French Cave Isolation Experiment Finishes After 40 Days

A controversial experiment in France has finished after a group of 15 volunteers spent 40 days in a cave in southern France, ABC News reports. The experiment, which has been compared to the infamous 1971 Stanford Prison experiment, ended on Saturday, April 24.

During the experiment, dubbed “Deep Time,” the volunteers had no way of telling the time, as they were not allowed to take any clocks with them or anything that could help them discern the time of day in the dark cave. 

The volunteers also had no contact with the outside world and lived in almost total darkness — a small pedal-powered electric lantern was provided.

As they emerged, the 40-day cave dwellers were given special glasses to protect their eyes from the effects of sunlight. 

The volunteers largely said that time seemed to move much slower during their time in the caves. In an interview with ABC News, 33-year-old volunteer Matina Lançon said the experiment felt “like pressing pause” on her life.

Interestingly, Lançon said she would have happily spent a few more days in the cave, and that she won’t be turning on her smartphone for a few days yet.

40 days with no concept of time

Scientists from the Human Adaptation Institute behind the €1.2 million ($1.5 million) “Deep Time” project say the experiment will help the scientific community to better understand the effects of isolation and may provide useful insight for future space missions.

“Our future as humans on this planet will evolve,” Project director Christian Clot, who also volunteered to go into the cave, said. “We must learn to better understand how our brains are capable of finding new solutions, whatever the situation.”

Time disorientation was, unsurprisingly, one of the overriding effects felt by the volunteers. One of the volunteers reportedly thought the group had spent 23 days in the cave when the time was up.

Christian Clot said, “for [the group] it was a real surprise,” when they were told it was time to come out. “In our heads, we had walked into the cave 30 days ago.”

While the volunteers were inside the cave, scientists monitored the 15 members’ sleep patterns and social behaviors via sensors — including a body temperature-reading capsule that was ingested by the participants before entering the cave. The researchers will now continue to analyze data from the experiment and will present their findings in the coming months.

The hope is that the study will add to the growing scientific literature on social isolation, a topic that is increasingly relevant with the ongoing pandemic, and plans for humans traveling to the Moon, Mars, and beyond.