Companion animals are animals that live with humans and do not have an obvious function [1
]. Although companion animals have no apparent function, research shows that both humans and animals benefit from this coexistence.
Adequate coexistence between the two species is facilitated when the individuals are compatible. Compatibility is the fit between a companion animal and its owner in regard to physical, behavioral and psychological dimensions [2
For all three dimensions, the companion animal and owner have the things that they require of, as well as the things that they are able to contribute to, the relationship. The match between these requirements and contributions represents the compatibility of particular companion animal and owner combinations [2
]. The basic physical requirements are water, food, shelter and health care, and most companion animals are dependent on their owner to provide these requirements. The behavioral requirements include exercise and playful interaction. Physical and behavioral requirements are relatively easily identified. An example of the psychological component would be the amount of affection that a person desires from an animal compared with the amount that the pet is prepared to offer [3
In its behavioral dimension, compatibility has been related to lower aggressive behavior, trainability [4
] and the human-dog relationship [5
Human-dog interaction has become popular as a line of research documenting health benefits for humans. For example, data from the National Health and Nutrition Examination Survey of a representative sample of people living alone in the United States (n
= 2474) showed that dog and cat owners had better physical health than nonowners or owners of other types of companion animals [6
There are review studies on the subject, such as those of Amiot et al. [1
] and Wells [7
]. In the former study, the authors indicate that epidemiological and longitudinal studies have revealed positive associations between the presence of companion animals and human physical well-being, revealing that people who lived with companion animals had fewer doctor visits than similar people without companion animals [1
In latter study, Wells [7
] reviews the research on the relationship between the physical and psychological health of humans and companion animals, focusing on well-being and quality of life. The review shows that people exposed to a psychological or physical stressor had a lower heart rate and blood pressure in the presence of companion animals—dogs or cats—than in the presence of a friend or spouse, leading to the conclusion that in this context, companion animals function as a distraction from the stressful situation. Another study reported that in a population with hypertension, dog owners had a lower risk of fatal cardiovascular events compared to nonowners [8
However, other studies have found opposite results. For example, the review by Wells [7
] shows that there are inconsistencies and methodological limitations among studies, which leads to the conclusion that further research in areas such as depression and the benefits for people with cardiovascular diseases is needed.
Empirical evidence indicates that relationships between humans and animals benefit not only human health but also the health of the animals [1
]. For example, in military dogs, time spent with their handlers is associated with a decrease in behaviors related to chronic stress in dogs [9
Thus, both the significant and nonsignificant results of research should be considered to gain a complete picture of the relationships between humans and animals and to understand when and for whom these relationships are beneficial [10
]. However, evidence and a unified theoretical framework that explains how and why human-animal relationships are potentially therapeutic are still lacking in the discipline [11
Companion animals confer some benefits for human health, but it is not known exactly how. For example, in the previously described longitudinal study with a representative sample from the United States, it was reported that there is no increase in physical activity associated with the active care of companion animals [6
], whereas another longitudinal study with a small sample (n
= 17) found that 8 months after acquiring a dog, humans had increased their physical activity [12
]. These contradictions support the need to investigate other variables that explain the benefits of the human–animal relationship and to not attribute the benefits simply owning a companion animal.
To clarify the concepts used in this research, it is necessary to explain that a relationship is dyadic and that a bond refers to the characteristics of an individual, that is, the bond of an individual with another individual [13
]; thus, it can be said that a human has an emotional bond with his dog, regardless of how the animal perceives the relationship [14
]. In this research, I analyze details about the human-animal relationship, specifically the way in which humans and their dogs interact: human-animal interaction.
