It is summer time, and the living is easy. You can, at last, indulge in what is surely the most enjoyable of human activities—doing absolutely nothing. But is doing nothing really enjoyable? A new study in the journal Science shows that many people would rather get an electric shock than just sit and think.

Neuroscientists have inadvertently discovered a lot about doing nothing. In brain-imaging studies, people lie in a confined metal tube feeling bored as they wait for the...