While money may or may not be able to buy you happiness, it turns out that the opposite may be true. According to a study published Monday by the Proceedings of the National Academy of Sciences. being a generally happy person will greatly increase young people’s chances of having a higher income by the time you’re 29.

According to the study, test subjects, who graded their happiness on a five-point scale, were shown at age 22 to have a $2,000 increase in income when compared to test subjects just one point below them. Between the happiest and most depressed extremes of the scale, the average difference in income amounted to $8,000.

When looking at the response’s given when the subject’s were in their teens, extremely miserable teens frequently saw their income levels dip 30% lower than the average, while the happiest teens instead saw their income levels rise 10% before the average level.

For the study, 10,000 test subjects were asked to rate their general happiness at ages 16, 18 and 22, and then finally checked their income level at age 29. In order to get an accurate assessment, the research team controlled variables such as education level, self-esteem, height, and IQ scores.

Additionally, the research team compared the levels of happiness and income for 3,000 people in sibling pairs, raised by the same parents. The happier of the siblings tended to out-earn the other.

This study suggests that strategies for promoting positive thinking may be more important for ensuring the success of teens than previously thought.

“It’s kind of like losing weight,” said Sonja Lyubomirsky, a social psychologist at the University of California, Riverside that was not involved with the study. “If you’re genetically predisposed to not being a happy person, you have to put a lot of effort into it.”

Given the nature of the research as a study and not as an experiment, it remains unclear if the resulting higher incomes are causally connected to a happier state of mind, but the study did show that happier teens were more likely to successfully earn a college degree, get hired more readily and have a more upbeat outlook on life.

“Early happiness probably changes so many things about your life that even if later in life you’re not as happy as you were, those formative experiences continue to play themselves out,” said Norton, coauthor of the book “Happy Money: The Science of Smarter Spending.”