The behavioral economist Daniel Kahneman argues each person is comprised of two selves: the experiencing self, the one who is always in the present, continually pushing through time, and the remembering self, who looks back on his or her life and uses memory to form impressions of the world. These two selves are at odds with each other, yet go a long way toward explaining happiness.

They also explain the opposite side: depression. A growing body of evidence suggests overall well-being isn’t found in the short-lived experience of material pleasure — an afternoon of video games, binging on Game of Thrones, or buying an expensive pair of shoes. Rather, researchers are finding happiness is found in selflessness, and now a new study from the University of Illinois at Urbana-Champaign and the University of California, Los Angeles, argues depression may tell the opposite story.

Brain Scans and Selfishness

The researchers distinguish between hedonic well-being and eudaimonic well-being — basically selfish pleasures versus selfless pleasures. You get a certain amount of joy from helping a friend move and another kind from buying beer for yourself afterward. In their study, the research team examined cases of both hedonic and eudaimonic well-being in 39 teenagers, taking brain scans with fMRI (functional magnetic resonance imaging) to see how certain activities correlated with depression levels over the course of year.

Subjects were given a set of tasks. The first gave them the option either to give their families a certain amount of money or keep it for themselves. They also played a game that assessed their propensity to take risks. Each of these tasks was carried out at the beginning and end of the yearlong trial period, along with questionnaires designed to gauge their depression levels.

Ultimately, the team found a region in the teens’ brains known as the ventral striatum played a vital role in determining what kinds of choices the subjects made. The ventral striatum is buried deep in the center of the brain, and it’s home to dopaminergic responses — or those that release dopamine, the pleasure-seeking hormone. Teens have acutely sensitive ventral striata, evidenced by their impulsivity and often lack of will power. It’s what makes addiction so problematic and attention spans so short.

By the end of the year, teens who engaged in hedonic activities displayed the greatest depression levels of the group. Meanwhile, those who had the greatest response to the selfless eudaimonic behavior option, giving rather than receiving, saw a substantial decrease in their depression levels, if they had any at all. These findings are correlative, of course — meaning that people who aren’t depressed may be more likely to give than seek. What the team emphasizes is the relationship between the two factors.

"For example," the authors wrote, "adolescents who show heightened activation in the ventral striatum during eudaimonic decisions likely experience a sense of reward from supporting their family and may therefore show increases in the time they spend helping their family."

Happiness at Large

These findings echo prior research into happiness, namely, that when people are Deprosocial they derive a more meaningful sense of joy. Daniel Kahneman’s theory of the experience and remembering selves upholds this, too, arguing that while the experiencing self is constantly living in three-second bursts of moment-to-moment happiness, the remembering self has an entire well of fond memories to look back on. And the crucial part is that the stickiest memories are those where the experiencing self was helping someone at the time.

Prosocial benefits span all ages and seemingly all countries. A 2012 study found that 2-year-olds were visibly happier when they gave some of their goldfish crackers away than when they received some. These findings were then replicated in over 100 countries. Another study, conducted in 2008, found that when subjects had to spend windfalls of either $5 or $20, or keep either one, they were markedly happier when they gave them away, regardless of the amount. The act of giving, irrespective of magnitude, brought people happiness.

The current researchers believe their study hits at a fundamental principle of human behavior. “The pursuit of rewards and attainment of well-being is perhaps the most important motivation in individuals’ lives,” they wrote, adding the fact is especially true of teenagers, whose lives are fraught with turbulence and pressure.

“Rewards are salient and important during adolescence,” they conclude, “and the ways in which youth respond to different rewards can have significant implications for their attainment of well-being over time.”

Source: Telzer E, Fuligni A, Lieberman M, Galvan A. Neural sensitivity to eudaimonic and hedonic rewards differentially predict adolescent depressive symptoms over time. PNAS. 2014.