Nice, France — Michel Siffre, the esteemed speleologist and pioneer of groundbreaking time perception experiments, has passed away at the age of 85. Siffre, who significantly advanced our understanding of human biological rhythms, died on Saturday, August 24, 2024, in Nice, France.
Siffre was best known for his innovative experiments on time perception, particularly his 1962 underground confinement experiment in the Scarasson chasm near the French-Italian border. At just 23 years old, Siffre isolated himself for two months to study how the absence of external time cues would affect his sleep and wakefulness. Deprived of all time-keeping devices, he emerged from the experiment with a distorted sense of time, believing it was August 20, when in reality, it was September 14—a discrepancy of 25 days. This experiment revealed how isolation could alter the human perception of time, laying the foundation for future research in chronobiology.
Siffre continued his exploration of human biological rhythms with further experiments, including a notable 1972 study funded by NASA, where he spent 205 days in the Midnight Cave in Texas. His final significant experiment took place in 1999 in the Clamouse cave in Hérault, where he focused on the impact of aging on biological rhythms over a 69-day confinement.
Tributes have poured in from across the scientific community. Charles-Ange Ginésy, president of the Alpes-Maritimes departmental council, honored Siffre’s passion for speleology and his pioneering work in underground time experiments. Siffre’s legacy in the field of time perception and biological rhythms remains a cornerstone of scientific research.
Luc Requier, reflecting on his interactions with Siffre, expressed his gratitude on Facebook, writing, "Happy and touched by our exchanges at the time of my research on our great uncle Colonel Augustin Blaquière. I wish you serenity ‘Out of Time.’"
Michel Siffre’s death marks the end of an era of extraordinary scientific exploration. His contributions to the understanding of human time perception have had a lasting impact on both the scientific community and public knowledge, ensuring his place in history as a pioneering figure in the study of chronobiology.