Americans grow happier as they grow older, according to a University of Chicago study that is one of the most thorough examinations of happiness ever done in America.

The study also found that baby boomers are not as content as other generations, African Americans are less happy than whites, men are less happy than women, happiness can rise and fall between eras, and that, with age the differences narrow.

“Understanding happiness is important to understanding quality of life. The happiness measure is a guide to how well society is meeting people’s needs,” said Yang Yang, Assistant Professor of Sociology at the University of Chicago and author of the article, “Social Inequalities in Happiness in the United States, 1972-2004: An Age-Period-Cohort Analysis,” published in the April issue of the American Sociological Review, the official journal of the American Sociological Association.

The research relies on data that social scientists consider the gold standard of happiness research—responses to questions about contentment with overall life gathered in the General Social Survey of the National Opinion Research Center, which the National Science Foundation supports at the University of Chicago.

Since 1972, the GSS has asked a cross section of Americans the same question: “Taken all together, how would you say things are these days—would you say that you are very happy, pretty happy, or not too happy?” The question was administered in face-to-face interviews of population samples that ranged from about 1,500 to 3,000.

Yang charted happiness across age and racial groups and found that among 18-year-olds, white women are the happiest, with a 33 percent probability of being very happy, followed by white men (28 percent), black women (18 percent) and black men (15 percent).

Differences vanish over time, however, as happiness increases. Black men and black women have just more than a 50 percent chance of being very happy by their late 80s, while white men and white women are close behind.

The increase in happiness with age is consistent with the “age as maturity hypothesis,” Yang said. With age comes positive psychosocial traits, such as self-integration and self-esteem; these signs of maturity could contribute to a better sense of overall well-being. Second, group differences in happiness decrease with age due to the equalization of resources that contribute to happiness, such as access to health care, Medicare and Medicaid, and the loss of social support due to the deaths of spouses and friends, Yang added.

The length of the survey also helped determine how different people in the same generational group fared. The baby boom generation (born from 1946-1964) were the least happy among those surveyed.

“This is probably due to the fact that the generation as a group was so large, and their expectations were so great, that not everyone in the group could get what he or she wanted as they aged due to competition for opportunities. This could lead to disappointment that could undermine happiness,” Yang said.

On another measure, Yang found that happiness in the country is not static. Looking over the study’s 33-year period, she noticed definite upticks when the nation flourished economically. For example, she found that 1995 was a very good year on the happiness scale.