Last January, researchers suggested that the wrinkles that form on fingertips after a long soak might help humans and other primates better handle objects in wet conditions . A new study has failed to reproduce those results. Researchers had 40 volunteers—sometimes with dry hands, other times with wrinkly, wet ones—grab 52 items (including small and large glass marbles, rubber balls, and brass weights), one item at a time, with their thumb and forefinger and then pass each object through a 5-by-5-centimeter hole. In some tests, the hole was 45 cm above the table top; in the others it was 75 cm. On average, volunteers with wrinkly fingers completed the task no more quickly than their dry-handed counterparts , researchers report this week in PLOS ONE. Results of two other tests—one designed to test feeling in the skin of the fingertip on the index finger, the other designed to assess sensitivity of nerves in the underlying tissues to vibration—suggested that water-wrinkled fingers were no more or less sensitive than dry, smooth ones. Altogether, the researchers contend, the work suggests that skin puckering doesn’t provide any evolutionary advantage. Maybe wrinkling is just an odd side effect of extended immersion, they say. Although the new study’s test of dexterity wasn’t quite the same as the one used by the team reporting last year’s findings (those tests used fewer objects overall and included glass marbles and lead fishing weights), the new research used twice as many volunteers and therefore might be considered more reliable.
ScienceShot: Wrinkly Fingers May Not Give You a Better Grip