Do dogs know we love them? What the science says

Do dogs know we love them? Emory University neuroscientist Gregory Berns has said that philosophers treat the question of what it is like to be a dog as one that cannot be answered. So researchers measure what they can: where a dog looks, how its hormones change, and which parts of its brain respond to its owner. This guide goes through what those studies found about how dogs know their owner's love, how many dogs each study used, and what each one could not show.

The long look: eye contact and a bonding hormone

In April 2015, the journal Science published a study by Miho Nagasawa and colleagues in Japan. They measured oxytocin, a hormone that the paper links to the bond between a mother and her baby. In the first experiment, 30 dogs and 11 wolves raised by people each spent 30 minutes with their owner. The team measured oxytocin in urine before and after.

Eight of the 30 dogs looked at their owners for the longest time. Their owners' oxytocin went up, and so did the dogs' own. The wolves rarely made eye contact with their owners, and neither the wolves nor their owners showed a rise.

In a second experiment with 27 owners and their dogs, the team gave each dog a nose spray of oxytocin or of salt water. Female dogs that got oxytocin looked at their owners for longer, and those owners' oxytocin rose, although the owners got no spray. Male dogs showed no such change. The authors describe a loop: the dog's look raises the owner's oxytocin, and the owner's attention raises the dog's. They also say that their sample was small.

Two researchers, Sylvain Fiset and Vickie Plourde, raised questions in a commentary in Frontiers in Psychology. Every dog in the study was an adult, so the loop might come from what each dog learned during its own life with people. They also point out that the rise showed up only in the dogs that looked longest.

Dogs also have a face that suits this look. In 2019, a University of Portsmouth team led by Dr Juliane Kaminski reported in PNAS that dogs have a small muscle above the eyes that lets them raise the inner eyebrow strongly. In wolves, the same spot has a thin, uneven cluster of fibres. When exposed to a person for two minutes, dogs raised their inner eyebrows more often and higher than wolves did. The team suggests that the movement makes the eyes look larger and more like a baby's, which makes people want to care for the dog. It is the look people call "puppy dog eyes".

What a dog's brain does with your scent and your praise

Berns runs the Dog Project at Emory University. His team trained dogs to walk into an MRI scanner, a machine that shows which parts of the brain are working, and to lie still while awake, with no straps and no calming drugs.

In one study, reported in 2014, the scanner recorded twelve dogs as they smelled the scents of people and of dogs. A reward area of the brain, called the caudate, responded more strongly to the scent of a familiar person than to the scent of a stranger, or even of a dog the dog knew. The people who gave the scent were not in the room. Berns said this shows that dogs keep an idea of us in their minds that stays while we are away.

A second study, reported in 2016, asked whether dogs care more about food or about their owners. Of the 13 dogs that completed it, most preferred their owner's praise to food or liked both equally. Two dogs showed a strong preference for food. One terrier mix named Ozzie chose food every time.

The two parts of the study matched. Dogs whose brains responded most to praise in the scanner went to their owners 80 to 90 percent of the time when they could choose between owner and food. Berns said this may be similar to how people feel when someone praises them.

How dogs read your face and your voice

In 2016, the University of Lincoln in the UK and the University of São Paulo in Brazil tested 17 dogs. Each dog saw two photos of the same person or dog side by side, one happy or playful and one angry or aggressive. At the same time, it heard a voice or a bark. The dogs looked longer at the face that matched the emotion in the sound. The researchers say this is the first evidence that dogs recognise emotions in people and in other dogs.

The dogs had no training for the test. The faces and voices came from strangers. The human voices spoke Brazilian Portuguese, a language new to the dogs, so the dogs could not rely on words they had learned.

Also in 2016, Attila Andics and his team at Eötvös Loránd University in Budapest scanned the brains of 13 dogs as they listened to their trainer. The trainer said praise words and neutral words, each in a praising tone and in a neutral tone. The dogs' reward area responded only when praise words came in a praising tone. Andics said that dogs can tell apart what we say and how we say it, and put the two together.

How do dogs show love to their owners?

The American Kennel Club (AKC) says dogs show affection with a lick to the face or by dropping a favourite toy at your feet.

Licking has more than one cause. In an AKC article, Dr Alexandra Horowitz of Barnard College explains that wild pups lick their mother's face so she will bring up food for them. For many pet dogs, she says, licking has since become a greeting. Certified applied animal behaviourist Dr Mary Burch says licking can be a sign of affection, and that dogs may also like the salt on our skin after exercise. If your dog licks itself, you or objects all the time, the article advises a visit to your veterinarian first.

Researchers also study attachment, the bond a dog forms with the person who cares for it. In a 2022 Oregon State University study, Monique Udell and Lauren Brubaker tested 48 owners and their dogs. Each owner sat with the dog in a room, left, then came back. Dogs whose owners set clear expectations and responded to their needs were the most likely to be securely attached. Those dogs preferred to stay near their owner over a stranger, and they kept trying longer at a puzzle. Brubaker said the bond between a dog and its owner may be similar to the bond between a parent and a child.

How to let your dog know you love them

The AKC's advice on showing a dog love starts with its daily needs: regular meals, exercise, training and structure. It suggests calm, predictable arrivals and departures. For some dogs, it says, excited greetings at the door can create stress and add to separation anxiety, which is distress when the owner leaves.

The AKC also says that each dog is different. One dog may love treats and another toys. Watch what yours enjoys, and give it time to sniff, run, play and explore.

The Budapest study adds one small point. When you praise your dog, use kind words in a warm, praising voice, because the reward area responded when both matched. The 2015 study also linked long looks between dog and owner to a rise in the bonding hormone in both. For more on the dogs that kings and queens owned, read about royal dogs in history.

Keeping the look your dog gives you

The look that raised oxytocin in the 2015 study is a dog's long, steady gaze at its owner. A portrait can keep it. The portrait studio takes one clear photo of your pet, up to 5 MB, and you choose one of 15 royal styles. In the gallery, the Patiala Royal portrait shows a Pomeranian in a blue coat and jewelled turban on a red throne.

The photo decides whether that look shows in the portrait. Take it when your dog is calm and looking at you. The guide on how to photograph your pet for a portrait explains how to get the eyes sharp and the light right, so the face in the portrait is the one your dog shows you.