Using points and examples from the talk explain the concept of diffusion.
请用课上的观点和例子解释说明传播的概念。
Listen to part of a talk in a sociology class.
请听社会学课上的部分内容。

Now let's talk about a particular cultural process: diffusion.
今天我们来学习一下一个特殊的文化进程--传播。
Since the beginning of human history,
自人类历史开端以来，
diverse cultures have taken advantage of one another's innovations when they've come into contact.
不同的文化在相互碰撞的时候都会利用彼此的发明创新。
Diffusion is the process whereby something cultural...like a custom,
传播，就是某种文化性的东西，比如一种习俗，
a type of food or an invention is spread from one group to another, or from one society to another.
一种食物或者一个发明，从一个群体扩散到另一个群体，或者从一个社会扩散到另一个社会的过程。
One group adopts a cultural item, or, more selectively, just part of a cultural item of another group, you see?
一个群体会采用另一个群体的文化项目，或者更有选择性地只采用一个文化项目的某个部分。
Now diffusion can occur through a variety of ways:
传播可以通过各种不同的方式产生，
military conquest or tourism or even something like the influence of satellite TV shows around the world.
比如通过军事占领、旅游或者甚至像可在世界各地收看的卫星电视一样的某些事物。
For example take something like reading a modern newspaper here in the US.
就拿我们在美国看一份现代报纸这样的事情来说吧。
Have you ever thought about where the letters, the characters on the page you're reading, where they came from?
你有没有想过，你看的报纸上的这些字母、文字究竟都是怎么来的？
They were borrowed from another culture many centuries ago.
它们都是很多个世纪以前从另一种文明中借用过来的。
Then, the printing of the words, well, that process was invented in Germany,
另外，文字印刷这项工艺是德国发明的，
and finally, the paper itself, paper was invented in China.
还有纸张本身，纸张是中国发明的。
These innovations from all over the world were shared across cultures over time,
这些来自世界各地的发明随着时间的推移为各个文明所共享，
and so today we have newspapers in the US.
也就因此有了来自美国的报纸。
So the process of diffusion might take place over long distances and over long periods of time.
所以，传播的过程可以远距离长时间地进行。
Now I'm not saying that diffusion happens easily, as I mentioned, sometimes it's selective.
我的意思并不是说传播很容易就能产生。就像我提到过的，传播有时候也是有选择性的。
For instance, many people in the US have accepted the practice of acupuncture.
比如，很多美国人都接受过针灸疗法。
The Chinese practice of using needles to cure disease or relieve pain.
这种中式疗法是通过用针来治愈疾病或者舒缓疼痛。
So, lots of people in the US have realized that acupuncture is effective.
所以，很多美国人意识到针灸原来是有效的。