The Frontal Cortex

Ever since David Hume - our first great psychologist - it has been a well known fact that causation is a figment of our imagination. Although we perceive event A as causing event B, this perception is an illusion: necessary causation is not inherent in nature. As Hume wrote:

"We have no other notion of cause and effect, but that of certain objects, which have been always conjoin'd together, and which in all past instances have been found inseparable. We cannot penetrate into the reason of the conjunction. We only observe the thing itself, and always find that from the constant conjunction the objects acquire an union in the imagination."

This sleight of mind has endless implications. For starters, if we weren't so addicted to seeing chains of causation everywhere, then science wouldn't exist. The experimental method is all about disentangling cause and effect, clarifying the mess of variables that underlie reality.

And now, in a witty little study by Emily Pronin, a psychologist at Princeton, scientists have shown that mental causation also underlies "magical thinking," a polite euphemism for religiosity. The paper consisted of two separate studies, but I'll just discuss the first one, which used a voodoo hex to spook some Harvard summer students. Pronin's experiment was simple: Harvard students were shown a voodoo doll and told that they were part of a study of "physical health symptoms that result from psychological factors...in the context of Haitian Voodoo." (In fact, dolls are not used in Haitian Voodoo but "they were used here to conform to participants' expectations about Voodoo practice.") Unbeknownst to the volunteers, the scientists had recruited a "confederate" as part of their experimental design. The confederate dressed and behaved normally with half of the participants - and very badly with the other half. He arrived late, tossed an extra copy of a consent form toward the trash can, but missed and left it on the floor. While the subjects read the voodoo death article, "he slowly rotated his pen on the tabletop, making a noise just noticeable enough to be grating." In other words, he acted like he deserved a hex.

The test participant was then assigned to play the "witch doctor." The confederate was the "victim" and wrote his name on a slip of paper, which was attached to the voodoo doll. The newly-minted witch doctor and victim were then asked if they had any of 26 physical symptoms. With the witch doctor listening, the victim said that he had no symptoms.

The witch doctor was then left alone and told to think "concrete thoughts" about the victim. When the victim was brought back into the room, the witch doctor, again acting on instructions, stuck five pins into the Voodoo doll. The victim was again once again asked if he had any ailments. He now complained about a headache.

The witch doctor-participants then completed a subtle questionnaire asking whether they felt responsible for the victim's headache. Sure enough, subjects confused their ill-intention with actual causation. "The participants led to generate evil thoughts about their victim were more likely than the neutral-thinking participants to believe that they caused his headache" the researchers reported.

In fact, test subjects who had thought bad things about the deserving victim were, on average, twice as likely to feel they were at least partially responsible for causing the headache than those who had neutral thoughts. What's more, these witch doctors felt no guilt about what they thought they had done. Cronin speculates: "Perhaps participants saw the victim's headache as a just reward for his unpleasant behavior."

What's the moral? Magical thinking is built into our brain at a pretty basic level. Although these Harvard students don't really believe in Voodoo, a few experimental tricks can seduce them into delusion. A similar psychology probably explains why the vast majority of Americans (between 70 and 85 percent) believe that their prayers are being answered. Reality has a way of tricking the mind.