Because it's easier to pick up wet objects with wrinkly fingers. Wrinkles on your fingers may give you more grip, kind of like treads on a car tire. What should you do if this happens to you? It goes away quickly on its own. You'll have more sebum on your skin in no time. Larger text size Large text size Regular text size. In , Changizi and his colleagues found evidence that wrinkled fingers indeed act as rain treads, channelling water away from the fingers and toes during wet conditions, allowing primates — humans and macaques, to be specific — to maintain tighter grips.
In other words, the wrinkles that result from exposure to water can be thought of as tiny, manual river drainage systems. The pieces of land between the streams and brooks, on the other hand, are disconnected. To see if wrinkled primate fingers had similar features to river basins, Changizi and his team analysed photos of 28 human fingers.
Credit: Getty Images. Rivers combine water, while the channels on a wrinkled finger and meant to force water away. And it occurs far more quickly in response to freshwater than seawater, which could reflect the circumstances in which it may have originally evolved in primates. Indeed, a study conducted by British neuroscientists uncovered evidence that wrinkled fingers aided people in manipulating wet objects. In the experiment, 20 people had to transfer 45 objects of different sizes — all marbles and fishing weights — from one container into another.
In other cases, the objects were submerged. They found that wrinkled fingers allowed the participants to more quickly transfer the objects when submerged, though they made no difference for dry objects.
However, a similar study conducted by German researchers found the opposite. In that study, the researchers had 40 people transfer 52 marbles and dice of different sizes and weights from one container into another. Likewise, a group of Taiwanese researchers conducted a series of experiments aided by a year-old male volunteer. They assessed the friction applied to a smooth surface by his smooth or wrinkled fingertips, for example, and how much force his hands applied when sliding across a bar.
What remains to be done, he adds, is to check that similar wrinkling occurs in other animals for which it would provide the same advantages.
Given that wrinkles confer an advantage with wet objects but apparently no disadvantage with dry ones, it's not clear why our fingers are not permanently wrinkled, says Smulders. But he has some ideas. This article is reproduced with permission from the magazine Nature.
The article was first published on January 9, Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options. Go Paperless with Digital.
0コメント