Touch, a social phenomenon The skin is the organ of physical sensation; it allows humans to experience the pleasure of sensual touch and the unpleasantness of pain. Heat, cold and pressure are all experienced through the skin. The skin is rich in sensory nerve endings, particularly the fingers, toes and lips. Touch is not only a physical experience but also a personal and social phenomenon; it is the way we connect physically to other humans and the way that we express a vast range of human experiences including power, love, abuse and caring. (Classen, 2005) describes touch as:
…a fundamental medium for the expression, experience and contestation of social value and hierarchy. The culture of touch involves all of culture. (Classen, 2005, p. 1)
Different cultures have unique ways of describing their experience of how the skin interacts with the world around it. The Cashinuahua tribe of Eastern Peru describes ‘skin knowledge’ as the knowledge of the world one acquires through the skin, through the feel of the sun, the wind, the rain and the forest. This allows them to find their way through the jungle and to locate the animals that they hunt for.
Western culture would advocate close contact between mother and baby as vital for bonding; however, this has not always been the case. In the late 19th and early 20th century, Dr L.E Holt wrote that babies should not be rocked and only kissed infrequently on the forehead. Dr Watson wrote in his 1928 book entitled
Psychological care of infant and child:
Mothers just don’t know, when they kiss their children and pick them up and rock them, caress them and jiggle them upon their knee, that they are slowly building up a human being totally unable to cope with the world it must later live in (p. 42)
Thus, attitudes towards touch are not just related to cultural norms but also to time.
Sensation as a physical experience The skin is part of the sensory nervous system and as such contains a number of mechanisms for sensation including touch, pressure, vibration, itch and tickle.
Touch Touch sensation can either be crude or fine. Crude implies that there is knowledge that the skin has been touched but the exact location and size of stimulus may not be determined. Fine touch means that the exact part of the body, shape, size, texture and source of the stimuli can be distinguished.
Fine touch is experienced through the stimulation of Meissner’s corpuscles which are found in hairless skin. They are an egg-shaped mass of dendrites enclosed in a capsule of connective tissue. These are rapid acting and generate nerve impulses at the beginning of a touch. They are abundant in fingertips, hands, eyelids, tip of the tongue, lips, nipples, soles, clitoris and the tip of the penis. Crude touch is experienced through the stimulation of hair-root plexuses. Again this produces a rapid response when movement on the surface of the skin which disturbs hairs stimulates free nerve endings wrapped around hair follicles.
Slowly adapting touch receptors are generally more sensitive to pressure, vibration and stretching. Type I receptors (Merkel discs) are saucershaped free nerve endings that contact Merkel cells in the epidermis. They are particularly prevalent in fingertips, hands, lips and external genitalia. Type II (Ruffini corpuscles) are elongated, encapsulated receptors found deep in the dermis (particularly in hands and soles) and in ligaments and tendons; they are sensitive to stretching.
Itch Cutaneous itch is caused by the stimulation of free nerve endings of C fibres. These unmyelinated C fibres transmit impulses relatively slowly and although functionally they are the same as those that transmit pain, functionally they are distinct. There are a number of mediators which lead to the stimulation of these fibres and the consequent sensation of itch. These include histamine, cytokines, neuropeptides and prostaglandins.
Tickle is a curious sensation as it only occurs when an individual is touched by someone else. It is thought to be mediated by free nerve endings and lamellated corpuscles.
Pain Whilst pain is generally considered an unpleasant experience, its biological functions are firstly to help protect us from noxious substances or dangerous situations and to help pinpoint an underlying cause of disease.
Nociceptors are free nerve endings which are found all over the body, except in the brain. Tissue irritation or injury releases chemicals such as potassium, prostaglandins and kinins, all of which can stimulate nociceptors. The pain may continue long after the stimulus is removed as the pain-stimulating chemicals may persist and the nociceptors exhibit very little adaptation.
Pain may be experienced as fast or slow pain, the sensation being determined by the type of fibres transmitting the pain impulses. Perception of fast pain occurs 0.1 seconds after the stimulus as impulses are sent along medium-diameter myelinated A fibres. This generates an acute, sharp, pricking pain. Generally fast pain is not felt in deeper tissues of the body. Slow pain begins a second or more after the stimuli has been applied and builds up in intensity over seconds or minutes. The impulses are transmitted by small-diameter unmyelinated A fibres and generate a more chronic, throbbing, burning or aching sensation. Pain can occur in skin, deeper tissues and internal organs.
Biochemical reactions in the skin The most commonly reported biochemical function of the skin is the synthesis of vitamin D. This occurs mainly in the prickle and basal layers where UV light stimulates the conversion of 7-dehydrocholesterol to vitamin D3. Vitamin D is essential for the skeletal development as it controls the balance of calcium and phosphorous absorbed through the small intestine and mobilised from the bone. The amount of melanin in the skin affects the exposure time required to synthesise the vitamin; black skin requires 12 times the length of exposure to UVB than white skin. This is probably due to the fact that only 2–5% of UVB penetrates the epidermis in black skin whereas in white skin this is 20–30%.
Androgen metabolism also occurs in the skin; testosterone is converted to 5α-dihydrotestosterone by the enzyme 5α-reductase.
Psychosocial The skin is the organ of display, it is how humans present themselves to the world, and often judgements are made (rightly or wrongly) on appearance. The skin is often adorned in a multitude of ways in order to produce social signals of cultural significance. This may be through permanent marks such as tattooing, piercing and scarification or temporary decoration such as make-up and jewellery. The amount of skin that is displayed allows others to make judgements about lifestyle choices or religious convictions. Often one can determine racial groupings by the colour of the skin or hair, and age may be guessed by noting wrinkles, skin tone and hair colour. Of course, all judgements made on the basis of appearance may be wildly wrong, but this does not stop people making them!
In an appearance-based society, to appear ‘abnormal’ can have an enormous impact on an individual’s psychological well-being. The feeling of being unwelcome or discriminated against because of the skin is a potentially devastating experience that means individuals have a range of negative responses including withdrawal from society, developing low self-esteem, having mental health problems or failing to achieve their full potential.
The profound almost instinctive distaste often engendered by skin disease, which more-oftenthan- not is totally out of proportion to its objective manifestation, may be related to a deeply held, almost primeval fear of contagious infection or infestation. It is clear through historic documents, including the Bible, that those with signs of disease through the skin were outcast, leprosy being the prime example of this. It is thought that many of those who were labelled as lepers actually had other skin diseases such as psoriasis. As communities who did not have the benefit of understanding of the modes of disease transmission, an outward sign such as a diseased skin was an obvious thing to ‘blame’. These issues will be examined in more detail in
Psychological and social aspects of skin care.
In summary, our skin and hair can reflect both our physical and mental well-being. A ‘bad hair day’ can mean a day where everything seems to go wrong and where a person feels unprepossessing and incapable. Conversely, a new hair style can boost confidence and make an individual feel younger and more confident. General health will also affect the health of the skin, when someone is relaxed and healthy their skin is more likely to ‘glow’. Good skin health not only means that the physical attributes of the skin are functioning well, but also that an individual feels psychologically comfortable in his/her own skin.
