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Pursuit of Happiness

The Science of Happiness

Happiness research has found no single secret. It has found a handful of habits that each help a little, and that work best in combination. The ingredients that matter most differ from person to person, so the most useful skill is learning to try them out and notice what works for you.

Last reviewed October 2026 · Based on 32 studies and reviews

The seven habits

  1. Relationships: People who are more socially connected tend to be happier and live longer. Strong, mostly observational evidence.
  2. Kindness: Doing kind acts, and treating yourself kindly, makes people a little happier in experiments.
  3. Physical wellbeing: Better sleep and regular exercise each reduce depression and anxiety in randomised trials (Scott et al., 2021; Singh et al., 2023). Strongest evidence.
  4. Flow: Being absorbed in a challenging activity goes with more wellbeing and meaning.
  5. Strengths: Using what you are good at goes with higher wellbeing; short exercises give small gains.
  6. Meaning: A sense of purpose goes with less depression and a longer life.
  7. Positive mindset: Gratitude, mindfulness and hope give small average gains in trials.

Level 1 · The basics

Is there a secret to happiness?

No single secret has been found. Scientists have found several habits that each help a little: spending time with people you care about, being kind, sleeping and moving well, getting absorbed in something you enjoy, using what you are good at, doing things that matter, and noticing the good around you.

Happiness soup

Think of happiness like a soup. One ingredient on its own does not make much of a soup. Several good ingredients together make something much better. That is why we talk about seven habits, not one.

But everyone's favourite soup is different. One person feels much better after exercise. Another feels the biggest change from spending more time with friends. The only way to find your own recipe is to try the ingredients and notice what happens.

You can change how you feel

Many people think happiness is something you either have or you don't. Research suggests that is not quite true. Your mood can change, and some of what changes it is in your hands. People who believe this tend to handle hard feelings in healthier ways. We think a good way to realise it is to see it for yourself, through small experiments.

Try your own happiness experiment

  1. Pick one habit. For example, a 15-minute walk outside each day.
  2. Write down how you feel each evening for a week before you start, on a scale from 1 to 10.
  3. Do the habit for two weeks, and keep writing down your score each evening.
  4. Compare. Did your scores go up, stay the same or go down?
  5. Keep it, change it or try another. No result is a failure. Every test teaches you something about your recipe.

Safety first: Never stop or change a medicine as an experiment. Don't test skipping meals, cutting sleep or taking supplements without talking to a doctor, and a parent if you are under 18. If you feel low most days for two weeks or more, or ever think about hurting yourself, that is not something to experiment with: tell a trusted adult and get help.

Level 2 · The evidence explained

Small effects, honestly reported

Most single happiness practices produce small average effects. A 2025 meta-analysis of gratitude practices across 28 countries found an effect of about 0.19 standard deviations, falling to 0.15 after correcting for publication bias (Choi et al., 2025). A re-analysis of positive psychology intervention reviews found wellbeing effects shrink to about r = 0.10 once small-study bias is corrected (White et al., 2019). A review of the happiness advice most often given in the media found that the most rigorous studies supported only two strategies, gratitude and socialising, and mostly for short-term mood boosts (Folk & Dunn, 2023).

We think it is better to say this plainly than to promise big results. Small effects still matter: they are real, they cost little, and they can be combined.

Why combining habits matters

Wellbeing has many inputs, much like physical health. No one expects one vegetable to make them healthy; health comes from many habits working together. The seven habits work in a similar way. They also support each other: more sleep makes it easier to be active, being active often means time with others, and so on, although one habit does not automatically fix another.

There is a limit. Taking on too many practices in a short time can backfire. In an online trial, people given two or four positive psychology exercises had better outcomes on depressive symptoms than people given six, though neither group clearly beat doing nothing, and about half of participants dropped out (Schueller & Parks, 2012). The lesson is to add a few ingredients at a time, not all of them at once.

People differ, but less than you might think

An average effect can hide differences between people. In psychotherapy for depression, a review of 306 trials found outcomes vary about 9% more in treatment groups than in control groups, which suggests people do respond differently: individual responses probably spread by about 3 to 4 points either side of the average on depression scales (Kaiser et al., 2022). For online and app programmes for depression, a review of 102 trials found no clear sign of such differences, though most participants had mild to moderate depression (Terhorst et al., 2024).

So it is reasonable to expect that some habits will suit you better than others, but not that one hidden habit will transform your life while the rest do nothing. What seems to matter is choosing habits that suit your personality and your life, putting real effort into them, and keeping them up. In one experiment, gratitude and optimism exercises helped mainly people who had chosen to take part in a happiness study and who put real effort into the exercises (Lyubomirsky et al., 2011).

Realising you can change

People who believe their own feelings can change tend to handle stress in healthier ways, for example by rethinking a situation instead of avoiding it, and tend to report less depression over time (Tamir et al., 2007; Ford et al., 2018; Kneeland & Dovidio, 2020; Kim et al., 2024). This is a link, not proof of cause, and the causes may run in more than one direction (Kneeland et al., 2024).

