How much money you make may impact your happiness. Overall contentedness rose steadily in line with income and accelerated faster once incomes reached above $100,000, according to a new study from Nobel Prize winning psychologist Daniel Kahneman published in the Proceedings of the National Academy of Sciences, Conrad Quilty-Harper reports for Bloomberg.

How money correlates to happiness

In 2010, Kahneman and economist Angus Deaton published a paper that found happiness increased with income, but the relationship started to "flatten" once incomes hit between $60,000 and $90,000 a year.

In the new study, Kahneman re-analyzed his work alongside Matthew Killingsworth, a Harvard University psychology doctoral student and former software product manager.

They surveyed 33,391 people between the ages of 18 and 65 living in the United States, asking the participants several times a day about their happiness using an app developed by Killingsworth.

They found that contentedness increased with income and accelerated once incomes surpassed $100,000, provided the person had a certain baseline level of happiness to start with.

Kahneman and Killingsworth did find a plateau of happiness, but only among the unhappiest 20% of people in the group, and only once their earnings surpassed $100,000. That group of people saw their happiness increase as their income approached $100,000, but once their income hit six figures, the happiness effect stopped working and "the miseries that remain are not alleviated by high income," Kahneman and Killingsworth found.

"For very poor people, money clearly helps a lot," Killingsworth said. "But if you have a decent income and you're still miserable, the source of your misery probably isn't something money can fix."

For participants outside of the unhappiest 20%, more money generally meant more happiness, Kahneman and Killingsworth found. For the happiest 30% of people, happiness increased and accelerated as incomes surpassed $100,000.

However, compared to other circumstances, including taking two days off at the end of a week, the overall emotional effect of money on a person was small. "An approximately four-fold difference in income is equal to the effect of a weekend," the study said.

The study included participants whose incomes were above $500,000, but Kahneman and Killingsworth said it was impossible to say definitively the happiness effect was present for people at that income level or higher.

"The trend rises steadily up through the top income group [$500,000] in my data, but how much farther it extends is an open question," Killingsworth said. "I am engaged in some work to solve this, but it's not done just yet."(Quilty-Haper, Bloomberg, 3/7)