Another way to figure out whether moral and microbe disgust really are the same emotion is to peer into our brains. Do the same brain areas light up in an fMRI scan when people are exposed to the viscerally and the morally disgusting? In one of the first studies to look at this issue, neuroscientist Jorge Moll found that that this was indeed the case.22 Since then, neuroscientist Alan Sanfey has shown that the region of the anterior insula that is associated with disgust is also activated when subjects are made unfair offers in the ultimatum game.23 The story is complicated because some of the regions are shared (anterior insula, basal ganglia) and some are different, as one might expect. And neuroscientists have tended to work from a motley selection of disgust stimuli, many of which are not pure disgust elicitors by our definition of disgust. Better studies comparing moral and microbe disgust are needed to clinch this one.
So, while we still can’t be sure that moral and microbe disgust are the “same” emotion, there is clearly some overlap. The overlap is at three stages—with brain inputs, with brain processing, and with brain outputs. On the brain input side, many moral infractions involve elicitors of basic microbe disgust. Taking examples from the school list: rape, murder, torture, and cannibalism are all revolting crimes, and perhaps they are particularly revolting because they involve bodily fluids. In the brain processing box, there is certainly some overlap, in that people report that they are sickened and disgusted by moral infractions, and scans show similar brain-area involvement. And there is certainly overlap on the brain output side, with microbe and moral disgust eliciting similar use of words and facial expressions, and similar actions of avoidance/shunning and public pointing out of the contaminating nature of the disgusting object or person. On the principle that if it looks like a bear, sounds like a bear, and acts like a bear, then it probably is a bear, I’m prepared to take it, on current evidence, that moral disgust really is disgust, or a close relative.
It seems that the disgust system evolved first of all to help us avoid microbes, then its mechanisms were borrowed and extended to help us avoid and shun those people who posed a parasite risk through their poor manners, and then its role extended further to encourage us to avoid and shun those people who were behaving immorally. Shame evolved as disgust’s counterpoint: helping us to behave in ways that stop us from disgusting others, so underpinning our manners and our morality. And then, because disgust focuses on contamination, it can be employed to label others as contaminated, making them morally contagious and, like the plague, to be avoided.
To find out more about moral disgust, we are running a web experiment called “the city of morals” with the BBC (you can participate at www.bbc.co.uk/labuk/experiments/morality/). An analysis of the first sixty-five thousand respondents shows that every one of thirty different morally dubious scenarios was scored as disgusting, as well as wrong. For example, someone setting fire to a museum, thus destroying priceless historical artifacts, scored an average of 8.8 out of 10 on wrongness and 7.7 on disgust. A person stealing a dress from a shop scored 8.0 for wrongness and 5.6 for disgust. When we ranked the results, however, there were some interesting patterns. Offenses that involved the spilling of bodily fluids—such as rape and incest, spreading flu, and failing to mend a broken sewer—came higher in the disgust ranking than in the wrongness ranking, as one might perhaps expect for parasite-relevant stimuli. But one other type of behavior also ranked more highly on disgust than wrongness. This category included a mother having children for the sake of welfare payments, a banker avoiding paying taxes, and a rich sports star not giving to charity. These offenses all come under the heading “social parasitism”: people who blatantly exploit society for their own ends, without contributing fair shares. So perhaps there’s another connection with the PAT of disgust here too. Moral disgust extends to parasites on the social system.
