In 1979, back when my parents were large in my life, my dad had a curious habit. Each evening as we sat in the kitchen after dark, the green linoleum tabletop reflecting the light of candles and kerosene lamps, he would stare off at nothing. In between the whine and squeal of the shortwave radio, we heard the evening news from Voice of America–boring talk, I thought. But there must have been something important in it, because I remember him often leaning against the kitchen counter glassy-eyed and doing a funny thing with his mouth. He’d pull his jaw from side to side and tap his top and bottom teeth together, and stare, and squint sometimes.

His habit made an impression on us. One day, my little sister stood on the porch working on her jaw moves. I vaguely remember asking my mom what my dad was doing. He was thinking about something, I was told. It didn’t make sense to me at the time, but I see now that he was in what’s called a brown study. We can get so engrossed in thinking that we shut out the activity in our environment and stop noticing what our eyes are seeing. The classic reaction to someone else’s reverie is to say “Earth to you!” Besides the rudeness of such a call, I wonder if it’s interrupting a productive process. Having time to focus and think deeply might help us sort out life, create things, and solve problems. I wonder whether our modern technology prevents us from “leaving earth” in our minds as much as we used to.