Fingerprints filter the vibrations fingers feel

The intricate patterns of swirls on human fingers may do more than help cops nab crooks. A study online January 29 in Science helps crack the case of fingerprints’ real job: Epidermal ridges, fingerprints’ professional name, likely serve as filters to help in the efficient detection of fine textures.

“The functional role of fingerprints has remained something of a mystery,” says Sliman Bensmaia, a neuroscientist at Johns Hopkins University in Baltimore who studies touch sensations. But the new results show that “fingerprints enhance our ability to perceive surface texture.”

When a finger sweeps over a finely textured surface, such as a cotton sleeve or a wooden coffee table, the interaction sends a large range of vibrations into the skin. Specialized sensors called Pacinian fibers, the tips of nerve fibers, detect only a select few of the vibrations — those right around 250 hertz — before sending the signal to the brain,