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The Effects of Canine Presence on Human Welfare under the Biopsychosocial Model

Abstract

Dogs have been involved in human society for millennia. They are considered a member of the family in many homes and leave emotional imprints that last a lifetime. This review explores research regarding the impacts of dogs on human lives. Meta-research has shown overwhelming flaws in the methodology of research on human-animal relationships, which can lead to excessive inconsistencies, questions about validity, and a narrow application of results. Even so, research has shown that dogs have a strong positive influence on human welfare, but with a much more consistent correlation between dog presence and impact to emotional well-being than with physical health. There are benefits to children and adolescents with regard to development and behavior, although differing methodologies lead to disputes and inconsistencies in results regarding the extent of the impact. Another benefit of dogs is their use in service dog partnerships. Service dogs have been used for a variety of disabilities, such as seeing-eye, medical alert, mobility assistance, and psychiatric services [1]. These service dogs have an extensively positive impact on their human partners’ lives, as seen in all three main components of the biopsychosocial model [4,8]. 

Introduction

Figure 1
Figure 1: The Biopsychosocial model is an integrative approach to evaluate cause and effect on our lives, with each aspect simultaneously separate and overlapping. It provides a basis for a more analytical approach to studying HAI.

Dogs share many relationships with humans, namely as pets, emotional support animals, and working dogs, such as in law enforcement, search-and-rescue, service, and therapy. Following the infamous attack on the Twin Towers on September 11, 2001, a seeing-eye dog named Roselle became well-known for her role in guiding her blind partner, Michael Hingson, down seventy-eight flights of stairs and several blocks away to safety; in 2002, Roselle was given the Award for Canine Excellence [3]. In situations like this, the usefulness of dogs in a service capacity is obvious, but dogs also provide benefits in much less public and visible ways. There is an abundance of colloquial beliefs regarding the relationship between humans and their canine companions, and the effects that interactions have on both partners. Due to the high public interest factor, there is a wealth of research on the impacts of human-dog interactions, or Human-Animal Interactions (HAI). Most studies focus on the three primary aspects of the biopsychosocial model. The biopsychosocial model, first conceptualized by George Engel in 1977, is an all-encompassing model used in clinical and philosophical settings which describes the expression of biological, psychological, and sociocultural factors as interrelated and interdependent aspects of human welfare [4]. The biological component focuses on physiology and pathology, with the “psycho” component focusing on emotions and behaviors, and the social component focusing on socio-economic, socio-environmental, and cultural involvement [4]. Additionally, for the context of this paper, “service dogs” will refer only to working, trained, legally protected service dogs which perform specific tasks for their partners according to the Americans with Disabilities Act (ADA), and will not include emotional support animals or therapy animals [1]. 

Studies have shown performance improvement in humans due to HAI. Research has also shown that HAI improves psychological and social welfare according to the biopsychosocial model for humans with physical and mental disabilities, as well as benefiting child development. However, studies have yielded contrasting results regarding the physical health benefits of canine presence. This review addresses both cohesive and contradictory findings regarding the impact of dogs on humans, as well as potential explanations for the dramatic variation in conclusions. 

Studying the Effects of Dogs on Human Welfare

A significant part of understanding the research on the impacts of dogs on humans is understanding what questions are addressed and how conclusions are reached, especially when viewing null results or questionable findings. One flaw of the research, specifically when addressing HAI influence on general human well-being, is that researchers can compare people who do have pets and don’t have pets, but cannot definitively compare how a person’s own life would be different with or without pets. Likewise, every person is an individual with individual circumstances, and HAI effects cannot necessarily be applied to a whole population, even if found to be statistically significant. 

Consider this concept in Torske et al.’s (2017) long-term study of dog ownership’s influence on mortality: while any difference in mortality was not found to be statistically significant in the studied Norway population [5], that does not conclusively prove that dogs have no effect on physical welfare. Torske et al. (2017) discuss the shortcomings of their study, noting how dog ownership may still have an effect on health during one’s life, even if it does not necessarily affect the length of one’s life [5]. The sole measurement from which Torske et al. (2017) drew their conclusions was mortality, which may not provide a broad enough view [5]. The narrow parameters of the study leave unanswered questions. This study lacks the specificity to address how a person’s life could potentially change due to having or not having a dog. Having a dog could potentially influence major life decisions which are not measurable. Potential impacts to mortality include suicide or how active a lifestyle someone lives, and there is no basis for comparison regarding these factors. A pet may not improve the physical health of someone who is already living a sufficiently healthy lifestyle, but it is difficult to compare data to people who would otherwise not. This clarification cannot be quantified using current research methods, as no one can definitively hypothesize about what “could have been.” No study accounts solely for this discretion, and would be very difficult to conduct. If a method was found, the requirements to perform a study that would give definitive results may not be realistic or ethical, so this may not ever be able to be accurately studied. 

