Limitations in the behaviorist theory of learning began to be recognized by researchers in the early 1920s. The major problem for researchers was that behaviorism was unable to explain most social behaviors. Cognitive theory emerged as an extension of and a reaction to behaviorist theory. The rise of cognitivist learning theory was a response to behaviorism's rigid emphasis on the direct link between "stimulus and response". Cognitivist theory was concerned with what comes between stimulus and response, seeking to understand the processes of the mind-the processes that the behaviorists had rejected. Emerging as it did during the rise of cognitive science and computing, cognitivist learning theory absorbed and was influenced by the era. The concept of schema in cognitivist learning theory is related to mental representation and structural knowledge. Schema theory or schema perspectives hold that learning is easier if new subject matter is compared to existing knowledge and is structured or representational.