英语听力文摘 English Digest 186、猫与色彩

　　Cats And Colors
人类能够很容易的分辨出不同的颜色。那么猫呢？虽然猫的视力很好，即使在非常昏暗的光线条件下也能看见，但它对于如何分辨不同的颜色似乎并不擅长。
"Cats and Colors" on this moment of science.
You can look at that quilt your cat is curled up on and see a patchwork¹ of greens, blues², and yellows. Your cat, however, cannot see color variation in the quilt.
Both humans and cats depend on the back layer of the eye, which is called the retina, to sense light and to distinguish between colors. The retina is made up, in part, of nerve cells that convert color and light into messages they send to the brain.
There are two types of cells: rods and cones³.

　　Rods are very sensitive to light, though they are not used in color vision. Cones on the other hand are not very sensitive to light but can be used in color vision.
Because cats have more rods than humans, they use these light-sensitive cells to see in even very dim light. Likewise, because cats have fewer cones than humans, they cannot distinguish between colors the way humans can.
But cat eyes do have some cones, and with work cats can learn how to distinguish between colors.
In experiments, scientists have taught cats to discriminate⁴ between two symbols when the only difference between them is their color.
Cats have learned how to make this discrimination, but only when the objects used were very large and the difference between the colors very pronounced. It’s not likely you’ll be able to teach your own cat how to tell the difference between two colors unless you are very patient.
Even under controlled laboratory conditions, cats do not learn how to differentiate⁵ between two colors until after making over 1,400 attempts.
These experiments showed researchers that though cats technically⁶ have the ability to tell the difference between two colors, they don’t use that ability in their daily lives.

1 patchwork   

n.混杂物；拼缝物

参考例句：

• That proposal is nothing else other than a patchwork.那个建议只是一个大杂烩而已。
• She patched new cloth to the old coat,so It'seemed mere patchwork. 她把新布初到那件旧上衣上，所以那件衣服看上去就象拼凑起来的东西。

2 blues   

n.抑郁，沮丧；布鲁斯音乐

参考例句：

• She was in the back of a smoky bar singing the blues.她在烟雾弥漫的酒吧深处唱着布鲁斯歌曲。
• He was in the blues on account of his failure in business.他因事业失败而意志消沉。

3 cones   

n.（人眼）圆锥细胞；圆锥体( cone的名词复数 )；球果；圆锥形东西；（盛冰淇淋的）锥形蛋卷筒

参考例句：

• In the pines squirrels commonly chew off and drop entire cones. 松树上的松鼠通常咬掉和弄落整个球果。 来自辞典例句
• Many children would rather eat ice cream from cones than from dishes. 许多小孩喜欢吃蛋卷冰淇淋胜过盘装冰淇淋。 来自辞典例句

4 discriminate   

v.区别，辨别，区分；有区别地对待

参考例句：

• You must learn to discriminate between facts and opinions.你必须学会把事实和看法区分出来。
• They can discriminate hundreds of colours.他们能分辨上百种颜色。

5 differentiate   

vi.(between)区分；vt.区别；使不同

参考例句：

• You can differentiate between the houses by the shape of their chimneys.你可以凭借烟囱形状的不同来区分这两幢房子。
• He never learned to differentiate between good and evil.他从未学会分辨善恶。

6 technically   

adv.专门地，技术上地

参考例句：

• Technically it is the most advanced equipment ever.从技术上说，这是最先进的设备。
• The tomato is technically a fruit,although it is eaten as a vegetable.严格地说，西红柿是一种水果，尽管它是当作蔬菜吃的。