Overall, no difference between age groups. Survey of 170,000 of all ages in 16 different countries, found mean score of 80% satisfaction with life in all age groups (Inglehart 1990). Different factors contribute to happiness at different ages e.g, social relations & health are more important with age (Herzog et al, 1982). McCrae & Costa (1990)- people do experience crises but these aren't restricted to particular age such as the supposed mid-life crisis in one's early 40s.