I never understood the description of wrinkled fingers after swimming, soaking, or just doing dishes as being “waterlogged.” After all, most things that took on too much water became bloated. Why do fingers look as shriveled as prunes?

Turns out, my childhood observation was the correct one. Our fingers wrinkle not because they have taken on water, but due to a complex physiological reaction in which our nerves signal our body to narrow our blood vessels in our extremities to prevent loss of heat and, possibly, to give us fingers that are better at gripping slippery surfaces.

Now, recent research has concluded that our fingers actually wrinkle the same way every time. Based on a child’s question about the nature of finger wrinkles, a new study puts this theory to the test.

Binghampton University of New York’s Guy German explains. ““A student asked, ‘Yeah, but do the wrinkles always form in the same way?’ And I thought: I haven’t the foggiest clue!” said German, a biomedical engineering researcher.

“This work conclusively reveals for the first time that topographical wrinkle patterns caused by prolonged human hand immersion in water are repeatable and consistent at different timepoints,” the team writes in their study. “Qualitatively, images from each of the five fingers on subjects are compared at different time points. These reveal similar wrinkles over a 24 h period.”

I’m not sure why they need research to prove that. If it’s due to the narrowing of blood vessels, it’s not surprising that they don’t change. After all, our blood vessels remain int eh same places in our body and are not free-floating.

German agrees.

“Blood vessels don’t change their position much—they move around a bit, but in relation to other blood vessels, they’re pretty static,” German explained. “That means the wrinkles should form in the same manner, and we proved that they do.”

Think about that the next time you’re washing dishes.

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