William Glasser was a psychiatrist who developed Choice Theory and Reality Therapy. Some key aspects of his theories include:
1) He believed that people choose their behaviors to meet their basic psychological needs of survival, love/belonging, power, freedom, and fun.
2) External control models focus on criticizing and blaming others, while internal control models emphasize respect, support, and negotiation.
3) Choice Theory proposes replacing the "7 Deadly Habits of External Control" with the "7 Caring Habits of Choice Theory" to improve relationships.