I once knew a dog named Newton who has a unique sense of humor. Whenever I tossed out a Frisbee (飞碟) for him to chase, he’’d take off in hot pursuit but then seem to lose track of it. Moving back and forth only a yard or two from the toy, Newton would look all around, even up into the trees. He seemed genuinely puzzled. Finally, I’’d give up and head into the field to help him out. But no sooner would I get within 10 ft. of him than he would run invariably straight over to the Frisbee, grab it and start running like mad, looking over his shoulder with what looked suspiciously like a grin. Just about every pet owner has a story like this and is eager to share it with anyone who will listen. On very short notice, TIME reporters came up with 25 stories about what each is convinced is the smartest pet in the world. Among them: the cat who closes the door behind him when he goes into the bathroom; the cat who uses a toilet instead of a litter box... and flushes it afterward; the dog who goes wild when he sees his owner putting on blue jeans instead of a dress because jeans mean it is time to play; and the cat who used to wait patiently at the bus stop every day for a little girl, then walk her six blocks home. And so on. These behaviors are certainly clever, but what do they mean Is Newton really deceiving Can a cat really desire privacy in the toilet In short, do household pets really have a mental and emotional life Their owners think so, but animal-behavior experts would have gone mad on hearing such a question. The worst sin in their moral vocabulary is anthropomorphism (拟人化). projecting human traits onto animals. A dog or a cat might behave as if it were angry, lonely, sad, happy or confused, but that is only in the eye of the viewer. What is going on, they insist, is that the dog or cat has been conditioned, through a perhaps unintentional series of punishments and rewards, to behave certain way. The behavior is a mechanical result of the training. Newton seemed puzzled about not knowing______________.