Animal Frontiers

The healing role of assistance dogs: What these partnerships tell us about the human-animal bond

By Dr. Sally Irvin


• There are more than 22,000 individuals in the United States who are partnered with an assistance dog.
• Partnership with an assistance dog has been shown to have significant benefits for the human partner. These benefits include increased ability of people to perform activities of daily living; psychological/emotional health, and participation in social, work, and school activities outside the home.
• The relationship a person has with an assistance dog is mutually interdependent and can be characterized as representing an attachment bond. Both the dog and the human interchangeably provide a sense of security and safety for each other.
• Assistance dog providers need to help human partners understand the reciprocal effect that their behaviors and quality of their relationship with their assistance dogs have on the ability of 
the dogs to maintain a healthy, helpful, and low-stress lifestyle.


Though the first established school for training guide dogs in the United States was in 1929, there is evidence in historical records of medieval times depicting a dog on a leash leading a blind man, suggesting that we are only rediscovering a very old concept. What has developed over the years is an understanding of how the role of assistance dogs touches on a mutual need of humans and dogs for companionship, assistance, and security. It is critical that we understand the nature of the relationship between humans and their assistance dogs; the behaviors that promote healthy growth and development and the behaviors increase stress. Though assistance dogs provide incredible benefits to their human partners, it is critical that we remember that though the relationship is interdependent, the assistance dog is not there by its own choice. We humans have a responsibility to ensure that the bond with an assistance dog is truly mutually beneficial.

Brief History of Assistance Dogs

Assistance dogs provide support for people with disabilities at a level we could not have predicted decades ago. Over the past 35 years, the role of assistance dogs has increasingly expanded and become more challenging. 

Assistance Dogs International (ADI; 2014) defines three types of assistance dogs: 1) guide dogs for the blind and visually impaired, 2) hearing dogs for the deaf and hard of hearing, and 3) service dogs for people with disabilities other than those related to vision or hearing. The category of service dogs broadens to include dogs trained to assist people who have mobility or balance challenges, alert or respond to medical issues such as diabetes and seizures, and support people with psychiatric disabilities and autism (ADI, 2014).

There are approximately 22,000 assistance dogs working in the United States; approximately 12,000 guide dogs and 10,000 service and hearing dogs (Humane Society of the United States, 2014). The history of the assistance dog field began in 1929, with the establishment of the first guide dog school, The Seeing Eye. Today, there are 82 nonprofit guide dog programs that are members of the International Guide Dog Federation, which is the standard setting and accreditation organization for guide dog program.

Compared with people who are blind, people with physical disabilities and hearing loss have had only about 35 years of working with service dogs. In the early 1970s, Bonnie Bergin pioneered the concept of a service dog and founded Canine Companions for Independence. Canine Companions for Independence was the first program in the United States for the training and placement of service dogs. Today, in the United States, there are 106 nonprofit assistance dog organizations that are members of ADI, which was established in 1987 to set standards and policy for the training, care, and placement of assistance dogs and to advocate for programs and human partners of assistance dogs. Assistance Dogs International only maintains statistics on nonprofit organizations that train and place assistance dogs. There is no reliable source of information concerning for-profit organizations or individuals who train and partner assistance dogs.

Burrows et al. (2008) reported 1997 as the first placement of an autism assistance dog. The benefits for children on the autism spectrum and their family, after the placement of a service dog, have been reported as: decreased meltdowns and repetitive behavior; increased language use and attention; improved sleep; decreased stress for the family and increased social acknowledgement; decreased anxiety, screaming, and other disruptive behavior when out in public; and decreased salivary cortisol secretion (McNichols and Collins, 2000; Odendaal and Meintjes, 2003; Burrows et al., 2008; Viau et al., 2010; Berry et al., 2013). The significant benefits that are reported for autism assistance dogs have dramatically increased their demand. Many service dog organizations report the number of applications for this type of dog is growing the fastest (Richard Lord, Assistance Dogs International, personal communication).

Assistance dogs trained to respond/alert to diabetes and other medical conditions such as seizure disorders and allergies are the newest type of assistance dog (Rooney et al., 2013; ADI, 2014).

