Scientists believe the discovery explains why women tend to be more tactile than men, as the gender difference is down to finger size: small slender fingers are more densely packed with touch receptors than chunky digits.

Researchers in Canada investigated finger sensitivity in 100 students, whom they asked to feel progressively narrower parallel grooves with a fingertip.

Individuals with smaller fingers were able to discern tighter grooves.

“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 Dr Daniel Goldreich, from McMaster University in Ontario. “Our discovery reveals that one important factor in the sense of touch is finger size.”

Several types of sensory receptor lie under the skin’s surface, each designed to detect a specific kind of stimulation.

Merkel cells, for instance, respond to static indentations, such as grooves, while others capture vibrations or

movement.

Skin receptors act like pixels in a digital camera to generate a picture in the brain of what an object “feels” like. More receptors per inch provide a clearer image.

Merkel cells are known to cluster around the base of sweat pores. To assess the density of the cells, the scientists measured the distance between sweat pores in the students’ fingers.

They found that individuals with smaller fingers had more closely packed sweat pores, and were therefore likely to have more concentrated touch sensors. “Previous studies from other laboratories suggested that individuals of the same age have about the same number of vibration receptors in their fingertips,” said Dr Goldreich. “Smaller fingers would then have more closely spaced vibration receptors.

“Our results suggest that this same relationship between finger size and receptor spacing occurs for the Merkel cells.”

The findings are published today in The Journal of Neuroscience.

Commenting on the research, Dr Ethan Lerner, from Massachusetts General Hospital, said: “The difference between the sexes appears to be entirely due to the relative size of the person’s fingertips. So, a man with fingertips that are smaller than a woman’s will be more sensitive to touch than the woman.”