My current hypothesis is that all moral failings (i.e., defections from doing one’s bit for society) occasion disgust, but that there are two categories of moral failings that have an extra-disgusting component: those that involve organic disgusts (acts of violence involving bodily fluids like rape, child abuse, murder, genocide, and torture) and those that involve social parasitism (like the ancient Greeks who begged bread at the temple when they did not need charity, who gave the name to parasites).24
Disgust is one of our moral emotions; it is a voice in our heads encouraging us to punish those who cheat, steal, spill bodily fluids, and exploit others without paying their fair share of the costs of sociality. As with other emotions, disgust evolved to bias our behavior, to help us make those hard choices about what to do next. Emotions lay bets as to what would be good for us to do now, based on the odds in the environments of our ancestors.25 Antonio Damasio and others have shown that without emotions we are lost, unable to choose a course of action.26 Disgust is one of these decision-making emotions, deeply entwined not just in microbe avoidance, but in our social life, through manners and morality. When we express repugnance at immoral acts, we are being deeply moral. We warn the potentially corrupt politician and the child abuser that the punishment of repulsion awaits, that if they persist they may become shamed exiles: a heavy, if not insupportable, price to pay for their selfish action.
Disgust is an essential component of human society. Yet our dual brains resist the idea that an irrational ancient emotional driver of behavior determines our modern morality. The philosophers argue that we are higher beings, able to make rational choices about right and wrong. The true story is that we are both rational and emotional. While immediate decision making is largely driven by the emotional brain, humans have also evolved new brain components that can see further into the future, imagine what would happen as the result of different courses of action, override emotional responses, and make choices that are sometimes, but not always, “better.”
The disgust emotion, coupled with the mirror emotion of shame, remains a ubiquitous, potent, and effective deterrent to antisocial behavior. It is an ever-present, invisible threat to social defectors, and it underpins social order. Without moral disgust, we cannot dwell in our supercooperative Eden.
CHAPTER SIX
DISGUST MATTERS
This book has told a story. It has traced the history of the evolution of the powerful emotion of disgust from its origin as a defense against pathogens and parasites, to the role it plays in the manners that facilitate social interaction, to its expanded role as a moral emotion that holds together our complex and productive modern societies. But all good stories should have a moral. They should teach us a lesson, help us learn something that we can take away and use. So what is the moral of the disgust story?
For me, the moral of the story is that using science to unweave the complex rainbow of human behavior is a desperately important enterprise. Delving into the evolved drivers of human behavior offers many benefits: Understanding disgust’s basic antimicrobial functions can help us to fight disease and to diagnose and treat certain psychiatric problems. Understanding the manners side of disgust can help to stop stigmatization of the sick and the different and so build more humane societies. And understanding moral disgust can help us to be fairer in our justice systems and perhaps in the end to be better human beings.1 What could be a more important moral to this tale than that?
Using Disgust to Fight Disease
The most obvious benefit of understanding the disgust emotion is its practical use in the fight against infectious disease. While those of you living in developed economies have only a 5 percent chance of dying of an infection, if you live in Africa that chance is 65 percent, and in Asia it is 35 percent. This huge disparity remains an affront to modern societies and a challenge to public health practitioners, like me.
Diarrhea is one of the world’s biggest killers, responsible for 0.85 million child deaths every year, mostly in the poorer regions of the poorer countries.2 Perhaps because it is disgusting, and despite the fact that it kills more children than HIV/AIDS, malaria, and measles put together, d
iarrhea is still neglected. It’s an orphan condition, with no global fund to tackle it, no film stars enlisted as global ambassadors to fight it, and insufficient research into how to defeat it.
Caused by a huge variety of pathogens, including viruses, bacteria, and gut parasites, the main source of diarrheal disease is the product of other people’s guts. Human feces contain billions of microbes per gram. Hardly surprising, then, that poo comes near to the top of most people’s disgust lists. These bugs have evolved to be past masters at getting out of one person and into another by catching a lift on every available sort of transport—hands, doorknobs, taps, water supplies, food, cleaning cloths, flies, cockroaches. As most mothers know, it’s a losing battle to contain the runny stools of a child with diarrhea; the stuff gets everywhere, as it is designed to do by the microbes that it carries.
