Things You’ve Always Thought Were True

Cracking your knuckles gives you arthritis.

THE MYTH: People who crack their knuckles are slowly twisting their hands into hideous wizened claws.

THE TRUTH: Multiple studies have found no link whatsoever between the annoying habit and arthritis. The cracking sound isn’t bones being mangled out of shape but the release of pockets of gas from between joints. That said, long periods of knuckle cracking may contribute toward lower grip strength.

Fish have short memories.

THE MYTH: Like a 4 AM drunk trying to order Taco Bell, your goldfish swims around its bowl in a perpetual state of confused awe, its tiny brain resetting the world every four seconds.

THE TRUTH: Fish are smarter than you think. Researchers from the Institute of Technology in Israel trained young fish to associate a sound played through a loudspeaker with feeding time. Each time they played a particular sound, the fish would return for food. Up to five months later, they responded in the same way.

Chewing gum stays in your body.

THE MYTH: Accidentally swallow a chunk of Wrigley’s and your gastrointestinal tract will be wrestling with it for more than half a year.

THE TRUTH: Pediatric gastroenterologist David Milov of Nemours Children’s Clinic in Florida told Scientific American that this is 100 percent untrue. “That would mean that every single person who ever swallowed gum within the last seven years would have evidence of the gum in the digestive tract,” he said. “But colonoscopies and capsule endoscopy procedures turn up no such evidence.” In reality, it’ll hang around for about a week.

Nails and hair continue to grow after you die.

THE MYTH: As though corpses weren’t disturbing enough, our nails and hair keep growing after our death.

THE TRUTH: From the moment you’re dead, your hair and fingernails decay with the rest of you. This myth comes from the fact that skin recedes from a dead body, making nails and hair appear longer.

Hats keep in lots of heat.

THE MYTH: You lose so much heat through your head that you’d be better off stark naked when it snows.

THE TRUTH: Your mom meant well when she said that 40 to 45 percent of your body heat escapes out of your head like a boiled kettle. A study discovered that in normal circumstances, children only let out about 10 percent of their body heat from their noggin.