Vaccines may backfire.
There are many products that aim to protect us in various ways. We install smoke alarms at home to keep us safe from fires that may start while we are asleep. Every fall, people line up for flu vaccines to protect against the flu viruses expected that year.
Despite the best intentions of these products, though, they sometimes fail. A smoke detector may have a faulty sensor and may not wake up a family in time for them to escape a burning house. A child may get very sick after a vaccination.
Research by Jay Koehler and Andrew Gershoff published in Organizational Behavior and Human Decision Processes in 2003 found that people are particularly sensitive to cases in which safety products backfire. They feel betrayed by these products.
For example, they found that people preferred a car with an airbag system that gave them a 2% chance of dying in an auto accident to a car that had an airbag where the airbag led to only a 1% chance of dying in an accident, though there was also a .01% chance that someone might be killed by the airbag in an accident they would otherwise have survived. That is, people felt so betrayed that in a very small number of cases they might be harmed by the safety device that they preferred a car that was less safe overall.
This behavior in an experiment is similar to the behavior of parents who may avoid vaccinating their children because of the small number of cases in which vaccines have harmful side-effects. The vaccines ultimately save far more lives than they prevent, but parents still avoid the vaccines.
In a 2011 paper in the Journal of Consumer Research, these same authors explored ways to minimize the effects of this betrayal on people's choices. It would be particularly useful for people to pick the safest option in the long-run, even when there are rare cases where the safety device is itself to blame for a bad outcome.
Gershoff and Koehler reasoned that people may feel such negative emotion when they hear about a safety device that backfires that they are driven away from choosing that option. In those cases, they suggested that finding ways to minimize how much people experience an emotion might increase choices of the safer option. They conducted five studies in this paper, I'll describe two of them here.
In their experiments, participants all had to choose between the two cars described earlier. One would lead to a 2% chance of being killed in a serious accident, while the other would lead to a 1.01% chance of being killed in a serious accident. However, the safer car included a .01% chance in which the safety device would lead to the death of someone who would otherwise have survived the accident.
In one study, the authors took advantage of previous work suggesting that people experience emotions less strongly when making a choice for someone else than when making a choice for themselves. In this study, people saw the descriptions of the two cars and asked which they would choose. Half of the people chose the car for themselves, while the other half chose for someone else. People were more likely to choose the safer car (despite the betrayal) when choosing for someone else than when choosing for themselves.
In another study, the authors asked all of the participants to fill out a survey measuring how often they go with their intuition or gut instinct when making a choice. This survey is a valid measure of how strongly people use their emotions. After filling out this survey, people chose between the cars. Consistent with the importance of emotion in experiencing this betrayal, people were increasingly less likely to choose the safer car as their reliance on intuition in choice increased.
Ultimately, when evaluating any option, it is important to look at its safety and reliability record. Products that are potentially dangerous (like cars and even medicines) will always carry some risk. The total risk for a product is the combined risk that a bad outcome will happen despite the protection of the product as well as the possibility that the safety devices in the product will backfire. In the end, it does not matter where those risks come from. The safest product is the one that is safest overall.
So, if you are inclined to avoid a product because of a small risk that it might backfire, you should find ways to minimize the influence of emotion on your choice. A simple way to do that is to imagine purchasing the product for a friend rather than doing it for yourself.
Follow me on Twitter.