Behavioural and physiological responses of therapy horses to mentally traumatized humans
Introduction
Over the past few decades, there has been a growing interest in equine-assisted therapy (EAT) as the benefits of interacting with horses for the treatment of individuals with mental illnesses become apparent (Bachi, 2012; Frewin and Gardiner, 2005). The basic premise of such programs is that the immediate and direct feedback from the horse allows the participant to gain awareness of his/her own behaviour or mental state. This presumes that horses perceive and respond to emotional changes in the human, and requires an understanding of horse behavior on the part of program facilitators to foster a positive learning environment and guide mutually constructive interactions between horse and human (Hausberger et al., 2008). However there is little research that analyzes these interactions from the viewpoint of the horse. More attention needs to be accorded to the benefits the animals receive in these programs (Hatch, 2007) as there is the potential for a therapy animal’s welfare to be negatively affected (Wensley, 2008).
Equine-assisted therapy programs begin by introducing the human patient to the horse he/she will interact with. The appropriate pairing of a horse with a participant is essential in developing suitable learning and discovery opportunities for the individual patient. Some EAT practitioners believe that a successful bond between the human and horse is built upon reciprocated trust and dependability that can help establish a successful therapy program (Frewin and Gardiner, 2005). Many practitioners consider the horse itself as the catalyst for therapeutic changes (Kendall et al., 2014). A widely held belief is that the horse can intuit what emotional support the human patient requires and the human is paired with a horse that can fulfill these needs. Anthropocentric labeling of human-horse interactions, such as “the horse knows what the human wants” or that horses are “willing to please” assumes that horses will act benevolently to achieve mutual goals (McGreevy et al., 2009). This assumption can lead to miscommunication and compromise welfare for both human and equine participants.
Literature abounds with the effects of stress placed on humans working in careers of social work, psychology and psychiatry (reviewed in Lloyd et al., 2002). It is reasonable to assume that animals placed in similar environments could also experience stress, and that a number of variables influence a horse’s response to his human partner. It is known, for example, that both the temperament of the horse and the attitude of the human (Hausberger et al., 2008) play a role in the horse-human relationship. Heart rate increased in horses that were petted by humans who were thinking negative thoughts (Hama et al., 1996) and horses being led through a maze by a handler with a negative attitude were less cooperative (Chamove et al., 2002). Humans that were anticipating the occurrence of a frightening incidence while leading or riding a horse caused an increase in both their own and the horse’s heart rate (Keeling et al., 2009), while humans that were nervous around horses caused a decreased heart rate in the horses themselves (Merkies et al., 2014). What is unclear is whether horses are responding to physical or emotional cues from the rider/handler. Programs utilizing EAT invariably encounter humans with physical and emotional emanations, as the focus of the therapy exercises is to allow the participants to recognize and face their mental limitations or fears. Only a handful of studies evaluating the effect of humans on horses involved in EAT have been published. None of these studies (Johnson et al., 2017; Kaiser et al., 2006; McKinney et al., 2015) found differences in mean behaviour scores in horses ridden by recreational riders or physically- or psychologically-handicapped riders. Fazio et al. (2013) found lower concentrations of circulating stress hormones (β-endorphin, ACTH and cortisol) in horses engaged in riding sessions with disabled riders than with recreational riders whereas Johnson et al. (2017) showed higher levels of cortisol in horses when ridden by veterans suffering from Post-Traumatic Stress Disorder (PTSD) compared to experienced riders.
Post-Traumatic Stress Disorder is described as a complex pathological reaction to trauma wherein traumatic experiences may compromise feelings of safety in the affected person’s own body or environment (Tsur et al., 2018). Trauma occurring during childhood can lead to disrupted neurological development which can have long-term impacts on cognitive function (Mueller and McCullough, 2017). These impacts, coupled with fear, anxiety and lack of trust can impede treatment of PTSD. Equine-assisted therapy is an attractive treatment modality as interactions with horses can provide a feeling a safety and modulate arousal and fear responses in humans. The simple act of grooming a horse can overcome touch avoidance and increase body awareness of the individual suffering from PTSD (Mueller and McCullough, 2017).
