On Nov. 1, 1941, an American internist named William Bennett Bean scratched a tiny mark into his left thumbnail where it emerged from the cuticle. Then he waited to see how long it took to reach the tip. He kept repeating the experiment, on the first day of each month, for the next 35 years.
The result was a rare decades-long self-experiment and a series of papers tracking how one man's fingernail slowed down as he aged. More than three decades after his death, Bean was awarded the 2025 Ig Nobel Prize in Literature "for persistently recording and analyzing the rate of growth of one of his fingernails over a period of 35 years."
