There is a particular unease that can arrive in middle age, when a life may look settled from the outside but feel crowded from within. Work has become less novel. Caring responsibilities overlap. The distance between early expectations and ordinary reality is easier to calculate.
For years, researchers have found that this period often coincides with a dip in reported wellbeing. Plot average happiness against age and the line frequently bends into a U: higher in youth, lower around the late forties or early fifties, then rising again. The pattern is striking, but it is an average, not a timetable for an individual life. Recent evidence also suggests that the shape is changing in some countries.
Where the age of 50 comes from
The 145-country figure comes from economist David Blanchflower’s analysis, published in the Journal of Population Economics in 2021. Drawing on several large international surveys, he reported U-shaped age patterns in subjective wellbeing across 145 countries, including both richer and developing economies.
Across 477 country-level estimates, the average low point was 48.3 years. The estimated nadir was 47.2 in developing countries and 49.6 in developed countries. That is the source of the neat shorthand that happiness bottoms out at about 50.
The paper combined different questions and datasets rather than following one enormous group from adolescence to old age. Some surveys asked about happiness or life satisfaction. Others captured worry, stress, pain or other forms of distress. Statistical models also adjusted for circumstances such as employment, education and relationship status in some analyses.
Those choices matter. A curve calculated after holding marriage or employment constant answers a different question from a simple comparison of people at different ages. The first asks how age relates to wellbeing among otherwise statistically similar people. The second includes the life changes that commonly accompany age.
A population curve is not a personal forecast
A cross-sectional survey compares people who are currently 25, 50 and 75. It does not necessarily show what will happen as one 25-year-old becomes 50 and then 75. The groups grew up in different economies, encountered different technologies and entered adulthood with different expectations. Researchers call these cohort effects.
Longitudinal studies, which follow the same people over time, can address part of that problem. An analysis of four long-running datasets reported within-person evidence for a midlife low in wellbeing. Yet the broader literature is not unanimous. A review led by Alberta psychologist Nancy Galambos argued that evidence for a universal U is mixed across both cross-sectional and longitudinal research, and that a single curve can hide substantial differences in individual pathways.
Health, money, partnership, work, caregiving and social connection do not arrive on a standard schedule. Neither does bereavement. People who reach older age are also a selected group, which complicates comparisons with younger populations. A later-life rise in the average does not mean every older person becomes happier, or that it always surpasses the high points of youth.
The useful reading is therefore modest. Many large datasets have produced a midlife dip and a later rebound. They do not promise that a birthday will turn the line upwards.
What the apes study actually measured
The most memorable extension of the U-curve came from 508 great apes. In a 2012 paper in Proceedings of the National Academy of Sciences, Alexander Weiss and colleagues studied 336 chimpanzees and 172 orangutans living in zoos, research centres and a sanctuary across five countries.
The apes did not fill out happiness questionnaires. Keepers, carers, volunteers and researchers who knew each animal rated qualities adapted from human wellbeing measures, including the animal’s mood, enjoyment of social situations and apparent success in achieving its aims. The researchers found a U-shaped relationship between age and rated wellbeing in the combined sample.
The estimated low points occurred at 28.3 and 27.2 years in the two chimpanzee samples and 35.4 years among the orangutans. These ages are roughly midlife for the species involved. The combined result remained statistically significant, although the age effects were not individually significant in two of the three samples.
This does not establish that apes experience a human-style midlife crisis. They cannot report regret, disappointed ambition or anxiety about ageing. Human observers may also interpret animal behaviour through a human lens. What the study suggests is narrower and more interesting: the curved pattern may not arise solely from mortgages, careers and modern social expectations. Age-related biology and changes in social behaviour could contribute as well.
The curve is already changing
The claim that the U appears everywhere has become harder to sustain. The World Happiness Report 2024 compared life evaluations across age groups using Gallup World Poll data from 2021 to 2023. A midlife low appeared in almost half of the countries examined, not all of them. In about half, people aged 60 and over were the least happy group.
Regional patterns differed sharply. Recent Western European results were almost flat across age groups. Norway and Sweden were among the countries where older people reported higher life evaluations than younger people, while Portugal and Greece showed the reverse. In Central and Eastern Europe, younger respondents tended to evaluate their lives more highly than older respondents. In the United States, Canada, Australia and New Zealand, the young had become the least happy age group.
Newer research has focused on that deterioration among younger adults. A 2024 NBER working paper by Blanchflower, Alex Bryson and Xiaowei Xu described the disappearance of the traditional hump in unhappiness across several datasets as distress rose among the young. A later-life advantage can still appear in the numbers, but it may now reflect a worsening starting point rather than the familiar descent and recovery.
That is an important distinction. A 22-year-old reporting less happiness than a 62-year-old creates an upward slope with age. It does not tell us that the younger person will steadily improve as the decades pass.
Why later life can feel lighter
No single mechanism explains the rebound where it does occur. Some pressures ease. Children may become independent. Careers can become more predictable or end. People may become better at selecting relationships and activities worth their limited time. Expectations can move closer to lived reality.
There is also a difference between evaluating a life and reporting yesterday’s emotions. The World Happiness Report found that positive emotions such as laughter and enjoyment were generally more frequent among younger people, even in places where older adults rated their lives more highly overall. An older person can give life a high score without claiming that every day contains more excitement.
Scandinavian comparisons require the same care. High national life evaluations in Denmark, Norway or Sweden do not reveal a regional temperament, much less a Nordic secret to ageing. Income security, health, housing, public services, working conditions and dependable relationships all shape what later life makes possible. Access to those supports is uneven within every country.
A curve best read in pencil
The U-shape remains one of the most recognisable findings in wellbeing research because it has appeared across large samples, long periods and very different societies. The great-ape study makes its possible biological component harder to dismiss. Neither result turns the curve into a law.
For someone approaching 50, the evidence offers perspective rather than prediction. A midlife low is common enough to be visible in population data, and later life is not destined to be a long emotional decline. At the same time, averages cannot settle the shape of one person’s years.
The line has always been drawn from millions of separate lives. As the latest data on younger adults show, it can move when the world around those lives changes.