The importance of fully understanding the variables that affect the horse-human relationship is essential considering that the most significant factor contributing to the risk of human injury when working around horses is the relationship between the horse and the human (Hawson et al., 2010; Keeling et al., 2009). One study reported over 80% of equestrians experienced an injury due to horse riding (Mayberry et al., 2007), leading Gombeski et al. (2017) to recommend that safety around horses be reviewed with staff in all horse organizations. A survey of businesses offering equine-assisted therapy in Florida revealed that all of them reported challenges with their horse training program, often having to resort to outside professionals (Rankins et al., 2017). Although all organizations that certify equine-assisted therapy practitioners consider the interpretation of horse behaviour critical to program success, there exist no standards for teaching or understanding equine behaviour in these certification programs (Kieson and Abramson 2016).
The purpose of this study was to quantify behavioural and physiological responses of therapy horses exposed to humans who have been clinically diagnosed with a psychological or emotional illness, namely Post-Traumatic Stress Disorder (PTSD), compared to those who have not been diagnosed with psychological ailments. Based on previous research in this lab showing less stress behaviours in horses exposed to humans who were nervous of horses (Merkies et al., 2014), it was hypothesized that horses would display fewer signs of behavioural and physiological stress when exposed to humans with PTSD compared to neurotypical individuals. Understanding the therapy horse’s role is fundamental for furthering research, providing suitable training for facilitators, and ensuring appropriate safety measures for all participants while gaining additional insight into the human-animal bond.
Section snippets
Humans
The procedures in this study were approved by the Research Ethics Board (REB) at the University of Guelph for use of human research subjects (REB#13MY036). Four mentally-traumatized females (47.5 ± 17.3 years, 60.3 ± 2.2 kg, 164.3 ± 8.2 cm) clinically diagnosed with PTSD and under current care of a psychotherapist contacted the principal researcher directly after a local media article regarding the research project was released, volunteering to be part of the study. Four neurotypical “control”
Horse heart rate
Horse HR remained relatively constant throughout the BASELINE period (49 ± 15bpm; F(1,9458) = 1.83; P > 0.17). When the horse was exposed to the human, average horse HR did not differ between treatments (48 ± 16bpm in PTSD vs. 46 ± 14bpm in CON; F(1,3725) = 1.56; P > 0.21) even with gait as a covariate. Over the TEST period, horse HR tended to increase by 1.6bpm when exposed to the PTSD individuals (F(1,1934) = 3.51; P < 0.06) whereas when exposed to the CON individuals, horse HR decreased by
Discussion
This study exposed horses individually to pairs of humans who physically resembled each other and moved in a similar way, however one of those humans suffered from PTSD while the other did not. Physiological and behavioural measures showed some differences in responses of the horses to the two treatment groups, however more salient results came from analyzing horse responses to any human presence and to the presence of humans experienced with horses.
Horses did not differentiate between PTSD and
Conclusions
This foundational study provided a quantitative basis for behavioural responses of therapy horses and found no major differences in typical equine stress behaviours indicated by gait, head height, ear position, and distance from the human between PTSD and neurotypical individuals. Horses were less stressed when any human was present with them, and more attentive toward humans who were more experienced with horses. Horses appear to respond more to physical cues from the human rather than implied
Conflicts of interest
The authors declare that there are no conflicts of interest.
Acknowledgements
This work was supported by the Horses and Humans Research Foundation through their Innovation Grant. The authors thank all the human participants and volunteers and Sunrise Therapeutic Riding and Learning Centre for use of their horses and facilities.
References (35)
- et al.
How do horses appraise humans’ actions? A brief note over a practical way to assess stimulus perception
J. Eq. Vet. Sci.
(2009) - et al.
Training methodologies differ with the attachment of humans to horses
J. Vet. Behav.
(2014) - et al.