Benefits of Partnership with an Assistance Dog

Service and hearing dogs

The majority of studies exploring the role of assistance dogs have focused on the benefits that the assistance dog provide their human partner. Most of these studies looked at service and hearing dogs, with fewer studies looking at guide dogs, autism assistance dogs, or medical alert/response dogs.

Two large literature reviews on the benefits of assistance dogs found very similar variables/themes. Sachs-Ericsson et al. (2002) reviewed outcome research regarding two types of assistance dogs: 1) service dogs that assist children or adults with mobility impairments and 2) hearing dogs that alert people who are deaf or hard of hearing.
Sachs-Ericsson et al. (2002) stated that in their review of studies that used “clinical observation, anecdotal reports, and retrospective and crosssectional studies, preliminary support was found for the conclusion that assistance dogs have a positive impact on individuals’ health, psychological well-being, social interactions, performance of daily activities, and participation in various life roles at home and in the community”.

More recently, Winkle et al. (2012) in an evidenced-based, review of the literature looked at the effectiveness of service dogs for children and adults with physical disabilities. They defined effectiveness as an increase in: socialization and participation in activities outside the home, daily function and psychological well-being. Out of 371 published articles only 12 papers met the authors’ criteria for methodological soundness (Winkle et al., 2012).

Winkle et al. (2012) concluded:

  1. Service dogs seem to positively influence socialization and community participation in a variety of environments”. Winkle cites: studies that show that the majority of people partnered with a service or hearing dog report a close, affectionate, and comforting relationship with their service dog (Lane et al., 1998); felt safer since being partnered with a service dog (Valentine et al., 1993); and were 77% more likely to feel comfortable traveling away from home after being partnered with a hearing dog.
  2. Service dogs for people with physical disabilities or hearing impairment seem to provide functional assistance to their partners. Adults and children with physical disabilities report that service dogs most commonly assist them with: opening doors, retrieving dropped items, tugging off shoes and clothing, getting around the house, shopping, working, and getting around the community (Lane et al., 1998; Sachs-Ericsson et al., 2002; Winkle et al., 2012).
  3. Service dogs for people with physical disabilities or hearing impairment seem to have a number of psychological benefits for their human partner. Sachs-Ericsson et al. (2002) and Winkle et al. (2012) These benefits included increases in: greater control of their life, self-esteem, feeling more capable, confidence, and positive affect (Valentine et al., 1993; Allen and Blascovich, 1996; Morey et al., 2010).

Austism Assistance Dogs

The benefits for children on the autism spectrum and their family after the placement of a service dog have been reported as: decreased meltdowns and repetitive behavior; increased language use and attention; improved sleep; decreased stress for the family and increased social acknowledgement; decreased anxiety, screaming, and other disruptive behavior when out in public; and decreased salivary cortisol secretion (McNichols and Collins, 2000; Odendaal and Meintjes, 2003; Burrows et al., 2008; Viau et al., 2010; Berry et al., 2013).

Diabetes alert dogs

In a sample of 19 clients partnered with a diabetes alert dog trained to alert to hypoglycemia, Rooney et al. (2013) concluded that: the acquisition of the dog was highly valued in the family and clients believed in the dogs reliability to alert to low blood sugar and reported fewer unconscious episodes, fewer calls for emergency care, and an overall increased sense of independence. Though researchers and service dog providers do not yet know what the volatile organic compound is that the dogs detect by scent, the trained dogs reliability has shown great promise (Rooney et al., 2013).

Trainers of diabetes alert dogs postulate that people with Type I diabetes experience a chemical change that results in a scent (not detectable by humans) that is transmitted in saliva and breath (Ball; 2013; Rooney et al., 2013). Diabetes alert dogs are taught to perform a specific behavior when they detect the scent of low blood sugar. Most diabetes alert dogs are taught to nudge, with their nose, the arm of their human when they detect the scent of low blood sugar.

Guide dogs

Refson et al. (1999) explored the health and social status of guide dog owners and other visually impaired adults. They found guide dog users to be younger, healthier, and more mobile than control groups of similarly visually impaired individuals. More recently, however, the average age of guide dog users has been increasing. Some schools are seeing a large number of applicants for successor dogs and individuals with age-related disease complications of blindness (i.e., diabetes and macular degeneration).

