Why do dogs tilt their heads?

In the iconic painting "His Master's Voice," a terrier cocks his head as he listens to his owner's voice coming from a gramophone. This gesture is one many dog owners will be familiar with, but why do dogs tilt their heads?

In a 2021 study in the journal Animal Cognition, researchers in Hungary conducted the first scientific investigation of head-tilting in pooches. They found that dogs may incline their heads as they are remembering details they find meaningful.

"Head tilts in dogs are a fairly known behavior, but the most surprising thing for me was that no one before us investigated it," study lead author Andrea Sommese, an ethologist (a scientist who studies natural animal behavior) at Eötvös Loránd University in Budapest, told Live Science. 

In an earlier 2021 study in the journal Scientific Reports, Sommese and his colleagues analyzed videos from around the globe in which dog owners asked their pets to fetch them a toy by saying its name. Although 33 pooches were not able to learn the names of any new toys after three months of practice, seven gifted dogs were able to learn more than 10 names during that time, with one female border collie, Whisky, correctly identifying 54 toys.

While conducting the study that appeared in Scientific Reports, the researchers noticed that all 40 of the dogs cocked their heads during the tests. The scientists next investigated when the canines performed these tilts.

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In the following Animal Cognition study, the scientists found that the gifted dogs tilted their heads 43% of the time when asked to retrieve a toy by name. The other pooches tilted their heads in only 2% of these cases.

"We are not claiming that only gifted dogs tilt their heads while typical dogs never do it," Sommese said. "Typical dogs also do that, some more often than others, but in this specific situation, when the owner asks for a toy by its name, only the gifted dogs show a nice tilt."

These findings suggest that dog head-tilts are related to sounds the pets have learned to find important. 

"Dogs tilt their heads in a number of situations, but it seems that they do this only when they hear something that is very relevant to them," Sommese said. "It seems that this behavior is strongly associated with sound perception, and it might be something they do when they're trying to listen more closely, or maybe when they are a bit confused, just like humans do."

In addition, the researchers found the side of the tilt was consistent in the gifted dogs across 24 months of tests, but the favored side differed from canine to canine. This suggests one side of the brain of each dog may favor the mental activity underlying head-tilting, the scientists noted. Just as humans typically prefer using one hand over the other, many dog behaviors favor one side, such as the paw with which dogs reach for an item, the direction in which they favor wagging their tail and even the nostril they use more during sniffing, they explained. 

Future research can explore what other sounds or contexts might trigger canine head-tilting, said Monique Udell, a human-animal interaction researcher at Oregon State University, who did not take part in the studies.

"Studies like this one are important because they remind us that we, as humans, also have a lot to learn about what a dog's body language is communicating to us," Udell told Live Science.