practice in modern ABA is the Functional Behavior Assessment (FBA), which is conducted before any intervention begins. This process identifies the specific purpose, or function, of a challenging behavior, ensuring that intervention strategies address the reason for the behavior rather than just the behavior itself. This focus allows practitioners to teach more appropriate, alternative skills that serve the same function. Furthermore, contemporary practice incorporates various teaching methods beyond DTT, such as Natural Environment Teaching (NET), which uses natural surroundings to teach skills applicable in everyday life.
The professionalization of the field, including the establishment of ethical guidelines and certification for practitioners, such as the Board Certified Behavior Analyst (BCBA), has driven the shift toward compassionate and respectful care. Modern ABA prioritizes the dignity and autonomy of the individual. It has moved away from older practices that sometimes relied on aversive techniques toward methods based purely on positive reinforcement. This ongoing evolution ensures the methodology remains ethical and person-centered.