新编大学英语第二册unit5 Text C: Not Just Parrot-Talk
UNIT 5 AFTER-CLASS READING 2; New College English (II)
Not Just Parrot-Talk
1 Scientists have taught a parrot English. So what? This time, it seems, the bird not only says the words but also understands them. Alex, an African grey parrot residing at America's Purdue University in Indiana, has a vocabulary of about 40 words with which he identifies, requests and sometimes refuses more than 50 toys. He seems to manipulate words as abstract symbols in other words, to use a primitive form of language.
2 In many birds, communication takes the form of simple, stereotyped signals. Some birds, like parrots, are capable of learning huge repertoires of phrases by mimicking each other or other species. But, until now, there has been no evidence that any bird could make the big leap to associating one sound exclusively with one object or quality.
3 Alex can. Dr Irene Pepperberg, his trainer, exploited the natural curiosity of the parrot to teach him to use the names of different toys. The trainer and an assistant play with the toys and ask each other questions about them. To join in, the parrot has to compete for the trainer's attention.
4 The results have been spectacular. Alex rapidly learned to ask for certain objects, identifying them by words for shape, colour and material (e.g. three-cornered green paper, or five-cornered yellow wood). He is asked to repeat words until he gets them right and is then rewarded by being given the object to play with. Dr Pepperberg believes it is important that the bird is not rewarded with food, because that would make him think of words as ways of getting treats rather than as symbols for objects.
5 Twice a week, Alex is tested and he normally gets about 80 % of the objects right. The mistakes are usually small omissions (for instance, he forgets to name the colour of an object) rather than specific errors. To discover if he really is able to grasp concepts like colour and shape, he is shown entirely novel combinations. When first shown a blue piece of leather he said "blue hide" even though the blue objects he had previously seen were all keys or made of wood. This suggests that he is aware that words are building blocks that can be used in different combinations.
6 Still, a vocabulary of adjectives and nouns hardly amounts to mastery of a language. The scientists have been looking for evidence that Alex understands more complicated ideas. One unexpected breakthrough was when he learned to say "no". He picked this up from the conversations between the trainer and her assistant and seems to understand at least one meaning of the word rejection (for instance, when Dr Pepperberg tries to play with him and he does not feel like it). He can also count to five when asked how many objects are being shown.
7 There are occasional hints that he has grasped even more advanced concepts but Dr Pepperberg is cautious. Public reaction to the abilities of chimpanzees to use sign language has recently descended from excitement to bitterness and nobody dare make extravagant claims any more. It is not that people doubt the ability of apes to accumulate a large vocabulary of signs. The argument is about whether apes can understand syntax.
8 Examples which seem to show them doing so are few and disputed. For instance, Washoe, the first and most famous of the talking chimpanzees, once pointed to a swan and signed "water bird". Or did she? Dr Herbert Terrace of Columbia University pointed out that she might simply have signed "water" and "bird" in quick succession.
9 Other sceptics argue that, in the course of a lifetime, it would be surprising if such apes did not occasionally produce syntactical combinations of signs by pure chance. A more serious criticism is that the apes are responding to unconscious cues from their trainers.
10 Unconscious cueing is known as the "clever Hans effect" in honour of a famous horse in nineteenth-century Germany. Hans appeared to knock out the answers to mathematical sums with his hoof. In fact, the horse was not doing the sums but was responding to subtle signs from the crowd which told him when to stop. When the crowd did not know the answer, Hans could not do the sum.
11 Dr Pepperberg believes that her experiments are free of such an effect because speech is less easy to cue than sign language. She argues that this makes talking parrots better subjects than signing apes for probing the limits of animal intelligence. She would like to see Alex (or, even better, a young parrot) compared with children to see if the bird discovers ideas in the same order as the children do and exactly where the children leave the bird behind.