Hypothalamic-pituitary-adrenal axis responses of horses to therapeutic riding program: effects of different riders
Physiol. Behav.
(2013) - et al.
Preventing horse-related injuries by watching out for other humans
J. Outdoor Recreat. Tour.
(2017) - et al.
A review of the human-horse relationship
Appl. Anim. Behav. Sci.
(2008) - et al.
The roles of equine ethology and applied learning theory in horse-related human injuries
J. Vet. Behav.
(2010) - et al.
Horses working in therapeutic riding programs: cortisol, adrenocorticotropic hormone, glucose, and behavior stress indicators
J. Eq. Vet. Sci.
(2017) - et al.
Investigating horse-human interactions: the effect of a nervous human
Vet. J.
(2009) - et al.
Hypotheses about the psychological benefits of horses
Explore
(2014) - et al.
Equines as tools vs partners: a critical look at the uses and beliefs surrounding horses in equine therapies and argument for mechanical horses
J. Vet. Behav.
(2016)
Behaviour of horses in the “round pen technique”
Appl. Anim. Behav. Sci.
The horse-human dyad: can we align horse training and handling activities with the equid social ethogram?
Vet. J.
Effects of therapeutic riding on measures of stress in horses
J. Eq. Vet. Sci.
Preliminary results suggest an influence of psychological and physiological stress in humans on horse heart rate and behaviour
J. Vet. Behav.
An assessment of the educational needs of equine assisted activities and therapies (EAAT) centers
J. Eq. Vet. Sci.
The traumatized body: long-term PTSD and its implications for the orientation towards bodily signals
Psychiatry Res.
A comparison of sympathetic and conventional training methods on responses to initial horse training
Vet. J.
Cited by (23)
Equids in Equine Assisted Services: A Scoping Review
2023, Journal of Equine Veterinary ScienceEquine-assisted services: An overview of current scientific contributions on efficacy and outcomes on humans and horses
2023, Journal of Veterinary BehaviorCitation Excerpt :These results suggest that human attitude toward horses can impact horse behavior, and the behavioral response of horses can differ between experienced riders and at-risk humans because of different pathologies during EAS. A change in the behavioral response of horses in the presence of mentally traumatized versus control humans was not observed, while the horse HR increased during and after exposure to the mentally traumatized humans, suggesting that the behavioral response of therapeutic horses may rely on human physical traits rather than affective traits (Merkies et al., 2018). A study hypothesized that TR lessons would be more stressful for horses than a standard lesson program with an experienced rider, due to the physical and psychological challenges of the riders which could interfere with their ability to ride a horse (McKinney et al., 2015).
An observational evaluation of stress in horses during therapeutic riding sessions
2022, Journal of Veterinary BehaviorTherapeutic Riding Horses: using a hypothalamic-pituitary-adrenal axis measure to assess the physiological stress response to different riders
2021, Journal of Veterinary BehaviorCitation Excerpt :Furthermore, the temperament, experience and physical abilities of the horse, as well as the personality of the rider, affected horse-rider cooperation (Visser et al., 2008). Some studies focused on the impact of these activities on horses and their welfare (Suthers-McCabe et al., 2004; Fazio et al., 2013; Malinowski et al., 2018; Merkies et al., 2018). HPA hormone analysis is often used to monitor animal welfare (Mormède et al., 2007), emotional responses (Smith et al., 2006), and performance/fitness evaluation (Ferlazzo et al., 2009; Cravana et al., 2010).
A Commentary on the Contemporary Issues Confronting Animal Assisted and Equine Assisted Interactions
2021, Journal of Equine Veterinary ScienceCitation Excerpt :Any less should not be considered acceptable.” A few studies have examined the effect of AAI and EAI on the various animals, specifically looking at their stress levels during a variety of services [35, 36, 37, 38]. Overall, these studies determined that the stress on the animals was minimal, especially when proper welfare preparation was implemented.
Equine welfare in therapy and learning services: An overview
2023, Animal-assisted Interventions: Recognizing and Mitigating Potential Welfare Challenges