The Universal Law Of Touch

“Touch is a primordial sense, as important to our ancient ancestors as it is to modern-day mammals, but it’s also one of the most complex senses and therefore least understood.” Dr Tom Montenegro-Johnson
Credit: PublicDomainPictures

For the first time ever, scientists have established a “Universal Scaling Law for the Sense of Touch” by studying seismic waves that are bound with earthquakes. And the new find is turning pages in virtual reality.

The researchers from the University of Birmingham who were on a mission to discover novel technologies in virtual reality came up with the new finding. The prime aim was to discover ways to combine the sense of touch with virtual reality.

Touch

As a primordial sense that evolved in life, touch is used to express feelings, sense danger, assess things by touching, feel the temperature and many more. Among all these, touch can also sense nanoscale imperfections on surfaces otherwise appearing to be very smooth. And the new study is based on only one of these aspects, i.e. the sense of vibrations.

Explaining the need of such a law, Dr Tom Montenegro-Johnson, first author of the study, “While we have universal laws to explain sight and hearing, for example, this is the first time that we’ve been able to explain touch in this way.”

The Lesson From Earthquakes

According to the researchers, skin can sense vibrations the same way the earth’s crust feel earthquakes. And when they applied relative mathematics to configure how vibrations would travel through the skin, they were amazed to observe that, similar to earthquakes, “the largest signal comes from a rolling type of wave called a Rayleigh wave”.

And their study was based on a hundred-year-old theory by one famous Nobel-prized physicist, Georg von Békésy. According to his theory, the mathematics used to calculate seismic vibrations in earthquakes could also be used to connect Rayleigh waves with the sense of touch.

Rayleigh Waves

A type of surface acoustic wave, that travel along the surfaces. But with its vertical motion, it can also affect bodies as well as their surfaces. And they have both transverse and longitudinal motions.

Furthermore, these waves do not change with skin changes, such as the dehydration, ageing, wrinkles, or gender. They travel with the help of small bundles of nerves called, ‘mechanoreceptors’ that take these vibration massages to the brain. And they are working steadily even in so-called, ‘skin changes’.

Credit: University of Birmingham

The Universal Law Of Touch

Across species, all the animals have one common feature in the sense of touch. “The depth of vibrations that mechanoreceptors are tuned to” stays the same. This is what paved the way for a “Universal scaling Law for Touch”, a shared sensitivity!

Explaining their findings, James Andrews, co-author of the study, “The principles we’ve defined enable us to better understand the different experiences of touch among a wide range of species. For example, if you indent the skin of a rhinoceros by 5mm, they would have the same sensation as a human with a similar indentation—it’s just that the forces required to produce the indentation would be different. This makes a lot of sense in evolutionary terms since it’s connected to relative danger and potential damage.”

Future

According to the researchers, the finding would enable many possibilities in virtual reality in the sense of touch. In other words, we would be able to feel our video games in the near future. And how cool would that be!

The research has been published in the journal Science Advances.