Does the human voice calm horses?

In addition to being warned to move slowly around horses, many new riders are also instructed to speak in a soothing tone, in the belief that it can make the animal calm. A recent study presented at the 2013 conference of the International Society for Equitation Science investigated whether such advice actually had a beneficial impact on the horse.

According to Katrina Merkies of the University of Guelph, “Anecdotally, we know that horses respond better to calm and soothing tones, so our hypothesis is that speaking in a calm and pleasant voice will inspire calm behaviour in a horse.”

Merkies and other researchers from both the University of Guelph, Ontario, Canada and Agrocampus Rennes, Rennes, France set out to discover whether emotional tone and pitch of voice did have any effect on horses. For the study, eight draft horses were individually assessed in a 10 m round pen. Each horse was released into the pen, and baseline behaviour and heart rate (HR) readings were taken over a five minute period. Behaviours scored included: gait; head height position; ear and body position relative to the human.

After establishing baselines, a familiar human approached the pen, and one of four recorded voices was played for a 10 second duration: PL – pleasant voice low tone; PH – pleasant voice high tone; SL – stern voice low tone; SH – stern voice high tone.

Researchers found that the horses maintained the lowest head position when no human or sound was present, but all elevated their heads in the presence of a human or sound. The playing of a pleasant tone resulted in the horses positioning their bodies toward the human. While there was no treatment effect on ear position, the horses did orientate their ears more toward the sound if the human was present.

Horse HR did not increase solely in the presence of the human, but it did increase coupled with sound, with SL in particular resulting in the greatest effect. Results would indicate that fewer signs of behavioural distress are observed when a human speaks to the horse in a pleasant, low tone rather than a stern tone.

“We’ve shown that horses do in fact display different physiological and behavioural responses to different tones and voice. So horses are able to discriminate between different tones or qualities of voice.”

Research often creates more questions than it answers, and based on the results obtained, additional research may be required: “However, it’s not clear if the horse is interpreting or responding to the tone of voice alone, or if it’s looked at in combination - both tone of voice and the human’s body language. Which is the more salient clue to the horse? That certainly warrants further study.”