Meaning & LifeExplainer
What Does Science Say About Happiness?
Decades of research point to a surprising winner, other people, and give honest answers about money, gratitude, and the difference between pleasure and meaning.
THE QUESTION LIBRARY MEANING & LIFE
Science can’t pick your values for you, but decades of research keep pointing to one thing: the people in your life.

THE SHORT ANSWER
Nobody can settle this for everyone, because it depends on what you value. But the research points one way: good relationships. The Harvard Study of Adult Development has followed hundreds of men since 1938, and its director sums it up: “Good relationships keep us happier and healthier.” Money helps, most of all for people in hardship, but its link with daily mood is weak. Pleasure, purpose, virtue, faith and forgiveness all have serious defenders, and many people blend them.
WHERE THE EVIDENCE STANDS
WHAT WE DON’T KNOW YET
Most of this research shows links, not causes. We don’t know how much close ties make people happy, and how much happy people find it easier to keep close ties. The Harvard Study also began with men only: Harvard students and young men from inner-city Boston.
WHAT WOULD CHANGE THIS ANSWER
Long-term studies or experiments showing that building relationships does not improve well-being would weaken the main finding. New data on money from outside the U.S., or better measures of daily feelings, could change the money numbers.
Nobody can answer this for everyone. What counts as a life well lived depends partly on what you value, and that is a question science can’t settle. But science can tell us what tends to go with a good life. On that, one answer keeps showing up: other people.
People ask this at big turning points. A new graduate wonders if chasing money is worth it. A parent wonders what really matters. Someone who has left their childhood faith wonders what can take its place. Someone who still believes wonders if science has anything to add. These are all fair questions.
Start with the longest study of its kind. In 1938, researchers began following 268 students at Harvard. A second group of 456 men from poor Boston neighborhoods was later added. They tracked these men for decades, with interviews, medical records and blood tests. The study’s director, the psychiatrist Robert Waldinger, put its clearest message plainly in a 2015 talk: “Good relationships keep us happier and healthier.” The men most satisfied with their relationships at age 50 were the healthiest at 80.
What about money? It helps, most of all when it lifts people out of hardship. In 2023, researchers who had reached different answers joined forces to reanalyze the data. They found that for most people, happiness keeps rising as income goes up. But they also found the link is weak.
Then there is the bigger question of what happiness even is. Philosophers point out two different ideas. One is feeling good. The other is living well: growing, doing good and caring for others. Many faiths add that a good life is lived in relation to God. Those are questions of value, so we label them Beyond science.
So here is the honest summary. Science can’t hand you a purpose. But whatever you believe, the evidence says the people in your life are a good place to invest.
The Harvard Study of Adult Development began in 1938, during the Great Depression, by following 268 Harvard sophomores. According to the Harvard Gazette, 456 men from Boston’s inner city were enlisted in the 1970s as part of the Glueck Study. Women were not in the original study because Harvard College was then all male. Researchers later added the men’s wives and children.
Over the decades, the team collected medical records, questionnaires and hundreds of interviews. The Gazette reports that they found a strong correlation between the men’s flourishing and their ties to family, friends and community. In his 2015 TED talk, the study’s fourth director, Robert Waldinger, said the lessons “aren’t about wealth or fame or working harder and harder.” He named three:
When the team looked back at the men at age 50, it wasn’t their cholesterol that best predicted how they would age. It was how satisfied they were in their relationships. Waldinger added that the most happily partnered people in their 80s said their mood stayed just as happy on days when they had more physical pain. A smaller study by Waldinger and a colleague, of 47 older couples over eight days, points the same way: for people happy in their marriage, days of poorer health brought a smaller drop in happiness.
The World Happiness Report 2026 looks at whole countries. Its ranking rests on one question from the Gallup World Poll. People imagine a ladder, with the worst possible life at step 0 and the best at step 10, and say where they stand. Finland topped the 2026 ranking for the ninth year in a row, with an average of 7.764. The United States ranked 23rd. To explain the gaps between countries, the report looks at six factors: income per person, healthy life expectancy, having someone to count on, freedom, generosity and perceptions of corruption. The report’s own FAQ says these factors show links, not clean causes.
In 2010, the researchers Daniel Kahneman and Angus Deaton studied more than 450,000 survey answers from Americans. They split well-being into two parts. Life evaluation is how you rate your life when you stop to think about it. Emotional well-being is how your days actually feel. Life evaluation kept rising with income. But day-to-day feelings seemed to stop improving at about $75,000 a year.
