During the first half of the twentieth century, a new school of thought known as behaviorism rose to become a dominant force within psychology. Behaviorists believed that psychology needed to focus only on observable and quantifiable behaviors in order to become a more scientific discipline.
According to the behavioral perspective, all human behavior can be described in terms of environmental influences. Some behaviorists, such as John B. Watson and B.F. Skinner, insisted that learning occurs purely through processes of association and reinforcement. Later, psychologist Albert Bandura rejected this narrow perspective and demonstrated the powerful effects of observational learning.
Take a closer look at some of these ideas in this overview of the learning theories of development.