Less well-known, but equally well-documented, is the nocebo effect. "Nocebo" means "I will harm" in Latin, and it is more or less the placebo effect turned on its head. If a person is told that something will cause pain, or bring him/her to harm, it sometimes does -- even if there's no rational reason why it would. Individuals who believe in voodoo curses, for example, sometimes show actual medically detectable symptoms, even though such curses are merely empty superstition. Nevertheless, if you believe in them, you might feel their effects.
Naturally, this further bolsters the superstition itself, which ramps up the anxiety and fear, which makes the nocebo more likely to happen the next time, and so round and round it goes. And this seems to be what is happening right now in Uganda -- a bizarre phenomenon called "numbers disease."
In "numbers disease," an affected individual suddenly notices a raised pattern on his/her skin that looks like a number. The number that appears, it is said, represents the number of days the person has left. Once the number shows up, the individual begins to sicken, and when the allotted time is up, the person dies.
[image courtesy of the Wikimedia Commons]
The worst part is that this one-superstition-leads-to-another thing is generating an upswing in the belief in witchcraft, and is giving local religious leaders another tool for converting the fearful. "Unfortunately, some Pentecostal pastors are already using the fear of the strange disease as a beacon for luring more followers to their worship centres with promises of a 'cure,'" said Dr. Harriet Birabwa, a psychiatrist at a hospital in the city of Butabika. "It is a myth that needs to be dispelled immediately as very many people are dying because of harboring such baseless beliefs."
Which is all well and good to say, but as we've seen over and over, superstitions are awfully difficult to combat. In my Critical Thinking class, I ask, "How many are you are superstitious?", and usually about half the class will cheerfully raise their hands -- despite the fact that it's hard to see how self-identifying as "superstitious" could be a good thing. This generates a discussion about what they're superstitious about and why, and how we come to such conclusions despite there being little evidence for their veracity. Fortunately, most of the superstitions I hear about in class are minor silliness -- on the level of a lucky keychain, a special pen to take tests with, or making sure that they put their left shoe on first because otherwise it'd be "bad luck."
But the whole superstitious mindset is counterfactual and irrational, and that in and of itself makes it worth fighting. Why subscribe to a worldview within which sinister forces, over which you have no control, are capriciously doling out good and bad fortune, and for which (more importantly) there is no evidence whatsoever? As we're seeing in Uganda, superstition is sometimes not as harmless as it seems, and can lead to fear, anxiety, physical harm, and allowing yourself to be manipulated by the unscrupulous.
So call to mind any superstitions you might fall prey to, and think about whether it might not be time to reconsider them. Maybe it's time that irrationality's days are numbered... not yours.