how cribbers learn

Horses with stereotypies, such as cribbing or windsucking, sometimes get a bad rap. Some equestrians think they’re problem horses, and even scientists contend that they have difficulty learning. But Swiss researchers recently confirmed that cribbers learn just as well as noncribbers, as long as their stress levels are well managed.

“Crib-biters and windsuckers seem to be more sensitive to stress, which might mean it takes them longer to get used to a particular learning environment, but their cognitive function is clearly intact,” said Sabrina Briefer Freymond, PhD candidate, a researcher at the Agroscope Swiss National Stud Farm, in Avenches.

In their latest study on stereotypical horses, Briefer Freymond and colleagues showed that cribbers learn tasks—and even task reversal (doing the opposite of what they’d just learned to do before)—in the same amount of time as noncribbers. That’s in contrast to what previous studies have shown, she said. However, there was one significant difference: she let the cribbers crib.

“We should not be preventing them from cribbing while they’re learning,” she said. “On the contrary, we need to do what we can to reduce stress for them in their learning environment.”

Stress management for these horses is critical, said Briefer Freymond. “This is such an important point. We have to give the cribbers confidence, reducing their stress so that they can learn a difficult task. That means not only allowing them to crib while they learn (which lets them cope with the stress), but also being precise in our training, not confusing them, and respecting learning theory.”

How the Study Worked

Briefer Freymond and her fellow researchers designed an automated testing setup (to prevent human influence) in which horses would find food in one of two wooden boxes. The box openings were covered with flaps, and there was the smell of food in both boxes (inaccessible food in one box, accessible food in the other) to prevent the horses from finding the right box by following odors. Horses had to choose the correct box (to find the food reward) by recognizing a black-and-white shape on the box. A similar, but different, black-and-white shape appeared on a to the wrong box (where they wouldn’t find a food reward).

Once the horses had learned this task, the researchers then switched the symbols—the “correct” symbol now meant “incorrect” and vice versa—in a task reversal test. The researchers then repeated both parts of the test (initial learning plus the task reversal) with a whole new set of black-and-white shapes.

Briefer Freymond said the task reversal tests were critical in this experiment because scientists have claimed that stereotyping horses fall easily into habits and would have a hard time changing them. If that was true, the stereotypical horses would take much longer to learn where to find the food in the task reversal test.

how cribbers learn

However, that’s not what happened. On the contrary, the cribbers learned the task reversals just as fast as noncribbers, Briefer Freymond said.

In fact, the only difference between the learning capacities between the groups was that the cribbers took a little extra time to learn the flap-opening task in the habituation phase before actually starting the true part of the experiment, she said.

And interestingly, she said, the horses in both groups were faster to pick up the task inversion the second time compared to the first. “Clearly the horses had ‘learned to learn,’ ” she said.

Practical Stress Management

While the cribbers learned as well as the noncribbers, that doesn’t mean they’re the same as noncribbers in a learning environment, Briefer-Freymond cautioned. They’re sensitive to stress and need particular attention to stress management, especially in a new environment.

“A few years ago I showed that crib-biting horses have less stress if they’re allowed to crib while learning compared to those that weren’t allowed,” she said. “In this new study, we see that the cribbers take more time to succeed in the habituation and pre-training phases of the experiment than the controls, which suggests that they are, in fact, more sensitive to stress and need more time to habituate to something new.

“But in the task reversal phase,” she said, “they perform just as well as the controls, showing that once they’re motivated and have understood the task, they’re capable of learning something quite difficult. And actually, one of the crib-biters in our experiment learned the second task reversal test in a single try. That was incredible.”

Biologically speaking, the brain modifications caused by dopamine changes in stereotypic horses might primarily affect specific parts of the basal ganglia, which deals with stress management, and not necessarily other parts of the basal ganglia that affect flexibility in learning per se, said Briefer Freymond.

The study, “Stereotypic horses (Equus caballus) are not cognitively impaired,” was published in Animal Cognition.