Refson et al. (1999) also found that guide dog owners showed greater independence, confidence, and acceptance of their visual impairment. After being partnered with their dog, 89% of the guide dog owners felt that their quality of life improved. Similar to the benefits of partnership with a service or hearing dog, guide dogs were also found to be “highly successful as mobility aides and provide additional positive effects on lifestyle, such as companionship, improved health and self-esteem, and social integration” (Refson et al., 1999).

The majority of research on assistance dogs and their partnership with people with physical disabilities has looked at the benefits of being partnered with an assistance dog. We know considerably less about the nature or quality of the bond between the assistance dog and its human partner.

Bond between Humans and Dogs

There is growing evidence that the human-dog affectional bond can be characterized as an attachment bond. Dogs have beenshown to demonstrate attachment behaviors to their owners that closely resemble those reported in human infants and chimpanzees (Topal et al., 1998; Prato Previde et al., 2003; Beck and Katcher, 2003; Serpell, 1995; Serpell, et al., 2010).

Attachment can be considered a particular type of affectional bond. According to Cassidy (1999), to establish a bond as an attachment bond, it needs to be distinguished from other affectional bonds. Cassidy (1999) describes ALL affectional bonds as having four components: 1) endure over time; 2) involve a specific individual and are emotionally important; 3) people in affectional bonds tend to keep close proximity and contact; and 4) people in affectional bonds tend to become distressed when separated involuntarily. However, according to Ainsworth (1964), “there is one criterion of attachment that is not necessarily present in other affectional bonds; the experience of security and comfort obtained from the relationship with the partner, and yet the ability to move off from the secure base provided by the partner, with confidence to engage in other activities”. He refers to this as “secure base.” The attachment bond can be either bidirectional (i.e., adult to adult) or unidirectional (as in the case of parent and child). The bond between an assistance dog and its human partner most closely resembles a bidirectional attachment. The human depends on his or her assistance dog to provide help while the assistance dog relies on its human partner to provide food, shelter, and social connection.

Prato-Previde et al. (2003) looked at the characteristic of attachment in the human-dog relationship. They used the Strange Situation procedure of Ainsworth to test whether the human-dog relationship was an affectional bond that could be characterized as an infant-like attachment. They believe that to establish the presence of an attachment bond, the focus of the “behavior analysis must look at categories that indicate security-, proximity-, and comfort-seeking” (Prato-Previde et al., 2003).

Their results showed that the human-dog relationship is a strong affectional bond. They also found moderate support that it constitutes an attachment (Prato-Previde et al., 2003). Prato-Previde et al. (2003) found “a positive indicator of a secure base effect. They found that “dogs would only play with a stranger in the presence of the owner but not in his or her absence”.

What has not been explored in the previous research on attachment is the quality of the relationship between the person and their dog.

Quality of the relationship/attachment

Kwong and Bartholomew (2011) conducted the only study that applied an attachment perspective to understanding the relationship between human partners of assistance dogs and their dogs. Their study examined whether the attachment components of: 1) safe haven, 2) secure base, and 3) separation anxiety were evident in the human-assistance dog relationship.

Though considerable research has demonstrated that people form strong emotional bonds with their companion animals, much of the research is descriptive. Kwong and Bartholomew (2011) found that little research looks at why people love or feel connected with their companion animal. Working from the attachment theory of Bowlby (1969) that infants of many species develop behavior systems to protect them from danger and to facilitate safe exploration by maintaining proximity to a caregiver or attachment figure, Kwong and Bartholomew (2011) believe that attachment theory might address the reason for the deep connection between assistance dogs and their human partner.

Kwong and Bartholomew (2011) state that “to understand a close relationship from an attachment perspective, it is essential to consider both attachment and caregiving dynamics”. They describe four components of attachments to caregivers: 1) dependents tend to seek out and stay near their caregivers (proximity seeking and maintenance); 2) become distressed and resist separations (separation anxiety); 3) use caregiver as a safe base to venture out and explore (secure base); and 4) turn to their caregiver for comfort when distressed/fearful (safe haven).