The best way of preventing diarrheal infection is to deal with the fecal peril. Feces have to be removed from human settlements, and any contact with feces needs to be followed up by careful hygiene measures. This may be easy to say, but, to the world’s shame, fully 40 percent of the world has no safe place in which to defecate, having to go in the open or use unsafe or shared toilets.3 And fewer than one in five people in the world wash their hands with soap after going to the toilet.4 We calculated that if everyone in the world washed their hands with soap, it could save 600,000 lives a year.5 On top of that, hand washing can help prevent respiratory infections, including SARS and pandemic flu, infectious blinding trachoma, infections associated with AIDS, and it can also help combat malnutrition.6
Of course, if you ask people whether they wash their hands, most people say yes, but in every study that we carried out, we found that actual rates were far lower than what people reported. Sitting in people’s courtyards and watching what actually happens showed that only 3 percent of mothers in Ghana, 4 percent in Madagascar, 12–14 percent in China, Tanzania, and Uganda, and 18 percent in Kyrgyzstan were washing their hands with soap after using the toilet.7 In the UK we saw that only 43 percent of mothers washed their hands with soap after changing a dirty diaper.8 When faced with an interviewer, however, typically over 80 percent of people said that they did.
In studies in eleven countries including China, India, Vietnam, Senegal, Kenya, Uganda, and Peru, we explored the reasons why people washed their hands (or didn’t) and found motives that included nurture, affiliation, and status. However, disgust at the idea that fecal material might be present on hands was consistently reported to be the most powerful motivator of hand washing with soap after using the toilet.9 We took this idea to a commercial advertising agency in Ghana and used it to build a national campaign on hand washing with soap. We designed a TV commercial that showed an attractive Ghanaian woman exiting a toilet and then preparing and serving food to her kids. However, the film was doctored to add a purple smear to her hands as she left the toilet, which got transferred to the food that she fed to her children. We showed the first cut of the ad to mums in Accra, and the results were electric. We heard a sharp intake of breath and saw horror on their faces—feces were effectively being fed to children! Mothers were deeply shocked at this violation of the nurture motive and the evocation of disgust. After showing the ads on the three national TV channels for a year, a survey of the whole country showed that reported rates of hand washing with soap had gone up by 13 percent after using the toilet and by 41 percent before eating.10 We found that most people knew about the ad, even if they didn’t own a TV, and had discussed it with others. It had also encouraged teachers and health workers to take hand hygiene more seriously.11
Back in the UK, we wired up a public toilet in a service station on a highway to give us live data on how many people were using soap to wash their hands. We installed an electronic signboard that changed its message every hour, so we could see the effect that a series of carefully designed messages would have on the hand-washing habits of the quarter of a million people who came through during the study. The most effective of all the slogans in getting people to use soap was “Is the person next to you washing their hands with soap?”—attesting to the power of social approval and manners to influence behavior. Disgust-based messages such as “Soap it off or eat it later” also significantly increased soap-use rates, especially in the male loos.12
The UK government used disgust in their response to the swine flu epidemic in 2009/2010. They delivered to every house in the country a leaflet with an image on the cover of a man sneezing onto his hand, with a haze of droplets spraying from his mouth. The image was both attention getting and disgust inducing.13 Telephone surveys showed that people who had been exposed to the campaign were more likely to buy antibacterial hand gel.14 We continued to monitor hand washing in the highway service station during the pandemic; hand hygiene practices increased in line with media and blog coverage. However, they dropped back again to where they had started as soon as the social networks went quiet again about flu.15
Our recent hand-washing campaign in India uses a character called Laddu Lingam, a dirty fat man who makes sweets for children. In a skit acted out in schools and village meetings, he comes out of the toilet, doesn’t wash his hands, and concocts disgusting sweets from dirt, worms, and dirty water. Not surprisingly, there are few takers when the sweets are handed around the audience. The campaign significantly increased hand-washing rates in the seven trial villages.16
Disgust has also been employed to great effect in campaigns to get people to build toilets in Asia and Africa. An approach known as Community-Led Total Sanitation begins with a health worker taking villagers on a tour of their village, and sticking small flags in the ground whenever they encounter a human turd. Some of these are collected and used in graphic demonstrations. For example, a hair is dipped into one, and then into a glass of water. The villagers are offered the water to drink, which they, of course, refuse. The point is made that open defecation is similar to adding feces to the water supply. This approach, which was developed originally in Bangladesh, sometimes pushes into more sensitive territory. In some villages, kids were given whistles to blow when they spot an open defecator,17 which may be highly effective at instilling shame in the perpetrator, but presumably also leads to the social exclusion of the poorest in the village. Not a desirable outcome for a public health program.