Another study of a population of Mexican pet owners focuses on how compatibility between a pet and its owner may affect the extent to which HAI influences well-being [6]. Compatibility is measured as the activity preferences for exercise and play, including how much the partnership shares enjoyment of lifestyle, such as interaction and physical activity levels [6]. The study found that humans who had higher compatibility with their dogs reported higher happiness levels, lower stress scores, a stable feeding routine for their pet, and more frequent daily walks and playing sessions [6]. However, similar to Torske et al.’s (2017) study, no correlation was found between dog compatibility and improved physical health [5,6]. Both studies have narrow application due to methodology and measurement limitations. While physical health was studied through mortality in the Norway population, physical health was measured solely through the number of physician visits in the Mexico population [5,6], which could be influenced by other factors such as time, socioeconomic and geographic convenience, or other pre-existing or developing health conditions. Neither study can be considered definitive regarding the impact of HAI on physical health with such narrow bases for their conclusion, as neither lifespan nor number of physician visits are encompassing determinants of physical health. 

A third study focusing on the impact of pet ownership on physical well-being uses the National Health and Nutrition Examination Survey (NHNES), a representative sample of the non-institutionalized United States population [7]. From the survey, Utz (2013) determined that pet owners, particularly dog and cat owners, have more positive physical health outcomes when compared to both non pet owners or those owning other types of pets. Exceptions to health benefits include an increase in allergy and asthma symptoms in pet owners [7]. However, the increase in allergies and asthma amongst pet owners is not assuredly indicative of causation, as it may be a result of increased awareness and symptoms due to proximity to pets [7]. The study revealed further confounding as sociodemographic factors were also found to have an impact on health results [7].  

In an effort to clarify and analyze research on the effects of dogs on human well-being, Gee et al. (2021) address existing research and reframe it under the biopsychosocial model [8]. For example, one common topic of study is the effects of pets (particularly dogs) on depression. While there are many examples of studies which highlight benefits of dog ownership on reducing depression, there is also an abundance of inconsistencies in studies on dog ownership and its impact on lifelong depression rates [8]. As Gee et al. (2021) suggest, it could be possible that people suffering from depression or loneliness are more inclined to own a dog [8]. Studying results from interventions, such as dog-assisted therapy, would be a better gauge for impact than ownership studies [8]. Methodology is one explanation for opposing conclusions, as many studies are self-reported, and the relationship between a dog and a human cannot be standardized. One person’s mental state may be drastically impacted by having a dog as a companion, and another’s may not be impacted at all, thus, confounding results.

Figure 2
Figure 2: It is a challenge to find an ethical, conclusive, and consistent way to study canine impacts on humans that yields results that are applicable to a wider population and properly account for and reduce alternative influences on results.

While research combined, such as Gee et al.’s biopsychosocial framework combined with the Mexican population study, does draw cohesive conclusions [5,7], research regarding psychological welfare is contradictory. The four studies discussed above highlight one common issue amongst HAI research: methodology. Both Torske et al. (2017) and Gonzales-Ramirez (2019) discuss no conclusive evidence for a positive association between physiological welfare and dog presence, while the NHNES study does suggest an association, but does not cite pets as the cause of increased physical well-being [5,6,7]. None of the studies properly account for confounding variables. Torske et al. (2017) and Gonzales-Ramirez (2019) both provide unreliable bases for evidence. While the NHNES study does include some appropriate measurements, they are not sufficient enough for a definitive conclusion [5,6,7]. Furthermore, research continues to be too narrow in all aspects and neglects vital parts of the questions studies are supposed to address. To name a few exclusions, when investigating psychological benefits from dogs, studies do not consider how the financial stress, time-demand, life span gap, and many other considerations for pets affect the psychological well-being of humans. 

The Effects of Medical Alert and Assistance Service Dogs for People with Disabilities

Dogs have been trained for a diverse range of tasks, including search and rescue, assistance for physical disabilities, alerting to medical episodes, and psychiatric assistance. In contrast to some other more ambiguous HAI benefits, the benefits of service dogs to their partners are relatively cohesive and conclusive, and, in some cases, such as the story of Roselle and Michael Hingson[3], publicly obvious. Some service dogs, such as those used for medical alert, are trained for early detection of acute biological changes pertaining to a specific medical condition. Rooney et al. (2019) studied the effectiveness of glycaemic alert dogs and their performance in alerting their owners to changes in blood glycaemia levels [9]. Glycaemic alert dogs are trained to recognize and respond to the scent of blood sugar changes in handlers with diabetes or other blood sugar disorders, giving their handler extra time to correct the issue when needed. Rooney et al. (2019) found that while there was variation due to training and partnership, which would be expected, the dogs were highly effective at detecting and alerting out-of-range glycaemic incidents [9]. This can greatly improve the lives of people living with glycaemia-related health complications, as late awareness of an out-of-range episode can be uncomfortable and potentially dangerous, if not life-threatening. Seizure alert dogs, a medical alert dog also trained in scent-based detection, can have similar positive impacts on their humans by providing early warning of an oncoming episode [10].

