Perhaps, you might know that Mahatma Gandhi - Father of Nation (India) asserted a maxim - "Hear No Evil. See No Evil. Speak No Evil." with the help of a sculpture of three monkeys covering or closing ear, eye and mouth individually by palms. I think similar kind of maxim or paraphrase related to sensory wisdom might have been asserted by philosophers of your own country or region too.
|Just cover and avoid undesirable consequences!|
These monkeys are consciously trying to avoid unpleasant input/signals reaching to respective sensory organs. However, in case of covering mouth, it's about suppressing unpleasant words getting out of it that might hurt others and lead to conflict. Three organs play very crucial role not just in communicating with others but also in bridging a vital gap between brain and outside world.
|Rat rubbing its lips|
That's why zoo keepers or biologists cover the eyes of captured animals while carrying them to zoo, drugging, or tagging. By doing this, they try to suppress hostility or aggressive behavior of animal that could trigger in its brain after watching unpleasant or threatening activities happening around it. Unlike conscious suppression, similar kind of self-soothing is also done by our brain. At some extent, it can be also observed in animals too. We can see a rat rubbing or touching its lips in the face of a danger.
|Blocking eyes in fear|
Unconscious facial touching or covering to avoid signals (getting inside or outside) can be observed in human at large extent. In early childhood, facial touching is more prominent and can be observed very easily and frequently. As we get older and find obvious facial touching as an immature (childlike) act, we try to refrain it in public. However, our brain starts sending signal to respective body part and we experience tingling or itching sensation beneath the surface of skin of that particular body part.
More we try to suppress the impulse of acting or behaving in ways that are not socially suitable or acceptable, more our brain adds the sensation of tingling or itching to skin of the respective body part. However, it just only just skin of face but other body parts too tingle or itch. If you simultaneously pay attention to your thoughts and sensation of tingling or itching, you would probably be able to decode what exactly you were trying to suppress consciously - let it be scratching or rubbing scalp, back, back of neck, legs, forearms, palms etc.
Only reason behind the tingling or itching sensation is purpose of our brain to force an individual to scratch or rub the body part to act like a 'wise monkey'. Brain itself tries to sooth the distress or uneasy feeling caused by conscious restrain of an impulse in social world. Through self-rubbing or scratching, our brain soothes itself quickly - sort of impulse compensation mechanism evolved by it. Rapid and continuous rubbing of skin in repetition releases stress relieving hormones.
I've also observed that we scratch or rub body part even if we expect or like corresponding sensory input or desire (to act). For example - a waiter can be observed rubbing his palms rapidly in expectation of a good tip from customer or a young woman can be observed rubbing a small patch of skin exactly below her right eye after watching a beautiful man. As we know that left hemisphere controls the right side of body and right hemisphere controls the left side of body, the side of our body we scratch or rub is directly related to the positive or negative polarity of an underling impulse.
I've done a pilot study about this on my own. If somebody's interested in decoding the 'wise monkey' act of brain, an elaborate research can be conducted for sure. With the help of fMRI (functional magnetic resonance imaging) scanning, we could monitor neural activities in different brain parts that leads to the self-rubbing or scratching.