TOEFL Listening: ETS-TOEFL听力机经 - 418R4XO4313377J1Q$

Lecture: Animal Behavior: Bischof-Kohler hypothesisAuthor: QQ-464094252: Narrator: Listen to part of a lecture in an Animal Behavior Class. Professor: Okay. Today we're going to be looking at animal behavior patterns that involve caching. A-As you may already know, the word caching is related to the word cache. A cache is a hiding place, and caching, uh, when we say an animal caches, it's when the animal stores its food in a hiding place. Now many animals cache their food supplies, uh Yes Phels? you have a question? Phels: Well, there's something I've always wondered about. When animals cache food, are they really like – planning for the future? Like, when squirrels hide nuts, are they you know, just hiding nuts because they have some impulse that tells them that "go hide some nuts"? or are they really like thinking about the future? You know, planning ahead so they'll have food in the winter? Professor: Well, that's a great question! And there've been some studies that have attempted to find that out. In one study, oh well first I should mention a hypothesis about animal behavior called the Bischof-Kohler hypothesis. The Bischof-Kohler hypothesis is widely accepted today. It states that animals, aside from humans that is, are unable to anticipate future needs. That they're only able to think in the present. And that any future-oriented behavior is purely instinctive. They behave in certain ways only because they're programmed to, not because they're consciously planning for the future. But recently, researchers have been reexamining this hypothesis. And they've been conducting some studies in an attempt to demonstrate that animals w-w-well maybe some animals have an awareness of the future need for food and they decisively plan for later meals. They've been studying a species of birds known as the Western Scrub Jay. Western Scrub Jays cache food supplies, and in this one study that I read, researchers were trying to determine whether the Scrub Jays are actually thinking about the future, planning for future needs when they cache their food. The study is fairly complex, but uh well let me just summarize, the first stage of the study lasted for 6 days – on the morning of the first day, the Jays were put in a compartment of a large cage where they had access to food, so they began to associate that compartment with food in the morning. The researchers called this the Breakfast Compartment. On the second day, the Jays were put in a different compartment of the cage where there was no food – so they began to associate that second compartment with no food in the morning. That was the no breakfast compartment. And over the next few days, the researchers continued to alternate the compartments. On the third day, the Jays were put in the breakfast compartment on the fourth day in the no breakfast compartment and so on. So after several days the Jays had been trained to distinguish between the breakfast and no breakfast compartments. Then after that training period in the second stage of the experiment, the Jays were given the opportunity to cache food in both compartments, and what do you think happened? Jennifer? Jennifer: They stored the food in the no breakfast compartment? Professor: That's right! They stored significantly more food in the no breakfast compartment. So ... ? Does this mean they were planning ahead for the next time they'd be without food in that no breakfast compartment? Well, those researchers also did a second study. An interesting thing about Jays is that they'll steal from each others' food caches if they can. So what these researchers did was – they divided the Scrub Jays into two groups. While the Jays in the first group were caching their food, they were being observed by other birds in the cage. But while the Jays in the SECOND group were caching their food, there were no other birds around to observe them. Later, all the Jays in the first group returned to their caches, dug them up, and moved the food to a new location where the food was newly cached. They hid the food again, WITHOUT being observed by other birds, but the Jays in the SECOND group, the ones that were not being observed by other birds, they did NOT re-cache their food – maybe because they didn't need to, since there was no perceived threat of the food being stolen? Well, it does look like that first group, the group that re-cached their food, was planning ahead, maximizing their chances of finding food in their cache some time in the future! Does that mean the Bischof-Kohler hypothesis is wrong? Well, further research is needed here and we may never know exactly what mental processes the Scrub Jays were using when making their decisions. But it does seem likely that they somehow may have been able to behave in such a way as to meet their future needs.