January 9, 2013
Proven: Pruney Fingers Give You a Better Grip
A new study shows that when our fingers get wrinkly, they’re better at gripping wet objects. Image via Wikimedia Commons/Fir0002/Flagstaffotos
Standing in the shower or sitting in the tub, many of us have looked at our wrinkled fingertips and had occasion to wonder: Why do they get so pruney when wet?
Over the years, people have pointed to a number of explanations, most commonly the idea that the wrinkles are simply a reflection of the skin absorbing water. Now, according to a study published yesterday in the journal Biology Letters by researchers from Newcastle University in the UK, we have a definitive (and more interesting) explanation: Pruney fingers are better at gripping wet objects.
The idea was first suggested in a 2011 paper, which showed that the wrinkles that form on our fingers exhibit consistent patterns that allow water to sluice away—indicating that their role is to improve traction, like the tread on a tire. For this paper, an unrelated group of researchers put the theory to the test, letting twenty volunteers soak their fingers in warm water for 30 minutes to get them good and pruney, then testing exactly how long it took them to move wet glass marbles and fishing weights from one container to another.
On average, pruney-fingered participants moved wet marbles 12 percent more quickly than when they were tested unwrinkled fingers. When the same test was performed with dry marbles, the times were roughly the same. Thus, it seems, the hypothesis was proved: pruney fingers do help us grip better.
Other research has shown that the wrinkles form as a result of blood vessels beneath the skin constricting, as directed by the autonomic nervous system. Because this is an active process—rather than merely a byproduct of the skin absorbing water, as previously assumed—scientists began looking for the underlying reason why this might be the case.
The gripping hypothesis makes sense from an evolutionary standpoint, too. “Going back in time, this wrinkling of our fingers in wet conditions could have helped with gathering food from wet vegetation or streams,” study coauthor and behavioral researcher Tom Smulders said in a press statement. “And as we see the effect in our toes too, this may have been an advantage as it may have meant our ancestors were able to get a better footing in the rain.”
If pruney fingers are better at gripping wet objects and don’t slow us down with dry ones, though, the theory prompts a question: Why aren’t our fingers permanently wrinkled? The study’s authors acknowledge this query and admit they don’t have a ready answer, but speculate that permanent pruniness could limit our fingers’ sensitivity or even make them more likely to be cut by sharp objects.
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I found this article amazing! Totally awed by the fact that Scientist are pondering this idea of why our fingertips get wrinkley in water!
I am amazed, because as a really young child, when I asked my Mom why it happened, she said so you can hold things better…like shampoo bottles, dishes you are washing, and a slippery baby in the bath!
So that was sometime in the early 50′s. All my brothers and sisters grew up knowing this fact.
Knew my Mom was smart, (well, she wasn’t when I was a teen)But,I guess she was Brilliant!
Thanks for sharing this article…and the wee memory of my Mom.
Teleology anyone?
The teaser/link on Smithsonian.com is entitled “Why Fingers Get Pruney in Water”; however, this article tells only why pruning may be advantageous and significant in terms of man’s evolution in an aquatic or wet environment. Y’all kinda reversed cause and effect.
It would have been nice to have some real information, such as if other animals experience pruning or if pruning is the same for people of all races. This would have given your readers an idea of when pruning evolved.
It may have been helpful if your article discussed the other properties of pruned skin versus non-pruned skin – pruned skin is more sensitive rubber-like on a superficial level, and non-pruned skin is better adapted to tasks involving friction, grip, and force on a on a less sensitive level. Permanent pruning would not serve well for tasks involving manipulating rough, dry objects or for walking barefoot on dry ground.
Interesting subject – you ought to do an article on it some time.
When I cut the end of my little finger to the bone when I was 10 I severed the nerve to the tip losing feeling AND losing the prune wrinkle at the end of that finger. (I swam a lot as a kid.) Year later the nerve or nerves had self-repaired or grown new nerves to the tip of the finger. It now prunes like all the others. So there must be a neurological connection.
I notice this article didn’t link with the Aquatic Ape theory of human evolution. In my opinion, it should have.
Thank God for wet pruney fingers.
