Dogs have been man's best friends for 30,000 years—and now scientists think they know why.

Dogs are usually not relaxed in a lab environment, but with a little petting and lots of treats, they can be trained to sit still even in an MRI (磁共振成像) scanner. That's how researchers at Hungary's ELTE University were able to get images of their brains at work.

Researcher Attila Andics said it helped them better understand the dogs' relationship with humans. "We have known for a long time that dogs and humans share similar social environment, but now our results show that dogs and humans also have similar brain mechanisms (方法；机制) to process social information," said Andics.

After training 11 dogs to stay motionless while their brains were scanned, the researchers checked their neurological (神经系统的) responses to about 200 emotionally

significant sounds, from whining and crying to playful barking and laughing. They then compared the responses from human subjects. They found great similarities. Andics said it opened new possibilities for the research.

"It establishes a foundation of a new branch of comparative neuroscience, because until now it was not possible to measure the brain activities of a non-primate and a primate (灵长类) brain in a single experiment," said Andies.

Evan Maclean, Professor in Duke University, said that the Hungarian results were an important step forward.

"We've known for a long time that dogs have a lot of behavioral similarities compared to humans. But we don't know anything or very little at least about whether some of these behaviors are represented similarly inside the brain of the dog, so this research is providing a first glimpse into whether these behavioral similarities are underlined by similar neural processes," said MacLean.

The Hungarian scientists tell ordinary dog owners to treat their dog companions as intelligent friends, not mere animals, because they evidently understand human feelings.