“Want To Live Longer? Get a Dog!” a headline in the Daily Mail shouted. Unfortunately, the paper was wrong. In reality, epidemiologists have found that getting a pet will not add any years to your life. As Yale University’s Molly Crossman recently pointed out in an article in the Journal of Clinical Psychology the benefits of interacting with animals are routinely overstated. The media abounds with stories

fotojagodka/123RF
Source: fotojagodka/123RF

claiming that walking a dog will cause you to lose weight and that animals make good therapists. But the media seems to cover only research which finds positive results of clinical trials involving animals. In science, however, negative findings are just as important as positive results, especially when it comes to claims about health. To provide a bit of balance to the abundance of overly rosy press reports on the healing power of pets, here are nine recent studies that found pets and therapy animals had little or no beneficial impact on human health and well-being. All these studies were published in peer-reviewed journals in the last two years, and they are listed in the references below. While none of these findings  made the newspapers, here are my suggested headlines along with summary of the results.

(And hats off to the researchers with the courage to publish their negative results!)

Headline: “Study Finds Dog-Walkers Have More ‘Bad Mental Health Days’!”
Researchers at Purdue University conducted a year-long study of the impact of dog-walking. They assessed the effectiveness of e-mail reminders in motivating overweight and obese dog owners and non-owners to become more physically active and go for walks. The intervention worked; subjects that got the e-mails walked more than subjects in control groups who did not get the intervention.  But, unfortunately, more dog walking did not translate into improved physical or mental health. Indeed, among the dog walkers, the number of “bad mental days” and “bad physical days” per month actually increased during the study. And dog-walking did not affect any of the health assessment measures. As the researchers wrote in their grant results report, “There were no significant changes in weight, blood pressure, or blood lipids between groups or across time.”

Headline: “More Money (But Not Pets) Makes People Happier!”
Researchers from Mercer University investigated the impact of pet ownership and household income on life satisfaction among college students. They found having more money was related to increases in quality of life. Owning a pet, however, was not.  In summarizing their findings they wrote, “We found no evidence of a ‘pet effect’ as it relates to a general measure of satisfaction with life.”    

Headline: “Therapy Dogs Do Not Alleviate Pain and Fear in Hospitalized Children!”
Sandra Barker of Virginia Commonwealth University and her colleagues examined the impact of therapy dogs visits on anxiety and pain among children in a pediatric unit. Children in the experimental group interacted with a hospital therapy dog and its handler while children in the control group worked a jigsaw puzzle with a sympathetic research assistant. After they played with the dog or worked on the puzzle, the children were given scales to measure their levels of pain and anxiety.  The results were clear. The therapy dogs were no more effective than jig saw puzzles in reducing the fear and suffering of kids.

Headline: “Horseback Riding Is No More Therapeutic Than Learning to Ski!” 
Margaret Schneider and Lorah Harley compared the impact of therapeutic horseback riding with learning to snow ski on the mental health of people with a variety of disabilities.  They found that equine therapy was no more effective than skiing in reducing depression and anxiety or building self-esteem in the subjects.

Headline: “Dog-Walking Has No Effect At All on Obesity and Fitness in Kids!”
A research team headed by Dr. Carri Westgarth of the University of Liverpool examined whether owning or walking a dog reduced obesity and improved the fitness in 1,000 nine and ten year-old children. The researchers summarized their results clearly: “We found little evidence to support the idea that children who live with or walk with dogs are fitter or less likely to be obese than those who do not.”

Headline: “Living With Pets Does Not Improve the Mental Health of the Elderly!”
In a 2016 article published in the journal Geriatrics, Nancy Needell and Nisha Mehta-Naik of the Weill Cornell Medical College analyzed all the published studies on the impact of pets on the incidence and severity of depression in elderly individuals. After carefully examining 11 studies, they concluded, “At present, there is insufficient evidence to back the claim in popular culture that pet ownership is helpful in preserving the mental health of older adults.”

Headline: “Owning a Dog Does Not Reduce TV Time or Decrease Serious Mental Illness In Children!”
A 2015 study of 643 children published in the journal Preventing Chronic Disease examined the impact living with dogs on a wide variety of aspects of the mental and physical health of four to ten year-old children. Kids with dogs had a modest (9%) but statistically significant lower incidence of anxiety. The Center for Disease Control sent out a press release describing this results, and the study was widely reported in the media. But, neither the press release nor any of the media stories mentioned that dog ownership made no difference on any of the other aspects of health and well-being. These included having a history of mental illness, the likelihood of being overweight, the amount of time kids spent in front of a TV or computer screen, and their levels of physical activity. Having a dog also had no effect on whether a child had difficulty concentrating, or whether they experienced emotional and behavioral problems or had trouble getting along with people.

