A. To show that some birds have cognitive skills similar to those of primates
B. To explain how the brains of certain primates and birds evolved
C. To compare different tests that measure the cognitive abilities of animals
D. To describe a study of the relationship between brain size and cognitive abilities
NARRATOR:Listen to part of a lecture in an animal behavior class.
FEMALE PROFESSOR:As you know, researchers have long been interested in discovering exactly how "intelligent" animals are.Today we're going to talk about a particular cognitive ability some animals seem to have-the ability to recognize themselves in a mirror.
FEMALE STUDENT:Oh, I've heard about that-chimpanzees have it...
FEMALE PROFESSOR:Right...chimpanzees and other primates- [listing] chimps, gorillas, orangutans... and of course humans.But it's also been found in elephants and bottle-nosed dolphins-a bit of a surprise.It's very rare-most animals don't have it. And it's called mirror self-recognition, or MSR.
FEMALE STUDENT:[a little confused] Well...how does it work?[hesitating] I-I mean... how do researchers know if elephants or chimps recognize themselves?
FEMALE PROFESSOR:Researchers give them the mirror mark test.
In the mirror mark test, researchers put a mark on the animal where the animal is unable to see it- or smell it or feel it, like on the side of their head-without looking in a mirror.Now, typically, when animals first see themselves in a mirror, they think they're seeing another animal.Often they'll look for this animal behind the mirror. They may even exhibit aggressive behavior.But some animals, after this period of exploration, exhibit behaviors that show they know they're looking at themselves.For instance, elephants will touch the mark on their heads with their trunks.
Now, it's been assumed that primates and some other mammals stood alone at the top of the hierarchy of cognitive evolution.But recently, birds have been found to possess some of the same cognitive abilities.In particular, researchers have discovered these abilities in corvids-birds of the Corvidae family.
Corvids include ravens, jays, crows, and magpies, among others.And what kinds of cognitive abilities are we talking about?Well, corvids, and some mammals, have the ability to plan for the future-to store food, for instance, in places where they can find it later.It's been suggested, in fact, that jays-corvids known for stealing each others' food-may hide their food precisely because they're projecting their own tendency to steal onto other jays.
So let's talk about a study recently conducted with magpies.
As I said, magpies are corvids.And because corvids have these other cognitive skills, researchers wanted to see if they were also capable of mirror self-recognition.So they gave them the mirror mark test, placing a yellow sticker on the birds' black throat feathers.At first, the magpies all engaged in the same social behaviors that other animals do-looking behind the mirror, etc.But eventually, some of the birds, while looking in the mirror, kept scratching at the mark until they got rid of it. And they didn't scratch at it when there was no mirror around. So, they passed the test.
MALE STUDENT:Wow-do any other birds have this ability?
FEMALE PROFESSOR:Well, not that we know of.There was a study using pigeons, where researchers attempted to reduce MSR to a matter of conditioning—that is, they claimed that the ability to recognize oneself in a mirror could be learned.So these researchers basically trained some pigeons to pass the mirror mark test.But two things are noteworthy here.One, no one's ever replicated this study. But more importantly, it misses the point.The issue isn't whether some behavior can be learned; it's whether a species has developed this ability spontaneously.
MALE STUDENT:So what does the test tell us about corvids...or chimpanzees?
FEMALE PROFESSOR:Good question.For one thing, it's important because it sets animals with a sense of self apart from those without a sense of self.But more importantly, many researchers believe that MSR is indicative of other advanced cognitive abilities.Self-awareness, even in its earliest stages, might entail an awareness of others, the ability to see their perspective-to look at the world from another's point of view.This is crucial, because it implies a high level of cognitive development-it's perhaps the first stage toward the development of empathy.
MALE STUDENT:But, birds' brains are so small, compared to primates...
FEMALE PROFESSOR:True-though corvids do have unusually large brains, for birds.But size isn't the whole story. It's thought that primates are so "intelligent" because of a certain part of their brains, which birds simply don't have.But there is an area in birds' brains that researchers believe governs similar cognitive functions.So, primates' and birds' brains have evolved along different tracks, but ended up with similar abilities.
原文定位：Professor: As you know, researchers have long been interested in discovering exactly how intelligent animals are. Today we are going to talk about a particular cognitive ability some animals seem to have—the ability to recognize themselves in a mirror.
文章开头直接给出Today 作为提示，音频中给出的关键信息cognitive，然后分别详细阐述了bird brain 以及primate的信息。最后说到两者虽然进化路径不同但是有相似能力