手指越小 触觉越敏感

Smaller can sometimes be better, at least when it comes to fingers. It turns out that people with smaller fingers have more sensitive fingertips, according to a study in the Journal of Neuroscience.

Researchers at Canada’s McMaster University enlisted 100 volunteers, and measured each study subject’s index fingertip. The researchers pressed parallel grooves against the subjects’ fingertips. If they could feel those grooves, then the next set got narrower and narrower. Scientists compare it to an eye test, where you attempt to recognize progressively smaller letters until they’re no longer distinguishable.

Well, people with the smallest fingertips felt the narrowest grooves. The scientists postulated that this might be because they have a higher density of receptors crowded together and sending signals to the brain. It would be like a larger pixel count that makes up a clearer digital image.

To test the idea, the researchers measured the density of sweat pores. Because they knew that touch receptor cells cluster around sweat pores. And people with smaller and more sensitive fingers did have a higher concentration of sweat pores. Which means more receptors. And for their discovery, the researchers get a big hand.

—Cynthia Graber