Q: I'm wondering if there is any evidence that horses learn by observing other horses? I've been working with my 17-year-old Thoroughbred to get him over his fear of trailering, and we had gotten to the point where he would calmly enter the trailer and stand still. But when it was time to back out, he would take a couple of steps, then suddenly rush out the rest of the way in a panic.
One night I was walking him past a trailer when some other horses were unloading. He stopped on his own and watched intently as two horses unloaded calmly and quietly. The interested look on his face seemed to say, "Oh! So that's how it's done!"
The next day when I took him into the trailer and then tried to unload him, he calmly backed out one step at a time on command. He'd never done this before! Is it possible that he learned something from observing his herdmates, or is it just a happy coincidence that he started unloading perfectly?
A: First, you are to be congratulated on teaching your to horse to load calmly onto the trailer. I am sure that without this basis he would not have learned to unload so well.
Your question of whether horses can learn by observing other horses is interesting. Five years ago, I would have said that no one had been able to prove that they do, but recently an equine behaviorist in Germany, Konstanze Krueger, PhD, demonstrated that under the right circumstances horses can learn by watching others, a kind of social cognition that had already been demonstrated in a variety of species including primates, rats, chickens, dogs and cats.
Krueger found that a horse who watched another herdmate "join up"---that is, approach a person in the center of a round pen---would do the same more quickly than a horse who had not observed the scenario. The caveat was that the observing horse had to be subordinate to the demonstrator horse. In other words, this "observational learning" did not happen when a horse watched another who was lower in the hierarchy.
Prior to Krueger, all of the experiments into this behavior had involved visual or location learning, such as turning right or left or choosing the black bucket rather than the white bucket for a food reward. In your case, however, a more purposeful action like leaving the frightening trailer is more likely to be learned by observation.
That being said, you did not mention the style of trailer that you use, and that can be important. Horses are often reluctant to exit a step-up trailer, presumably because they cannot see where the ground is behind them. Sometimes it helps to back the trailer up to a mound of dirt so the hooves can easily reach firm footing. Perhaps that might be something to keep in mind as you train in the future.
Finally, be sure that your horse does not watch another horse misbehave. I bet they can learn bad things by observation, too.
Katherine A. Houpt, VMD, PhD