Kwong and Bartholomew (2011) analyzed 25 interviews of assistance dog partners about their relationship with their assistance dog (both guide dogs and service dogs). They found evidence for three attachment components: safe haven, secure base, and separation anxiety. They did not use the component of proximity seeking because most assistance dog partners are in contact with their dog.

They found the majority of participants felt that their “assistance dog provided comfort during times of distress, describing their dogs as being available to talk to and providing reassurance through physical contact and affection”. About half of the participants reported feelings descriptive of a secure base. They described their dogs as “giving them a sense of security, positive self-development, confidence, and a sense of being watched over” (Kwong and Bartholomew, 2011). Though participants reported that they seldom were separated from their dogs, when they were separated for more than a couple of hours, the majority missed their dogs. What the participants were concerned about during separation was the well-being of the dog rather than their own. Kwong and Bartholomew (2011) suggest that this is an “activation of the caregiving system”. Because of the interdependent relationship between assistance dogs and their human partners, when the humans were separated from them, their need to care for and protect the dog was amplified.

Stress as a moderator variable in the relationship

Recently, research has looked at the level of behavioral and physiological stress in dogs as it relates to the relationship with their owner/ partner and stressful situations. Hennessey et al. (1994) found that in military working dogs who were exposed a second time to a novel situation, their cortisol plasma concentration was two times greater IF they did not receive the program of human intervention between the exposures.

Schberl (2012) looked at saliva cortisol concentration of both owners and dogs in owner-pet dog dyads. What accounted the most for low saliva cortisol in dogs was the type of relationship the owner described having with their dog. Dogs whose owners described them as a “social partner and meaningful companion had the lowest cortisol levels” when engaged in a problem-solving task.

Fallani et al. (2007) looked at behavioral and physiological changes in guide dogs at different stages of their two-year journey to becoming guide dogs. Most all assistance dogs have a three-part longitudinal training program. Usually, dogs under a year are with puppy raisers becoming socialized. At 16 to 24 months, they enter formalized assistance dog training. When dogs are about two years old, they are matched with their human partner. The matching/teaching can take between two and six weeks. Fallani et al. (2007) found that guide dogs could successful establish positive bonds with people at all stages of their training program.

Fallani et al. (2007) found that “though guide dogs showed a more self-controlled reaction during separation from their owner, their emotional response was robust (increase in heart rate)”. This suggests that though guide dogs are trained to exhibit restrained behavioral reactions to environmental changes, their physiological response can still be considerable. Partners and trainers of guide dogs need to be aware that though a guidedog may look relaxed, this is a learned behavior that may be contrary to their emotional/physiological experience.

Rehn et al. (2014a,b) found that the endocrine and behavior responses of dogs at reunion with a familiar person were affected by how the human initiated contact. When dogs received both physical and verbal contact, the increase in oxytocin levels was sustained longer than when only receiving visual or verbal contact. Also, cortisol concentration decreased only when the dogs received both physical and verbal contact. Dogs receiving both physical and verbal contact also engaged in more approach behaviors and displayed little contact-seeking behavior. Rehn et al. (2014a,b) suggest these findings show that ” behavioral and endocrine repertoires are important for the maintenance of an affiliate bond between individuals and reciprocal physical contact between dogs and humans probably has beneficial and calming effects in both species”.

Horn et al. (2013) distinguished between social familiarity (exposure to a person) and the quality of the relationship with a person as the basis for the attention of a dog. This has significant implications for training service dogs and helping the human partner develop a meaningful (from the perspective of the dog) attachment. Horn et al. (2013) found that dogs paid significantly more attention (measured by eye contact) to a familiar person from the household than to an unfamiliar experimenter ONLY when the person had a “close relationship characterized by many joint activities and frequent feeding”.

Burrows et al. (2008) also identified factors affecting welfare and behavior of service dogs for children with autism. They found potential physical stressors including limited rest or recovery time after working, unintentional mistreatment and prodding by children, little predictability on daily routines, and not enough opportunities for play (Burrows et al., 2008). Similar stressors can be found in all types of assistance dog placements. Service dog programs have a duty to help individuals and families provide a “secure base and safe haven” for the service dog, just as they expect the dog to provide for them.

