托福听力TPO17听力文本(Conversation+Lecture)

　　TPO17 Lecture 1

　　Art History(Prehistoric Art Dating)

　　Narrator

　　Listen to part of a lecture in an art history class.

　　Professor

　　Good morning, ready to continue our review of prehistoric art? Today, we will be covering the Upper Paleolithic Period, which I am roughly defining as the period from 35,000 to 8,000 BC. A lot of those cave drawings you have all seen come from this period. But we are also be talking about portable works of art, things that could be carried around from place to place. Here is one example. This sculpture is called the Lady with the Hoody, and it was carved from ivory, probably a mammoth’s tusk. Its age is a bit of a mystery. According to one source, it dates from 22,000 BC. But other sources claimed it has been dated closer to 30,000 BC. Amy?

　　Amy

　　Why don’t we know the exact date when this head was made?

　　Professor

　　That’s a fair question. We are talking about prehistory here. So obviously the artists didn’t put a signature or a date on anything they did. So how do we know when this figure was carved?

　　Tom

　　Last semester I took an archaeology class and we spent a lot time on, studying ways to date things. One technique I remember was using the location of an object to date it, like how deep it was buried.

　　Professor

　　That would be stratigraphy. Stratigraphy is used for dating portable art. When archaeologists are digging at a site, they make very careful notes about which stratum(strata), which layer of earth they find things in. And, you know, the general rule is that the oldest layers are at the lowest level. But this only works if the site hasn’t been touched, and the layers are intact. A problem with this dating method is that an object could have been carried around, used for several generations before it was discarded. So it might be much older than the layer or even the site where it was found. The stratification technique gives us the minimum age of an object, which isn’t necessarily its true age. Tom, in your archaeology class, did you talk about radiocarbon dating?

　　Tom

　　Yeah, we did. That had to do with chemical analysis, something to do with measuring the amount of radiocarbon that’s left in organic stuff. Because we know how fast radiocarbon decays, we can figure out the age of the organic material.

　　Professor

　　The key word there is organic. Is art made of organic material?

　　Tom

　　Well, you said the lady with the hood was carved out of ivory. That ’s organic.

　　Professor

　　Absolutely. Any other examples?

　　Amy

　　Well, when they did those cave drawings. Didn’t they use, like chacoal or maybe colors, dyes made from plants?

　　Professor

　　Fortunately, they did, at least some of the time. So it turns out that radiocarbon dating works for a lot of prehistoric art. But again there’s a problem. This technique destroys what it analyzes, so you have to chip off bits of the object for testing. Obviously we are reluctant to do that in some cases. And apart from that, there’s another problems. The date tells you the age of the material, say, a bone or a tree, the object is made from, but not the date when the artist actually created it. So, with radiocarbon dating, we get the maximum possible age for the object, but it could be younger. Ok, let’ s say our scientific analysis has produced an age range. Can we narrow it

　　down?

　　Amy

　　Could we look for similar styles or motives? You know, try to find things common to

　　one time period.

　　Professor

　　We do that all the time. And when we see similiarities in pieces of art, we assume some connection in time or place. But is it possible that we could be imposing our own values on that analysis?

　　Tom

　　I am sorry. I don’t get your point.

　　Professor

　　Well, we have all kinds of pre-conceived ideas about how artistic styles develop. For example, a lot of people think the presence of details demonstrates that the work was done by a more sophisticated artist. While a lack of detail suggests a primitive style. But trends in art in the last century or so certainly challenge that idea. Don’t get me wrong though, analyzing the styles of prehistoric art can help dating them. But we need to be careful with the idea that artistic development occurs in a straight line, from simple to complex representations.

　　Amy

　　What you are saying is, I mean, I get the feeling that this is like a legal process, like building a legal case, the more pieces of evidence we have, the closer we get to the truth.

　　Professor

　　Great analogy. And now you can see why we don’t have an exact date for our sculpture, the lady with the hood.