Psychology sheds light on long shelf life for autism fears


Sitting in the clinic's little room where my baby was just about to have her first series of shots, it was hard not to wonder if that jab would cause her to be autistic later in life. In that brief moment, it was as if everything I had learned in my training as a psychologist and scientist flew right out the ventilation shaft of that windowless room.

But why did I have any doubts in the first place? I am an educated, fiercely rational person. It would be crazy of me to buy into the hysteria surrounding vaccines and autism. But I am also a scientist and we are supposed to be skeptical. So with that skepticism in mind, I went in search of answers.

First, I wanted to know if there are any studies that have found a link to autism - and second, I wanted to know their quality.

Googling the topic, like many other concerned parents do, turned up a virtual slew of information, some of which made me feel like I really was weeding through a slough. There was the now infamous and thoroughly debunked Wakefield study, which is what set off the whole MMR-vaccine-triggers-autism hysteria. There was Jenny McCarthy's personal crusade.

And then there were the conspiracy sites that told me there is a massive cover-up on the part of "BigPharma," mainstream media (I suppose the Union-Bulletin counts here) and various acronymed offices of the government to silence research that shows vaccines really do cause autism. Some even went to far as to say that vaccines are part of a genocide campaign! (And, no, not the extermination of the measles, mumps and rubella viruses.)

Amid the muck on the Web, though, are plenty of abstracts for sound, empirically valid studies in all kinds of scientific journals, published by scientists working in all sorts of academic fields, in all sorts of institutional settings and in a variety of countries. They cannot all be wrapped up in such a large-scale cover-up. That defies reason.

As I read these short summaries of the methods and results sections of study after study providing absolutely no evidence that demonstrably shows vaccines or the preservatives in them cause autism, it struck my psychological mind as weird that people would continue to fall for it.

But on further thought, it struck me as making perfect psychological sense.

The faulty attitude that vaccines cause autism represents a perfect storm of predictable ways of thinking that are known from the field of social psychology. Most are irrational but a few are perfectly logical, if not outright healthy in theory.

According to Harvey Crowder, director of the Walla Walla County Health Department, no vaccine is 100 percent safe, and no vaccine is 100 percent effective. Because of that, parents have to weigh some unknowns: What are the chances my child will experience a negative reaction to the vaccine? What are the chances my child's immune system won't mount a strong enough antibody response to be able to effectively fight off the disease if it's encountered? What are the chances my child would even come into contact with an infected individual in the first place?

Even though statistics are available on the risk and benefits to the public at large, no individual can be sure of his or her own personal risk or benefit. And because of that, it's a great real-life example of what psychologists call decision making under uncertainty, a category of situations where people are most prone to faulty logic. People erroneously come to the conclusion that the risks outweigh the benefits.

Part of what feeds this is something called the availability heuristic. People falsely judge an event as more common than it really is when it's easy to conjure up examples of it. The usual textbook example is the relative danger of traveling in a car versus by plane. People tend to overestimate the risk of dying in a plane crash because the extensive media coverage of such rare events makes them easy to recall.

It's easy to think of examples of autism. Who hasn't seen "Rain Man" or know someone who has autism or an autism-spectrum disorder? It's also easy to recall celebrity Jenny McCarthy's outspoken belief that vaccines cause autism.

Yet, when it comes to measles, mumps or rubella (I admittedly don't even know what rubella is), it's harder to recall cases precisely because the vaccines are effective.

Because the benefit conferred by vaccines is invisible, there isn't any emblematic image for people to latch onto - no psychological bonus to remind people they work.

"Vaccines are a victim of their own success," says Dr. Alison Kirby, chair of pediatrics at the Walla Walla Clinic.

Crowder agrees, "We just don't see these diseases much in our community anymore. Thank the effectiveness of vaccination campaigns for that."

Another problem is that people are naturally resistant to changing their view because they have new information. This phenomenon, known as belief perseverance, is a good explanation for why McCarthy, in spite of great evidence to the contrary, continues to aggressively assert that vaccines cause autism.

For a parent like McCarthy with an autistic child, it is appealing to think vaccines cause autism because it allows a parent to disavow any personal reason for their child's condition. This phenomenon, known as self-serving bias, gives them something external they can point to that says it's not them or their genes that caused this.

According to social psychologists, this serves to enhance and protect their self-concept, so in some instances - unlike this one - it can be considered healthy.

Here's one last thing to chew on, and it's a cause for hope. The last chapter of the social psychology textbook I've used in my classes addresses the subject of social conflict and altruism. In it, the problem of the free rider comes up. The name refers to the dilemma confronting public transit riders.

It's late at night, and there's no one in the subway station. Why not just hop over the turnstiles and save yourself the fare? A free rider lives off others' good will, reaping the benefit of a public transportation system without paying the cost. The problem is that if everyone hopped the turnstiles, the subway system would go broke and no one would be able to go anywhere.

Vaccines also illustrate the free rider problem. Fortunately for the sake of public health, most people get vaccinated.

In Walla Walla, 95-97 percent of children are vaccinated for MMR, according to Kirby.

Although it is not yet time for my child to be vaccinated against MMR or chicken pox, when it does come time for her to get those vaccinations, I won't let fear and cognitive biases get the better of me - I'll get her vaccinated.

Holly Nelson, Ph.D., is a copy editor at the Union-Bulletin and has taught psychology at Bowdoin College, Whitman College and the University of New Hampshire. She can be reached at


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