Listen to part of a lecture in an anthropology class.

So throughout history, ideas have spread from one culture to another. When different groups of people came into contact, they'd introduce new ideas to each other, ideas for new foods, new inventions, new ways of doing things. Researchers call these new ideas, cultural novelties. When groups of people were exposed to cultural novelties, they sometimes adopt them, make them part of their own culture. But other times for various reasons, they wouldn't adopt them. Why not? Well, one reason groups with sometimes not adopt the cultural novelty had to do with the availability of materials if it would be difficult for the group to obtain materials associated with the novelty, the group would be much less likely to adopt the novelty, even if they loved it, they wouldn't be likely to incorporate it into their culture if it required materials that weren't readily available to them, like, say one day a traveler comes to your country, just as a hypothetical example and introduces a tasty soup recipe. And he makes the soup using spices he brought with him. If those spices aren't readily available in your country, that soup probably won't become part of your regular diet.

Another reason groups would sometimes not adopt a cultural novelty was because they already had something similar in their own culture, something that could serve pretty much the same function as the cultural novelty. So in a sense, the novelty had to compete with something that was already well established. And in many cases, rather than adopt the novelty, the group would choose to stay with what they already had. Like again, if travelers come along from another land and introduce a stringed musical instrument to your culture, but you already have your own stringed instrument that everyone likes that makes a similar sound. Well, your culture is probably not gonna start using that new instrument.