But of course, we don’t always peruse the psychological literature before reaching for that fourth beer. Some people naturally seek out delights that are more corporeal and decadent—The Wolf of Wall Street comes to mind—and others will gladly spend the afternoon helping grandma paint her dining room because it’s “a good thing to do.”

Over the years, scientists have found they can measure the amount that a person enjoys something by taking MRIs of activation levels in the ventral striatum—the “reward center” nestled in the bullseye of the brain. The ventral striata of teens, in particular, tend to light up especially brightly in response to all kinds of rewards. Because teens brains are so sensitive to these little jolts of pleasure—or lack thereof—late adolescence is also when depression peaks for many people.

In a new study, researchers aimed to figure out how the tender brains of adolescents reacted to the more bacchanalian rewards, like video games and drugs, versus the more pro-social ones, like “helping others in need, expressing gratitude, and working toward long-term goals.” Would the teens who get their jollies from volunteering be happier, in the long run, than those who live only for Grand Theft Auto?

For the study, published today in the Proceedings of the National Academy of Sciences, the researchers followed a group of 39 teenagers over the course of one year to see whether the way their brains reacted to either eudaimonic or hedonic rewards correlated with how depressed they felt over time.

First, the subjects underwent an fMRI while making a decision about whether to keep money for themselves (a hedonic reward) or to donate it to their families (eudaimonic). They also played a game to determine if they were willing to take risks for the possibility of a greater financial reward (hedonic).

The subjects then filled out a self-report questionnaire of depressive symptoms during the initial scan, and again a year later.

It turned out the teens who had the greatest brain response to the generous, family-donation financial decision had the greatest declines in depressive symptoms over time. And those who got a boost from the risk-taking game were more likely to have an increase in depression. The types of rewards the teens responded to, it seems, changed their behavior in ways that altered their overall well-being.

"For example," the authors write, "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."

It’s important to note that this doesn’t necessarily mean parents can inoculate their teens against depression by forcing them to seek happiness through volunteering. But it could be that teens who already do that kind of thing because it really does lift their spirits are likely to have that lift stick with them.

“Taken together, our findings suggest that well-being may depend on attending to higher values related to family, culture, and morality, rather than to immediate, selfish pleasure,” the authors write.

So, good luck convincing teenagers of that.