Many people claim their best ideas come in the shower, and there’s quite a lot of anecdotal reports to back it up. There’s even a Reddit community called /r/ShowerThoughts where users post their strangest lather-dripping epiphanies. Some of my favorite shower thoughts from this subreddit include “We can see further at night than day. The furthest away things you’ll ever see are the stars” or “NPCs in video games look really awkward and unrealistic as they try to navigate around each other. Then you see real people in a busy airport or supermarket and realize it’s actually pretty accurate.”

What is it about showers that fosters creative thinking? In a new study, Zac Irving, a University of Virginia assistant professor of philosophy, explains that the ‘shower effect’ isn’t limited to the bathroom. He explains that there is evidence suggesting that a wandering mind is better able to come up with a creative solution when we’re engaged in a so-called ‘mindless’ task. There’s a caveat though: the routine task, whether it’s taking a shower or gardening, needs to be moderately engaging.

“Say you’re stuck on a problem,” Irving said. “What do you do? Probably not something mind-numbingly boring like watching paint dry. Instead, you do something to occupy yourself, like going for a walk, gardening, or taking a shower. All these activities are moderately engaging.”

Almost a decade ago, psychologist Benjamin Baird published a study that found “engaging in simple external tasks that allow the mind to wander may facilitate creative problem-solving.” Baird recruited volunteers and tasked them to come up with unconventional and creative new uses for everyday items such as a brick. They had to do this immediately after an “incubation period” that involved a demanding or undemanding task.

This study was cited quite a lot, both in the scientific literature and in the media. But when other researchers tried to do their own versions of this study, they couldn’t replicate the findings.

So was Baird’s research just bad science? Irving doesn’t think so. “They weren’t really measuring mind-wandering,” he said. “They were measuring how distracted the participants were.”

The researcher argues that the tasks that were supposed to simulate mind-wandering among participants look good in the lab but don’t actually translate to the real world. He gives as an example the “Sustained Attention Response Test”, in which a participant basically has to perform a tedious task, such as following a stream of digits from 1 to 9 on a computer screen and not clicking a mouse button when you see ‘3’.

“They’re just not like anything in people’s daily lives,” he added. “Mind-wandering might help in some contexts, like taking a walk, but not others, like a dull psych task.”

To test this theory out, Irving and University of Minnesota psychology professor Caitlin Mills recruited students from the University of New Hampshire campus. The participants had to, like in Baird’s original study, come up with creative alternative uses for either a brick or a paperclip.

The students were split into two groups that had to watch different three-minute videos, which serve as the ‘incubation models’. One group watched a video of two men folding laundry, while the other group watched a scene from the 1989 movie When Harry Met Sally, in which the character played by Meg Ryan demonstrates how to fake a convincing orgasm in the middle of a crowded restaurant.

“What we really wanted to know was not which video is helping you be more creative,” Irving said. “The question was how is mind-wandering related to creativity during boring and engaging tasks?”

He added, “The reason we used a video is because Caitlin is very much engaged in this movement within psychology to use naturalistic tasks” 

Right after they watched the videos, the participants had to immediately start their creative task. They also self-reported how much their mind wandered while watching the videos, meaning how much their thoughts wandered from topic to topic.

The researchers found that mind-wandering led to more creative ideas, but only when the participants were watching the ‘engaging’ rather than the ‘boring’ video.

While the researchers don’t plan to repeat their study in the shower, they plan to scale their experiment using virtual reality to study mind wandering in more realistic contexts, such as walking down a virtual street.

The findings appeared in the journal Psychology of Aesthetics, Creativity, and the Arts.