Fingerprint Myth Disproved

Those of you hanging on by your fingertips to get through the week better dig a little deeper. A new study from England suggests the familiar ridges and crevices we call a fingerprint won't do anything to help you keep a firm grip.

This notion that human fingerprints (and presumably footprints) evolved because they act like tire or boot tread—increasing the friction against a smooth surface so we don't slip or drop stuff—is a 100-year-old urban myth that, apparently, had never been put to the test.

So a pair of mechanical engineers in Manchester rigged a contraption that measured the friction exerted by a guy pushing his finger across a piece of plastic.

 

Turns out fingerprints actually produce *less* friction than if fingertips were smooth, because they reduce the skin's contact with the plastic by about 30 percent.

Of course, the engineers have new theories about why these whirls of the skin evolved. Maybe, says Roland Ennos, fingerprints are protective—enabling our skin to stretch around pointy objects instead of tearing. But that's just one idea.

What's your theory, and how could we test it? This sounds like an A+ project for a kids' science fair.

In the meantime, grown-ups, hang in there. The weekend's on its way.