Ask Tom Yendell how he learned to eat, use a computer, place phone calls or do anything else with his feet, and he’ll turn the question around. “How did you figure out how to do things with your hands?” he said recently. “You don’t need to be shown how to do it. You just do it naturally.”

Mr. Yendell, 57, is a painter in Hampshire, England. He was born without arms, after his mother was prescribed the drug thalidomide during her pregnancy, which was later found to cause birth defects. Mr. Yendell’s life has been “no different” from that of his able-bodied peers, he has noted on his website, except that he learned to perform everyday tasks with his mouth, chin and feet. That, in turn, seems to have wrought changes in his brain that help illuminate just how flexible young minds are.

“These guys have spent their lives gaining expertise with using their feet,” said Tamar Makin, a neuroscientist at University College London who led a study of Mr. Yendell and another foot-painting artist, published Tuesday in the journal Cell Reports. “If they can change the way the brain is organized, then that would mean that we have the opportunity to change that in others.”

For example, Dr. Makin said, perhaps the brains of people who were born with hands but have difficulty controlling them, such as those with cerebral palsy, could be trained to provide better control.