Your mare just walked calmly past that frightening yellow flower pot. Your gelding just placed one foot up on the trailer platform. And so you reward your horse’s behavior and bravery with soft, soothing, encouraging words.

Or do you? As it turns out, soothing, verbal praise might not convey a message of reward to horses. According to a group of international behavior researchers, it seems that horses don’t naturally understand the difference between our soft tones and our snippy ones.

"Based on our study, most horses did not appear to inherently distinguish between harsh vocal cues and soothing vocal cues," said Camie R. Heleski, PhD, a researcher at Michigan State University (MSU), at the 2012 International Society for Equitation Science conference. "Or if they did, it did not influence their performance of learning and performing a frightening task."

Heleski and a team of international researchers from MSU, the University of Delaware, the University of Göettingen (Germany), and the University of Milan (Italy) tested 95 horses of various breeds and ages at different locations in the United States and Europe. Researchers taught horses to cross a plastic tarp placed on the arena floor. To half the study horses the researchers said, "Good horse," in a soothing voice when they took a step toward the tarp. For the other half, the researchers loudly said, "Quit it!" when the horses took a step in the right direction.

Interestingly, the team found that, statistically speaking, horses learned to calmly cross the tarp regardless of whether they heard harsh voices or soft voices, Heleski said. In fact, a closer look at the figures reveals that the average time to learn to calmly cross was actually lower in the harsh voice group, although the difference is not statistically significant. And a similar number of horses in each group never succeeded in crossing the tarp calmly within the 10-minute limit.

What’s more, Heleski said, all the horses had similar heart rates regardless of study group. So the researchers concluded that the ones hearing the softer tones were not less stressed than those hearing the harsh tones.

The only difference researchers found during this study was one that they hadn’t anticipated: Warmblood horses learned to cross the tarp about five times faster than hot-blooded horses (e.g., Arabians and Arabian-types), Heleski said.

"These results were really contrary to our hypothesis," Heleski said. "But it’s important we recognize them. Because if horses are unable to understand this difference (between harsh and soft vocal cues), handlers can make poor assumptions that could potentially lead to unfair training."

Even so, horses might be able to be conditioned through training to recognize a soothing voice as rewarding, she added. "I still believe that horses can learn the difference between harsh and soothing tones if there are consistent reinforcements," she said. "In spite of our findings, I still use harsh and soothing vocal cues with my horses and lesson horses."

Heleski’s research on this topic is ongoing, she said.