Harvard researchers, using the iPhone to track people’s moods, have found a correlation between daydreaming and unhappiness.

The app, aptly named “Track Your Happiness,” contacts iPhone users at random times during the day to ask how they’re feeling and what they are doing while answering these questions. Users have the option to decide when and how often they’ll be notified.

The researchers’ findings, published in the journal Science, were based on samples from 2,250 adults. Out of those surveyed, 58.8% were male, and 73.9% of them reside in the U.S. The mean age of those involved in the survey was 34. As DISCOVER reports, responders said they were daydreaming 46.9% of the time when the iPhone rang to check in on their thoughts. And those who said they were daydreaming were more likely to reveal that they were feeling unhappy.

That said, Jonathan Schooler — a psychology professor at the University of California, Santa Barbara — told The Boston Globe that the findings should not just be used to determine that a wandering mind is an unhappy one.

According to Schooler, mind-wandering is key for one’s problem solving abilities — and there is also evidence that it could be important for creativity.

As Schooler told the Globe, “Even if here are times when mind-wandering causes one to be unhappy, it doesn’t necessarily mean it’s not the thing that one should be doing.”

Meanwhile, “Track Your Happiness” is still out there, being used as a scientific tool to help researchers figure out the causes of one’s happiness.