Vaccination passions


Vaccination seems to arouse stronger emotions than most other controversial issues. Jonathan Haidt’s research on the foundations of morality can help explain why.

When I started studying the Australian vaccination controversy several years ago, I was struck by the incredible passions aroused by the issue.

It is not a surprise that campaigners are committed and emotional – that was to be expected. I have studied other controversies, such as nuclear power and fluoridation, in which leading campaigners are personally invested in the issues. In the 1980s, the movement against nuclear war stimulated some fierce emotions: the future of humanity was at stake! (And still is.)

Vaccination is not as earth-shattering as nuclear war, but nonetheless evokes incredibly strong emotions. When acquaintances learn about my studies, many of them have asked me why this is so. I usually say I don’t really know, commenting that maybe it has to do with children’s health.

Both sides in the debate about vaccination put children’s health as their number one priority. They just draw different conclusions.

Supporters of vaccination say it is vital that every child be vaccinated (except for those for whom this is medically unwise) to create “herd immunity”, the protection for the population created when levels of immunity are high enough that an infectious agent cannot easily spread.

Critics of vaccination point to the risks of vaccination itself – it causes adverse reactions in a small percentage of children – and discount the importance of herd immunity, instead citing the importance of good nutrition, a healthy lifestyle and natural immunity acquired by contracting diseases.

There are other potential threats to children’s health, such as pesticides, x-rays, junk food, backyard swimming pools and parental violence. Nuclear war would harm children, to be sure, and continued global warming would be a major threat to the lives of future generations. However, vaccination is more personal: it involves a tangible intervention. Proponents can point to horror stories of deaths and disabilities from whooping cough, meningococcal and other infectious diseases, while critics can point to horror stories of adverse reactions to vaccines.

War – bad for children

The rider and the elephant

Jonathan Haidt’s book The Righteous Mind offers additional insights into why the vaccination issue can be so polarising. Haidt doesn’t address vaccination, nor indeed any other such controversial public issue, but his ideas are relevant. (See also my previous comments about Haidt’s work, as applied to whistleblowing and deliberative democracy.)

Haidt, like many other psychologists, subscribes to the picture of the human mind as having two aspects or components. One is slow, logical, contemplative and careful. This rational component of the mind Haidt calls the “rider”. The other component of the mind is fast, intuitive and judgemental. Haidt calls this component the “elephant”. He argues, provocatively, that humans are largely driven by their elephants, namely the intuitive sides to their minds. The primary function of the rider, namely the rational side of the mind, is to come up with logical-sounding explanations for the judgements made by the elephant.

Elephant and Rider

This certainly fits what I’ve observed in the vaccination debate. Most people have made up their minds, and it doesn’t matter what evidence is provided. They just ignore what is unwelcome and come up with arguments to justify their positions. This helps explain why the debate never seems to progress: the elephants hold sway and the riders are active in justifying the paths chosen by their elephants.

Only rarely do I meet someone who is undecided and who wants to hear both sides of the argument and ponder the issue before making a judgement.

The foundations of morality

Haidt’s special contribution concerns the biological foundations of morality. Citing a wide variety of research and ingenious experiments, he identifies six values that seem fundamental to people’s views of right and wrong: care, liberty, fairness, authority, loyalty and sanctity.


Haidt is especially interested in how these foundations of morality affect debates over politics and religion in the US. He discovered that libertarians, who oppose government regulations and support a free market, rely mostly on the value of liberty. He says that US liberals (who might be called progressives elsewhere), who support government interventions to assist the poor and disadvantaged, rely especially on the value of care, with liberty and fairness as additional influential values. He finds that US conservatives rely more equally on all six foundations.

This analysis helps explain why US people with different political orientations often seem to be talking past each other. What drives them is different. Their elephants are taking different paths, based on different intuitive moral judgements, and their riders give rational reasons to justify their choices. In this circumstance, rational analysis is, for most people, a sideshow that affects little.

Vaccination and morality

The six foundations of morality have obvious relevance to the vaccination issue. First consider care, something important for both liberals and conservatives. The morality of care derives, in evolutionary terms, from parents caring for their children. Groups of early humans with an innate commitment to protect and care for their own children were more likely to survive. In this sense, care is a fundamental aspect of most people’s sense of right and wrong: it is right to protect children and wrong to allow any harm come to them.


Wanting to protect children is intuitive and doesn’t need to be taught. So it is easy to see why vaccination can arouse such passions: it is about care for children.

But the limitation of Haidt’s analysis, at least when applied to vaccination, is that it doesn’t say how the value of care can come to be applied in different ways. It is straightforward to feed a hungry child or to protect a child from a threatening animal. However, vaccination is not such a simple matter.

Supporters of vaccination see children as the prime beneficiaries. Critics see vaccination as a possible danger. They both appeal to care, but have come to different conclusions about how to achieve it.

Supporters point to the dangers of infectious diseases such as measles and chickenpox. Critics point to the dangers of adverse reactions to vaccines. Pointing to the role of the morality of care helps explain why the passions around vaccination are so strong, but does not explain differences in attitudes towards it.

In part this can be due to personal experience. Some children contract infectious diseases and suffer seriously from them, or even die. Parents, other relatives and friends see this and may be influenced to support vaccination. Other children suffer adverse reactions to vaccines; their parents, other relatives and friends may be influenced to oppose vaccination.

Other aspects of morality are also relevant. Liberty is a value based around personal autonomy and resistance to overbearing rule. In evolutionary terms, according to Haidt, it derives from the value to groups of subordinates ganging up on any individual who assumes too much power. When vaccination is pushed on people, for example through mandatory vaccination of soldiers or health workers or through financial penalties for not vaccinating, this may trigger resistance in those for whom liberty is a key moral foundation.

Authority, as a moral value, means accepting the prevailing systems of hierarchy and leadership. When governments, health departments and doctors support vaccination, this invokes the moral foundation of authority.


Haidt says that conservatives are more likely to have authority as a key moral driver. However, this does not seem to fit the pattern for vaccination policy, given that many of the doctors and researchers promoting vaccination are “liberal” in Haidt’s sense. Still, it makes sense to say that vaccination gains support through the authority response in those for whom this moral foundation is salient.

Another moral foundation is sanctity. Disgust is one emotional response to a violation of the sense of sanctity or purity. Many people feel intuitively that certain practices are disgusting, for example incest or eating food that has fallen on the floor – even when the floor is perfectly clean. If that doesn’t disgust you, consider eating food that has fallen into a just-cleaned toilet. Sanctity, like the other foundations, is driven by the elephant, and people sometimes cannot give a logical justification for their reactions.

Some critics of vaccination may see the body as a sacred object that, when healthy, should not be assaulted by any medical intervention. If so, this can help explain their conscientious objection to vaccination. However, sanctity has declining relevance in societies like the US and Australia, where attitudes to personal behaviour have changed dramatically over recent decades.


To more fully understand how emotional reactions shape people’s views on vaccination would require research. Examining the role of the six foundations for morality elucidated by Jonathan Haidt is a promising basis for investigation. Each of the six foundations – care, liberty, fairness, authority, loyalty and sanctity – could play a role. However, the way that each of these values actually maps onto a person’s position on vaccination is not automatic, and may be influenced by personal experiences as well as the views of family and friends. This may be a fruitful area for study precisely because the passions are so great.

Brian Martin

Thanks to Don Eldridge for helpful comments on a draft.