Why do dogs tilt their head to the side?

By Stephanie Pappas for Scientific American

Ask your dog if they want to go to the park, and you might get an inquisitive-looking head tilt in response. This cute canine behavior is familiar to dog owners, but no one really knows why human’s best friend does it—and scientists have published just one study focusing on possible reasons for head tilting in dogs. That research suggests the animals might cock their furry noggins when processing familiar words.

“In humans, when you remember a story or something, you tilt your head to the side, and you have this mental image of something in your mind,” says Andrea Sommese, an animal cognition researcher at Eötvös Loránd University in Hungary and lead author of the study. “Probably it’s the same for dogs.”

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Many animals tilt their head as they encounter the sights, sounds and smells of the world. Much of this has to do with having a preferred ear (or sometimes nostril), Sommese says.

In other cases, it’s about localizing a sound, says Julia Meyers-Manor, an animal cognition researcher at Ripon College, who was not involved with the research. “Humans do it; birds do it; dogs do it,” Meyers-Manor says. “Lots of different species will do this head tilt because that changes the angle that your ears are at, and now the sound is reaching one ear faster than the other.”

Barn owls are champion head tilters, for example, and can also swivel their neck 270 degrees around. This adaptation helps them fix their eyes—which are largely immovable—on their prey, and it lets them point their sensitive ears in almost any direction, according to a 2017 study in the Journal of Anatomy.

But in at least some cases of canine head tilt, the behavior seems to be more about processing information than about collecting it in the first place. Sommese and his colleagues studied a subset of “gifted” dogs that could learn the names of many individual toys—a feat that’s nigh impossible for the average pooch. When comparing the performance of these overachieving dogs with their counterparts that couldn’t be trained to learn toy names, the researchers found the gifted dogs tilted their head 43 percent of the time when their owner said the name of one of their toys. That’s compared with just 2 percent of the time for the typical dogs.

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The gifted dogs tilted their head in the same direction no matter where their owner was standing, suggesting that the behavior wasn’t about pinpointing the sound but about processing it and matching it to a mental image, Sommese says.

“Probably it doesn’t happen in the typical dogs because typical dogs don’t associate a name to a particular toy, so they cannot recall a memory,” he says. But a typical dog might respond with a head tilt to something it does find relevant, such as the promise of a treat or a walk down the block.

Sommese and his colleagues published their findings in 2021 in the journal Animal Cognition, and they haven’t yet been able to follow up on the head-tilting aspect of canine cognition. So why might head tilting seem to help dogs process a familiar word? It could have to do with the fact that the brain is lateralized, meaning that the processing regions for certain stimuli are located on one side or the other. In humans, language processing is centered mostly in the left side of the brain. Dogs process familiar human words on the right side of the brain, according to a 2016 study published in Science, but the same concept might still hold true.

Over time, Meyers-Manor says, this could also become a social cue that could show others that you’re active and engaged in what’s going on around you. This social aspect might explain why humans interpret the doggy head tilt to indicate attentive curiosity—and why we can’t help finding it so cute.

(The author is a freelance science journalist.)