Smaller is better (Image: Lauri Rotko/Getty)

Women have a more sensitive touch than men, but not because of their gender. It’s just that their fingers tend to be smaller.

“We now understand that this sex difference is not actually a ‘sex effect’, but rather an effect of finger size,” says Daniel Goldreich of McMaster University in Ontario, Canada.

His team measured the surface areas of index fingers in 100 students and then asked them to feel surfaces marked with progressively finer grooves.


Dense receptors

When the grooves get too narrow for someone’s sense of touch, the surface feels smooth. On average, men could detect grooves down to 1.59 millimetres wide, whereas women detected grooves at 1.41 millimetres.

But what mattered was finger size, not gender. Spatial discrimination fell by 0.25 millimetres for every square-centimetre increase in finger area.

The team found that sweat pores become more densely packed as finger size decreases. They suspect that the skin’s touch receptors, or Merkel cells, are also more tightly packed, which might explain why small fingers are more sensitive.

Journal reference: The Journal of Neuroscience, DOI: 10.1523/jneurosci.3684-09.2009