It is possible that the interest in understanding the human-companion animal relationship has been focused more on the benefits for humans. For example, in a previous study performing structural equation modeling, it was found that the number of stressful situations faced recently and the human–dog relationship were predictors of perceived stress and that stress was a predictor of subjective happiness in humans. That study concluded that the quality of the human-dog relationship is a mediator of the benefits of human-animal interaction and that the quality of the relationship is determined by shared activities [15
There are different ways to define stress; in this study, perceived or psychological stress is defined as a particular relationship between the individual and the environment in which the environment is appraised by the individual as threatening or as overwhelming his/her resources and in which the environment threatens his/her well-being [16
It has been documented that humans who spend more time with their dogs in daily activities or playing at home report not only better relationships with their dogs but also lower perceived stress [15
]. Thus, it is hypothesized that individuals whose activity preferences are more compatible with those of their dogs will also experience lower stress levels and possibly other benefits. Activity preferences refer to the shared enjoyment of daily activities such as walking and interacting with others, and they are an indicator of the behavioral dimension of compatibility [5
], which mainly refers to exercise and play [3
Based on the above, the objective of this study is to compare the benefits of human–dog interaction for both humans and dogs between people who share and do not share activity preferences with their dogs. As indicators of benefits, for the humans, I considered the number of doctor visits in the last year, subjective happiness and perceived stress; for the dogs, a stable feeding routine and the frequency of walks and playing sessions were measured; and also the Canine Behavioral Assessment and Research Questionnaire (C-BARQ) [17
] was used to measure behaviors such as anxiety, aggressiveness and trainability.
When selecting a companion animal, compatibility in human-dog dyads is an aspect that should be considered. Ideally, owners will choose a dog based on their personal activity levels; thus, active people will select dogs that can be their companions on walks, while sedentary people will select less active breeds or companion animals that do not require as much exercise [6
Considering that relationships between humans and animals have consequences for both parties that range from the physical to the psychological [1
], the purpose of this study was to compare some indicators of the benefits of human-dog interaction between people with and without compatible activity preferences with their dogs. The groups were equivalent in terms of the characteristics evaluated, with the exception of dog age and years living with the family; the dogs in the group with lower compatibility were older dogs and had lived with the family longer, although the average difference was only 1 year. According to the measures of central tendency, the dogs in both groups were young adults; thus, a comparative analysis by age was not considered.
Previous studies have found that dog age is related positively to some aggressive behaviors and negatively to separation-related behaviors and energy level [4
]. For this reason, future studies should compare the behaviors evaluated by the C-BARQ between dogs of different developmental stages: puppies, adolescents, adults, and seniors.
Regarding the indicators of benefits for humans, in agreement with previous studies, it was found that the more compatible group had lower perceived stress scores. Previously, it was found that dog owners had lower stress levels than nonowners [23
], and the positive effect of companion animals on stress responses has also been reported [24
Regarding subjective happiness, in previous studies, this variable showed no differences between dog owners and nonowners [23
]. Similarly, another study reported a weak correlation between subjective happiness and the human–dog relationship and found no direct effect based on structural equation modeling [15
]. That study concluded that the benefits of human–animal interaction are mediated by the quality of the relationship with the dog, which coincides with the present results, considering that the more compatible individuals had a higher-quality relationship with their dog and higher happiness scores.
The third indicator of benefits for humans was the number of doctor visits in the last year. No significant differences were found in this indicator between people with and without compatibility with their dog’s activity preferences. This indicator has been used in previous studies [1
], including epidemiological and longitudinal studies revealing that people who lived with companion animals had fewer doctor visits than similar people without companion animals [1
] and a longitudinal study with data from Germany and Australia showing that owners of companion animals had 15% fewer doctor visits per year compared to nonowners [25
]. Considering the above, it is concluded that compatibility does not explain the doctor visits indicator. However, this indicator has its limitations because it is self-reported; thus, in future studies, it is necessary to use other indicators of physical health.
