Fingers and Faces

Because respiratory viruses such as COVID-19 enter your body through the mucous tissues at eyes, nose and mouth, right now touching your face can be problematic.

Actually, not just problematic. A problem because touching your face is a normal reaction to stress, so seemingly instinctive that you did it even before you were born.

It is also a way to deliver social signals, and most intriguing of all, an act that connects to the parts of our brain that enable thinking and memory.

First things first. In 2014, a group of British researchers at Durham University’s Department of Psychology used ultra-sound to scan the activity of 15 healthy male and female fetuses as they developed in utero. What they saw surprised them. When the mothers were stressed, the fetuses touched a hand to face. The greater the stress, the more frequent the touch – and always with the left hand. Because being right-handed is more prevalent among humans, the scientists expected that the hand movement would switch to the right as the fetuses grew. It didn’t. Nor did it predict who would be left-handed at birth. (Fetuses of mothers who smoked also seemed to touch hand to face more frequently.)

Chemo-Signaling

Now to social signaling. Back in the 1970s, a study of ground squirrels showed that a male will wipe his hand – okay, paw – across his face and then over his body before going into battle with another male. What he’s doing, of course, is spreading scent from facial glands to signal strength, warning his opponent to back off.

This is called chemo-signaling, and humans do it, too. Researchers at the University of Bern in Switzerland have found that men are definitely attracted to certain female body odors, most particularly those that change to indicate when a woman is most fertile. As for hand-to-face chemo-signaling, in 2015, when scientists at the Weitzman Institute in Israel observed what happened when humans met and shook hands, it turned out that after a handshake people often sniff the hand they used to shake, a gesture the scientists interpreted as testing the scents of people they had met.

Hand and Brain

Finally, there’s the link between hand and brain. Six years ago, brain researchers at the University of Leipzig who analyzed electrical activity in the brains of volunteers shortly before and after spontaneous facial self-touch gestures (sFSTG) saw changes in areas linked to thinking, emotion, and memory. They concluded that the “self-stimulation” touch helps humans balance how they process information and manage emotion. (Apes also exhibit sFSTG, but as yet no one actually knows why.)

All of which explains why it is so hard to stop touching your face. Even doctors have a hard time controlling the impulse. A very small study of 26 medical students at the University of New South Wales who had just completed classes explaining why it is vital for doctors working in hospitals to protect themselves and their patients by not touching the face showed the students putting finger to face on average 23 times in one hour.

Which is no reason to give up.

Try harder.

Carol Ann Rinzler the author of more than 20 books on health, including "Nutrition for Dummies."