In the womb, a foetus is thought to experience touch before it can hear, smell or taste. As the pregnancy progresses, twins even reach out to touch each other. After birth, we know that “kangaroo care” – where the baby is held close to a caregiver’s skin – helps the baby to feel calmer and to sleep better.
Physical contact with other people can reduce the effect of stress on our bodies.
The skin is the body’s largest sense organ
Human skin covers a surface area of at least two square metres. Sensors in the skin allow us to experience pressure, vibration, and pain as well as temperature and physical pleasure. These sensors adapt rapidly to light touch, which means that within moments of putting on our clothes, we forget that they’re touching our skin, provided they’re not itchy of course.
The touch of another human being can reduce stress in adults as well as babies
Research has shown that physical contact with other people can reduce the effect of stress on our bodies. In an experiment conducted in 2003 people were asked to watch a five-minute romantic video while holding hands with their partner, followed by a 20-second hug. After that, they were given just two minutes to prepare a speech which was recorded and then played back to them. Tests like this are designed to be so stressful that usually the blood pressure and the heart rates of the people taking part shoot up. But holding hands and having a hug from their partner meant they only rose half as much as usual.
We use different kinds of nerve fibers to detect different kinds of touch
Fast nerve fibers respond when our skin is pricked or poked, relaying messages to an area of the brain called the somatosensory cortex. But in recent years, the neuroscientist Prof Francis McGlone has been studying another type of nerve fiber (known as afferent C fibers) which conducts information at around a fiftieth of the speed of the other kind.
They relay the information to a different part of the brain called the insular cortex – an area that also processes taste and emotion. So why has this slow system developed as well as the fast one? Francis McGlone believes slow fibers are there to promote social bonding through gentle stroking of the skin.
