When boys first go bush at St Paul's Collegiate's Pureora Forest campus, their first instinct is to post about their experiences on social media.
"We give them lots of adventures, and in their first month or two all they want to do is post it," says Cyn Smith, director of the college's "venture school" at Tihoi, 50km west of Taupō.
But they can't. For six months, they are allowed no cellphones, no social media, no electronic games, not even television.
Now an Otago University study has found that this unique programme may boost the boys' creative thinking and lift their self-esteem and satisfaction with their lives.
Lead author Dr Helena McAnally has evidence from the famous longitudinal study of all children born in Dunedin in 1972-73 showing that those exposed to media for longer as teenagers - in those days it was just television - have experienced more anxiety in the subsequent 30 years than those who watched less TV.
At Tihoi, Smith has observed an exponential increase in anxiety among the boys arriving at her campus since she started 14 years ago.
"Ten per cent of any group suffer anxiety at some level about the change of lifestyle. They are just anxious, worry about life, worry about everything that is going to come up," she says.
"Fourteen years ago it would have been less than 2 per cent - maybe one student in a group, and we have 64 at a time. Now in some intakes I would have 10 out of 64.
"It's the loss of interpersonal skills, because people are just interacting with their phones and not others."
Smith has not found any other school in the world that cuts teenagers off from all media for six months and makes them cook and care for each other in small houses of eight boys each.
The boys at St Paul's, a Hamilton private school costing $22,000 a year for day boys and $34,000 for boarders, are a highly privileged group, but Smith says many "haven't had the opportunity to get out and about".
But in Year 10, every boy has to spend six months at Tihoi, doing class work four days a week and tramping, mountaineering, rock climbing, kayaking, caving and mountain biking on the other three days.
Smith has had to develop a "transition" teaching unit to wean the boys off their devices, allowing three hours on Chromebooks in class time only.
"A lot of kids are attached to their phone, it's like a part of their body," she says.
"We teach it like a healthy diet and not having much junk food - the use of the Chromebooks which we have in class is like healthy stuff, and there's unhealthy stuff, and there's toxic stuff like porn and addictive gaming."
"For a lot of parents now, it's a very attractive part of our programme, because they have lost control and they want us to be able to solve it for them," she says.
Half of each Year 10 cohort at St Paul's go to Tihoi in the first half-year and the other half in the second half-year, so McAnally compared the Tihoi group against those who stayed in Hamilton in the first half-year.
She found that the Tihoi group almost immediately did better on a test of creative thinking, and continued to do better than the Hamilton group through to the end of the six months.
Measures of self-esteem and life satisfaction also rose for the Tihoi group, but not for those who stayed in Hamilton, through the six-month period.
The differences were small, so McAnally is cautious about making big claims, but she says the Tihoi results are consistent with the Dunedin study where she found that teenagers who watched TV for more than two hours a day in the 1980s were about 40 per cent more likely than others to have symptoms of anxiety in subsequent tests up to age 38.
"What we considered high media use was more than two hours a day," she says.
"Teens' media use has changed enormously and many teens are now hitting media use of more than seven hours a day.
"The conclusions we draw would be we see long-term effects of childhood media use on mental health. Those effects, given current rates of media use, are likely to be greater in the future."