Those who perform long-held rituals such as throwing salt over their shoulder are less likely to worry about ill-fortune, according to researchers from the University of Chicago Booth School of Business.
Superstitions reverse perceived bad fortune by making participants believe ill-fortune was less likely to happen.
Professor Jane Risen, of Chicago University, said knocking on wood seems to create the sense bad luck is being pushed away.
The study published in the Journal of Experimental Psychology said: "General said knocking on wood is the most common superstition in Western culture used to reverse bad fortune or undo a "jinx."
Our findings suggest not all actions to undo a jinx are equally effective
Other cultures maintain similar practices - like spitting or throwing salt - after someone has tempted fate.
Even people who aren't particularly superstitious often participate in these practices.
People believe that negative outcomes are especially likely after a jinx.
If someone says “no one I know will ever get into a car accident” it often feels a crash is likely to occur.
But people's elevated concerns after tempting fate can be eliminated if they engage in a ritual to undo that bad luck.
The researchers noted many of the most common rituals for undoing bad luck - knocking on wood, spitting and throwing salt - all seem to involve movements that exert force away from a person.
So they set out to test whether the avoidant nature of the action is key for reducing the negative expectations and heightened concern generated by tempting fate.
Prof Risen said: "Our findings suggest not all actions to undo a jinx are equally effective. Instead we find avoidant actions that exert force away from one's representation of self are especially effective for reducing the anticipated negative consequences following a jinx."
Prof Risen, who conducts research in judgement, decision-making, intuitive beliefs, magical thinking, stereotyping and managing emotion, said: "Engaging in an avoidant action seems to create the sense bad luck is being pushed away."