14 DAY TRIAL // A team of researchers at the University of Gothenburg, in Sweden, and the University of North Carolina, in the US, working together with scientists from the Unilever company, have managed to discover what they call the skin sensors that are responsible for making us aware of the pleasurable kind of touches, BBC reports. The new study may be of a high value for behavior psychologists, as it may offer new insight into how touches increase the strength of social bounds, and thus influence human evolution. The researchers have determined that only a specific speed would trigger the receptors.
According to a paper detailing the finds, published in a recent edition of the journal Nature Neuroscience, the skin has to be touched at a certain speed – 4 to 5 centimeters per second – in order for the pleasurable sensations to be triggered. But the research is not important just for its application in behavioral science. The team say that learning exactly how the receptors are activated and how they convey their messages to the brain may offer new insight into treating diseases such as neuropathy.
In this condition, the peripheral nervous system is affected, and this can send the wrong “messages” to the brain, when the nerves malfunction. As it turns out, in some of the most unlucky patients, the nerves transmit pain stimuli to the brain even if no cause of pain is present. For these people, a treatment method squarely aimed at the root of their problem – the end of the skin nerves – could potentially alleviate a lot of their symptoms and offer them a better quality of life.
For the new study, the team have tested the tactile response of more than 20 volunteers, which were touched in the forearms at different speeds and intensities. The scientists relied on the test subjects to report whenever a sensation was painful or pleasurable. Following the experiments, the team concluded that “C-tactile” nervous fibers were the ones responsible for activating each time a participant described the sensation they were feeling as enjoyable.
“We believe this could be Mother Nature's way of ensuring that mixed messages are not sent to the brain when it is in use as a functional tool. Our primary impulse as humans is procreation, but there are some mechanisms in place that are associated with behavior and reward, which are there to ensure relationships continue,” Unilever scientist Professor Francis McGlone, who has had a fruitful academic career before moving to the private sector, shares.