Wilson reported some of his team’s results at a recent meeting of the Society for Personality and Social Psychology, and also published them in today’s issue of Science.

They report on 11 experiments. In most, they asked participants to put away any distractions and entertain themselves with their own thoughts for 6 to 15 minutes. Over the first six studies, 58 percent of participants rated the difficulty at or above the midpoint on a scale (“somewhat”), and 42 percent rated their enjoyment below the midpoint. In the seventh study, participants completed the task at home, and 32 percent admitted to cheating by using their phones, listening to music, or doing anything but just sitting there. (In the lab studies, one participant’s data was tossed because an experimenter had accidentally left a pen behind and the subject used it to write a to-do list. Another’s was tossed because an instruction sheet had been left behind and he used it to practice origami.)

Participants rated the task of entertaining themselves with their own thoughts as far less enjoyable and more conducive to mind-wandering than other mellow activities such as reading magazines or doing crossword puzzles.

In the most, ahem, shocking study, subjects were wired up and given the chance to shock themselves during the thinking period if they desired. They’d all had a chance to try out the device to see how painful it was. And yet, even among those who said they would pay money not to feel the shock again, a quarter of the women and two thirds of the men gave themselves a zap when left with their own thoughts. (One outlier pressed the button 190 times in the 15 minutes.) Commenting on the sudden appeal of electricity coursing through one’s body, Wilson said, “I’m still just puzzled by that.”

Why is entertaining ourselves so hard? Maybe subjects just couldn’t decide where to steer their thoughts? Nope. In several studies, some were offered topics to fantasize about (going on a beautiful hike, etc.), but that tweak had no effect on difficulty or enjoyment.

Maybe modern technology is rotting our brains? Nope. Enjoyment was unrelated to age or the use of smart phones or social media. Wilson says if anything, use of technology is more a symptom than a cause of our difficulty with entertaining ourselves, although there could be circular effects.

Wilson favors the “scanner hypothesis”: Mammals have evolved to monitor their environments for dangers and opportunities, and so focusing completely internally for several minutes is unnatural. “It would be a little odd to see a chimpanzee posed like Rodin’s thinker for extended periods of time,” he said.

To test the idea, Wilson and his collaborators gave some subjects just a bit of external distraction—a rubber band to fidget with. In other experiments, they told some subjects to monitor a computer screen that would occasional display relevant messages. Compared to enjoyment in the regular thinking task, these alternatives had muddled results—sometimes they led to more enjoyment, sometimes less, sometimes the same amount. Discussing the scanner hypothesis, Wilson noted that the researchers don’t yet have strong evidence, but, he said, “I’m convinced it’s correct.” Anecdotally, reverie’s not so hard when you’re exercising or knitting or staring out the window.