If you have a chance to take a walk in a park, look carefully at the people walking their dogs. You'll probably find friendly-looking people with friendly dogs; quiet people with quiet dogs; large men with oversized dogs and long-haired women with long-eared dogs. As you've probably noticed, dogs and their owners look alike. Have you ever wondered why?
These similarities are so common that researchers have tried to explain them. There are two theories (理论): the convergence (趋同) theory and the selection theory. The convergence theory says that as the owner and the dog spend more time together, they influence each other to the point where they grow similar. In other words, they “converge.” The selection theory, on the other hand, says that owners are interested in dogs that look like them, so they choose those dogs as pets.
Recently, researchers at the University of California decided to test the two theories by taking pictures of 45 dogs separately from their owners. Then they asked some students to match the dogs' photos with their owners. The students were quite successful with purebred (纯种的) dogs: they correctly matched 16 out of 25 with their owners. However, they had almost no success connecting mixed-breed (杂交的) dogs with their owners. When owners select a purebred dog, they can easily predict (预测) what it will look like later. But that is not true with mixed-breed dogs because it's hard to predict what a mixed-breed dog will look like when it grows up. And since it was the purebreds not the mixed-breeds that looked like their owners, the research seems to prove the “selection theory”.
But one bit of warning. Although many people look like their dogs, not all dog owners enjoy having the similarity pointed out to them. So, even if the similarity is amazing, don't go up to a stranger and say, “Wow, you look just like your dog!”
