Fifteen minutes. A bare room, a chair, no phone, nothing to read. Think about whatever you want. One thing before we shut the door, there is a button on the desk, and it will run current through your ankle.

An hour earlier you told the researcher you would pay five dollars never to feel that shock again.

Two-thirds of the men pressed it. A quarter of the women pressed it. One man pressed it a hundred and ninety times.

Timothy Wilson ran this at the University of Virginia and published it in Science in 2014. His colleagues had argued against including the button. They thought nobody would use it. We walk around with enormous brains loaded with memories and plans and fantasies, and fifteen minutes is nothing.