Headline: “Therapy Dog Visits Have No Effect on the Well-being of Nursing Home Residents!”
Karen Thodberg and her colleagues from Aahus University in Denmark examined the impact that six weeks of regular visits from a therapy dog, a cute robotic seal, and a soft toy cat had on the physical and mental health of 100 residents living in nursing homes.  Visits from the dogs (or the seal or toy cat) had no measurable impact on levels of depression, mental confusion, language usage, psychiatric symptoms, and daily living functions of the residents. 

Headline: “Women Who Walk Dogs Get Less Total Exercise!”
David Garcia of the University of Arizona and his collaborators examined the impact of dog ownership and dog-walking on exercise on 150,000 post-menopausal women. The results were surprising. As you would expect, the dog owners were less sedentary than non-dog owners, and they put in more time walking every day. The big surprise was that dog walkers actually got LESS total physical activity each week than non-dog owners. The women, it seems, walked more slowly when they were with their dogs.

Why Does the Public Have an Inflated View of the Impact of Pets on Health?

There are several reasons why the public has an exaggerated view of the healing powers of companion and therapy animals. The first is called the “availability heuristic.” This is the idea that our concepts about the world are based on the information we easily have at our disposal. And we are flooded with media reports slanted toward feel-good animal stories. One reason is that most journalists don’t have a background in research methodology or statistics, and they don’t have time or expertise to dissect the details of research reports. Thus, they are forced to rely on press releases sent to them by universities and industry public relations departments. My daughter is a journalist, and I have enormous respect for their work. But, when it comes to animals and human health, as the old song goes, press releases tend to “accentuate the positive, eliminate the negative.”

Second, researchers themselves can be guilty of “spinning” their results in published papers. Spin is now recognized as a major source of bias in science. In studies which involve multiple variables, for example, researchers will sometimes bury negative results in the middle of a table of numbers or simply omit them altogether.   

Finally, people just like the idea that pets are good for people and that animals are effective therapists. This preference for good news hit home when I was pitching the idea for a book on human-animal relationships to a New York literary agent. I told her that the chapter on pets would show claims about the curative power of swimming with dolphins bordered on fraud. There was a long pause, and she said, “Well….no one wants to read about that.” Fortunately for me, another agent thought people would be interested.

 *     *     *     *     *

For more on this topic, see Are the Results of Animal Therapy Studies Unreliable? and Puppies, Kittens, and Human Health.

Hal Herzog is professor emeritus in the Department of Psychology at Western Carolina University.  He is the author of Some We Love, Some He Hate, Some We Eat: Why It’s So Hard Top Think Straight About Animals.

References

Barker, S. B., Knisely, J. S., Schubert, C. M., Green, J. D., & Ameringer, S. (2015). The effect of an animal-assisted intervention on anxiety and pain in hospitalized children. Anthrozoös, 28(1), 101-112.

Crossman, M. K. (2016). Effects of interactions with animals on human psychological distress. Journal of Clinical Psychology.

Gadomski, A. M., Scribani, M. B., Krupa, N., Jenkins, P., Nagykaldi, Z., & Olson, A. L. (2015).Pet dogs and children’s health: Opportunities for chronic disease prevention?. Preventing Chronic Disease,12.

Garcia, D.O., Wertheim, B.C., Manson, J.E., Chlebowski, R.T., Volpe, S.L., Howard, B.V., Stefanick, M.L. and Thomson, C.A., 2015. Relationships between dog ownership and physical activity in postmenopausal women. Preventive medicine, 70, pp.33-38.

Lian, B., & Mathis, M. (2016). Pet ownership, attitudes, and experiences across income levels. North American Journal of Psychology, 18(3), 611.

Needell, N. J., & Mehta-Naik, N. (2016). Is pet ownership helpful in reducing the risk and severity of geriatric depression?. Geriatrics, 1(4), 24.

Richards, E. A., Ogata, N., & Cheng, C. W. (2016). Randomized controlled theory-based, e-mail-mediated walking intervention: Differences between dog owners and non-dog owners. Clinical Nursing Research, 1054773816657799.

Schneider, M. S., & Harley. L.P. (2016)  The impact of therapeutic riding for people with disabilities on variables related to mental health." Anthrozoös 29, no. 1 (2016): 59-72.

Thodberg, K., Sørensen, L.U., Christensen, J.W., Poulsen, P.H., Houbak, B., Damgaard, V., Keseler, I., Edwards, D. and Videbech, P.B., 2015. Therapeutic effects of dog visits in nursing homes for the elderly. Psychogeriatrics.

Westgarth, C., Boddy, L.M., Stratton, G., German, A.J., Gaskell, R.M., Coyne, K.P., Bundred, P., McCune, S. and Dawson, S., 2016. The association between dog ownership or dog walking and fitness or weight status in childhood. Pediatric Obesity.

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