Dog shit, dirty nappies, vomit, bad breath, stained towels, lice, nasal mucous, half-eaten food, saliva, worms, rotten meat, maggots, sores, urine, rats, sweat.

What do all these things have in common? The answer is that we find them disgusting. And surprisingly enough, people everywhere seem to find them disgusting too. In Africa, India and Europe people say such things turn their stomach and make them recoil. Touching excreta, mucous or maggots is hard for most of us, and we go to great lengths to remove unhygienic, revolting and yucky stuff from our lives.

Though disgust has been recognised as one of the six basic emotions since the days of Darwin, it has been very little studied. So much so, that one researcher called it 'the forgotten emotion of psychiatry'. Nevertheless, disgust is something we are all familiar with. We easily recognise the facial expression: a wrinkled nose and the corners of the mouth pulled down. We know the feeling of nausea, the shudder, the urge to drop whatever it is that is disgusting, and the way we almost automatically say 'Yuck!'.

Hygiene is what we do to avoid being disgusted. We scrub at the stains that might be evidence of bodily secretions, we scrape the food leftovers from the plate, we scour our toilets, soap away smells from our bodies and cast waste from our homes. But why do we do this? Why, for example is food on a plate enticing, but not the leftovers? Why is the boy disgusted by lipstick on a glass, but not the same lipstick on his lovers’ lips. And why do we fear worms, bugs and nits? We seem to be driven by primitive phobias, devoid of rationality.

Asked to explain their hygiene practices, educated people explain that they are avoiding germs. Yet germs are largely a figment of the twentieth century imagination. Hygiene has been around a lot longer. Six millennia ago toilets were constructed in the Indus valley. The Greeks prescribed hygiene for balance, harmony and order. Christians insisted on it so as not to offend their God. The sacred Vedas set out hygiene rules for Hindu society, placing pure “Brahmins” at the top of the hierarchy and dirty polluting “Untouchables” at the bottom. Jews and Muslims alike make hygienic separations between sacred and profane. Clearly hygiene is not just about avoiding germs.

Disgust is the key to understanding hygiene. Those of our ancestors who were repulsed by contact with bodily excretions, suppurating wounds, signs of illness and cues to contamination would have had more success staying healthy and passing on their genes. They were avoiding disease and doing it by an instinctual mechanism that didn’t require the invention of microscopes or the germ theory of disease transmission 2. Evolution designed our brains to repulse us from that which might make us sick.

If disgust explains much of our hygiene behaviour, how come hygiene is so deeply embroiled in the rules of our society? Why are paedophiles ‘dirty old men’? Why is pornography known as ‘dirty books’ and illegal wealth ‘dirty money’? The ‘civilising’ mission of the Christian church overseas included teaching that immorality, ignorance, laziness, vice and dirt were inseparable. Expansion and dominion were thus legitimised and control established over indigenous peoples. In Indonesia, the Dutch colonial administration destroyed a great number of indigenous settlements because they were ‘unhygienic’. Nazi Germany gave birth to the ‘science’ of Eugenics, which supported the idea of racial hygiene, and set out to destroy the group they designated ‘filthy Jews’. Pre-civil rights USA had a hygiene doctrine of racial segregation for those they labelled ‘Dirty Niggers’ who suffered appalling deprivation and discrimination. Scientists collaborated with the apartheid system in South Africa by accepting that a transfusion of black blood would contaminate white recipients.

Hygiene was also roped in for social control in Europe. In the eighteenth and nineteenth centuries, industrialisation and urbanisation brought fears that population concentrations were the breeding grounds for filth, epidemic and vice, all of which threatened the social order. As social unrest grew among the poor, England, France and the USA enacted public health legislation to maintain the social order in the interest of the élites. But views differed on explanation of disease. The masses saw their disease as a consequence of their poverty and the high price of corn. The élite used new theories about disease to justify their fear of the poor. Medical science in the mid 20th Century in the UK and its colonies focused on ‘social medicine’ and the need for sexual hygiene and the prevention of the venereal diseases. Even today, the rich and powerful harangue the poor in developing countries about their culpability in the death of their children. ‘If only you had washed your hands’ they say. Disgust is a powerful emotion and one that the powerful have learnt to manipulate for their own ends.

Dirt transgresses body boundaries, threatening sickness, disorder, decay and death. By accusing the poor, the marginalised or the refugee of being dirty; fear of transgression of the body politic is raised. Disgust and fear of disease and disorder are engendered. This is the dangerous side of hygiene; a side that needs to be understood and cast out before our societies can become healthy in all senses of the word.

1. Phillips, M.L.; Senior, C.; Fahy, T. and David, A.S. Disgust- the forgotten emotion of psychiatry. British Journal of Psychiatry. 172:373-375, 1998.
2. Curtis, V.A. & Biran, A. Dirt, disgust and disease: is hygiene in our genes? Perspectives in Biology and Medicine. 44 (1): 17-31 (2001).

Dr Valerie Curtis
Senior Lecturer
Environmental Health Group
London School of Hygiene and Tropical Medicine

Email: val.curtis@lshtm.ac.uk
Website: http://www.lshtm.ac.uk/itd/units/dcvbu/staff/val_curtis.htm

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