The major obstacle in recognizing psychology as a legitimate field of study was the abstract nature of human thought. To gain acceptance within the scientific community, psychologists had to employ scientific methods, including observation and experimentation, to understand how humans think and behave. Since we can observe ourselves only through introspection, our observations of internal thoughts are inherently subjective and fall short of providing definitive answers. But science requires an objective approach. Therefore, psychologists adopted a method called experimental psychology. Using this method, they studied how people process information internally.
This was a solution that behaviorists adopted to avoid attempting to examine the brain’s workings, instead observing how they manifest themselves in behavior. Not only can human and animal behavior be observed, but the behavioral response of an animal to specific situations can be examined under stringent laboratory conditions—allowing experiments to be replicated. Behaviorism, and its theories about stimulus and response, dominated psychological experimentation until the mid-20th century.
