A group of 15 French volunteers left a cave on Saturday where they stayed for 40 days, in an experiment that probed the limits of human adaptability to isolation.
Dazzled by the light and with pale but healthy faces, the group led by the Franco-Swiss explorer Christian Clot emerged around 10:30 am (8:30 am GMT) from the Lombrives cave in Ariege, southwest France.
The underground isolation experiment caused individuals, aged between 27 and 50 years, to abandon clocks, phones and natural light, exchanging modern comforts for a cave system with a constant temperature of 12 Celsius (54 Fahrenheit) and 95 percent of moisture.
Members had to generate their own electricity with a pedal bike and draw water from a well 45 meters below the ground.
Clot, founder of the Human Adaptation Institute, said the so-called “Deep Time” experiment would test the ability of humans to adapt to the loss of their time and space benchmark.
These issues gained urgency due to the widespread isolation that people experienced during the coronavirus pandemic.
But while some researchers joined the project, other scientists criticized the design of the experiment.
Etienne Koechlin, head of the cognitive neuroscience laboratory at the prestigious French graduate school ENS, said the research was “innovative”.
Data on participants’ brain activity and cognitive function were collected before entering the cave, for comparison with their levels after leaving.
But, like other experts, Pierre-Marie Lledo, from the CNRS government research center and the Institut Pasteur, noted that there was no “control group” in the experiment.
Comparing an unaffected group with those making changes is often a vital component of scientific studies.
The volunteers plan to give a press conference on Saturday about their experience.