A paper by myself, Romann Weber, Ritesh Kotecha and Joseph Palazzo just appeared in Brain, Behavior and Evolution. Its title is “Are Wet-Induced Wrinkled Fingers Primate Rain Treads?” We provide evidence that the wrinkle morphology on pruney fingers has the expected signature features for a drainage network, designed to efficiently squirt away water during grip.
See this TED video for an introduction.
The paper has, for a time, been given free access by the publisher.
News stories on our research have appeared widely, including Nature, NPR, MSNBC, Discovery, PBS News Hour, Gawker, NY Times, Washington Post, Innovation News Daily, Life’s Little Mysteries, Science Illustrated and FOX News. I also wrote a piece on it at Forbes, and another at WIRED UK.
Also… comics.
See the update, after another team does a new behavioral study showing converging evidence.
…and new press in 2013 coming out of this… NPR’s Science Friday, Bite Sci-zed video, Geek Beat TV, Smaller Questions, AOL, Robert Kurzban, Guardian, Scientific American, Science News, io9, WIRED, New Statesman, Le Monde, Eos Wetenschap, Oggiscienza, Origo, Scinexx, Humanistischer Pressedienst, 21 Stoleti, Heilpraxisnet, NY Times, Atlantic, Star Tribune, The Scientist, Jezebel, National Geographic, BR, C&EN, Science News, Courier, French students on pruney fingers.
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Mark Changizi is Director of Human Cognition at 2AI, and the author of The Vision Revolution (Benbella Books) and the upcoming book Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man (Benbella Books).
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Have you looked into other times when fingers prunes up?
I just shifted about 180 cardboard boxes into a warehouse.
When letting them down or adjusting my grip, I would use my fingertips to allow to slip in a controlled fashion so as not to slam them down. After doing this, I found my fingers had also gone pruney, but they were bone dry and a little dusty.
Hmmm. Interesting. We don’t understand very well the specific mechanisms involved, but it would seem that *that* kind of non-wet stimulation seems to have activated the usually-just-wetness-triggered mechanisms.
Dr. Changizi, thank you for thinking the way you do – and publishing. My son (8) and I have become fascinated with the idea behind pruney fingers. He has been working on a series of science projects related to your hypothesis. One is that if it is a neurological response to prepare for better grip in a wet environment should we see both hands get pruney even if only one hand is submersed in water? Unfortunately our small sample of tests failed as the dry hand remained smooth. Do you have any thoughts on this issue and why it may not work? Thank you and kind regards.
Hi Phil,
Certainly my hypothesis itself doesn’t predict one way or another. But I was curious about that. Hearing from a number of folks who’ve tried it, it seems that it really does need local contact. There *are* more general expectations for why we’d expect this. Whenever a primate’s hands or feet would get damp from rain or dew, it’s likely that all four would get damp pretty much at the same time. So, there wouldn’t be much occasion to need mechanisms where wetness on one hand “told” the other hand to wrinkle.
Best,
-Mark