Is having a pet good for you? The fuzzy science of pet ownership

For more than a decade, in blog posts and scientific papers and public talks, the psychologist Hal Herzog has questioned whether owning pets makes people happier and healthier.

It is a lonely quest, convincing people that puppies and kittens may not actually be terrific for their physical and mental health. “When I talk to people about this,” Herzog recently said, “nobody believes me.” A prominent professor at a major public university once described him as “a super curmudgeon” who is, in effect, “trying to prove that apple pie causes cancer.”

As a teenager in New Jersey in the 1960s, Herzog kept dogs and cats, as well as an iguana, a duck, and a boa constrictor named Boa. Now a professor emeritus at Western Carolina University, he insists he’s not out to smear anyone’s furry friends. In a blog post questioning the so-called pet effect, in 2012, Herzog included a photo of his cat, Tilly. “She makes my life better,” he wrote. “Please Don’t Blame The Messenger!”

Plenty of people believe there’s something salubrious about caring for a pet, similar to eating veggies or exercising regularly. But, Herzog argues, the scientific evidence that pets can consistently make people healthier is, at best, inconclusive—and, at worst, has been used to mislead the American public.

Few, if any, experts say Herzog is exactly wrong—at least about the science. Over the past 30 or so years, researchers have published hundreds of studies exploring a link between pet ownership and a range of hypothesized benefits, including improved heart health, longer lifespans, and lower rates of anxiety and depression.

The results have been mixed. Studies often fail to find any robust link between pets and human well-being; some even find evidence of harms. In many cases, the studies simply can’t determine whether pets cause the observed effect or are simply correlated with it.

Where Herzog and some other experts have concerns is with the way those mixed results have been packaged and sold to the public. Tied up in that critique are pointed questions about the role of industry money on the development of a small field—a trend that happens across scientific endeavors, particularly those that don’t garner much attention from federal agencies, philanthropies, and other funding sources.

The pet care industry has invested millions of dollars in human-animal interaction research, mostly since the late 2000s. Feel-good findings have been trumpeted by industry press releases and, in turn, dominated news coverage, with headlines like “How Dogs Help Us Lead Longer, Healthier Lives.”

At times, industry figures have even framed pet ownership as a kind of public health intervention. “Everybody should quit smoking. Everybody should go to the gym. Everybody should eat more fruits and vegetables. And everyone should own a pet,” said Steven Feldman, president of the industry-funded Human Animal Bond Research Institute, in a 2015 podcast interview.

The problem with that kind of argument, Herzog and other experts say, is that it gets out ahead of the evidence (and that not every person is equipped to care for a pet). “Most studies,” said Herzog, “do not show the pattern of results that the pet products industry claims.”