Although there is considerable evidence linking success -- including wealth, 
marriage, and friendships -- to happiness, this relationship might not reflect, 
as is often assumed, the effects of the proximate environment on well-being. 
Such an interpretation is contravened by evidence that both happiness and the 
environment are influenced by genetic factors and family upbringing. Using the 
National Survey of Midlife Development in the United States, which includes a 
subsample of twins, this study evaluates the relationship between happiness and 
various features of success before and after eliminating the influence of 
endowments. The results suggest that many putative indicators of the environment 
are highly heritable and, indeed, that the same genes that affect the 
environment may affect happiness as well. Yet the results also suggest that the 
role of genetic endowments varies considerably across different features of 
success, suggesting complex patterns of selection, reinforcement, and causation 
among genes and the environment.