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Animal Assisted Therapies - How Dogs and Horses Can Take Part In the Future of Autism Treatment

Updated: Sep 2, 2019

Having a therapy animal can significantly increase a child's social learning. This research paper evaluates how caregiver feedback along with animal assisted therapies can influence the outcomes for children with autism.

My brother, Andrew, leading a therapy horse on a practice run.


Smiling is a social mechanism we use to form relationships, cooperate, and communicate enjoyment. Children with Autism Spectrum Disorder (ASD) display lower levels of social smiling than typically developing children which sets them significantly below the curve for social learning. If children with ASD are not engaged in frequently shared emotions, they develop connections in a limited, ineffective fashion. Our study reviews literature from the past two decades that have experimental results on caregiver enhancement and animal-assisted therapy (AAT). Both of these treatments are accessible, inexpensive, and not as time-consuming compared to popular abstract treatments of autism.

Thus, it would be important for families and other professions related to autism to evaluate if these treatments have been systematically useful. Specifically, we focused on whether these methods would increase the level of social smiling in autistic children. We found that directed caregiver behavior towards younger ASD children is extremely effective at increasing social smiling as positive feedback. Having the caregiver demand immediate responses teaches social contingencies that ASD children often cannot develop by themselves. In AAT programs, children up to 12 years of age displayed significant improvement in not only smiling reactions but also verbal and eye contact measures.

A “positive field of emotion” is created in the presence of a therapy dog or horse which allows a child to freely express their emotions and learn social cues from their caretakers and instructors. Our conclusion that both these treatments are useful in improving symptoms of autism in children, especially social cognition which is manifested by appropriate contingent social smiles.


Evolution and Significance of the Human Smile

Smiling as a means of positive social reinforcement is a human phenomenon that emerged in early hominids as a solution to a fundamental problem in group living: forming long-lasting cooperative relationships with others (Bachorowski and Owren, 2001). Amongst all nonhuman primates, only humans use the silent bared-teeth face as a symbol of positive social engagement (DeWaal, 2019). This type of smiling is termed social smiling: smiling with eye contact directed towards a social partner (Messinger and Fogel, 2007). The ability to react to a positive stimulus or promote social engagement with a smile is something that we obtain through early neural pruning that arises from interactions with our caregivers. Social smiling first emerges around 2.5 months when infants smile to almost everything including nonsocial stimuli. After three months, however, smiling becomes more selective and reserved for positive social interaction. This phenomenon is likely due to infants realizing that smiling at nonsocial objects does not benefit them while smiling at people does (Emde, 1972). Interestingly, blind infants show the same social smile under the same social stimuli as a normal infant (Peterson et al., 2000). This suggests that mechanisms that influence the bared teeth response to be positively associated with social situations has been adapted by our species, making the social smile crucial to navigate human society.

In typical development, emotional representations grow in tandem with a child’s social and emotional experience. Infants learn that smiling is a reliable signal of cooperative intent. Smiling with eye contact is essential for learning since it is the earliest behavior available for infants to initiate and maintain interaction with caregivers (Harker et al., 2016). Thus, smiling not only functions to successfully form relationships but also as a critical learning feedback mechanism.

Consequences Social Smiling on Autism

Developmental social milestones are guided by social smile-eye contact behavior between infants and caregivers. When these cues are missed, the effects are detrimental. Impaired contingent expression of emotion is common in children with Autism Spectrum Disorder (ASD) and may be an early marker for ASD in infants (Shutlz et al., 2018). Children with ASD express lower levels of social smiling than typically developing children (TD) and even children with other developmental disabilities (Webb and Jones, 2009). Differences in social engagement and smiling have also been observed within the first two years of life for infant siblings of children with ASD who have a higher risk for receiving an ASD diagnosis by virtue of family history (Ozonoff et al. 2011). Researchers at the Marcus Autism Center are currently conducting projects that attempt to find even more subtleties in social smiling at even younger ages (Shultz, 2019). It is very likely that early detection may include deficits in social smiling in order to predict the phenotype of ASD.