Brief online lessons that teach that feelings and personality can change have helped some teenagers feel more hopeful and more in control, with small drops in depressive symptoms three months later (Schleider et al., 2022). Other trials have found little or no effect on symptoms (Ball et al., 2025; Zhu et al., 2025). Being told that change is possible seems to work best alongside a concrete method and steady practice.

That is why we suggest treating each habit as a small experiment. Telling someone they can change is one thing; noticing your own mood rise after a week of walks is another. Small, honest experiments are a way of realising for yourself that you can change how you feel. This is our advice, based on the research above, not a tested finding in its own right.

Our own classroom trial

In a classroom-randomised trial at a Beijing high school, first-year high school students (equivalent to US tenth grade) who took an 18-session course based on these habits improved more than students taking the standard psychology course on six of seven positive attitudes, including hope and a sense of competence (Desan et al., 2021). By the end of the course they were also more likely to agree that they could improve their own happiness. The effects were small, measured in one school with no long-term follow-up, and changes in depression, life satisfaction and happiness were in the right direction but not statistically significant.

Disclosure: this trial tested the Pursuit of Happiness curriculum, and Pursuit-of-Happiness.org staff were among the authors. The study was funded by a grant from the school to Yale University and Pursuit-of-Happiness.org.

Self-experiments: useful, with limits

Testing habits on yourself is not the same as a scientific trial. In one study of app-guided self-experiments, how people read their own results, which was partly shaped by what they expected, mattered more than the actual numbers in whether they planned to keep the habit (Kravitz et al., 2020). In a randomised trial, personalised self-experiments for stress did not beat simply using the same techniques however people liked, and only about half of participants followed their own results (Goodwin et al., 2026).

Placebo and expectation will play a part in any self-test. That is fine for everyday habits such as walks, sleep or calling a friend, which are low-risk and good for you anyway. Write your scores down every day rather than relying on memory, test one change at a time, and give it at least two weeks. Be more careful with anything you buy, such as supplements, where the evidence is often thin and industry-funded (see the FAQ below).

Level 3 · Deep dive

Effect sizes in context

Pooled effects for single positive psychology interventions are small and sensitive to bias correction. Choi et al. (2025), a preregistered meta-analysis of gratitude interventions (24,804 participants, 28 countries), reported Hedges' g = 0.19, or 0.15 after publication-bias correction. White et al. (2019) re-analysed two earlier meta-analyses and found wellbeing effects of about r = 0.10 after correction for small-study effects. Folk and Dunn (2023) reviewed the strength of evidence for commonly recommended happiness strategies and found that, among 57 well-powered, preregistered studies, only gratitude and socialising had supporting evidence, mostly for short-term effects; exercise, mindfulness and time in nature lacked such evidence.

Combination and dosage

Multicomponent programmes are not simply additive. In Schueller and Parks (2012; N = 1,364), two or four exercises outperformed six on depressive symptoms, but neither beat no-intervention significantly, attrition was about 50%, and analyses were of completers only. Recommendations for "happiness soup" should therefore stress a few well-chosen components at a time.

Heterogeneity of response

Variance-ratio meta-analyses estimate whether individuals respond differently to an intervention. Kaiser et al. (2022; 306 trials, 51,853 patients) found treatment-arm variance about 9% higher than control-arm variance in psychotherapy for depression, consistent with modest individual differences in response (roughly 3 to 4 points on depression scales). Terhorst et al. (2024; 102 trials, 19,758 participants) found no evidence of treatment-effect heterogeneity in internet- and mobile-based depression interventions, mostly internet CBT for mild to moderate cases, with variability increasing with baseline severity. Person-activity fit and effort moderate gains (Lyubomirsky et al., 2011; N = 330; NIH-funded), although self-selection in that study was not randomised.

Malleability beliefs and agency

Prospective studies link emotion malleability beliefs to more reappraisal, less avoidance and fewer depressive symptoms (Tamir et al., 2007; Ford et al., 2018; Kneeland & Dovidio, 2020), and a meta-analysis confirms these associations, though its mediation model rests on cross-sectional data (Kim et al., 2024). Direction is not settled; in one longitudinal study, symptoms also mediated the link between beliefs and later rumination (Kneeland et al., 2024). In the largest trial, a 20 to 30 minute growth mindset of personality single-session intervention for US adolescents with elevated depression symptoms (N = 2,452) reduced 3-month depression by d = 0.18 and increased perceived agency by d of about 0.15, with only 37 to 41% retention at follow-up (Schleider et al., 2022; NIH-funded). Smaller independent trials of similar sessions found no advantage on symptoms (Ball et al., 2025, UK, n = 104, waitlist control; Zhu et al., 2025, Hong Kong, n = 731, all arms including the active control improved similarly). The academic growth mindset literature is contested, with near-zero effects after bias correction in one meta-analysis (Macnamara & Burgoyne, 2023) and small heterogeneous effects in another (Burnette et al., 2023). No trial we found shows that changing such beliefs leads people to try a wider range of wellbeing habits; that link is our inference.

