I can’t speak for the female of our species but males need to scratch. We usually ascribe scratching as an answer to an “itch”. This is most likely true since, according to an article in the Science section of the NY Times this morning, we have had a relationship with lice most likely from the beginning of our journey from tree-living, ape-like beings to clothes wearing human-like persons like you or me.

I do not always scratch because of an itch. I scratch my head when I am thinking and this seems to help. I rub the back of my neck when there is pressure from the cares of daily living.  Some, I notice, scratch their behinds and not just because of being numb from sitting too long.  Others rub their arms and some wring their hands.  These are all manifestations of having arms, hands and fingers that encourage checking out the body parts and responding to pressures.

The article mentioned is basically about the human louse that occupies three parts of our bodies.  The head louse, the pubic louse and the clothing louse have been with us for a long time. For many peoples, inspecting the hair and picking out the insects is part of social interaction. Fine-tooth combs have been used to combat cradle-cap in babies, but there is a popular song about one Bill Baily whose lady friend finally had to throw him out; thoughtfully she sent along a fine-tooth comb and this tells us something. One piece of information that really caught my attention is the fact that the three types of lice do not interbreed and specialize in living either in the hair, pubic region or in the nooks and crannies provided by sewed garments.

There is a relationship between the divergence of our humanoid ancestors from contact with gorillas and chimpanzees and this causes many questions to arise.  But it is the existence of lice in connection with human populations that provided researchers with data about ancestors as to how far back we picked up these critters that not only cause an itch but also provide us with at least three terrible diseases that can result in death.

We seem to have a need to scratch.  I have noticed that females NEVER scratch the region of their crotch except for the very public performance of a non-singer who was asked to sing the national anthem at the start of a baseball game some years ago.  She sang badly and included a gratuitous scratching of her groin in imitation of male ball players who did this unconsciously all the time.

I can conclude with this observation: we scratch, therefore we itch or conversely, we scratch because we have developed a way to communicate inner or outer stresses. Like yawning, seeing someone scratch, makes us want to do the same for we might have an unwanted visitor in or about our persons.