Children with ASD have many challenges with expressing their thoughts and feelings, especially the pleasant ones through norms of social interaction and verbal/nonverbal communication behaviors. The biological reason may be alterations in basic developmental mechanisms, such as impairments in the social reward system (Scumann et al., 2009). If undiagnosed and untreated, the deficit in social learning leads to individuals with autism being perpetually trapped in a world where no one can understand them. This emotional isolation has cascading, destructive effects on one’s wellbeing. Anxiety and depression are frequent and disabling comorbid psychiatric conditions that disproportionally affect those with ASD. Around 40% of ASD individuals develop an anxiety disorder by adolescence and a range between 15-70% are diagnosed with clinical depression (Cai et al. 2018).

The broken bridge of communication between those with ASD and their caregivers has an adverse effect on their caregivers too. Children with ASD often have tantrums and actions that serve as their way of communicating since they will grab the attention of their caregivers most effectively. Troublesome behavior has led to abuse and even murders of ASD children by their caregivers (Offit, 2008). Furthermore, most ASD individuals do not have a clear path or program they can rely on when their caregivers pass away. The inequality of social learning lowers the standard of living for those with ASD and there need to be treatments that facilitate social learning.

Social Smiling Therapy

Recent studies with infants with ASD have shown that attention towards social stimuli, such as faces and eyes, are present during the first few months of life, and even occur at higher rates than normally developing babies. This trajectory, however, plummets around 2.5 months, when social smiling emerges (Klin et al., 2014). Due to the missed social cues when smiling becomes a learning tool, toddlers with ASD look less to faces and eyes than control participants (Jones and Klin, 2013).

Social smiling is the catalyst for social learning in normally developing infants. We believe that it is worthwhile to create treatments that enhance the smiling reaction in children at high risk of autism to bridge the gap in missed social cues. The aim of this paper is to provide a comprehensive review of two popular social smiling therapies: caregiver engagement (actively education caregiver of most effective behavior) and animal-assisted therapy (AAT). Not only are these inexpensive and accessible, but they are also simple to understand. Unlike the almost science fiction treatments of hyperbolic oxygen, parasite introduction, and head compressions, educating a caregiver or meeting with a therapy dog/ horse is much more approachable for families.


Caregiver Enhancement

Previous studies found that ASD children orient less to the faces and eyes of people (Jones and Klin, 2013). Vernetti et al. found that this is not the case when caregivers and coaches encourage engagement by presenting profile views of faces and only establishing eye contact when and if the child decided to do so. There was not, however, an increase in social smiling in the condition where stimuli were unpredictable. The implications for treatment is that reinforcing stimuli should be predictable since ASD children may interpret change as harmful or unpleasant. Vernetti et al.’s result rebut popular theories suggesting impaired social orienting or impaired motivation engage with social stimuli.

The effect of parenting style is often ignored when looking at therapy outcomes for autism. Moreover, the effect on parents that ASD children have is often overlooked as well. Ample evidence suggests parents of ASD report heightened stress compared to those of typically developing youth which presents with symptoms of anxiety and depression (Hayes and Watson, 2013). Harker et al. underscore the importance of accounting for caregiver behavior when seeking a better understanding of social behavior development and expression in HR-infant and LR-infant samples. Directed behavior is much more effective for ASD children since they are focused on contingent physical behaviors such as synchronized clapping (Jones, 2019). If more directed behavior is implemented in a caregiver’s routine, ASD children may have a greater chance of normalizing their smile response. Additionally, improvements of the ASD child are bidirectional since the caregiver is also rewarded and more motivated by social successes.

