Be optimistic. Think happy thoughts. Lots of happiness advice makes it sound as if we could flip a switch and fill our heads with puppies and rainbows—and wouldn’t that be great?

But it turns out that positive thinking isn’t so easy. In an infamous 2014 study where people had 15 minutes to mentally entertain themselves, about 40 percent chose to help pass the time by—no, not meditating—receiving an electric shock.

In fact, a recent study found that only 13 percent of people’s thoughts are positive and inner-directed, and they enjoy those thoughts more when they arise spontaneously. (In other words, they prefer that happy thoughts come naturally rather than putting in the effort to “think positive.”)

Could this process be easier and more enjoyable? It’s not an idle question: According to the researchers behind the new study, if people were better able to generate pleasant thoughts, they might rely less on technology for constant stimulation. It could help those who have trouble falling asleep, or who start pounding the steering wheel in traffic.

The researchers didn’t find a magic switch. But they did discover a simple trick.

Across four studies, more than 250 college undergraduates and 800 online participants started by listing eight topics they’d enjoy thinking about, including memories, fantasies, and things they were looking forward to. People wrote down everything from their wedding day to Valentine’s Day, their family or the summer, eating decadent cake, or living in the World of Warcraft universe.

Next, participants (alone in a room) were instructed to entertain themselves for four to six minutes with thoughts about the topics they had listed. “Your goal should be to have a pleasant experience, as opposed to spending the time focusing on everyday activities or negative things,” the researchers advised.

That was it, except for one small difference: Half of the participants had access to their list of topics, either written on notecards or displayed on a computer screen one by one. The other half didn’t.

Afterward, participants rated how pleasant the activity was (how enjoyable, entertaining, and boring) and how cognitively difficult it was (how hard it was to concentrate, how much their mind wandered, and how much time they devoted to irrelevant topics).

Ultimately, the researchers found that the group who could look at their list of topics found the experience more pleasant and less cognitively demanding. All the participants had made lists in the first part of the experiment, but having access to that “thinking aid” was key.

“Often when we have a few free minutes, we reach for our cell phones to entertain us,” says Erin C. Westgate of the University of Virginia. “But with a little planning ahead of time, we might be able to use our own minds instead.”

She and her co-authors (including Daniel Gilbert of Harvard University) speculate that the list might have made it easier for people to concentrate; to remember their go-to, happiness-boosting topics; or to decide which one to think about when.

After reading this study, I’m tempted to put up some kind of poster in my apartment and fill it with images of loved ones, Paris, swing dancing, and cats. Those are certainly better than an electric shock!