The adaptation theory that came up in 1971 argued that people react to good and bad events in their life, but they eventually return to a stable level of well-being. Researchers from Michigan State University, University of Illinois at Urbana-Champaign, France and England confirmed this theory based on a study conducted to evaluate the effects of marital transitions on life satisfaction. 24,000 individuals were followed for 15 years and were frequently questioned about their life satisfaction. The study specifically looked at individuals who were single and then married and those who were married and were widowed during the study. They found that though people initially reacted strongly to good or bad events they then returned to their baseline stable emotional state. The study also revealed various other findings like those individuals who are happy are more likely to get and stay married. They found that people took more time to adapt to widowhood when compared to adapting to marriage. It typically took 8 years for someone to fully adapt to being a widow. The extent to which people adapt was different for each individual and this depended upon the degree to which they react to the initial event. The stronger the reaction to the initial event, the longer it takes to get back to normal.