It won't come as much of a surprise to most dog owners, but new research has shown that man's best friend is a lot more likely to steal food when nobody's looking, suggesting for the first time that dogs can understand a human's point of view.
Dr Juliane Kaminski, of the University of Portsmouth, has shown that when a human forbids a dog from taking food, they're four times more likely to disobey in a dark room than a lit room, suggesting they take into account what the human can or cannot see.
"That's incredible, because it implies dogs understand the human can't see them, meaning they might understand the human perspective," she says.
"But we still can't be completely sure if the results mean dogs have a truly flexible understanding of the mind and others' minds. It has always been assumed only humans had this ability."
Dr Kaminski ran a series of experiments in varied light conditions. In each test, a dog was forbidden by a human from taking food. When the room was dark, the dogs took more food - and took it more quickly - than when the room was lit.
"The results of these tests suggest that dogs are deciding it's safer to steal the food when the room is dark because they understand something of the human's perspective," says Kaminski.
Previous studies have shown that chimpanzees seem to know when someone else can or can't see them, and can also remember what others have seen in the past. It's not clear how sophisticated dogs' understanding is in comparison.
Many earlier research papers have found that, for dogs, a human's eyes are an important signal when deciding how to behave, and that they respond more willingly to attentive humans than to inattentive ones.