Researchers have found evidence to suggest that the class divide in happiness is expanding in the United States. An analysis of national survey data revealed that the positive link between socioeconomic status (SES) and happiness escalated between the 1970s and 2010s. The findings were published in the journal Emotion.

There has been great discussion about the increasing class divide in the U.S., with many suggesting that the elite, high-SES population is thriving while the low SES population is declining. With both income inequality and the importance of a college education growing, it might be expected that the happiness levels of these two groups should grow further apart.

Study authors Jean M. Twenge and A. Bell Cooper wanted to empirically examine whether this “happiness gap” has indeed increased in recent decades. To do this, the researchers explored nationally representative survey data from the General Social Survey conducted in the U.S. since 1972. The survey includes a measure of general happiness and the SES indicators of yearly income, education, and occupation.

A first analysis examined the association between SES and happiness. As expected, a higher SES was linked to greater happiness. Specifically, those in the top quintile for income were 83% more likely to say they were “very happy” compared to those in the lowest quintile.

Interestingly, the benefits of income did not dwindle at the higher income levels — those at the top quintile were still 13% more likely to be “very happy” than those in the fourth quintile.

Notably, this positive relationship between SES and happiness grew over the years. The difference between the happiness levels of those with the lowest versus the highest SES was much greater in the 2010s than in the 1970s.

This pattern was similar when the researchers examined only white respondents, suggesting that race did not account for the growing relationship between SES and happiness. Religious service attendance also did not account for the effect, although marital status weakened the relationship somewhat.

The researchers say that this suggests that the lower likelihood of marriage among low SES individuals partly explains the growing association between SES and happiness.

Next, the researchers wanted to hone in on why this association has grown, by pinpointing which class has increased, decreased, or remained stagnant when it comes to happiness.  “In other words,” Twenge and Cooper say, “is SES more strongly related to happiness because high-SES Americans are happier, or because low-SES Americans are less happy?”

Overall, the data revealed that the happiness advantage for high-SES individuals grew over the years. However, the way it grew differed by race.

While high-SES white individuals remained stable in their happiness levels over the years between the 1970s and 2010s, the happiness of those with low-SES plummeted. By contrast, the low-SES Black population remained stable in their happiness levels over the years, while those with high-SES saw gains in happiness that were often large.

“For example,” the researchers illustrate, “12% fewer Black adults without a college education were “very happy” in 1972-74 compared to 2014-16, but 63% more Black adults with a college education were “very happy” in 2014-16 compared to 1972-74.”

The researchers point out that the effects sizes they found were substantial, particularly when it came to the link between income and happiness — these effects fell within the moderate to large range.

They say their findings may have political implications. Americans without a college degree make up the greatest proportion of the population, and if their unhappiness is growing, politicians and systems that are more socialist may see gains in popularity.

The researchers note that their study relied on self-report measures for SES indicators, which are less reliable than objective measures. They also note that their findings are specific to the U.S. population and it is unclear whether they would generalize to other cultures.

The study, “The expanding class divide in happiness in the United States, 1972-2016”, was authored by Jean M. Twenge, and A. Bell Cooper.