This article has good observations, and good testing, but a flawed conclusion. The evolution pat answer for the obvious intelligent design for fingers pruning in such a useful way is not proven by just seeing it work so well. It shows more how our bodies have a wonderfully made design. Evolution is not as likely for such a small difference in abilities. The amazing display of this design having a function is another evidence for backing creationists.
Maybe it’s nature’s way of saying “You’ve been in the water too long.”
Many years ago I published a letter to Lancet about skin wrinkling.It appeared to be less in the non dominant hand probably from less use.Also it is necessary for an intact nerve supply(not autonomic)and its absence may indicate neuropathy.
At 82 I notice my finger tips get “pruney” later in the day and it is not due to putting them in water for 30 minutes, so probably it has more to do with constriction of blood vessels, at least at a certain age.
A nice article, marred by the gratuitous reference to the evolutionary “explanation”. A theory that can be made to explain everything does not explain anything. It makes as much sense as saying “further evidence of our alien ancestors having self-modified their bodies to better suit earth’s watery environment”.
I have never heard a satisfactory explanation of how an “advantage” like pruned fingers can be made to happen by the human body for the sole reason it is an advantage.
It implies some sort of intelligence beyond what the brain does is at work. For example when evolutionists say things like “eyes evolved from light sensitive pits in the skin” or something similar, I say so what? Why were the pits light sensitive to begin with?
Just because it is nice to have eyes doesn’t mean they can just “appear” over time. Why not have a pair in the back of our heads too, that would come in handy I’m sure. It would be nice to have wings too but humans will never have them. I don’t care how many trees we may fall out of.
The presuposition that wrinkles help grasp wet objects, so evolution evolved this response is rather thin to the point of being idiotic.
First, for nature to cause such adaptation to occure, the need, to grasp wet obects like a fish or wet vegetables, the need must be so great that those original people who had the adaptation, were so able to out perform their non-wrinkly bretherin, that it gave their decendants a singnifican’t advantage, thus allowing their offsriong to be more successful than non-wrinkly humans, and so eventually replace them. That is unlikely because;
Secondly, it requires that ancient peoples be evolving in a VERY WET environment, thus causeing the wet grip fingers to be a necessity for survival. There is no evidence that ancient people had any need for this adaptation. While they obviously lived around rivers and lakes so that they had access to fresh drinking water, there are no great pits filled with fish bones yet found to suggest that this grip was a singnificant factor in their lives.
I’ve seen people catch cat-fish with their bare hands, so this method may well have been used to some extent, however, the lack of substantial quantities of fish bones in ancient encampments that have been found, show clearly that fish was not on their diet much. Ergo it is unlikely that nature would have adapted puckered fingers to adapt to a need they didn’t significan’t have.
Better grip- that’s why it feel better in the shower.
Thanks, Science!
Cricket,
As opposed to a “theory” along the lines of “God created everything?” Look up the word “theory” as it applies to science. You’re confused. Read the study. It’s even hyperlinked for you, and clearly gives more information than can be presented in a summary article.
Matt,
Cricket was close, what we actually did was modify our /alien-human hybrid/ bodies to better suit SBDN7-3′s, or as you would say, “earth’s,” watery environment.
Believe me, before us your race was destined for failure. By the way, Sasquatch? That was us too.
I have my found when my fingers go pruney and very soft to the point of peeling off,would be no help in catching food or picking up difficult objects.Hence I feel theory needs further investegation.I don’t agree with the idea!
The reason why skin on the fingers go prune is that this skin, together with the skin of the toes and the penis, is that these areas of glabrous skin…I.e. skin without hair. This means that there are also no sebaceous glands, which are glands associated with hairs and produce sebum, which is an oily substance which nourishes hairs and also renders the skin relatively impervious to water absorption. So in fact the skin does swell from water absobtion, while wrinkly pattern is due to the layout of fibrous bands which tether the skin in the pattern observed. Whether this helps significantly in the grasp is at best moot.
David, thank you for the explanation. It actually has helped my brain (that other wrinkled part of our bodies) to wrap around the concept that we wrinkle for wreasons!!!