英語時差：貓是“色盲”（下）

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 discriminate 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 differentiate between two colors until after making over 1,400 attempts. These experiments showed researchers that though cats technically have the ability to tell the difference between two colors, they don’t use that ability in their daily lives.