Touch is a vital sense in human survival and experience, not just because of how it informs personal connections, but also as an important early warning system for detecting harm. But not all touch is created equal. Scientists recently discovered that men have lower touch sensitivity than women, and this is based on biology. In a creative experiment using 3D imaging and biomechanical observations, we now know exactly why the male touch mechanism is less effective, and how hyaluronic acid could bring men together on equal terms when it comes to touch.
Researchers from the University of Virginia (UVA) have discovered that women have greater sensitivity in their fingertips due to the soft skin that estrogen helps to provide and maintain. In their study, they found that the more elastic skin 'deforms' more effectively at the point of contact than the harder skin, resulting in better communication from the hand to the brain.
They undertook an innovative experiment to demonstrate the physics of touch and how it maps to our levels of perception. And the result was a leap forward in understanding touch sensitivity, which is essential for designing better sensors in wearables and prosthetics, and for advancing robotics and other biotechnologies.
“We basically confirmed that women are better at tactile discrimination than men, but that's not because they have smaller fingers, but because they have softer fingers in general,” said Gregory J. Gerling, a systems engineer and professor in the UV School of Engineering and Applied Sciences.
Tom Daly/UVA Engineering
Gerling heads up the Touch Lab and specializes in haptics, the science of touch technology. This has become a major focus in recent years as touch screens and touch-dependent systems have advanced across a wide range of technologies.
Using new 3D imaging and biomechanical observations of the skin on our fingertips and what happens when it comes into contact with another surface, researchers have detailed for the first time the biological mechanism that gives women a slight advantage over men. They then processed data from participants pressing their fingertips against a specially designed tracker to comprehensively analyze the process of touching and perceiving, using statistical analysis and machine learning.
Forty participants with varying ranges of finger size, skin hardness, and fingerprint ridge width were filmed from above as they pressed against a glass plate positioned beneath the camera, and detailed impressions were also assessed. What was discovered was that softness, not size, produced a greater rate of change in surface contact from the fingertip to the object. These softer fingertips were better able to discern subtle changes in the hardness of an object being touched.
“The mechanism appears to be that the properties of the surface contact control the firing of sensory nerve fibers in the skin,” Gerling said.
UVA Engineering
But back to hyaluronic acid. This natural compound in the body has a lot of jobs—from supporting joints to helping maintain the elasticity and viscosity of extracellular material. A thick, sticky substance, hyaluronic acid is clear but gel-like and also plays a role in wound healing, reducing inflammation, and tissue repair. It’s also used as a well-tolerated drug delivery vehicle in cancer treatment.
And scientists have shown that it’s something that can increase sensitivity to touch. While hyaluronic acid is a popular addition to cosmetics—especially skin-rejuvenating and anti-aging products—the area is still under-researched in terms of its true effectiveness. But when applied to the fingertips of a new group of participants, selected for their skin firmness characteristics, as shown in the 40-person study, the team found a clear difference in how the skin behaved before and after the treatment.
“The results show that this treatment significantly and systematically reduced participants’ skin stiffness,” the researchers noted. “Furthermore, after application of hyaluronic acid, participants’ discrimination performance also improved significantly, especially for those with relatively stiffer fingers.”
While these small-scale changes observed in the lab may not make a big difference in daily life, men may find that hyaluronic acid can improve their sense of touch. It may also help aging skin regain some of the elasticity needed for acute touch sensitivity, which declines with age.
The study was published on: Journal of Physiology.
Source: UVA Engineering