It's hard to imagine what my schooldays would have been like if I had a smart phone. I didn't even have a landline never mind a smart phone. It meant that I very much lived in a boarding-house bubble, completely removed from the outside world. There was no TV or radio or newspapers so world events passed me by. We were discouraged from wandering around the adjacent town so there was little chance of making outside friends.
If I was at school now and I had a smart phone, above all that would connect me to the outside world. I could keep up with world events, check out websites that interested me, keep in touch with my family, get advice on personal problems. But at the same time I would have access to all sorts of undesirable websites promoting porn or anorexia or racism or dangerous drugs or simply plausible misinformation.
On balance I think that despite the deprivations I experienced I probably had a healthier childhood without a smart phone and without all the hazards it would have presented me with. I could enjoy simple pleasures like reading and walking without being glued to that beguiling little screen.
And there was something to be said for not being constantly in touch with my family and all their oddities.

