SUPERSTITIOUS people do all sorts of puzzling things. But it's not just the superstitious who knock on wood. From time to time, we all rap our knuckles on a nearby table if we happen to let fate-tempting words slip out. "The cancer is in remission, knock on wood," we might say.
In fact, it's so common we often don't think about it. But it's worth asking: why do people who do not believe that knocking on wood has an effect on the world often do it anyway? Because it works.
No, knocking on wood won't change what happens. The cancer is no more likely to stay in remission one way or the other. But knocking on wood does affect our beliefs, and that's almost as important.
Research finds that people, superstitious or not, tend to believe that negative outcomes are more likely after they "jinx" themselves. Boast that you've been driving for 20 years without an accident, and your concern about your drive home that evening rises. The superstitious may tell you that your concern is well founded because the universe is bound to punish your hubris. Psychological research has a less magical explanation: boasting about being accident-free makes the thought of getting into an accident jump to mind and, once there, that thought makes you worry.
That makes sense intuitively. What's less intuitive is how a simple physical act, like knocking on wood, can alleviate that concern.
In one study, to be published in the Journal of Experimental Psychology: General, one of us, Jane L. Risen, and her colleagues Yan Zhang and Christine Hosey, induced college students to jinx themselves by asking half of them to say out loud that they would definitely not get into a car accident this winter. Compared with those who did not jinx themselves, these students, when asked about it later, thought it was more likely that they would get into an accident.
After the "jinx," in the guise of clearing their minds, we invited some of these students to knock on the wooden table in front of them. Those who knocked on the table were no more likely to think that they would get into an accident than students who hadn't jinxed themselves in the first place. They had reversed the effects of the jinx.
Knocking on wood may not be magical, but superstition proved helpful in understanding why the ritual was effective. Across cultures, superstitions intended to reverse bad luck, like throwing salt or spitting, often share a common ingredient. In one way or another, they involve an avoidant action, one that exerts force away from oneself, as if pushing something away.
This pushing action turns out to be important, because people's beliefs are often influenced by bodily feelings and movements. For example, other research shows that people tend to agree with the same arguments more when they hear them while they are nodding their head up and down (as if they were saying "yes") rather than shaking it from side to side (as if they were saying "no").
Because people generally push bad things away, we suggest that they may have built up an association between pushing actions and avoiding harm or danger. This led us to speculate that when people knock on wood, or throw salt, or spit, the ritual may help calm the mind, because such avoidant actions lead people to simulate the feelings, thoughts and sensations they experience when they avoid something bad.
To test this, in our knocking-on-wood experiment we asked some people to knock down on the table and away from themselves, while we had others knock up on the underside of the table, toward themselves. Those who knocked up engaged in an approach action, not an avoidant one. Despite knocking on wood, people who knocked up failed to reverse the perceived jinx; if anything, their concerns were made worse compared with people who did not knock at all.
Next we tested whether avoidant movements would have the same effect in situations free from the baggage of superstition. Instead of having participants knock down on wood after jinxing themselves, we had them throw a ball (also an avoidant action, but not one associated with a superstition). We conducted two studies, one in Chicago and another in Singapore. We found that the act of throwing a ball also reduces people's concerns following a jinx, in either culture. Even pretending to throw a ball has the same effect as actually throwing it.
While almost any behavior can be turned into a superstitious ritual, perhaps the ones that are most likely to survive are those that happen to be effective at changing how we feel. We can seek to rid ourselves of superstitions in the name of enlightenment and progress, but we are likely to find that some may be hard to shake because, although they may be superficially irrational, they may not be unreasonable. Superstitious rituals can really work — but it's not magic, it's psychology.