- Dogs have been man's best friend for at least the past 15,000 years.
- Science now shows that this symbiotic relationship has been as beneficial for humans as their canine companions.
- Benefits of dog ownership include familial ties, a reduce risk of schizophrenia, and improved cardiovascular health.
Under cover of darkness, a pack of ancient wolves slowly stalk the camps of our nomadic ancestors. But they are not on the prowl. These timid, congenial Canidaes have discovered they can scavenge human kills and midden piles for more reward, and far less risk, than the hunt.
Over successive generations, their offspring grow more docile and more dependent on their human benefactors. In time humans adopt these four-legged moochers, taking them into their service with the tacit agreement of better food and companionship. And so, the human-dog relationship was born.
That’s one possibility at least. All that’s generally agreed upon is that dogs became man’s best friend as early as 15,000 years ago — though some fossil evidence suggests domestication as far back as 30,000 years. As science writer James Gorman points out, this means we loved our tail-wagging besties before inventing agriculture, language, or permanent homes and even before we domesticated cows, goats, and, of course, cats.
“As we became friends with them, they became friends with us, and we have a dependency that’s charming,” Bill Nye, science guy and lover of all good dogs, told us in a 2015 interview. “It’s enriched both the dog lives and the human lives.”
For humans, the perks of the dog-human relationship run much deeper than games of fetch or a handy excuse to go for a nice, long walk.
Dogs see us as family
It’s not our imaginations or a poetic attempt to explain behavior through personification. Dogs do view their people as family.
Cognition scientists at Emory University placed dogs in an MRI machine and scanned their brains while presenting them with different odors. Some aromas were of food. Others were from other dogs. And some were from the dogs’ human companions. The dogs’ brains’ reward centers lit up most when presented with the human scents, showing they prioritized human relationships.
These results bolstered other research that shows dogs act similarly to human sounds and that they are the only non-primates to run toward humans for protection and comfort.
Dogs reduce the risk of schizophrenia
Dogs may be able to curb the risk of some mental diseases. That’s the conclusion of research published in the peer-reviewed journal PLoS ONE,which found a link between dog ownership and a reduced risk of schizophrenia.
The researchers looked at 1,371 men and women across the socioeconomic spectrum. Roughly 400 participants suffered from schizophrenia, another 400 from bipolar disorder, and about 600 were controls. After a survey in which the participants were asked about pets, the researchers compared ownership with rates of mental illness.
They discovered that dog ownership before the age of 13 correlated with a 25 percent reduced risk of schizophrenia. Participants who owned dogs in the first years of life showed the largest protective effect.
“There are several plausible explanations for this possible ‘protective’ effect from contact with dogs,” lead author Robert Yolken said in a statement. “Perhaps something in the canine microbiome that gets passed to humans and bolsters the immune system against or subdues a genetic predisposition to schizophrenia.”
Sorry, ailurophiles. Cats did not show a similar link between ownership and a reduced risk of mental diseases.
Dogs are your heart’s best friend, too
The health benefits aren’t just in the mind. Preliminary research published in Mayo Clinic Proceedings: Innovations, Quality & Outcomes suggests that pet ownership boosts heart health, especially if that pet is a dog.
Researchers evaluated roughly 1,800 participants using the American Heart Association’s Life’s Simple 7, seven life factors that people can improve to help achieve cardiovascular well-being. They then compared the health of pet owners with those who did not own pets and found a correlation between dog ownership and heart health. The researchers associated this salubrious effect with increased engagement and physical activity.
“In general, people who owned any pet were more likely to report more physical activity, better diet and blood sugar at an ideal level,” Andrea Maugeri, a researcher with the International Clinical Research Center at St. Anne’s University Hospital in Brno, said in a statement. “The greatest benefits from having a pet were for those who owned a dog, independent of their age, sex and education level.”
Follow-up evaluations are scheduled until 2030.
Dogs make life better (and longer)
Better heart health means a better chance to live longer. That’s according to a recent study and meta-analysis published in Circulation: Cardiovascular Quality and Outcomes.
The research found that dog owners who survived a heart attack were at a 33 percent reduced risk of early death compared to non-dog survivors. The same held true for stroke survivors (27 percent). Better still, dog ownership correlated with a 24 percent reduced risk of all-cause mortality, likely explained by an increase in physical activity and a decrease in depression and loneliness.
A study published in Scientific Reports corroborates a canine’s life-giving, heart-healthy impact. The researchers reviewed the national registries for more than 3.4 million Swedes with no cardiovascular disease before 2001. Looking at the association between dog ownership and cardiovascular health, they found that single dog owners had a lowered risk of death, either due to cardiovascular disease (11 percent) or other causes (33 percent).
In a statement, lead junior author Mwenya Mubanga noted, “A very interesting finding in our study was that dog ownership was especially prominent as a protective factor in persons living alone, which is a group reported previously to be at higher risk of cardiovascular disease and death than those living in a multi-person household. Perhaps a dog may stand in as an important family member in the single households.”
Dogs teach us ways to learn
Put simply, dogs are better at ignoring bad advice than their human peers. Research out of Yale University’s Canine Cognition Center tasked dogs with retrieving treats from a puzzle. The researchers presented the steps to solve the puzzle but included many extraneous steps in the demonstration. When it was the dogs’ turn, they nimbly skipped the unnecessary steps, thereby showing their ability to filter information effectively.
How did human children perform? Not so great. The children settled on pure imitation, regardless of whether a step proved useful in solving the puzzle.
“This tells us something really important about how humans learn relative to other animals,” Big Think author Arpan Bhattacharyya wrote on the study. “We’re really trusting of the information that we get from other individuals – even more trusting than dogs are.
“And what this means is we have to be really careful about the kinds of information we present ourselves with. We’re not going to have the right filter for bad information, so we should stick to looking at information that’s going to be positive, information that’s going to be good.”
Dogs teach us about ourselves
Dogs resemble their owners in more ways than floppy jowls or a perky gait. Dogs mirror their owners’ personalities, and owners can use this information to better understand themselves.
Research published in the Journal of Research in Personality surveyed more than 1,600 dog owners, representing about 50 different breeds. They found that dog owners shaped their dogs’ personalities. Extroverted owners rated their dogs as more active and playful, while the owners of more fearful dogs tended to exhibit more negative emotions. Similarly, more agreeable owners were guardians of less aggressive pets.
“We expected the dogs’ personalities to be fairly stable because they don’t have wild lifestyle changes humans do, but they actually change a lot. We uncovered similarities to their owners, the optimal time for training and even a time in their lives that they can get more aggressive toward other animals,” lead author William Chopik said in a release.
Another study in Scientific Reportsshowed similar findings regarding stress. The researchers took hair and fur samples from owners and their dogs to measure both for the stress hormone cortisol. They found a correlation in long-term stress between the two.
More than simply good dogs
These are six ways that science has discovered dogs aid their interspecies partner. As genetic research advances, dogs may prove they are man’s best friends in unforeseen ways. Scientists studying the canine genome have found a number of canine disorders that closely resemble those found in humans, including some cancers. Further study may provide a wealth of information that could help us solve our own genetic mysteries.