Narrator: Listen to part of the talk in a Sociology class.

Professor: Now let's talk about a particular cultural process, diffusion.

Since the beginning of human history,

diverse cultures have taken advantage of one another's innovations when they've come into contact.

Diffusion is the process whereby something cultural, like a custom, a type of food,

or an invention is spread from one group to another, or from one society to another.

One group adopts a cultural item, or more selectively just part of a cultural item of another group, you see?

Now diffusion can occur through a variety of ways: military conquest or tourism,

or... even something like the influence of satellite TV shows around the world.

For example, take something like reading a modern newspaper here in the U.S.

Have you ever thought about where the letters, the characters on the page you're reading,

where they came from?

They were borrowed from another culture many centuries ago.

Then the printing of the words, well, that process was invented in Germany.

And finally, the paper itself, paper was invented in China.

These innovations from all over the world were shared across cultures over time.

And so today we have newspapers in the US.

So the process of diffusion might take place over long distances and over long periods of time.

Now I'm not saying that diffusion happens easily.

As I mentioned, sometimes it's selective.

For instance, many people in the US have accepted the practice of acupuncture,

the Chinese practice of using needles to cure disease or relieve pain.

So lots of people in the US have realized that acupuncture is effective,

but few of them fully understand or have committed themselves to the philosophy behind acupuncture.

Cultures tend to resist ideas which seem too foreign, too different from their own beliefs and values.

But the ideas which aren't perceived as too different are often incorporated, absorbed, diffused into their culture.

So the practice of acupuncture has been absorbed into U.S culture,

but not the philosophies of Chinese medicine.