听力文章：鸟类并不笨头笨脑神经系统科学家关于鸟类大脑的传统观念发生了转变。 In humans and other mammals,the roof of theforebrain has evolved into the cerebral cortex, astructure responsible for flexiblelearning andreasoning. 人类和其他哺乳动物的前脑顶层已经进化为大脑皮层，这一构造主管弹性学习和推理力量。 Early neuroanatomists thought that the forebrainroof was small and simple in birds, with itsforebraininstead being dominated by structures in its base, called the basal ganglia. 早期的神经系统科学家认为鸟类的前脑顶层在大脑中面积小，构造简洁，且并非由大脑基底部名为基底神经节的构造组成。 Without anelaborate forebrain roof, it seemed that birds couldn”t be very smart. 因此，鸟类并不拥有简单精妙的前脑顶层，这好像打算了鸟类智商有限。 Recent research shows that birds are a lot smarter than scientists once thought. 最近的讨论说明鸟类要比科学家想象的聪慧得多。 To give just afew examples, the New Caledonian crow can manufacture and use tools. 例如，新喀里多尼亚乌鸦会制作和使用工具。 The African grey parrotcan learn to classify objects into categories, and the Florida scrub jaystores food in dozens ofcaches and can remember their locations for future use. 非洲灰鹦鹉能学会对东西进展分类，佛罗里达灌丛鸦会将食物存储在不同的地方，并且能记住位置，以备将来之需。 It turns out that neuroanatomists had it all wrong about bird forebrains. 结果是神经解剖学家 对鸟类前脑的讨论完全错误。 During more than 300 million years of separate evolution, the forebrain roofs of birds and ofmammals each grew largerand more elaborate, but in different ways. 在3亿多年各自的进化过程中，鸟类和哺乳动物的前脑顶层分别以不同的方式变大变精。 The roof of a bird”s forebrain is so different from thecerebral cortex of a mammal that theneuroanatomists had confused most of it with enlargedbasal ganglia. 鸟类的大脑顶层与哺乳动物的大脑皮层差异如此之大以至于神经解剖学家 将其与增大的基底神经节根本都弄混了。