Fingerprints do not improve grip: Study

On the contrary, the marks, the ridges and the crevices, which we refer to as fingerprints, may actually reduce the friction, suggests a new study.

Dr Roland Ennos, a biomechanicist at the University of Manchester, and lead author of the study, who was also aided by colleague Peter Warman, noted, “Because there are all the gaps between the fingerprints, what they do is reduce the contact area with the surface."

Dr Ennos’ study
Dr Ennos, with the help of a machine that he himself designed, conducted a series of tests to measure the amount of friction generated by the fingerprints when the finger came in contact with an acrylic glass.

The researcher worked with the hypothesis that the amount of friction would increase in ratio to the strength with which the acrylic glass would be held. This, obviously, would have corroborated the existing theory that the fingerprint improves the clench by ramping up friction levels.

The results of the test, however, revealed otherwise. The frictional force increased by a much smaller amount than what was expected.

A noteworthy finding is that the region of skin in contact with the acrylic glass was one third less, if the finger pads were totally smooth. The result confirms that fingerprints do not aid in making the grip stronger as they reduce the skin's contact with the object that it holds.

Skin not a solid, but rubber
Dr Ennos observed that the skin behaved like rubber, wherein friction is relative to the contact area between the two surfaces and not like a normal solid, wherein friction is relative to the strength of the contact.

Dr Jon Barnes, a biomechanics expert at the University of Glasgow, commended Dr Ennos’ work. He said, “It's always nice to knock down an urban myth with good data.”

The study appears in the latest edition of Journal of Experimental Biology.