In 1962, French geologist Michael Siffre became curious about darkness and isolation. The nature of his job meant that he spent a lot of time underground, and this made him curious about how our minds and bodies can be affected by loneliness and darkness. In his experiments, Siffre and a number of other subjects ventured alone into dark caves. They stayed there for months with no clock, calendar, or contact with the outside world. The only electrical light they had would turn on when they woke up, and turn off when they slept. The results that the research team found were astounding. They discovered that without light, the subjects’ biological clocks could not follow the normal 24 hour, day and night routine. The subjects’ perception of time completely changed too, and some would stay awake for over 36 hours and then sleep for over 12. When they were finally allowed to leave the cave, many of them could not believe that the experiment was over - they thought they still had weeks to go.
