Behaviorism started in 1913, when American psychologist John B. Watson published a paper titled “Psychology as the Behaviorist Views It.” This paper, now widely called the “behaviorist manifesto,” argued that psychology should stop trying to study people’s inner thoughts and focus entirely on observable behavior. While Watson didn’t invent every idea behind behaviorism, he was the first to pull those ideas together into a coherent system and give the movement its name.
Watson’s 1913 Manifesto
At the time Watson wrote his manifesto, mainstream psychology relied heavily on introspection: asking people to carefully describe their own thoughts, feelings, and sensations, then treating those reports as scientific data. Watson thought this approach was unreliable and unscientific. He argued that if psychology wanted to be a real science, on par with chemistry or physics, it needed to study only things that could be directly observed and measured. That meant behavior.
Watson’s core proposal was straightforward. Psychology should abandon the study of consciousness and instead focus on what organisms actually do in response to their environment. He wanted to take the objective methods already used in animal research and apply them to human beings. Interestingly, his manifesto had little immediate impact in the years right after publication. The revolution it sparked took time to build momentum. But Watson’s standing in the field grew quickly. By 1915, just two years after publishing his manifesto, he was elected president of the American Psychological Association.
Ideas That Came Before 1913
Watson didn’t work in a vacuum. Several researchers had already been doing the kind of objective, behavior-focused work he was calling for, even if they hadn’t framed it as a new school of psychology.
Edward Thorndike published his famous puzzle box experiments in 1898, studying how cats learned to escape from enclosed boxes to reach food. By 1911, he had formalized his findings into the Law of Effect: behaviors followed by a satisfying outcome become more likely to happen again, while behaviors followed by discomfort become less likely. This principle, that consequences shape behavior, became a foundational idea in behaviorism long before the term existed.
Ivan Pavlov’s research on conditioned reflexes in dogs also predated Watson’s manifesto, though Pavlov’s landmark book on the subject wasn’t published until 1927. Pavlov showed that animals could learn to associate two unrelated things (like a bell and food) when they occurred close together in time. This discovery of what we now call classical conditioning gave behaviorists a concrete, measurable mechanism for explaining how learning works without referring to thoughts or feelings.
Behaviorism Becomes Dominant
The movement truly hit its stride in the 1920s. Watson’s ideas gained wider acceptance, and a growing number of psychologists embraced the view that studying behavior, not consciousness, was the proper business of their field. The period from the 1920s through the early 1960s is considered one of the most productive and exciting eras in the history of psychology, largely because behaviorist thinking dominated the discipline during those decades.
As the movement grew, it also split into different camps. The term “methodological behaviorism” first appeared in 1923, coined by Abraham Roback. Methodological behaviorists didn’t necessarily deny that consciousness existed. They simply argued that private mental experiences couldn’t be studied scientifically, so psychology should limit itself to public, observable events.
Skinner and Radical Behaviorism
B.F. Skinner took behaviorism in a different direction with what he called radical behaviorism. Where methodological behaviorists drew a hard line between public behavior (worth studying) and private experience (off limits), Skinner rejected that division. He argued that private events like thoughts and feelings were real, but that they were themselves forms of behavior, shaped by the same environmental forces as any observable action. There was no need to treat them as a separate category or to invoke a special “mental” realm to explain them.
Skinner’s approach put even more emphasis on how consequences shape behavior. His research on reinforcement, showing how the timing and pattern of rewards influence what organisms do, became enormously influential in education, therapy, and animal training. His work extended behaviorism’s reach well beyond the laboratory and into everyday life.
When Behaviorism Lost Its Grip
Behaviorism’s dominance began to fade in the late 1950s and early 1960s with what’s often called the cognitive revolution. Psychologists increasingly argued that you simply couldn’t explain complex human abilities like language, memory, and problem-solving without talking about internal mental processes. Treating the mind as a “black box” and studying only inputs and outputs wasn’t enough.
This didn’t mean behaviorism disappeared. Its principles remain central to fields like applied behavior analysis, which is widely used in education and therapy. Conditioning and reinforcement are still fundamental concepts in psychology. But behaviorism lost its position as the dominant framework for understanding the mind, replaced by cognitive psychology’s willingness to study mental processes directly. The era of behaviorism’s peak influence lasted roughly 40 years, from the early 1920s to the early 1960s.