What is happiness? Findings from 50 years of happiness research

What is happiness—and why does it so often seem to vanish just when we seek it most? This question has preoccupied humanity for millennia. Philosophers have debated it, poets have sung of it, and for about five decades, science has also been trying to get to the bottom of it. So-called happiness research—also known as positive psychology—has gathered remarkable insights during this time that could turn our everyday understanding of happiness on its head. For what we commonly consider to be the sources of our well-being often has surprisingly little in common with what research suggests. This article invites you to take a look at what scientists have discovered about happiness, life satisfaction, and well-being—and what that might mean for your everyday life.

What is happiness? A question with many answers

The question itself is more complicated than it first appears. Do you mean the fleeting elation after receiving good news? The deep satisfaction of a fulfilling evening with people who matter to you? Or the quiet sense that your life, on the whole, makes sense? Happiness science deliberately distinguishes between different levels here.

The pioneer of modern well-being research, Ed Diener, presented a framework as early as 1984 in his seminal work on so-called subjective well-being, which remains the starting point to this day. Diener (1984) described well-being as an interplay of three elements: frequent positive emotions, infrequent negative emotions, and a personal assessment of one’s own life satisfaction. This distinction is important—because it shows that happiness is not simply the absence of sadness, nor is it merely a string of pleasant moments.

Some people experience deep contentment even though their daily lives are full of struggles and challenges. Others, on the other hand, report a nagging feeling of inner emptiness despite seemingly ideal external circumstances. This suggests that happiness may depend less on life circumstances than we intuitively assume—a realization that can be both unsettling and liberating for many people.

The Fortune Cookie Model: How Much Can We Influence Ourselves?

One of the most frequently cited findings in happiness research comes from psychologist Sonja Lyubomirsky. Lyubomirsky (2005), together with colleagues, developed a model that has since become known as the “Happiness Pie.” It describes how our subjective well-being might be roughly composed:

• About 50 percent could be determined by our genetic makeup—a kind of biological starting point over which we have little influence.
• About 10 percent could depend on our external life circumstances—that is, whether we are married, how much we earn, or where we live.
• About 40 percent could be influenced by our own thoughts, actions, and habits.

These figures are approximations and are certainly debated in research—they should not be taken as established truth. Nevertheless, the model points to something encouraging: A significant portion of our experienced well-being could lie within our own sphere of influence. Some people see this idea as an invitation to realign their own attitudes, habits, and focus—without feeling the pressure to “have to be happy” all the time.

PERMA: What Might Make for a Fulfilling Life

One of the most well-known names in positive psychology is Martin Seligman. In his 2011 book Flourish, Seligman (2011) described a model of human flourishing that goes far beyond the mere experience of joy. He called it the PERMA model—and it could serve as a helpful roadmap when asking what constitutes a truly fulfilling life.

PERMA stands for:

• P – Positive Emotions: joy, gratitude, love, curiosity, and hope—feelings that can enrich life.
• E – Engagement: Being fully absorbed in an activity, the so-called “flow” – when time and self-awareness fade into the background.
• R – Relationships: Deep, meaningful connections with other people, which many consider one of the most important sources of life satisfaction.
• M – Meaning: The feeling of contributing to something greater – whether it be family, community, faith, or a task that extends beyond one’s own self.
• A – Accomplishment: Pursuing and achieving goals that are important to oneself—not for the sake of recognition, but for the sake of growth.

Seligman (2011) suggested that well-being is not a single state, but rather an interplay of these five dimensions. Not every dimension needs to be fulfilled to the same degree—and some people naturally prioritize different areas. The model invites self-reflection rather than optimization: What might be missing in my life right now? Which dimension has received little attention lately?

Key idea from happiness research Seligman (2011) described well-being not as a fixed state that is achieved and then maintained - but as something alive that needs to be nurtured, lived and constantly rediscovered. Happiness could be less a goal than a way of living.

The Difference Between Experienced and Recalled Happiness

One of the most fascinating—and for many, initially confusing—findings in the science of happiness comes from Nobel laureate Daniel Kahneman. Kahneman (2010) distinguished between two different ways we experience and evaluate happiness: the experiencing self and the remembering self.

The experiencing self perceives what is happening right now—second by second, hour by hour. The remembering self, on the other hand, evaluates experiences in retrospect and tells us how pleasant or difficult something “was.” The interesting thing is that these two instances often arrive at very different judgments.

