Puppies, Kittens, and Human Health: Science Versus Wishful Thinking

What do scientists really know about "the pet effect?" —

Posted Aug 20, 2012

This morning an NPR reporter proclaimed over my kitchen radio, “Good news sells, bad news doesn’t.” The statement reminded me of a recent Psychology Today post by clinical psychologist Melanie Greenberg. The title was "Why We Love Our Pets: They're Just Like Us!" The post discussed the impact of pets on human health and well-being.

I am sure Greenberg is a good clinician, and I enjoy her blog The Mindful Self-Express. But, as far as I can tell, her area of expertise is not human-animal relationships. In her post, Greenberg assessed the validity of some commonly held stereotypes about people and pets. Among the claims she examined is the widely held notion that getting a pet will make you healthier. This phenomenon has been called "the pet effect." She correctly notes that pet ownership has been linked in some studies to decreased stress and lower blood pressure, lower incidence of heart attacks, and greater muscular flexibility in elderly people. After briefly reviewing the research, she confidently proclaimed the theory that pets make their owners healthier is, indeed, "Confirmed!"

Unfortunately, she is wrong.

Fact: Pets Are NOT Panaceas

While Greenberg promised her readers “an objective view” of current research, in reality she ignores the results of studies that did not support the pet effect hypothesis. The file cabinet in my office contains a two-inch thick folder of studies Greenberg would like. These studies found beneficial effects of living with pets. The bad news is that I have another two-inch stack of studies which found that pets had no effect on human health and happiness or that pet owners were actually worse off than people without pets.

Here, for example, are a dozen studies that did not support the pet effect hypothesis. I encourage you to check them yourself. The hyperlinks will send you to the reference for the original articles.

-Among 425 heart-attack victims, pet-owners were more likely than non-pet owners to suffer remissions or die. Click here.

-Australian pet owners were in worse physical condition and were more depressed than non-pet owners, and they took more pain medications. Click here.

-A study of 1,179 older adults found no differences in blood pressure or rates of hypertension in pet owners and non-owners. The pet owners, however, exercised less and were more likely to be over-weight. Click here.

--Researchers at Queen’s University in Belfast found that people with chronic fatigue syndrome that owned pets were no better off than pet-less CFS sufferers. Click here.

-In a study of people in retirement communities, pet owners were just as lonely as their pet-less peers. Click here.

-Finnish pet owners had higher rates of ulcers, depression, panic attacks, and hypertension than non-owners.Click here.

-People who were more attached to their companion animals were more depressed than people who were less attached to their pets. Click here.

-A six month longitudinal study found that acquiring a companion animal had no effect on the loneliness of new pet owners. Click here.

-Among 40,000 Swedes, pet owners had better physical health than non-owners -- but they suffered more from anxiety, fatigue, depression, and insomnia. Click here.

-Adolescents with pets were less physically active and had more psychological problems than adolescents without pets. Click here.

--Spending time with a dog did not improve the mental states of patients undergoing radiation therapy. Click here.

-Older women who are more attached to their pets tend to have poorer general health. Click here.

-Pet-owning mothers of young children were more likely to be overweight or obese that non-pet owning mothers. Click here.

My cat Tilly. She makes my life better.

Please Don't Blame The Messenger!

My cat Tilly. She makes my life better.

When it comes to pets, I am not the Grinch. Our household has always included animals — a proliferation of dogs ( big friendly Labs and Goldens), cats, tropical fish, Sam — a red-tailed boa constrictor, chickens, a grey mouse named Willie. (That does not count the half a dozen alligators my wife and I had running loose in our apartment in Gainesville back when I was studying crocodilian love songs.)

I know that the animals in our home have enriched our lives. But I am also a scientist. After reading hundreds of research-based articles on the effects of pets on people, I have concluded there is insufficient evidence to support Greenberg's pronouncment that owning a pet will make you happier. It is true that some excellent studies have found that pets can lower blood pressure and reduce stress and serve as social lubricants. But the bottom line is that the best researchers can say at this point is that pets seem to be good for some people and not others. (For a more extended discussion of why research on this topic has produced conflicting results see this recent article in the Current Directions in Psychological Science.)

Telling People What They Want To Hear

This is not welcome news for the $50 billion dollar pet products industry. Indeed, pet company execs are in a tizzy because, for the first time in 100 years, pet ownership is going down in the United States. This trend is also of great concern to the American Veterinary Medical Association. (see here).

I suspect, however, that the substantial body of evidence indicating that pets are not panaceas will not dampen the facile but unsupported claims of the authors of feel-good books such as Marty Becker's The Healing Power of Pets ... or pop psychologists.

After all, as the man on the radio said this morning, "good news sells."

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Hal Herzog is the author of Some We Love, Some We Hate, Some We Eat: Why It’s So Hard To Think Straight About Animals. A professor of psychology at Western Carolina University, he has published over 100 research articles and chapters on animal behavior and human-animal relationships.

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