No other day of the year brings out the superstitious among us more than Friday the 13th. It can seem like the one day that people actually care about black cats, broken mirrors and four-leaf clovers. Some people are so terrified of the number 13 that they refuse to board airplanes or even leave the bed on this ominous day.

But while specific superstitions only seem to surface once a year, the underlying pattern of behavior that gives rise to them is virtually universal. Superstitions arise because at some point, a random incident preceded a fortunate or unfortunate event, and someone decided the former caused the latter.

A somewhat trivial example of this is the rain dance. During a long drought, a group of people started dancing, and before long, it started raining. The group came to believe that their dancing somehow caused the rain to fall.

Philosophers call this kind of faulty reasoning the post hoc fallacy, the error of assuming that because one event follows another, they must be causally connected.

Many apparently silly superstitions probably arise in just this fashion. Someone in Europe sees a black cat and then loses a loved one; they blame the misfortune on the black cat. Another person in Japan sees a black cat and soon after strikes gold, thus attributing the good luck to the black cat. Centuries later, Europeans and their descendants regard black cats as bad luck, while the Japanese see them as good luck.

This story is likely too simple, but something like it probably underlies much seemingly bizarre human behavior.

This behavior probably even predates humanity itself. The behavioral psychologist B.F. Skinner described superstitious behavior even in pigeons. His caged pigeons would receive water at random intervals, but before long, each one would have its own rituals to receive water. Some would bob their head back and forth, while others would turn in counterclockwise circles. They apparently believed that this behavior would produce the desired outcome, in this case water.

I suspect that many pet owners have probably seen such strange behavior in their own homes. For several months, my cat apparently believed that sitting in the bathroom sink after my alarm clock went off caused food to appear in her bowl, because she repeated this behavior day after day.

While some human superstitions seem silly and harmless, others have been deadly throughout history. To take an extreme example, some civilizations sacrificed innocent humans in the belief that this would stop natural disasters. This behavior likely began when the death of an innocent person preceded the end of a famine or disease.

A modern-day example can be found in the illusory connection between vaccination and autism. What makes the connection so intuitive to many parents is that the signs of autism do not usually become obvious until just after the age by which most kids get vaccinated. Parents uncritically assume that the two are linked, and children die of preventable diseases as a result.

A less horrific but still unjustifiable example is that many peddlers of natural medicine or homeopathy simply rely on the placebo effect, charging their customers huge markups for inactive ingredients and water. Even without the placebo effect, some people who take the product will start getting better on their own, but they will superstitiously attribute the improvement to the useless drug.

If superstition really is older than humanity, it is unlikely to go away anytime soon. It may be an unfortunate bias of human psychology, much like our natural tendency to distrust people who do not look and act like ourselves, giving rise to xenophobia.

I am not suggesting that the silly superstitions associated with Friday the 13th are on par with human sacrifice. Nor am I suggesting that we must give up all superstitious thinking. They can be fun as long as we relegate them solely to the imagination. But when they start keeping us from taking off the covers, they have lost any entertainment value.

Leon Mire is a senior philosophy and English major. He can be reached at 581-2812 or lkmire@eiu.edu.