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Size matters in finger sensitivity

December 15, 2009 |  2:01 pm

Smaller fingers are more sensitive fingers, according to new research out today.

Hbrvq8kf A study in The Journal of Neuroscience found that people's finger size determines sensitivity, not necessarily their gender or even the softness of fingertips.

Researchers from McMaster University in Ontario, Canada, and Duquesne University in Pittsburgh tested the index fingers of 50 men and 50 women ages 18 to 27 for finger sensitivity; the participants also had their finger size measured. The sensitivity test involved pressing fingertips against an increasingly narrower set of grooves.

Those with smaller index fingers were better at distinguishing smaller grooves. And although women in general have smaller fingers than men, gender was not a factor. Men with smaller fingers had more sensitivity than women with larger fingers. Fingertip softness, or compliance, wasn't linked with greater tactile perception.

The study authors speculate that a higher density of Merkel cells may account for the extra sensitivity. Merkel cells are receptors that allow us to discern shapes and textures, sending signals to the brain about what they feel. The more Merkel cells, the more refined the sense of touch.

To find those Merkel cells, researchers measured the distance between the study participants' sweat pores. Merkel cells gather around those pores, and those with smaller fingers had higher sweat pore density. Ergo, they probably had more Merkel cells that were closer together.

"Neuroscientists have long known that some people have a better sense of touch than others, but the reasons for this difference have been mysterious," said Daniel Goldreich, a study co-author from McMaster University, in a news release. "Our discovery reveals that one important factor in the sense of touch is finger size."

-- Jeannine Stein

Photo credit: Francine Orr / Los Angeles Times