Every Thursday, Laboratory Equipment features a Scientist of the Week, chosen from the science industry’s latest headlines. This week’s scientist is Tom Smulders from Newcastle Univ. He and a team found that water-wrinkled fingers have an evolutionary purpose.
Q: What made you interested in studying the science behind water-wrinkled fingers?
A: Pure curiosity, really. Like many people, I had wondered about wrinkled fingers and what caused them to wrinkle up. However, I had never really thought about what it was for, until I read a scientific paper by Mark Changizi and colleagues proposing that the wrinkles had a function, and that the function was to serve as “rain treads,” removing water from between fingers and objects/surfaces, and improving grip. When I saw that hypothesis, I immediately thought that that was a very testable hypothesis, and proposed it as a student project. When a student — Kyriacos Kareklas, the first author on the study — picked the project, the rest was history.
Q: What are the future implications of your research and findings?
A: Mostly it opens up many more questions. There is still no good data on how the grip is improved, for example. This could be through the “rain tread” mechanism, but other mechanisms are possible too. And we also still don’t know when and for what purpose it evolved. It is even possible that it is a side effect of vasoconstriction in the fingers that itself has a different function, but given the clear improvement in handling objects, that is a bit less likely.
Q: What was the most surprising thing you found in your research?
A: The most surprising was probably the strength of the effect and the consistency among participants. We only used 20 participants, and all of them showed an improvement in handling with wrinkled vs. unwrinkled fingers in water (but not for dry objects).
Q: What is the take home message of your research and results?
A: The take-home message of the results is still very [preliminary]: wrinkled fingers improve our grip on objects under water. Anything else, either about how they do this, or why they do this is pure speculation. It does suggest that this wrinkling may have evolved for that very purpose. Another take-home message is that good scientific hypotheses, no matter how strange they may sound to people, need to be testable. We might very well have found no differences, and this would have been strong evidence against the idea that wrinkles improve grip. Science is all about testing hypotheses and being willing to reject the ones that aren’t upheld by the data.
Q: What new technologies did you use in your lab during your research?
A: None, this was a very low-tech experiment. We needed some plastic storage containers, some glass marbles and some cardboard. This is low-budget science to the extreme. Providing another take-home message: science is not about technology, it’s about ideas and ways of testing ideas. Of course, advanced technology has allowed us to test many more ideas than we would have been able to test without, but it’s not about the technology, it’s about testing hypotheses.
Q: What is next for you and your research?
A: On the wrinkled fingers front, we are going to explore the advantage a bit more under slightly different conditions: what if the marbles are just wet, but not in 15cm of water? What if we use objects with different textures? The other crucial question for understanding the evolution of this trait is to investigate which other animals share this trait with us. I am talking to colleagues who work on different types of primates to investigate what happens to their hands and feet when submerged in water.
But the wrinkly fingers are just a side project. We are about to start a major project looking into a novel way of using molecular neuroscience to measure the welfare of commercially housed chickens, which may help in the future to improve housing and conditions for these birds.