You eat a certain food and get sick, but the illness was caused by a virus or bacteria, not by the food. Next time you have the opportunity to eat the same kind of food, you hesitate and possibly go hungry. Or your illness completes its natural course and you get well, right about the time you engaged in some unusual activity like dancing around the fire. So next time you get ill, you dance around the fire until you get well again. B. F. Skinner used to study the laws of behavior by placing pigeons in a special cage with an electrically actuated food tray and a lever they could peck.
Food is a good behavioral reinforcer when the pigeons are hungry, but they quickly satiate.
So Skinner's first step would be to leave individually caged pigeons overnight during which their food trays would click open every few minutes and make food available for a few seconds each time. By morning Skinner observed that every pigeon was engaging in some sort of ritualistic behavior or dance. Each pigeon's behavior was unique but repetitive. This empirical nature of learning is the basis of many human superstitions and myths. Along with many useful and survival-enhancing behavior patterns we also learn many useless and sometimes harmful patterns.