SNOWBIRD, UTAH--Many dog owners will be quick to tell you that their beloved canines can understand what their masters are thinking. Though the dogless among us aren't always convinced, new research suggests that dogs do in fact have a rudimentary "theory of mind."
Most people understand that others have beliefs, interests, and intentions that are different from their own. Although this so-called theory of mind is critical for our social development and survival, the ability has not been conclusively shown in our close relatives, apes and monkeys. Since studies in other species are scarce, Alexandra Horowitz, an animal cognition researcher at Barnard College in New York City, turned to man's best friend.
In humans, social play is considered important in the development of complex thought, problem-solving skills, and even language. So Horowitz videotaped dogs play-fighting in a "natural" setting: a 2.5-acre grassy, off-leash dog park. In the 39 playful interactions Horowitz recorded, a canine hoping to initiate play would first make sure it had its partner's attention. Typical attention getters included barks, play bites, and bumps, which are easy to distinguish from play signals, such as running off while looking back, and exaggerated, loping approaches.
Often if two dogs were playing and one became distracted, the other would use one or more attention getters to cause its partner to look its way and then signal that it wanted to play some more. Importantly, the initiator would usually scale its attention-getting tactics according to how distracted its partner was. If the distracted dog was just looking away, a gentle nose bump usually did the trick. But if the distracted dog had turned its back entirely and focused on something else such as another dog, its partner would usually escalate to a more forceful attention getter, such as a nip on the shoulder.
The results indicate that dogs can sense the degree of their playmate's distraction, suggesting a low-level theory of mind, says Horowitz, who presented her results here 7 August at a meeting of the Animal Behavior Society. If the dogs had no theory of mind, she says, they would play signal even to dogs that could not see it.
"This is the first attempt to quantify this kind of thing," said Camille Ward, an ethologist who studies canine behavior at the University of Michigan in Ann Arbor. But Ward, who has three dogs of her own, says that the dogs' behaviors should also be tested in other situations, such as when a dog is alone, to support the assertion that attention-getting behavior is specific to the appropriate play situation.