Our pilot trial

Desan et al. (2021) randomised 18 classrooms at Beijing No. 19 High School (intervention n = 252, control n = 263; first-year students, equivalent to US tenth grade) to an 18-session Pursuit of Happiness curriculum or the standard psychology curriculum. The primary outcome, a composite positive attitude scale, improved (effect 1.33, 95% CI 0.39 to 2.27), with significant subscale effects of 0.17 to 0.27 z for relatedness, competence, autonomy, gratitude, mindfulness and hope (largest for hope) and none for calmness. Positive affect balance improved, mainly through reduced negative affect. Depression (CES-D), life satisfaction, subjective happiness and meaning in life improved non-significantly. Single course-rating items showed more agreement that people in general (p < .01) and the students themselves (p = .02) could improve their happiness. Limitations: one school, short-term follow-up, lower scale reliability than in reference samples (e.g. competence alpha 0.65), and higher baseline positive affect in the intervention group. Authors include Pursuit-of-Happiness.org staff; funding was a grant from the school to Yale and Pursuit-of-Happiness.org.

Self-experimentation (N-of-1)

Kravitz et al. (2020) found that in app-supported N-of-1 trials of wellbeing practices, participants' interpretation of their own results predicted their enthusiasm for continuing the practice more than the measured results did, and prior expectations (recalled after the trial) also predicted enthusiasm and modestly shaped how results were read (NIH-funded; some authors report digital-health industry ties). Goodwin et al. (2026; N = 212) found personalised N-of-1 trials for stress were not superior to standard care (p = 0.50), with about half of participants adhering to their personalised recommendation. Self-experiments are best presented as a tool for engagement and self-knowledge, not as proof of causal effects for the individual.

Full sources

See the bibliography below. Evidence for each habit is reviewed on its own page.

Frequently asked questions

What is the science of happiness?

It is the scientific study of wellbeing: what helps people feel good, find life satisfying and function well. It draws on psychology, medicine, neuroscience and economics. Its findings on what people can do for themselves group into seven habits.

Can you really become happier?

Yes, on average, though usually by modest amounts. Trials of exercise and of better sleep show moderate drops in depression and anxiety (Scott et al., 2021; Singh et al., 2023), and gratitude practices show small gains (Choi et al., 2025); evidence for kindness from the strictest studies is mixed (Folk & Dunn, 2024). People who believe their feelings can change tend to cope better. We think combining a few habits is likely to help more than relying on one, though piling on too many at once can backfire (Schueller & Parks, 2012).

Which habit works best?

For mental health, the strongest trial evidence is for sleep and exercise (Scott et al., 2021; Singh et al., 2023). Beyond that, the best habit is the one that suits you and that you will keep doing. A simple two-week experiment is a good way to find out.

Does money make you happier?

For most people, happiness keeps rising with income, but each extra dollar adds less: going from $50,000 to $100,000 a year brings about the same rise as going from $100,000 to $200,000. For the least happy fifth of people, happiness stops rising above about $100,000 a year, which suggests money can ease some kinds of unhappiness but not all. The link is real but small, and it comes from a survey of employed US adults rather than an experiment (Killingsworth, Kahneman & Mellers, 2023).

Do probiotics or "psychobiotics" improve mood?

The evidence is early. A 2025 review of probiotics for depression in adults not taking antidepressants pooled six small trials and found a small benefit. But five of the six were funded by industry, and the only independently funded trial, with about 35 people, found no clear effect (Liu et al., 2025). Some people feel they benefit, but personal experience is not proof. Talk to a doctor before trying supplements, especially if you take other medicines.

Is it safe to experiment with happiness habits?

Everyday habits such as walking, sleeping regularly, spending time outdoors or calling a friend are low-risk. Don't experiment with medication, extreme diets or sleep loss. If you have felt low most days for two weeks or more, or have thoughts of self-harm, please seek professional help rather than experimenting on your own.

What makes people happy, according to psychology?

No single thing. Research points to a handful of habits that each help a little: close relationships, kindness, sleep and exercise, absorbing activities, using your strengths, a sense of meaning and a positive mindset. The strongest trial evidence is for sleep and exercise (Scott et al., 2021; Singh et al., 2023), and good relationships are one of the most consistent links to happiness (Diener & Seligman, 2002).

Is positive psychology the same as the science of happiness?

Not quite. Positive psychology is the branch of psychology that studies what makes life go well, set out by Martin Seligman and Mihaly Csikszentmihalyi in a landmark 2000 paper (Seligman & Csikszentmihalyi, 2000). The science of happiness is broader: it also draws on medicine, neuroscience and economics, such as trials of sleep and exercise and studies of income and happiness.

Bibliography

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This page is reviewed regularly as new research is published. Earlier version: archive.