In 2021, the researcher Matthew Killingsworth used people’s smartphones to collect 1,725,994 in-the-moment reports from 33,391 working U.S. adults. He found no plateau. Feelings kept rising with income, even above $75,000.
Then the two sides did something unusual. Killingsworth and Kahneman teamed up, with Barbara Mellers as a neutral facilitator, in what is called an adversarial collaboration. Their 2023 paper found that both sides were partly right. For the least happy 15 to 20% of people, happiness rose with income and then leveled off at about $100,000. For everyone else, it kept rising, and for the happiest people it rose even faster. The authors also stressed how small the effect is. The median happiness of people earning $15,000 and people earning $250,000 differed by only about five points on a 100-point scale.
What about sudden money? A popular idea says lottery winners soon drift back to where they started. A study of Swedish lottery players, published in 2020, found otherwise. Five to 22 years after their win, large-prize winners were still more satisfied with their lives than a matched comparison group of players. The effects on day-to-day happiness and mental health were smaller.
So money matters, most of all when it eases hardship. It matters more for how you rate your life than for how your days feel.
The Stanford Encyclopedia of Philosophy explains that “happiness” has two main senses. In one, it is a state of mind: pleasure, feeling good, or being satisfied with your life. In the other, it means well-being or flourishing, a life that goes well for you. Calling a life happy in that second sense is a value judgment. Psychologists use a similar split. Hedonic well-being is about pleasant feelings. Eudaimonic well-being covers things like meaning, personal growth and good relationships.
The word eudaimonic comes from Aristotle. In his ethics, as the Stanford Encyclopedia explains, eudaimonia means living well. It is the highest goal, and things like health and wealth are sought because they help you live well. For Aristotle, living well means a life of virtuous activity, and he gave two whole books of his ethics to friendship.
Many religious traditions answer differently. The Stanford Encyclopedia notes that the oldest and most influential God-based view in the Western tradition holds that a life is significant if it fulfills a purpose God has assigned.
Does faith go with happiness? A 2019 Pew Research Center study found that 36% of actively religious Americans, those who attend services at least monthly, called themselves very happy. That compares with a quarter of both less active believers and the religiously unaffiliated. In 12 of 25 other countries, active believers were happier than the unaffiliated by a statistically significant margin. But Pew says it is unclear whether religion causes the difference. Pew notes that earlier research suggests one factor may be the social connection that comes with regular worship.
The evidence suggests it can be. A 2014 meta-analysis, a study that combines many studies, pooled 54 research reports on programs led by trained professionals to help people forgive a specific hurt. People in these programs forgave more than people who got no treatment. They also saw greater drops in depression and anxiety, and more hope. Longer programs led to more forgiveness.
Forgiving is not the same as excusing what happened, or going back to someone who hurt you. The Stanford Encyclopedia says the more common view among philosophers is that you can forgive without reconciling. The research can’t say whether you should forgive a particular person. It suggests that working toward forgiveness can help the one doing the forgiving.
The strongest objection is that most of this evidence shows links, not causes. The Harvard Gazette itself describes a strong correlation. Maybe good relationships make people healthier. Or maybe healthier, more cheerful people find it easier to keep good relationships. Pew makes the same point about religion: happier people may be more active, rather than the other way around.
A second objection is about who was studied. The Harvard Study began with men only, from Harvard and from Boston’s inner city, in one era. The money studies used U.S. data, and the 2023 paper warns that the link between money and happiness is weak.
These are fair limits. But the relationship finding shows up again and again. The Stanford Encyclopedia lists supportive relationships among the generally accepted chief correlates of happiness.
“Good relationships are smooth.” Waldinger said some couples in their 80s bickered day in and day out. As long as they felt they could count on each other, the arguments didn’t take a toll on their memories.
“Money can’t buy happiness.” That is too simple. Income is linked to higher life ratings, and for most people to better days, but the effect is small.
“Your happiness is fixed.” The Stanford Encyclopedia reports that the dominant view now seems to be that early claims about a fixed happiness “set point” were exaggerated. Many things can have lasting effects.
The answer stays the same. What makes a life well lived is partly a question of values, and science can’t settle it. But across studies, countries and traditions, good relationships stand out as one of the surest supports of a good life.
THREE THINGS TO REMEMBER
WORDS WORTH KNOWING
KEEP ASKING
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