Prune Fingers and Evolutionary Explanations

The ways various news organizations cover the same news story – why swimmers’ fingers get wrinkled – provides a test case on whether evolutionary theory adds any value.

It’s one of those things we all know from experience but only a scientist would want to explain: why do our fingers get wrinkled like prunes after about 5 minutes underwater?  Recent studies show that the phenomenon is controlled by the autonomous nervous system.  Tom Smulders, an evolutionary biologist at Newcastle University in the United Kingdom, decided to run some experiments.  Bottom line: the wrinkles may serve a purpose, helping us to grip things better underwater.

We could leave it at that, but some news sources wanted to invoke evolutionary theory to explain it.  Other sources, though secular and supportive of evolution, didn’t refer to it.  Here’s the breakdown:

• Jonathan Amos at the BBC News gave evolution the most credit.  Right off the bat, he said prune fingers “suggest our ancestors may have evolved the creases as they moved and foraged for food in wet conditions.” Finding that they are under nervous system control “led scientists into thinking there must be some deeper evolutionary justification for the ridges.”  Smulders considered it “less of a leap to assume there must be a function for it, and that evolution has selected it. And evolution wouldn’t have selected it unless it conferred some sort of advantage.“
• Helen Thomson at New Scientist didn’t refer to evolution at all.  “Why do our fingers do prune impressions when soaked? It could be an adaptation that gives us better grip underwater,” she said, referring only to the functional purpose of a better grip.  A lot of her readers, though, got into evolution debates in the comments.
• Sid Perkins at Science Now invoked evolution three times.  “Having something under the direct control of a nerve, even an involuntary one, suggests it serves an evolutionary purpose,” he said, adding later, “It’s also unclear whether wrinkles evolved to help us grasp underwater objects, or whether they’re simply a byproduct of a nervous system quirk. Weber says finding out whether such puckering occurs in other primates might shed light on the evolutionary origins of the phenomenon.“
• Becky Summers at Nature News brought in evolution only tangentially, mentioning that “In 2011, Mark Changizi, an evolutionary neurobiologist at 2AI Labs in Boise, Idaho, and his colleagues, suggested that wrinkling, being an active process, must have an evolutionary function.”  But the next statement focused on the design, noting that wrinkling “appeared to be optimized for providing a drainage network that improved grip. But until now, there was no proof that wrinkly fingers did in fact offer an advantage.”
• Charles Choi at Live Science repeatedly gave evolution the credit, quoting Smulders that the “functional feature” has”very likely been selected for by evolution.” Looking for “a potential explanation of why this effect might have evolved,” he quoted Smulders speculating that “it could have helped with gathering food from wet vegetation or streams.”  Smulders took more of a leap to assume, further, that the wrinkling on the toes might have helped our ancestors in the trees.  It will take further research to “shed light on when and why it evolved.“
• Science Magazine‘s feature “Random Samples” didn’t mention evolution at all in four paragraphs on the subject, other than to note that Tom Smulders is an evolutionary biologist.  “The pale wrinkles that adorn fingertips after an extended soaking may be unsightly, but they serve a purpose: They help us get a stronger grip on slippery objects,” the article said, focusing on purpose.

So while most reporters invoked evolution, a couple did not.  Were they lacking anything for the omission?  All of the articles noted that there appears to be a purpose for wrinkled fingers underwater, but none of them explained how a purposeless process could arrive at purpose.

The only vestigial organ left in evolutionary theory is evolution itself.  You can see how it was completely useless as an explanation for this simple phenomenon, a vestige of an outworn Victorian myth.  The reporters either (1) cheat or (2) misunderstand evolution when they say that prune fingers “evolved to” or “evolved for” anything.  Evolve is not an active verb; it’s passive.  It’s a passive result of happenstance, not a force leading to a purposeful end.  If wrinkly fingers appeared by happenstance, and they happened to have a function, evolution couldn’t care less.  It’s especially hilarious to believe that the evolution made the autonomic nervous system fine-tune this adaptation, enabling it on fingers and toes but not on biceps or buttocks (don’t monkeys sit on rocks underwater?).  When speaking of purpose, adaptation, and function, we should be thinking intelligent design – the only cause capable of achieving purposeful ends.

Here are some new oxymorons provided by the reporters to add to your Darwin Funnies file: evolutionary justification, evolutionary purpose, evolutionary function.  Think about that first one for awhile until you LOL.

Evolution gets tacked onto these stories by human beings who innately understand purpose.  They purposefully add evolution as an entertaining wrinkle on their story, but it doesn’t help scientific explanation get a grip.