The dog routine indicators show that owners who are more compatible also have a better routine with regard to engaging in daily play and daily walks and feeding the dog at fixed times. These aspects can provide benefits for both the human and the dog. Exercise and feeding management are associated with obesity in dogs [26
], and play is a benchmark for behavioral compatibility in activity preferences [3
]. Previously, it has been found that people with dogs take longer [12
] and more frequent walks than do nonowners and that in older adults, walking the dog has been associated with greater improvement in physical health than walking with other humans [27
In the majority of the behaviors evaluated by the C-BARQ, significant differences between the groups were found. The intention was not to attribute causality between the compatibility of activity preferences and dog behavior; instead, the hypothesis was that the differences would arise because the more compatible dyads had a better relationship. Thus, the humans would perceive the behaviors of their dogs as less bothersome. In addition, it has previously been reported that when humans spend short periods of time at home, there is a greater risk of behavioral problems in their dogs [28
]. Therefore, when humans and their dogs share more activities and time together, the dogs will focus their energy on behaviors that are more acceptable to their humans.
The frequency of instinctive behaviors, such as chasing, or of behaviors and characteristics that reflect the dog’s temperament, such as excitability, attention-seeking and energy level, were equivalent between the groups. There were also no differences in separation-related problems, a result that coincides with previous research reporting equivalences in compatibility in activity preferences between groups with and without separation-related problems [29
The results of the different subscales of the C-BARQ may be explained by the fact that in the more compatible dyads, the needs of the dogs were better met, a finding that is consistent with previous reports on the influence of owner activity levels on the exercise needs of dogs [6
Considering a recent review by Scandurra et al. [30
], who reported differences between sexes in dogs in some variables, it is possible that the differences found in this study can be explained by the sex of the dogs or their sterilization status. However, in the variables for which differences were found, these differences are not consistent in both groups; thus, compatibility can be an important variable to consider, regardless of the sex of the dog.
It is possible that people who have sterilized female dogs feel more comfortable walking them; thus, they walk them more frequently. However, this difference was found only in group 1, consisting of individuals with less than 50% compatibility.
Also, in group 1, female dogs had higher scores in dog-directed fear, chasing and stranger-directed fear, which coincides with results reported in the review by Scandurra et al. [30
Sterilized dogs showed higher scores in trainability and excitability, but these behaviors did not show differences between sexes, although Scandurra et al. [30
] mentioned that females tended to be more excitable than males. A more detailed analysis showed that trainability was higher in sterilized females within group 1.
Within group 2, sterilized males showed higher scores in dog rivalry. Unsterilized males showed higher scores in touch sensitivity and attachment/attention-seeking. Sterilized females showed higher scores in dog-directed fear only within group 2.
Based on sex or sterilization status, no differences in behaviors related to aggressiveness were found, which is not consistent with the findings of the review by Scandurra et al. [30
], who mentioned several studies that reported that ovariectomy results in increased aggressive behaviors in females. These inconclusive results motivate the suggestion that future research on human–animal interaction can focus on the differences between males and females and on the sterilization status of dogs.
An important aspect to consider is that the dog-owner compatibility index of activity preferences evaluates the behavioral component of compatibility, referring to the shared enjoyment of daily activities such as walking and interacting with others [5
]. People and dogs with active lifestyles seem to complement each other [31
]; however, future research should evaluate the other components of compatibility: the physical and the psychological.
Continuing this line of research is relevant because companion animals play a significant role in today’s society [7
] and are considered family members by approximately 90% of owners [1
]. However, it should also be considered that the results of available studies disagree, perhaps due to differences in the variables included, the methodological designs and the lack of control of extraneous variables [7
]. This last element was controlled in this study through the inclusion of groups that were equivalent in terms of various variables, although limitations related to sample size and type of sampling are acknowledged.
Some limitations should be mentioned. No objective measures were used; thus, the results are based on owner perceptions. The sample size and sampling method are additional limitations. It is important to consider that in Mexico, there are 23 million dogs and cats, and between 57 and 70 out of every 100 households have pets, with dogs being the favorite animal, according to the National Institute of Statistics and Geography (Inegi) [32
]. This study represents a contribution to this line of research; however, its results cannot be considered representative of the country.