As you're sitting at your computer reading this story, you'll probably find yourself scratching random parts of your body. That's because itchiness can be contagious, as scientists recently proved for the first time. You've probably been aware of the phenomenon for a while—as with yawning, seeing someone else scratch an itch can make you feel itchy. In a new experiment, volunteers were more likely to scratch themselves while watching a video of someone else scratching, the Telegraph reports.
Volunteers who watched such a video scratched twice as much as those who watched a different video of a person doing nothing. Dermatologists believe that, while watching someone else scratch, the brain becomes hypersensitive and misinterprets any sensation on the skin as an itchy sensation. Researchers also believe this "itch transmission" may have evolved as a way for social groups to identify parasite infections and halt their spread. Click for more on where itches come from, or why yawning is contagious. (Read more itch stories.)