Simplify the following text for a Grade 10 native English-speaking person.
Original: He went on to earn a master 's degree in experimental psychology in 1976 , and a Ph. . D in clinical psychology in 1979 at the University of North Texas , where his dissertation was titled `` Rheumatoid Arthritis : A Psychological Intervention '' .
Simplified: He then got a Ph. . D in clinical psychology in 1979 at the University of North Texas . At the University of North Texas , his dissertation was titled `` Rheumatoid Arthritis : A Psychological Intervention . ''