Pet dogs may understand a human's point of view, according to new research which suggests they are more likely to steal food when they think nobody can see them.
Dr Juliane Kaminski, of the University of Portsmouth's department of psychology, found that when a human forbids a dog from taking food, dogs are 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.
Dr Kaminski said: "That's incredible because it implies dogs understand the human can't see them, meaning they might understand the human perspective."
She said that although many dog owners think that their pets are clever and understand humans, this had not yet previously been tested by science.
Dr Kaminski said: "Humans constantly attribute certain qualities and emotions to other living things. We know that our own dog is clever or sensitive, but that's us thinking, not them.
"These results suggest humans might be right, where dogs are concerned, 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."
The research, published in the journal Animal Cognition and funded by the Max Planck Society, involved a series of experiments in varied light conditions.
In each test, a dog was forbidden by a human from taking the food. When the room was dark, the dogs took more food and took it more quickly than when the room was lit.
The tests were complex and involved many variables to rule out that dogs were basing their decisions on simple associative rules, for example, that dark means food.
Dr Kaminski said that there was no evidence on how well dogs could see in the dark, but the results of her research showed that dogs could differentiate between light and dark.