when you concentrate on one problem to the exclusion of survival data. I was, as a child, notoriously good at concentrating on one thing at a time. Only physical contact or a very loud clear call of my name would get me out of a good book. Then I wrecked my father's car at age 18 because I got obsessed with the question of whether it was raining hard enough to run the windshield wipers.

I can't quite lose the world the way I used to, after a concentrated effort to learn to be distractable.