Our animal friends may not make us healthier, but they earn their keep in other ways

From WSJ. The Wall Street Journal.

It's referred to as "the pet effect." Some researchers have proposed that having a pet bestows a dazzling array of health benefits, such as lower cholesterol, reduced blood pressure and a reduced risk of cardiovascular disease. Others have claimed that pets can combat stress, relieve depression and enhance self-esteem, and that their company makes children more empathetic. "Pet therapy" is widely practiced in hospitals and facilities for the elderly.

Until fairly recently, many animals were seen as harmful-carriers of parasites and disease. But now they're considered part of a healthy lifestyle. While most people probably don't acquire a pet because they think it will make them live longer, they might believe it will be a kind of panacea for modern living.

The problem is that these claims about the benefits of pet ownership don't always hold up to scientific scrutiny. Some early studies did show that dog owners were generally in better shape than those without dogs, but a recent analysis of the health records of more than 40,000 California residents by the Rand Corp., working in conjunction with the University of California, Los Angeles, shows that these differences can be attributed to other characteristics of pet owners.

Owners are more likely to be white, married and homeowners— attributes that are all linked to good health.

Rather than pets making people healthy, it's more likely that healthy people choose to own pets. Anyone with a hint of declining health will think twice before going out to get a dog. (They may choose a cat instead. Several studies indicate that cat owners have poorer-than-average health. There is no reason to believe that cats make people sick; it's more likely that less healthy people choose cats for companions, given that they require far less work than a dog.)

The Rand study also cast doubt on the fact that children raised alongside pets become more empathic, acquire better social skills to have higher self-esteem. Once the many other advactages enjoyed by pet-owning families were factored in, these differences disappeared.

Children whose parents have spare cash to spend on education, have stable jobs and live in a house with a yard to play safely all outperform their less fortunate peers on measures of health and behavior. These same factors make it more likely that parents will add a pet to the family. Caring for a pet may teach children responsibility, but it doesn't necessarily make them better people.

Even if pets don't make us healthier, or better, they do earn their keep in other ways. For one, they can have a strong calming effect. Studies have shown that interacting with a dog can improve a person's mood.

Stroking a dog results in a surge of oxytocin and endorphins— hormones that promote bonding and feelings of well-being.

These hormonal effects are generally short-lived, but in the same way that people in long-term relationships tend to be healthier than those who live alone, the effects may accumulate over time. Still, as every pet owner knows, a relationship with an animal isn't just about snuggling. For every relaxing moment on the couch, there is a frustrating one: the dog that won't come back when called, the cat that scratches the drapes. This ongoing stress may explain why pet owners aren't ultimately healthier than those who live without them.

Of course, pet ownership can change human behavior in ways that could improve our health. Logically, a dog that needs to be exercised daily ought to improve the owner's health. However, studies suggest that most owners don't walk their dogs with sufficient vigor to improve their cardiovascular fitness. (This is good news for dogs, for whom the daily walk is not so much a workout as a chance to catch up on sniffing for signs of other dogs in the neighborhood, which requires a leisurely pace.) Other aspects of the walk may provide more benefits. Recent studies have shown that regular exposure to green spaces lowers stress in itself.

People who walk their dogs in public places may have noticed another manifestation of the "pet effect" —that having their dog nearby brings them into conversation with passersby. Research has confirmed that this is a real effect, applying to men and women alike. In a 2015 study published in the journal Anthrozoös, a young man walking around a shopping precinct with a friendly Labrador retriever by his side was able to persuade one woman in three to part with their phone numbers, compared with less than one in 10 when he was on his own.

This aura of trustworthiness may be the true power behind the "pet effect." A 2015 study published in PLOS One surveyed almost 2,000 residents in Nashville, San Diego and Portland, Ore., and found that pet owners were more likely to get to know people in their neighborhood than those without pets. Dog owners met other owners on walks, of course, but cat owners also bonded with one another through mutual offers to watch each others' pets while they were on vacation. Pets help build communities, breaking down barriers between people and paving the way for us to build networks of friendships.

The same effect may account for much of the effectiveness of animal-assisted therapies, with the animal drawing the patient into relaxed conversation with the human therapist.

Pets make people happy, and bring people together. Does it really matter if they don't have the power to prolong our lifespans?