Colleagues working in Cambodia designed a toilet-building campaign that used shocking images of people and dogs defecating, with the tag line: “A dog can’t buy a latrine, but you can. Have a latrine yet?” And to bring more attention to the problem of toilets and diarrheal diseases, we helped organize a film competition called the Golden Poo Awards. The entries were full of imaginative uses of disgust.18 Time Magazine commented that people might be offended by such efforts but asked which is more offensive: to talk about shit, or for millions of children to die because we don’t talk about it?
While disgust’s proper domain is that of infectious disease, it also works for other public health issues, such as smoking. The British Heart Foundation’s most successful media campaign, entitled “Give Up Before You Clog Up,” graphically depicted the impact of smoking on arteries by showing cigarettes dripping globs of fat.19 The World Health Organization now recommends that images of diseased organs be carried on all cigarette packs. A Canadian study showed that the greater the disgust reported at such pictures, the greater the likelihood that people would have attempted to quit, and sometimes have succeeded.20 Attempts to do the same in the United States were recently stymied because a judge ruled that this would violate the cigarette companies’ freedom of speech.
Perhaps the most important reason that smoking has declined in developed economies, however, is that it has become bad manners. Once it became widely known that smoking harmed not just the smoker, but the bystander as well, smoking got added to the list of acts such as spitting and going ungroomed that are antisocial because they can cause disease. And people with bad manners meet with social exclusion. That exclusion for smokers is now even more explic
it; they are ostracized, forced to visibly demonstrate their addiction to the world on office steps and in glass-walled pens in airports. It takes a lot of nicotine-fueled commitment to carry on smoking in the face of so much social disapproval.
Disgust can even be employed to combat obesity. In Jamie’s School Dinners, a popular TV series on the UK’s Channel 4, the celebrity chef Jamie Oliver, knowing that lectures about healthy eating weren’t working, instead piled all of the snack and junk food brought to school by one class into one huge disgusting heap.21 The campaign helped spur the UK government to improve the quality of school dinners. And in New York the consumption of sugar-rich soda drinks dropped by 12 percent after a public health campaign showing a fizzy drink turning into gobs of fat as it was drunk.22
Our approach to behavior change for public health stresses the power of emotions such as disgust, rather than rational drivers of disease avoidance. But emotions are powerful and need to be handled with care. Disgust may be a great candidate to employ in campaigns against disease, but it can offend or turn people off, rather than making them want to engage with a communication campaign. And it clearly has to be handled responsibly, since it can encourage stigmatization and exclusion of the individual involved in the unhealthy behavior.
Disgust’s Downsides
While we’re lucky to have vigilant disgust systems in our heads, ready to alert us to any sign of infection, as well as to be exploited in public health communication, the parasite-avoidance system doesn’t always lead us to do what’s best for ourselves or others. Disgust has plenty of downsides.
Like fear, disgust is an emotion with a hair trigger. Because it operates on the precautionary principle, it can lead us to reject things or people that it might have been better to interact with. Because it is so automatic and powerful, it can get in the way of carrying out essential tasks like caring for the sick or removing wastes. Because evolution designed it for a different era, it can misfire in our modern world. And because the system can go wrong, it can cause a variety of psychiatric problems. Disgust is a maker of misery, as well as of manners and morality.
Don't Look, Don't Touch, Don't Eat: The Science Behind Revulsion Page 9