By Valerie Battaglia

“BARK! BARK! BARK!” Neurons fire to one another in response to a feline, fire hydrant, mailman, or dog treat. “BAAAAAAARK,” neurons fire again as the owner walks out the door and leaves the canine behind for an eight-hour shift.

Dogs have been “man’s best friend” for thousands of years, reports a study published in Nature Communications – but, is man dog’s best friend? How do they regard human relationships? What do dogs think and feel? How do they communicate?

How Dogs Think

Researchers can use eye tracking to monitor what dogs are paying attention to and functional magnetic resonance imaging to monitor brain activity.

An MRI scan depicts brain activity by detecting changes in blood flow, according to the University of Utah. There’s an increase in blood flow to portions of the brain that are in use, which gives a real-time image of neural activity.

fMRI is similar to MRI, but it depicts metabolic activity in the brain to represent energy being consumed during various states of brain activity, according to Neurosurgery Clinics of America.

While researchers may not be able to ask dogs what they’re thinking, there are tools at their disposal that can provide better insight on canine cognition.

Through eye tracking, researchers can observe when something visually captures a dog’s attention. Through fMRI scans, researchers can observe what dogs find rewarding and the neurological basis for a dog’s response to stimuli.

How Dogs Feel

In a 2015 Behavioural Processes study, researchers used an fMRI machine to measure dog brain activity when exposed to familiar and unfamiliar scents.

The study found a specific response to human scents; the scent of their owners activated the reward response. The same wasn’t the case when exposed to the smell of other dogs.

However, there’s not a definite answer to whether dogs find the smell of their owners rewarding due to a social connection or a connection to their owners feeding them.

Alternatively, there are a number of studies that quantify the emotional connection between dogs and humans.

A 2017 Frontiers in Behavioral Neuroscience study found when dogs look at humans, their brains release oxytocin.

Oxytocin, sometimes touted as the “love hormone,” plays an important role in human social connections, according to the Hormone Health Network.

Women produce oxytocin during childbirth and breastfeeding that triggers a bond with their infants. Oxytocin also increases recognition, trust and arousal between partners.

Dog brains releasing oxytocin when they look at humans lends a neurochemical basis to being “man’s best friend.” It indicates a bond to our species that encourages them to recognize and trust humans.

The Frontiers in Behavioral Neuroscience study also used eye-tracking to detect that dogs pay particular attention to the emotionally expressive regions of the human face. They tended to focus their gaze on human eyes, rather than their neck or forehead.

Additionally, dogs produce different facial expressions depending on the emotion behind the stimuli they presented, says a 2017 Scientific Reports study.

A 2016 Biology Letters study presented dogs with facial expressions from both humans and dogs while playing a sound that represented different emotions. The dogs looked longer at faces that matched the emotion of the sound played, which is a trait that had only been observed in humans prior.

In other words, dogs can recognize emotions both visually and auditorily.
A 2014 Current Biology study compared how dogs turned their head in response to various commands and emotional sounds played from speakers on both sides of them simultaneously.

When the dogs heard a familiar command without emotional context, they turned to the right 80 percent of the time. When an emotional-sounding sentence was played, the dog turned to the left 76 percent of the time.

These results further demonstrate a dog’s ability to separate emotion from the words themselves, but how much information dogs truly understand from each remains a mystery.

How Dogs Communicate

Dogs use a blend of body language, vocalization, and odors to communicate, according to a 2018 Animals review. There are also differences and similarities between how dogs communicate with other dogs v.s. humans.

Some of the physical expressions dogs use include raising and lowering their bodies as well as wagging their tails. They also use eye contact to intimidate other dogs.

Additionally, dogs use their facial expressions to communicate with humans and indicate they’re paying attention to them.

In regards to vocal communication, dogs vary the length and pitch of barks to convey emotion. The study found dogs use shorter frequency barks for greeting, calling for attention, reacting during play, or to warn.

Growling is another important form of vocalization in dogs. Longer and lower frequency growls generally indicate warning or caution as a stranger approaches them, whereas higher frequency growls are reserved for when they’re isolated and lonely.

Dogs are also able to detect emotion through chemicals emitted in body odor. Through urination, defecation, and rolling on the ground, dogs mark territory to mark their scent. They can distinguish between the scents of different dogs and humans, as well.

Another 2017 study in Royal Society Open Science used different growls to indicate playfulness v.s. aggression. Slower, shorter growls paired with a lowered stance were viewed as more playful.

Of course, canine communication isn’t one-sided. Humans actively speak to dogs. Without non-auditory cues, dogs were highly reactive to speech directed towards them, and pitch played a role in how they behaved in response, according to a 2017 study in the Proceedings of Royal Society B.

Humans tend to speak to dogs like human babies, in a higher pitch with a higher level of harmony, regardless of whether they’re puppies or fully grown.

The study showed that puppies were more attentive to verbal cues when spoken to “like a baby,” whereas older dogs didn’t show a preference. However, dogs across the board are more attentive to dog-directed speech.

Dogs actively listen to humans, but we aren’t sure how much of the message they comprehend. So far, research shows that dogs do understand and recognize emotion as well as familiar commands.

Humans don’t have to bark, growl, or urinate on the ground in order to communicate with dogs. The pitch of their voice and the expressions on their face are more than enough to signal, “Ri ruv rou, roo.”

Contact Valerie Battaglia at communitarian@mail.dccc.edu