Kahneman (2010) showed that the remembering self is strongly influenced by the end of an experience and its emotional climax—not by its total duration. A long trip with a wonderful final day may be remembered more fondly than a shorter trip that ended somewhat blandly—even though the overall enjoyment experienced may have been different. This insight might encourage us to make a more conscious distinction: Am I currently focused on truly experiencing a moment—or on being able to tell a good story about it? Both have their value, and some people find it helpful to ask themselves this question from time to time.

For personal life satisfaction, this also means: Our retrospective assessment of our lives may depend heavily on how we tell our story—not just on what actually happened.

What Really Makes Us Happy: The Harvard Study of Adult Development

If there is one scientific study that has had a lasting impact on the field of happiness research, it is undoubtedly the Harvard Study of Adult Development—one of the longest-running longitudinal studies in the world, which has been ongoing since the late 1930s and has tracked the lives of over 700 men and, later, their families.

Robert Waldinger and his team published a comprehensive summary of this research in 2023. The central finding reached by Waldinger (2023) and his colleagues sounds almost simple—yet is profound: it is above all the quality of our relationships that may be linked to a long, healthy, and fulfilling life. Not wealth, not fame, not professional success.

People who reported living in stable, warm relationships reported higher well-being over decades—and in some cases also showed physical benefits in old age. Waldinger (2023) emphasized: It is not about having as many contacts as possible, but about the depth and reliability of the connections. Loneliness, on the other hand, could have a similarly detrimental effect on subjective well-being and health as other known risk factors—even if this is, of course, no substitute for individual professional counseling.

What this insight might mean: The time we invest in relationships—whether with partners, friends, family, or the community—could be one of the most effective forms of self-care available to us.

Adaptation: Why Happiness Slips Away—and Why That’s Normal

Anyone who delves deeper into happiness research inevitably encounters a phenomenon that psychologists refer to as hedonic adaptation—sometimes also described as the “hedonic treadmill.” This refers to the human ability—or perhaps inclination—to quickly adapt to changes in our lives, both positive and negative.

A new car, a bigger apartment, a promotion—at first, they can bring genuine joy. But after a few weeks or months, they become the new normal. Our experience of happiness often settles back down to a level similar to what it was before. Lyubomirsky (2005) pointed to this mechanism to explain why external circumstances may contribute less to our long-term life satisfaction than we expect.

At first, this sounds sobering—and for some people, it can be. At the same time, it points to something interesting: Perhaps it is less the magnitude of the event that matters than the way we are present in everyday life and what we focus our attention on. Small, regular sources of joy and meaning—a conversation that truly touches us, a walk at dusk, a moment of genuine connection—might contribute more to our well-being in the long run than the big, rare events we so often wait for.

Happiness and Life Satisfaction – Are They the Same Thing?

In everyday language, happiness and life satisfaction are often used as synonyms. In research, however, a careful distinction is sometimes made. In his work on subjective well-being, Diener (1984) pointed out that life satisfaction is more of a cognitive assessment—a kind of balance sheet we draw up regarding our lives: “Does my life match my expectations? Am I satisfied with what I have achieved?”

Happiness in the narrower sense, on the other hand, refers more to the emotional level—how frequently and intensely we experience positive feelings. Both dimensions can influence each other, but they do not necessarily go hand in hand. There are people who report high life satisfaction even though their daily lives are emotionally rather quiet. And conversely, some people may experience intense joy but at the same time feel that their lives are not heading in the direction that truly suits them.

This distinction can invite us to take a more nuanced look at our own inner world: Am I currently seeking more positive moments in my daily life? Or am I looking for a deeper sense of meaning and coherence? Some people find it enlightening to ask both questions separately.

What research on habits that promote happiness suggests

If, according to Lyubomirsky’s (2005) model, about 40 percent of our experienced well-being could be shaped by our own actions and ways of thinking, the question naturally arises: Which habits might play a role in this?

