In 1990, Cosby earned a master's degree from the University of Massachusetts, followed by a Ph. D. in 1992. In an interview with Oprah Winfrey, Cosby stated, "I became keenly aware of myself in my mid thirties. I went through a transition. I decided to go back to school, because I had dropped out of college to marry Bill when I was 19. I had five children, and I decided to go back. I didn't feel fulfilled educationally. I dropped out of school at the end of my sophomore year. So I went back, and when I did, my self-esteem grew. I got my master's, then decided to get my doctoral degree. Education helped me to come out of myself. "