Homo Deus: A Brief History of Tomorrow

by Yuval Noah Harari

One groundbreaking experiment was conducted by Daniel Kahneman, who won the 2002 Nobel Prize in Economics. Kahneman asked a group of volunteers to join a three-part experiment. In the ‘short’ part of the experiment, the volunteers inserted one hand into a container filled with water at 14°C for one minute, which is unpleasant, bordering on painful. After sixty seconds they were told to take their hand out. In the ‘long’ part of the experiment, volunteers placed their other hand in a different water container whose temperature was also 14°C. But after sixty seconds hot water was secretly introduced into the container, slightly increasing the temperature to 15°C. Thirty seconds later they were told to pull out their hand. Some volunteers did the ‘short’ part first, while others began with the ‘long’ part. In either case, exactly seven minutes after both parts were over came the third and most important part of the experiment. The volunteers were told they must repeat one of the two parts; and it was up to them to choose which. Fully 80 per cent preferred to repeat the ‘long’ experiment, remembering it as less painful.