Rodriguez et al. (2019) studied the effects of service dogs on psychosocial health among individuals with physical disabilities or chronic conditions. The study looks at the effects having a service dog has on subjects’ anger, human companionship, sleep disturbance, and psychological well-being according to the Pediatric Quality of Life scale, which measures psychological well-being factoring in age [11]. The study compared individuals who are partnered with a service dog to individuals who were currently on a waiting list for a service dog [11]. This allows an appropriate evaluation of the benefits of having versus not having a service dog. Rodriguez et al. (2019) reveal that individuals with a service dog exhibited significantly better psychosocial health including higher social, emotional, and work/school functioning, but reported no significant effect on anger, companionship, or sleep disturbance [11]. This study focuses solely on psychosocial perception, but could open doors to research on the biological explanations for these changes, for example via functional MRI, blood tests for hormonal changes, or changes in physical activity from having a service dog. 

Another application for service dogs that is increasing in popularity is for Post-Traumatic Stress Disorder (PTSD) patients, especially within veteran populations. Both McCall et al. (2020) and Rodriguez et al. (2021) found a significant improvement in quality of life for veterans with PTSD that had service dogs compared to those without service dogs, but who were on a waitlist to receive one [12,13]. McCall et al. (2021) focus on the quality of life for veterans and their partners (spouse, significant other, or families), and Rodriguez et al. (2021) focus on quality of life for veterans in partnership with their medication regimens to treat PTSD. McCall et al. revealed a significantly reduced severity in PTSD symptoms as well as PTSD “checklist” scores (which allows a psychiatrist to measure PTSD symptoms on a numerical scale) for veterans with a service dog compared to those without [12]. The study also covered quality of life from the partners’ perspectives, reporting less angry behaviors from partners with a service dog than the partners of those on the waitlist, increased resilience among partners, less social isolation, increased companionship, and less impairment to cognitive and workplace functioning [12]. Both the veterans with service dogs and their partners reported increased relationship satisfaction and fewer family conflicts [12]. A significant majority reported the presence of the service dog as a benefit, with a few reporting them as challenges [12]. Reported benefits include higher chance of social involvement and less hesitancy to go out into public, alongside the comfort and companionship [12]. Rodriguez et al.’s (2021) study agrees, noting that veterans with a service dog were more likely to report a reduction in their prescription for medication taken for PTSD, while veterans on the waitlist were more likely to report no change or an increase in dosage [13]. Rodriguez et al. (2021) ultimately concluded that their results could not be considered statistically significant due to the nature of the study as a self-reported questionnaire that was not cross-confirmed with prescribers or pharmacies [13]. However, it provides further context to McCall et al.’s (2021) research, as well as warrants additional research with different potential approaches. 

The Effects of Canine Presence on Child Development, Behavior, and Wellbeing

Figure 3
Figure 3: The various situations in which HAI are studied can be more easily interpreted and evaluated according to their relationship to the three aspects of the biopsychosocial model.

HAI can have many benefits for child development, welfare, and future success, but not all research agrees on whether these benefits are definitive. Mueller et al. (2021) focus on Animal-Assisted Intervention (AAI), which has been increasing in popularity for its use to counter anxiety [14]. The study focuses on empirical evidence targeting adolescence, including an anxiety report, physiological measurements of heart rate and electrodermal activity, and cognitive performance [14]. The researchers concluded that there was not a significant difference between the scores of those who interacted with dogs compared to those who did not [14]. However, this study contrasted with other research on adolescent HAI. For instance, Beetz et al. (2011) did find increased comfort and lower cortisol levels correlated with increased interactions with dogs [15]. Similarly, Rincón et al. (2021) found increased postural control, eye-motor coordination, expression of sensations and feelings, spontaneous interaction, autonomy, and confidence as a result of HAI in children with severe disabilities [16]. The contradictory results of the findings between these two studies and Mueller et al.’s (2021) study could potentially be due to the differences in sample measurements, as Mueller et al.’s (2021) study focuses strictly on anxiety levels and uses only brief HAI, while Beetz et al. (2011) and Rincón et al. (2021) both focus on children with either behavioral, learning, or physical disabilities and prolonged HAI [14,15,16]. The varying results are consistent with the findings of Giraudet et al’s (2016) review of child-dog interaction research studies, namely in the inconsistency of these studies [17]. The review discusses the abundance of contradictions in HAI research, but does agree to the benefits to children of a childhood pet [17]. 

