I take this as a lesson in how science communication and public engagement can go wrong. As a scientist I feel hurt not to be trusted. As a mother I can imagine what it’s like when you are told you should vaccinate your child. I have been there and I have learned from the episode when the use of the triple MMR vaccine was blamed for the increase in autism, when Andrew Wakefield was celebrated as a hero speaking out for parents. The pharma industry, government and scientists were all accused of bias. What basic cognitive processes are involved in the way we make the decision to vaccinate or not to vaccinate? How can these processes undermine scientifically based advice?Why doesn’t rational explanation as provided by scientific evidence speak for itself? Here’s where our social minds play tricks with us. We basically prefer the inaccurate message given out by a trusted person over the accurate message given by a possibly untrustworthy person. But perhaps these are not tricks. Although it pains me to say this, trust can be more important than scientific truth. Here’s why. Evolution has endowed social creatures, including human beings, with the predisposition to cooperate. And for cooperation to work we need to trust each other. Many animals show reciprocal altruism: ‘I scratch your back and you scratch mine’, and human beings go one step further by showing indirect altruism: ‘I scratch your back, and one of your kin will scratch the back of one of mine. Thus, people help each other without the explicit idea to get something in return, but perhaps with the implicit belief that someone else will give help at another time. Because this belief is unspoken, and because helpers are often anonymous, free riding becomes very tempting. And as we know, if there are too many free riders, trust and cooperation will collapse.
Evolutionary theorists suggest that cycles of cooperation and trust alternate with lack of cooperation and distrust. To reinstate trust both forgiveness and punishment are needed. For instance, if people are prepared to punish free riders, then this eventually reinstates trust in the group. This is called altruistic punishment because it actually costs the person who does the punishment. At the very least, he attracts the dislike of the person he punishes.
Trust weighs heavily in the decision to vaccinate or not. We remember vividly the old family doctor who once mentioned that vaccination was not a good thing. But why is our memory so good for messages that tell us not to vaccinate?
When our social mind makes a choice then trust and the person making a recommendation, are not the only factors. The big players are our emotions. Our brain is particularly responsive to any kind of threat. But even more important may be an emotion known as anticipated regret.
Imagine you are bidding in an auction, and you do not get the item you bid for. You will show disappointment. Now imagine you are told that your bid was only very slightly less than that of the successful buyer. You will show regret. You regret that you did not offer a slightly higher bid. It has been shown that in auctions where the final price is revealed, buyers offer higher bids, than when it is not. This is a sign of anticipated regret. We feel this emotion automatically as a result of internal computations, of which we are not aware. Now it has also been shown that you are more likely to feel regret when you commit an act and something bad happens. You won’t feel so regretful when you omitted to do something. This is the case when you decide not to vaccinate. You didn’t commit something that might turn out to be wrong. You just omitted something.
The MMR story is a story of lack of trust, and a story of the wrong kind of anticipated regret. It is wrong because it disregards the consequences of not vaccinating. Several factors contributed to the lack of trust. To begin with, there may be a predisposition to distrust scientists who are often portrayed as callous and more interested in abstract generalisations rather than the fate of individual people. The decision to vaccinate means you are allowing a temporary hurt to your child, while your overarching inclination is to protect your child from hurt. Why should you allow this hurt, when you have no personal memory of the severity of illnesses such as mumps, measles and rubella. Protecting your child from these almost mythical illnesses seems somehow less pressing than protecting your child from an immediate danger. So, when Dr. Andrew Wakefield, came forward as taking a stand against vaccination, his opinion fell on fertile ground. Further, the possibility that the package of a triple vaccination – a triple injury – might cause a brain disorder, such as autism, seemed plausible.
As so often correlation turned into causation: autism had increased recently; the triple vaccination was introduced recently; ergo, the triple vaccination caused the increase. In the UK the Medical Research Council immediately set up projects designed to answer the question whether indeed there was a causal connection. The answer was no, and the scientific advice was that the triple vaccination is safe.
In spite of this advice, nobody believed it. This was strange and needs further explanation. Why was the trust in Wakefield continuing, when there was at the same time a lack of trust in scientific advice? Here is where the concept of anticipated regret comes in. Parents were ‘playing safe’, or so they thought, by not giving their children a single triple short vaccine. In fact, playing safe was an act of omission, and this is less linked to regret than commission. However, if you choose not to vaccinate your child, then you are a free rider, because the protection remains as long as everyone else (or the vast majority) does vaccinate their child. In order to be effective 90% of the population has to be vaccinated. Many middle class people thought they were justified in becoming free riders for the sake of their child. In consequence there have been outbreaks of measles.
Here is the gist of an interview that illustrates the role of anticipated regret in the MMR story. Interviewer: “Would you let your child get the controversial MMR vaccine?” Father: “Certainly not. If I let my child get the MMR vaccine and he later becomes autistic, I will never forgive myself.” Interviewer: “What, if your child then contracted the measles and died?” Father: “This would be an act of God. I would be very sad, but not feel guilty.”
We all know the end of the story. Remarkably, the reason that MMR vaccination became acceptable again for parents had nothing to do with the restoration of trust in scientists. Quite the opposite. It became known that Andrew Wakefield had a commercial stake in the development of single vaccines. Now, people who previously believed him to be a brave hero who spoke against powerful lobbies, such as big pharma, lost their trust in him. Another reason in favour of vaccination is the increase in measles, mumps and rubella outbreaks. This reminded people that these diseases are very dangerous. There are still people who firmly believe that their child’s autism was caused by vaccination and nothing will weaken them in this belief. However, our social nature strongly inclines us to do what others do, and to value what others value.
Image credit New Media Science Communication