Researchers Link Behaviors with Type, Intensity of Emotions

Researchers Link Behaviors with Type, Intensity of Emotions

High-frequency vocal sounds indicated increased emotion intensity, the researchers found.

Photo: Thinkstock

Do you wish you could definitively determine whether your horse is feeling positive or negative emotions in a particular scenario? Good news! A team of Swiss and Israeli researchers recently developed a scale of behavioral indicators to identify both the valence (is the emotion positive or negative?) and the intensity of equine emotions.

While it might sometimes seem obvious when horses are “happy” or “upset”—and how much so they are—in some situations the emotion isn’t so easy to read, said Elodie Briefer, PhD, of the Institute of Agricultural Sciences and the Swiss Federal Institute of Technology, in Zurich.

“Our indicators—especially the valence indicator—allow us to identify which situations provoke negative or positive emotions, and this knowledge will help promote better animal welfare,” Briefer said during the presentation of her research at the 2014 Swiss Equine Research Day held April 10 in Avenches.

Previous studies on equine emotions have focused more on intensity (cortisol, or stress hormone, levels and heart rate, for example) without necessarily identifying behavioral indicators that represent a positive or negative valence.

“The approach that we used, which simultaneously compares intensity and valence, could be useful for establishing more precise emotional indicators,” she said.

In her study Briefer and her colleagues evaluated 20 horses in five different situations designed to provoke different kinds and intensities of emotions. Each horse:

  • Was left alone in its stable, watching all the other horses on the farm leave;
  • Saw all the horses returning again;
  • Saw one companion horse being taken away, leaving it with other horses in the farm;
  • Saw the companion horse coming back again; and
  • Stayed in its stable with the other horses around and with no human intervention (control phase).

The researchers filmed the horses' behavior and measured respiration and body temperature with a noninvasive monitor. The team also recorded the horses’ vocal activity.

Upon reviewing their results, the researchers found six reliable indicators of intensity and seven of valence, Briefer said. For example, increased respiration and body movement and high-frequency vocal sounds indicated increased intensity.

With regards to valence, horses in negative situations tended to keep their heads higher, whereas horses in positive situations spent more time chewing.

“Chewing could be a sign of relaxation,” Briefer said, “especially when a strongly negative situation (such as moving all the horses away) is followed by a low-intensity, positive-emotion situation.”

Vocal sounds in positive situations were generally lower in frequency than in negative situations, and they were shorter in duration.

“Horses can communicate their emotions through their behavior and their vocalizations,” Briefer said. “Emotional expression is important for regulating the interactions between individuals and is therefore a crucial phenomenon in social species.”

About the Author

Christa Lesté-Lasserre, MA

Christa Lesté-Lasserre is a freelance writer based in France. A native of Dallas, Texas, Lesté-Lasserre grew up riding Quarter Horses, Appaloosas, and Shetland Ponies. She holds a master’s degree in English, specializing in creative writing, from the University of Mississippi in Oxford and earned a bachelor's in journalism and creative writing with a minor in sciences from Baylor University in Waco, Texas. She currently keeps her two Trakehners at home near Paris. Follow Lesté-Lasserre on Twitter @christalestelas.

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