Conclusion

The potential applications for dog presence are endless, both inside and outside the medical purview. While research is abundant, it also leaves many unanswered questions. However, there is significant data connecting dogs to improved human biopsychosocial well-being that, despite additional questions, do exemplify the many benefits of Human-Animal Interactions, and more specifically, human-dog interactions. The existing research opens the gateway for further investigation and application of HAI in avenues of life that humans have not even begun to explore. 

Author's Note

Dogs are a vital part of today’s society, and there is no question as to how important they are to so many people. As someone who grew up raising service dogs for the blind and works with organizations as a passion project, as well as a Biochemistry and Molecular Biology major who values the deep factual basis for the world around us, this topic came naturally. People talk about dogs as being sweet and cute and so many people express their endless love for them, but there is also a lot of misinformation and misconceptions about dogs, especially service dogs! In this paper, I hope to approach the idea of the importance of dogs in our lives but from a more scientific perspective, and find the strengths and shortcomings of research that exists today regarding the impact of dogs in our lives. 

References

  1. “Service Animals.” ADA.Gov, US Dept of Justice and Civil Rights, 20 Nov. 2023, www.ada.gov/topics/service-animals/. 

  2. Most Popular Pets by Country 2023. [accessed 2023 Feb]. https://worldpopulationreview.com/country-rankings/most-popular-pets-by-country. 

  3. Boccone B. Guide Dog Roselle Helped Her Blind Owner Escape 9/11. American Kennel Club. 2021 [accessed 2023 Feb]. https://www.akc.org/expert-advice/news/guide-dog-helped-blind-partner-escape-wtc/

  4. Biopsychosocial Model. Physiopedia. [accessed 2023 Feb]. https://www.physio-pedia.com/Biopsychosocial_Model

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  8. Gee NR, Rodriguez KE, Fine AH, Trammell JP. 2021. Dogs Supporting Human Health and Well-Being: A Biopsychosocial Approach. Front Vet Sci.  

  9. Rooney NJ, Guest CM, Swanson LCM, Morant SV. 2019. How effective are trained dogs at alerting their owners to changes in blood glycaemic levels?: Variations in performance of glycaemia alert dogs. PLOS ONE 14(1). 

  10. Catala, A., Grandgeorge, M., Schaff, JL, Cousillas H, Hausberger M, Cattet J. 2019. Dogs demonstrate the existence of an epileptic seizure odour in humans. Sci Rep 9. 

  11. Rodriguez KE, Bibbo J, O’Haire ME. 2019. The effects of service dogs on psychosocial health and wellbeing for individuals with physical disabilities or chronic conditions. Disability and Rehabilitation. 42(10):1350-1358. 

  12. McCall CE, Rodriguez KE, MacDermid Wadsworth SM, Meis LA, O’Haire ME. 2020. “A Part of Our Family”? Effects of Psychiatric Service Dogs on Quality of Life and Relationship Functioning in Military-Connected Couples. Military Behavioral Health 8(4):410–423. 

  13. Rodriguez KE, Anderson LM, Ott CA, O'Haire ME. 2021. The Effect of a PTSD Service Dog on Military Veterans’ Medication Regimens: A Cross-Sectional Pilot Study. Anthrozoös 34(3):393-406 

  14. Mueller MK, Anderson EC, King EK, Urry HL. 2021. Null effects of therapy dog interaction on adolescent anxiety during a laboratory-based social evaluative stressor. Anxiety, Stress, & Coping 34(4): 365-380. 

  15. Beetz A, Kotrschal K, Turner DC, Hediger K, Uvnäs-Moberg K, Julius H. (2011). The Effect of a Real Dog, Toy Dog and Friendly Person on Insecurely Attached Children During a Stressful Task: An Exploratory Study. Anthrozoös. 24(4): 349-368. 

  16. Rincón LLL, Martín BR, Sánchez MAM, Villafaina S, Merellano-Navarro E, Collado-Mateo D. 2021. Effects of Dog-Assisted Education on Physical and Communicative Skills in Children with Severe and Multiple Disabilities: A Pilot Study. Animals. 11. 

  17. Giraudet CSE, Liu K, McElligott AG, Cobb M. 2022. Are children and dogs best friends? A scoping review to explore the positive and negative effects of child-dog interactions. PeerJ. 10.

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