It seems that the bond between an assistance dog and its human may vary in relationship to the type of assistance dog partnership. With assistance dog partnerships that require the dog to make independent decisions, the bond may look more unidirectional with regard to specific task behavior. For example, with diabetes alert dogs (hypoglycemia alert), hearing alert, and guide dogs, the dogs make decisions without human direction. Diabetes alert dogs pick up a scent and alert their human to low blood sugar even when the person does not notice any symptoms. Similarly, guide dogs engage in “intelligent disobedience” when they appropriately disregard the direction of their human to cross a street when there is traffic that the human does not notice.

With assistance dog placements with children on the autism spectrum, the bond between the child and the dog is often fostered and developed by the interaction of the parent with the dog and child. This bond can be described as a three-way bond created between the child and dog because of the bonding activities that the parent performs. A simple example is having parents engage in classical conditioning by feeding the dog high-value treats when the dog is lying close to the child. The hoped for result is that the dog makes the association that laying close the child is a rewarding experience.


Burgess-Jackson (1998), in his discussion of our responsibilities to animals, states that the act of forming a bond or relationship with a sentient being generates responsibilities to care for its needs. We have a responsibility to provide for the physical, social, and emotional needs of all dogs but even more so with assistance dogs. There is a bond of interdependence and trust between an assistance dog and its human partner that needs to be consistently nurtured and developed and never broken.

Assistance dog programs need to continue to teach human partners a variety of ways to establish positive bonds and attachments with their assistance dog. Most programs stress the need for the human partners of assistance dogs to establish a strong bond with their dogs. This bond can be intensified by having the human partner be the person in the household who provides “all good things for the assistance dog.” The human partners are shown how to create this bond by feeding, playing with, and grooming their assistance dogs.

For many human partners, their disability makes participation in these bonding activities difficult. Programs need to continue to take into great consideration how physical limitations of a person may make this difficult. For example, people who are living with significant impairment or paralyses may not be able to physically interact with, or even pet, their assistance dog. This difficulty with physical interaction may affect their relationship and the creation of a bond with their assistance dog. Because both verbal and physical interaction was needed to see a sustained increase in oxytocin level and a decrease in cortisol in a dog, programs need to help human partners find ways to provide both of these interactions for their assistance dog.

Creative problem solving is needed. Programs can help people with significant physical impairment find ways to create positive bonds with their assistance dogs. Using adaptive aids, people may be able to play “fetch” with their dog by propelling a ball with their wheel chair or brush or massage their dog by use of a motorized “massager” that is attached to their wheelchair.

Placements of assistance dogs with children with physical disabilities and with autism can pose unique challenges to the development of a bond with the dog. Davis et al. (2004) found that though 88% of families reported benefits of the placement for their children, drawbacks were also significant. They found that 53% of the families identified risks that included behavioral, financial, and time/cost issues that became a significant burden where the parents questioned the placement.

It is the responsibility of organizations that place assistance dogs, and the human partner of the assistance dog, to assure that the needs of the beings on both ends of the leash are met. All parties involved in the partnership of a human and an assistance dog need to make an objective assessment regarding how the attachment bond can be developed and maintained throughout the life of the partnership. Assistance dog providers and human partners need to make difficult decisions when the bond and/or needs of the assistance dog cannot be met. This may mean increasing the involvement of nondisabled individuals to assist in “bonding activities” or may mean reconsideration of the placement.

So what does the partnership between an assistance dog and its human partner tell us about the human-animal bond? The relationship between humans and their assistance dogs is interdependent, very fluid, and possibly more complex that that between nondisabled human-animal (dog). The level and balance of this interdependence is not linear and can abruptly change with a decline in the physical or psychological health of the human or dog. Clothier (2002) writes, “each relationship with an animal and a human is a bridge uniquely shaped to carry only these two, and so must be crafted by them”. Nowhere is this bridge more interdependent and uniquely shaped to carry these two than in the relationship between an assistance dog and its human partner.