Many people would rather inflict pain on themselves than spend 15 minutes in a room with nothing to do but think, according to a US study out Thursday.

Researchers at the University of Virginia and Harvard University conducted 11 different experiments to see how people reacted to being asked to spend some time alone.

Just over 200 people participated in the experiments. Some were college students, others were volunteers who ranged in age from 18-77 and were recruited from a church and farmers' market.

Researchers asked them to sit alone in an unadorned room, with no mobile phone, reading or writing materials, and then report back on what it was like to entertain themselves with their thoughts for between six and 15 minutes.

Turns out, more than 57 percent found it hard to concentrate and 89 percent said their minds wandered.

About half found the experience was unpleasant.

"Most people do not enjoy 'just thinking' and clearly prefer having something else to do," said the study in the journal Science.


'Cheating, self-shocking'

Then, researchers turned their attention to what people were doing to avoid being alone with their thoughts.

In one experiment, students were asked to do the "thinking time" exercise at home.

Afterward, 32 percent reported they had cheated by getting out of their chair, listening to music or consulting their mobile phone.

Even more of the adults recruited from outside the university -- 54 percent -- broke the rules, said co-author Erin Westgate, a PhD student at the University of Virginia.

"And that's probably an underestimate, because those are just the ones who were honest and told us afterward that they had cheated," she told AFP.

Then researchers wondered how far students would go to seek some stimulation while sitting alone with their thoughts.

An initial pilot study found, surprisingly, that students preferred to hear the sound of a scraping knife to hearing no noise at all.

"We thought, surely, people wouldn't shock themselves," said Westgate.

They offered students in one of the studies a chance to rate various stimuli, from seeing attractive photographs to the feeling of being given an electric shock about as strong as one that might come from dragging one's feet on a carpet.

After the participants felt the shock, which Westgate described as mild, some even said they would prefer to pay $5 rather than feel it again.

Then each subject went into a room for 15 minutes of thinking time alone. They were told they had the opportunity to shock themselves, if desired.

Two-thirds of the male subjects -- 12 out of 18 -- gave themselves at least one shock while they were alone.

Most of the men shocked themselves between one and four times. However, one "outlier" shocked himself 190 times.

A quarter of the women, six out of 24, decided to shock themselves, each between one and nine times.

All of those who shocked themselves had previously said they would have paid to avoid it.

Westgate said she is still astounded by those findings.

"I think we just vastly underestimated both how hard it is to purposely engage in pleasant thought and how strongly we desire external stimulation from the world around us, even when that stimulation is actively unpleasant."

She added that the research showed that by and large, people prefer some positive stimulation, like reading a book or playing a video game.

Whether the effects seen in the experiment are a product of today's digital culture or not is a matter of debate.

Sherrie Bourg Carter, a psychologist and CEO of the Institute for Behavioral Sciences and the Law, a forensic psychology practice in Fort Lauderdale, Florida, said modern technology may contribute to the inability to slow down.

"We are socially trained to be impulse sensation-seekers in our work and play," said Carter, who was not involved in the study.

"Therefore, sitting down for a single, non-connected activity, like thinking, has become quite foreign to most people, even the elderly who were not raised in an electronically-driven world."