•Narrator: Now listen to two students discussing the announcement.

•Man: They're making a mistake.

•Woman: What do you mean?

•Man: Look, they're trying to do away with distractions,

•so we can study better.

•But with this change,

•we won't have anywhere in the library to get together to work on group projects.

•Woman: True. Group project work is common these days.

•Man: So instead of buying these new units,

•they should use the money to build meeting rooms,

•and that would reduce any noise in the main library areas.

•Woman: Yeah. That's what we could really use.

•There's just not as much need to work in isolation.

•Man: Exactly. And the other thing is,

•what's this about overcrowding?

•Sure, we have more students enrolled at the university this year,

•but do we really have a problem with overcrowding?

•Woman: I don't think so.

•I always get a whole table to myself.

•Man: Right, I see empty tables there all the time.

•It'll just be a waste of money to replace what we have,

•since what we have now is sufficient for the amount of students that use the library

•Narrator: Now listen to part of a lecture on this topic in a Zoology class.

•Professor: Let's start with an example you may be familiar with.

•What's one thing dogs typically do when they feel threatened,

•when they want to protect themselves.

•That's right, they show their teeth.

•And when we see this,

•we know this behavior means basically "stay away".

•Now here's how this behavior became a recognizable warning.

•A long long time ago,

•a dog sensing danger would get ready to bite whatever animal was threatening it.

•It started by baring its teeth.

•But the purpose of doing this was something very simple.

•The dog instinctively was making sure it wouldn't bite its own lips when it bit the other animal. OK?

•But what happened?

•Other dogs, other animals, over time,

•they learned that this teeth-baring always came before a dog was going to bite.

•And so they started to read it as a signal to be careful, to keep away or risk getting bitten.

•This scenario, repeated time after time,

•also led to the dog's awareness that by simply showing its teeth,

•a lot of the time, that was protection enough.

•What had been a simple physical preparation to bite had developed into a kind of defense mechanism in and of itself.

•The dog learned it did not need to actually attack,

•but could get the right result from just communicating the possibility of an attack through showing its teeth.

•It started to use this behavior as a warning signal.

•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.