Research points to several areas that could be relevant for many people—though there is no one-size-fits-all solution:

• Gratitude: Studies suggest that consciously noticing and recording positive experiences—for example, in a gratitude journal—could support subjective well-being over time. Not as a duty, but as an invitation to mindfulness.
• Cultivating meaningful relationships: As Waldinger (2023) and his team demonstrated, investing in genuine connection—including small, everyday gestures of care—could be one of the most effective long-term contributors to one’s own life satisfaction.
• Presence and engagement: Seligman (2011) described the state of flow—being completely absorbed in an activity—as a potential source of deep satisfaction. Perhaps you might ask yourself: When was the last time I lost track of time while doing something that matters to me?
• Meaning and contribution: The feeling of doing something that extends beyond one’s own self—for others, for a community, for something greater—could, according to research, have a stabilizing effect on well-being.
• Exercise and Nature: Even though this article focuses primarily on psychological research, many studies suggest that physical exercise and time spent in nature could support emotional well-being—of course as a supplement, not a substitute for professional support in cases of more serious stress.

It’s important to note: None of these habits work like a switch you can flip. They’re more like seeds that grow over time—sometimes slowly, sometimes in unexpected ways. And they are by no means a substitute for professional support when life feels too heavy to bear alone.

Happiness is not a permanent state—and that might actually be good news

Perhaps one of the most liberating insights from five decades of happiness research is this: Happiness is not a state that one achieves once and then possesses permanently. It is more like breathing—something that comes and goes, that needs to be nurtured, and that changes depending on what stage of life one is in.

Kahneman (2010), with his distinction between the experiencing self and the remembering self, has shown how subjective and constructed our perception of happiness can be. Seligman (2011) has suggested that flourishing does not lie in the absence of difficulties, but in the presence of sustainable internal and external resources. And Waldinger (2023) has impressively illustrated that genuine human connection may be what matters most—across all age groups, cultures, and life circumstances.

What might this mean for you? Perhaps that it’s worth not answering the question “What is happiness?” once and for all—but rather asking it anew again and again. Curiously, openly, without pressure.

Because some people believe that this question alone—asked attentively and considered honestly—can already set something in motion.

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What does science understand by happiness?

In psychological research, happiness is often described as subjective well-being - a concept that Ed Diener fundamentally defined back in 1984. Accordingly, it encompasses both the emotional level (frequent positive and infrequent negative feelings) and a cognitive component: the personal assessment of whether one's own life meets one's own expectations. In this sense, happiness is not an objective state, but a deeply personal experience that can vary from person to person.

How much of our happiness can we influence ourselves?

The much-cited model by Lyubomirsky (2005) suggests that around 40 percent of our subjective well-being could be shaped by our own thoughts, actions and habits - while around 50 percent could be due to genetics and around 10 percent to external circumstances. These figures are approximate values that are discussed in research and should not be taken as a fixed formula. However, they indicate that our own scope may be greater than we assume.

According to research, what are the most important sources of life satisfaction?

The Harvard study by Waldinger (2023) suggests that the quality of our relationships could be one of the most important factors for long-term well-being. Seligman (2011) added further dimensions with his PERMA model: positive feelings, engagement, meaning, connectedness and the experience of self-efficacy. Research suggests that it is rarely a single source, but rather an interplay of several factors that can contribute to a life that is experienced as fulfilling.

Why doesn't more money automatically make you happier?

This phenomenon can be partly explained by hedonistic adaptation: People adapt quickly to new life circumstances - even positive ones - so that the initial happiness effect often fades. Lyubomirsky (2005) pointed out that external circumstances such as income or possessions may only play a small part in our long-term well-being. This does not mean that financial security is unimportant - but it alone cannot create a lasting sense of happiness.

What is the difference between the experiencing self and the remembering self?

This distinction goes back to Daniel Kahneman (2010). The experiencing self perceives what is happening in the present moment. The remembering self evaluates experiences retrospectively - and the end and emotional climax of an experience play a major role here, not its overall duration. This can lead to our memory of past experiences differing greatly from what we actually experienced moment by moment.

Can happiness be trained or learned?

Research suggests that certain habits and attitudes may support subjective well-being over time - such as consciously cultivating gratitude, fostering meaningful relationships or seeking out activities that enable engagement and flow. Whether and to what extent these practices work can vary from person to person. They are no guarantee and are no substitute for professional support for serious stress - but for many people, they can be a helpful starting point for dealing more consciously with their own well-being.

Here’s an idea for you: Maybe tonight—or whenever it feels right for you—you could take five minutes to write down three moments from the past week when you felt truly connected, alive, or grateful. Not just to complete an exercise, but to get a little closer to your own inner map of well-being. What you discover in the process might surprise you.