Helt et al. suggest the limited range of effect on ASD children desensitizes them to stimuli that increase enjoyment for normally developing children. The suggested mechanism that allowed the no-ASD group to experience enhanced social enjoyment in the presence of physical stimulator or companion may be due to neural associations. It can be speculated that a child who experiences positive internal states in tandem with a position emotional expression such as the social smile will develop significant neural connections linking these two representations. Over time, the link will become so well established that it operates bidirectionally – internal emotion may trigger facial expression and vice versa (Helt and Fein, 2015). Due to the lack of social smiling in ASD children, they do not develop this link which may explain these non-associative results. It is important to note that the Helt and Fein study had participants who were much older:6-14 years (Table 1). Experiments that had a toddler or younger participants all had enhanced social smiling rates (Table 2) which suggests that early intervention is crucial to deter negative traits of autism. Even at elementary school ages, social smiling therapy may be too late; early intervention and early detection are imperative for steering ASD children towards normative social responses.

Educating caregivers about the benefits of directed, engaged behavior towards ASD children is extremely important in maintaining mental health in them and also their caregivers. Our results propose that social smiling improves with appropriate caregiver response from 9-36 months; it is difficult to establish smiling links at older ages.

Animal Assisted Therapy (AAT)

Funahashi et al. and Silva et al. established that social recognition of a pleasant environment instead of a harmful one is very critical in supporting a child with ASD. All conditions for both studies observed higher levels of social smiling and lower levels of negative behavior. When a “positive field of emotion” is created, the child with ASD may see the environment through a new cognitive strategy and therefore change their emotional evaluation. The studies pointed out that these results are not due to just having a charismatic animal present but having a well-trained therapy animal that does not startle or harm the ASD child. Thus, friendliness of the therapy animal is a major factor in promoting positive social responses in an ASD child.

Behavioral and communicational, including smiling at enjoyable stimuli, improvements of all four children in Keino et al.’s study was observed. This indicates that having guided horseback riding lessons enriches the social interaction of children with ASD and PDD. The “positive field of emotion” created by the horse track allows ASD children to feel safe to express emotions. Along with the increased attention given by side walkers and instructors, children with ASD receive ample attention and patience. In contrast, classrooms, workplaces, and other people-filled places have many social stimuli that ASD individuals become overwhelmed with. Communication failures in these hectic environments lead to stress and symptoms of anxiety. Stress factors are majorly reduced in a positive field of emotion which promotes the ASD child to manifest their feelings onto others. It is also important to note that when subject 3 stopped AAT, improvements in behavior stopped. This suggests that a child may become reliant on AAT to show improved social cognition.

These studies quantitively advocate the benefit of therapy animals to participate in therapeutic interactions. All AAT treatments resulted in higher levels of social smiling and we conclude that this is an effective treatment to bolster social smiling in ASD children, given that the animal is certified for therapy. It is also interesting to note that increases in social smiling were observed in ASD children up to 12 years of age. Unlike caregiver enhancement therapies, AAT can target an older range of ASD individuals.


All caregiver enhancement studies had crucial aspects in their design that were not controlled for. In Helt and Fein’s study, the caregiver was given no a priori instruction so laughter was not controlled across all groups. Both Vernetti et al. and Harker et al. had similar confounding factors to their caregiver treatment conditions. The limitation with our AAT literature is that they all had extremely small population; our search only found six published total cases of ASD children. Since ASD is so variable, we can only exrapolate how AAT will affect a larger population of children. The population of all six studies did not have much ethnic or socioeconomic diversity. Recruitment was mainly done through university-affiliated outreach and those who participated primarily came from educated, caucasian families.

Future Directions

Both therapies examined are promising procedures for increasing appropriate social smiling in ASD children which can help them become more effective at cooperating and expressing themselves in social situations. Our papers revealed that negative behaviors were reduced with caregiver enhancement and AAT therapy. Thus, we should explore the effects of feedback on negative stimuli and emotion, as well as the effects of inhibiting feedback in a group of individuals with ASD. If there is an effective way caregivers can enhance the smiling of children older than three, it would be a worthwhile investment since the average age of a child to be diagnosed with autism is five years of age (Klin, 2019). Based on our findings, five years is too late to alter social smiling responses solely due to caregiver efforts. As for AAT, future endeavors should investigate whether positive effects can be generalized to therapeutic contexts that do not involve the presence of an animal and be maintained outside a therapeutic environment.

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