If you repeat something long enough, it often becomes accepted as fact.
• You shouldn’t swim for an hour after eating. This started in the ’40s when the American Red Cross published a manual on lifesaving, claiming that stomach cramps and possible death awaited the swimmer who went right from the table to the pool. In 1961, the Journal of Health, Physical Education and Recreation debunked the stomach cramps thing, saying they had never once seen such an occurrence. Today, the American Red Cross is even down with it too.
• The more you cut your hair, the faster it grows. When hairs start to grow back, they may feel coarser because they’re short and all the same length, but the speed of growth doesn’t vary.
• Couples should be aware of the seven year itch. About two percent of married couples divorce during the first year, four percent of those remaining split the following year. Roughly five percent of marriages end in each of the next three years, and after that, the divorce rate drops off.
• Carrots are good for your eyes. They contain beta carotene, which your body turns into vitamin A. Since it’s needed by your retinas, a complete deprivation of this vitamin would cause night blindness. But the body has immense reserves of beta carotene in the liver, easily replenished by any number of foods. So practically speaking, eating carrots won’t benefit your vision.
• Reading in the dark will ruin your eyes. As the American Academy of Ophthalmology puts it: Reading in dim light will no more harm the eyes than taking a photograph in dim light can harm a camera.
• You can catch cold from being chilled. It’s true that more people catch colds in winter than summer, but cold temperatures aren’t directly responsible. The only way to catch a cold is to be exposed to one of the relevant viruses. Cold weather is a factor in that it keeps people inside and thus closer together for longer periods.
• Women show more empathy than men. Research shows that when children are asked to imagine what another person is feeling, boys are just as skilled as girls. Yet studies also show that females are slightly better at interpreting body posture, facial expression and tone of voice.
• The full moon makes people crazy. In a compilation of 37 different studies on the subject, no evidence could be found of any special lunar effect. The only correlation that did come up was a built in bias. Essentially, if a person believes that the full moon has an effect, he will be more vigilant and notice what happens then.