Many of us who ride and work with horses have likely experienced how our emotions can affect the interactions with our four-legged companions, whether it's during riding, groundwork, or simply while grooming or feeding them. What causes this phenomenon?
Over the past few years, significant scientific evidence has emerged showing that pet dogs can perceive and respond to our feelings. Whether we attribute this to a biological necessity for survival in a symbiotic relationship or label it as empathy, depends largely on our worldview. However, the idea that pet dogs understand our emotions won't be surprising to anyone who has ever owned a dog.
But what about horses? Horses are as flight animals very different from dogs, who are related to wolves and are therefore socially hunting predators, just like humans. Nonetheless, horses are also very social animals as well and throughout millennia, humans have utilized horses for transportation, as farm “equipment”, and in warfare. However, in more developed nations, the role of horses has shifted over time. Due to technological advancements, they are no longer essential as "machinery". Despite this change, horses remain significant in the lives of many humans. In many cases, they are cherished as pets, even though keeping them comes with significant expenses. This shift reflects a change in the way we perceive and interact with horses, from utilitarian to companionship-based relationships.
So, there appears to be a fundamental connection between humans and horses, akin to the bond between humans and pet dogs, which may have developed over thousands of years of shared history and living together. As a result, there has been increasing interest in the behavioral science of horses, particularly in the area of human-horse interspecies communication. Today's blog focuses on three scientific publications that explore the transmission of emotions from humans to horses.
In the first study conducted by Linda Keeling, Liv Jonare, and Lovisa Lanneborn (2009), the researchers examined how the presence of a nervous human affected the heart rate of horses they were interacting with. Heart rate serves as an easily measurable indicator of arousal and stress, increasing as part of the fight-flight response, decreasing with relaxation. A phenomenon extensively studied in humans and other species.
In their experimental setup, the participating horses were led or ridden four times over a distance of 30 meters. The humans involved were informed that a co-investigator standing at the end of the distance would open an umbrella during the fourth round. However, the umbrella was never opened; any reaction observed in the fourth trial would be due to the expectation of the human that an umbrella would be opened.
Throughout the first three rounds, both humans' and horses' heart rates decreased, indicating habituation to the situation over time. However, in the fourth round, the heart rates of both increased. This effect was especially pronounced when the horses were being ridden and thus had direct physical contact with the human. The increase in heart rate was partially accompanied by behavioral changes in the rider, such as using shorter reins.
This study demonstrates that humans reacted to the anticipation of something unexpected happening in the fourth round with a slight stress response. This response was then transferred to the horse, likely leading to a higher stress or preparedness level in the horse as well (it's important to note that the horses could not anticipate anything unforeseen happening in the fourth trial). One explanation for this transfer of the human stress response to the horses could be the behavioral changes on the part of the humans.
However, a study by Antonio Lanata and colleagues (2018), suggests an additional possible pathway for emotion transfer between humans and horses. They also investigated changes and reactions in the horses' heart rate as an indicator of the activity of the autonomic nervous system and thus emotional responses. However, this time, they examined the horses' responses to human odors of fear versus happiness, derived from human sweat samples. The horses reacted differently to the two opposing emotions associated with human odors, indicating that they were able to perceive human emotions through human sweat-associated odors. The authors concluded that "human chemo-signals affect the physiological status of horses as seen by the changes in their autonomic activity." The ability of horses to discriminate human odors of fear and joy was recently corroborated by Jadat and colleagues (2023) thus confirming a likely pathway of emotional transfer between humans and horses.
Odors are processed "subconsciously" in humans, unlike visual and auditory information. The olfactory (smell) system reaches the older parts of the brain where emotions, especially fear and stress, are processed directly and unfiltered. Similarly, horses can immediately pick up human fear through fear odors. These findings replicate those from studies on pet dogs, which also react differentially to human emotional states and seem to be able to read and respond to human emotions.
A word of caution is warranted when interpreting these scientific findings: Understanding how dogs and horses react to our emotional states is not straightforward. It depends on their relationship with humans, their individual personality, previous experiences, and the specific situation. The idea that our pets simply "mirror" us is quite anthropocentric and overlooks their true nature and capacities.
Nonetheless, these scientific results about the non-verbal communication of stress, fear, happiness, and joy tell a fascinating story of cross-species communication between humans and horses. This mutual line of communication likely stems from a common history of thousands of years. What are the consequences for us humans? We cannot lie to our horses! They know when we are happy, angry, or afraid, and most likely also whether we like and accept them or not. Therefore, if we cannot deceive our horses, we might as well be honest with ourselves about our fears, desires, worries, as well as hidden agendas. At the same time, our horses will recognize and understand whether we handle and encounter them with honesty, respect, and understanding, and whether we show compassion for their true nature and needs.
The invisible bond of communication between humans and horses provides an ancient and fundamental platform on which trust and, if you will, love can grow between us humans, and our equine companions. And maybe it is exactly that, why we still love horses even though there are not exactly “needed” any more in our modern world: they cannot pretend, they don’t lie, they are truly honest. Horses give what many of us value very high, namely honesty, truthfulness, and appreciation of who we are.
References:
Jardat P, Destrez A, Damon F, Menard-Peroy Z, Parias C, Barrière P, Keller M, Calandreau L, Lansade L. Horses discriminate human body odors between fear and joy contexts in a habituation-discrimination protocol. Sci Rep. 2023 Feb 25;13(1):3285. doi: 10.1038/s41598-023-30119-8. PMID: 36841856; PMCID: PMC9968287.
Keeling LJ, Jonare L, Lanneborn L. Investigating horse-human interactions: the effect of a nervous human. Vet J. 2009 Jul;181(1):70-1. doi:v10.1016/j.tvjl.2009.03.013. Epub 2009 Apr 25. PubMed PMID: 19394879.
Lanata A, Nardelli M, Valenza G, Baragli P, DrAniello B, Alterisio A,Scandurra A, Semin GR, Scilingo EP. A Case for the Interspecies Transfer of Emotions: A Preliminary Investigation on How Humans Odors Modify Reactions of the Autonomic Nervous System in Horses. Conf Proc IEEE Eng Med Biol Soc. 2018 Jul;2018:522-525. doi: 10.1109/EMBC.2018.8512327. PubMed PMID: 30440449.
