For decades, philosophers, economists and sociologists have debated the question: Can money buy happiness?

For most people in the United States, the answer is, apparently, yes. Two prominent researchers, Daniel Kahneman and Matthew Killingsworth, came to this conclusion in a joint study published in the Proceedings of the National Academy of Sciences .

Previously, it was believed that "emotional well-being increases with income, but there is no further progress beyond an annual income of $75,000."

Kahneman and Killingsworth said their latest study contradicts previous thinking. The latest research is adjusted for inflation, they said.

In their research, researchers surveyed 33,391 adults between the ages of 18 and 65 who live in the United States, are employed and report an income of at least $10,000 a year.

To measure their happiness, participants were asked to report on feelings at random times during the day through a smartphone app developed by Killingsworth called Track Your Happiness.

The study concluded that "happiness continues to increase as income increases" for most people, showing that for many of us, having more money can make us increasingly happier.

Happiness improves as high earnings rise, up to $500,000 a year. There are also people - 15% - for whom money has no influence on their emotional state.

"The exception is people who are financially rich but unhappy. For example, if you are rich and miserable, more money will not help," the researchers point out.