The Believing Brain - Michael Shermer [32]
As I write this, there is a major brouhaha over a form of anecdotal association involving vaccinations and autism, with some parents of autistic children claiming that shortly after they took their children in for (A) the MMR (measles, mumps, rubella) vaccine they were (B) diagnosed with autism. This is patternicity where it really counts. On National Autism Awareness Day in 2009, Larry King hosted a debate on his show in which he had on one side of his table a couple of medical researchers and experts on autism and vaccines who explained that no connection between the two has ever been made, that the allegedly toxic chemical thimerosal was removed from vaccines in 1999, and that children born after thimerosal was removed are still being diagnosed with autism. On the other side of the table were the actor Jim Carrey and his ex–Playboy bunny partner Jenny McCarthy, with videos of her adorable son exhibiting obvious signs of autism. Who are you going to believe—a couple of nerdy brainiacs with expertise, or a couple of glamorous maniacs with celebrity? It was a classic case of the emotional brain running roughshod over the rational brain, as McCarthy tugged on the heartstrings of viewers while the scientists struggled to elucidate how proof is established in science through careful controlled experiments and epidemiological studies. Once again, the rational bit was in the emotional horse’s mouth, but the reins gave no direction that day.
The problem we face is that superstition and belief in magic are millions of years old whereas science, with its methods of controlling for intervening variables to circumvent false positives, is only a few hundred years old. Anecdotal thinking comes naturally, science requires training. Any medical huckster promising that A will cure B has only to advertise a handful of successful anecdotes in the form of testimonials.
B. F. Skinner was the first scientist to systematically study superstitious behavior in animals, noting that when food was presented to pigeons at random intervals instead of more predictable schedules of reinforcement—for which pecking a key inside a box in which the pigeon was placed would result in delivery of the food through a small food hopper (see figure 1)—the pigeons exhibited an odd assortment of behaviors, such as side-to-side hopping or twirling around counterclockwise before pecking the key. It was an avian rain dance of sorts. The pigeons did this because they were put on something called a variable interval (VI) schedule of reinforcement, in which the time interval between getting the food reward for pecking a key varied. In that interval of time between pecking the key and the hopper delivering the food, whatever the pigeons happened to be doing was scored in their little brains as a pattern.
Supporting my thesis that such patternicities were important in the evolution of response behaviors to changing environments, Skinner noted, “each response was almost always repeated in the same part of the cage, and it generally involved an orientation toward some feature of the cage. The effect of the reinforcement was to condition the bird to respond to some aspect of the environment rather than merely to execute a series of movements.” These superstitious behaviors were intensely repeated, typically five or six times in a matter of fifteen seconds or so, as Skinner concluded: “The bird behaves as if there were a causal relation between its behavior and the presentation of food, although such a relation is lacking.”5 In the bird’s brain, (A) twirling around once and pecking the key was connected to (B) food. That is basic patternicity. If you doubt its potency as a force in human behavior, just visit a Las Vegas casino and observe people playing