Science of Happiness

Psychologists have spent decades studying mental illness. But what makes people genuinely happy? This is your VocaCast briefing on Science of Happiness for Monday, April 27.

We start with why this question matters, then move to the discoveries that changed how scientists think about wellbeing.

For most of the 20th century, psychology focused on one thing: treating mental disorders. ^[1] Psychopathology — the scientific study of mental illness — was the field's north star. The goal was to reduce suffering, to move people from dysfunction toward normal. But around the turn of the 21st century, something shifted. ^[2] Wellbeing science saw a sharp increase in activity, with researchers, grant funding. And public interest mobilizing under the umbrella term "positive psychology. " The positive psychology subfield underwent a period of great change, metaphorically described as waves, shifting from a focus on dysfunction and pathology to broader well-being, according to Doctor Paul Wong. ^[3]

A shift from an exclusive focus on symptoms to the cultivation of strengths and positive outcomes occurred in some areas of psychotherapy. ^[3] This wasn't just a rebranding. It was a fundamental change in what science asked.

The timing mattered. In the late 20th century, an intensely capitalist and individualist, markets-only socio-economic model had spent its efficacy. The old framework was breaking down. Meanwhile, the tools governments used to measure national success were collapsing under their own weight. ^[4] Gross Domestic Product — GDP — became the gold standard for measuring national prosperity. ^[5] For decades, economic success was measured by GDP, which institutions like the World Bank and IMF used as a primary indicator of a country's progress. Yet traditional economic metrics like GDP fail to capture many aspects of human wellbeing, community health, and environmental sustainability. ^[6] The number told you how much wealth a nation produced.

It told you nothing about whether people flourished in that nation.

The science of wellbeing has yielded extensive knowledge and measurement instruments over more than three decades. ^[7] The field of psychopathology evolved toward dimensional models where symptoms and diseases are seen as extremes of dimensions. ^[8] These advances in measurement and theory created new possibilities. ^[9] The COVID-19 crisis has been seen as an opportunity to imagine a new social contract that promotes cooperation and ensures citizens can flourish in the 21st century, according to Brookings. ^[5] The UN Summit of the Future officially embraced the need to move beyond GDP-centric growth in the UN Pact for the Future. What happiness science discovered wasn't theoretical anymore — it became policy.

When researchers set out to measure happiness, they quickly discovered a fundamental problem: there isn't one single thing called happiness to measure. Understanding wellbeing means grasping two distinct frameworks that have shaped the science itself. Psychological well-being and subjective well-being are often divided into two perspectives, shaped by the philosophical concepts of hedonism and eudaimonism, respectively. ^[10] The first framework, subjective well-being, is rooted in what philosophers call hedonism — the pursuit of pleasure and the avoidance of pain. This approach measures happiness through life satisfaction and emotional experience. ^[10] The second is eudaimonic well-being, derived from the ancient Greek concept of living virtuously and fulfilling your potential. These aren't the same thing.

A person might feel satisfied with their life yet lack a sense of purpose, or vice versa.

Yet when researchers compared two major models that measure these concepts, Seligman's PERMA model and Diener's Subjective Well-Being model, they found something striking: the correlation between them was extraordinarily high — 0.98 on a scale where 1.0 is perfect alignment. ^[11] The study used confirmatory factor analysis on data from 517 adults, suggesting the two frameworks capture a similar type of wellbeing despite their philosophical differences.

But here's what complicates the picture. The satisfaction you feel today isn't necessarily the satisfaction you'll feel tomorrow, even if nothing in your circumstances changes. The hedonic treadmill, a concept developed by researchers Philip Brickman and Donald Campbell in 1971, describes the tendency for humans to return to a baseline level of happiness despite life events, due to adapting and always wanting more. ^[12] You get a promotion, feel elated, then slip back to your normal emotional state. You move to your dream house, experience novelty, then adjust. The treadmill keeps turning. This isn't pessimism — it's how our brains are wired to normalize.

What actually sustains happiness over time is something quieter: appreciating life's small pleasures rather than chasing big, dramatic changes or ambitious self-improvement goals.

Across different populations, certain predictors keep emerging as powerful. The satisfaction of psychological needs for autonomy, competence, and relatedness directly affects subjective well-being and health outcomes across cultures. ^[10] In one machine learning analysis of 559 Korean adults, meaning in life, self-esteem. And essentialist beliefs about happiness were the strongest predictors of eudaimonic well-being, while depressive symptoms, subjective socioeconomic status, and emotional stability were salient predictors of subjective well-being. ^[13] A large analysis drawing on data from 1,567,295 individuals in 165 countries from the Gallup World Poll found that subjective health was uniquely associated with both hedonic well-being. Defined as positive affect, negative affect, and life satisfaction — and eudaimonic well-being, defined as psycho-social functioning.

Genetics account for roughly 20 to 48 percent of variation in personality traits, and genetic correlation patterns between eudaimonic and hedonic well-being and other phenotypes are largely similar. ^[14]