So, how did it go? Well, before being left alone, participants were shown how to press a computer key which was wired up to a machine that delivered an electric shock. You might suppose that having tried it once no one would want to do it again. Wrong. In fact, 71% of the men and 25% of the women gave themselves at least one electric shock during their time in solitary – and one man shocked himself a shocking 190 times. It turns out that having nothing to do was so excruciating, that many of the participants preferred to, in effect, torture themselves rather than put up with no distractions whatsoever.

This experiment is an extreme example, but we know from everyday life that people constantly choose to do things they don’t need to do and which are sometimes painful. Think of all of your friends who run marathons or have punishing regimes at the gym. They go way beyond what is required for health and fitness. And what about the people who trek across the ice to reach the poles of the Earth or sail around the world?

Michael Inzlicht from the University of Toronto calls this the paradox of effort. Sometimes we take the easy route and do as little as we can get away with, but at other times we value situations more if we have to expend considerable effort. The intrinsic joy of the effort gives us so much pleasure that we don’t take the short cut. We might spend hours puzzling over a cryptic crossword instead of using a search engine to find the solution.