What specific area in modern psychology is behaviorist

Watson
Watson made a major contribution to the world of personality psychology when he introduced behaviorism. After reading this week’s selections and watching the assigned video on learning, address the following:

What specific area in modern psychology is behaviorist theory and treatment valid?
How is this theory applied?
Why do you feel behaviorism is valid in this specific area? Give specific support for your opinion.

Post should be at least 300 words.