American adults’ sense of well-being as they age resembles a U-curve, decreasing during their 20s and 30s to the lowest point in their late 40s before sharply increasing in their 50s onward, notwithstanding the effects of aging on health, according to a recent study.

In a study published Dec. 2 in the journal PLOS One, a team of academics from the University of Southern California examined 12 social and psychological variables in adults that could account for the U-curve in subjective well-being, which refers to an individual’s self-reported sense of meaning, their satisfaction with life and their everyday moods.

“There are many demographic factors that relate to subjective well-being, including income and gender, but age is one that’s particularly interesting,” Arthur Stone, a psychology professor at USC and lead author of the study, told The Academic Times.

“Because health deteriorates over age, a reasonable speculation is that people’s subjective well-being would also decline,” Stone said in the study. “However, dozens of cross-sectional and longitudinal studies have shown in the U.S. and Western Europe that [subjective well-being] increases [around] age 50, which may reasonably be considered a paradox.”

The study sample was a group of approximately 3,300 Americans between 40 and 70 years old. Through an online survey in spring 2019, the researchers used the Cantril Ladder, one of the most commonly used measures of subjective well-being in psychology, to assess the adults.

The Cantril Ladder asks participants to rank how satisfied they are in life, on a scale ranging from poor to excellent. Previous research in this field has shown the greatest increase in Cantril Ladder scores in older adults. In the study, Stone assessed which variables had the strongest impact on the association between age and the Cantril Ladder scores. 

Measures of subjective well-being are associated with age, but the patterns of association are not always found to be consistent with common beliefs about aging, according to the study.

The research, which was funded through a National Institute on Aging grant provided by Princeton University, found higher levels of satisfaction with social relationships in older age, which explained some of the increase in well-being. Perceptions of strain from family and friends were also lower in older age, partly explaining the well-being increase.

The results of the study partially confirmed the theory of socioemotional selectivity, according to Stone, which suggests that adults make decisions and select relationships more carefully as they get older. “As people age and as they start realizing that life is finite, [they] start making their social circles a little smaller and more selective,” he said.

Stone and his team found that the social and psychological variables they examined — including perceived stress, social network size, social satisfaction, social comparison and support from family and friends, among others — explained about two-thirds of the U-curve, and accounting for them significantly flattened it. Most of the explanatory variables were associated with both age and subjective well-being outcomes in the same positive direction.

Stone noted that the team’s research was a cross-sectional study that only analyzed the participants at one age and one point in time, meaning that it didn’t account for their adult lifespan or the entirety of the U-shaped curve. “We believe that this work contributes to a more complete understanding of the potential roles of social and psychological factors in well-being over the lifespan,” Stone said in the study.

For future studies on this topic, Stone suggested longitudinal research, a study design that observes the same variables or subjects repeatedly over a period of time. He noted that his findings cannot provide a causal explanation between age, the variables and the U-shaped curve due to the study’s cross-sectional nature.

Stone has studied well-being for more than 20 years. He said that during this time there has been greater recognition beyond psychologists, including by policymakers and economists, that subjective well-being is important to improve and is a “major concept of interest for augmenting other economic and social measures of welfare.”

The study, “Age Patterns In Subjective Well-Being Are Partially Accounted For By Psychological And Social Factors Associated With Aging,” was published in the PLOS One online journal. Arthur Stone of the University of Southern California was the lead author of the study, and Joan E. Broderick, Diana Wang and Stefan Schneider, scientists at the University of Southern California, were co-authors.