Q.I saw a trainer “habituating” a mare to scary objects at a clinic last year. When he was done with the process, the mare looked as if she’d simply given up or zoned out about the tarp-flapping, etc., which to me looked a lot like the “learned helplessness” I’ve read about on Approaches that could lead to learned helplessness seem unethical. Is it possible to desensitize a horse in a welfare-friendly way?

—Carole, via e-mail

A.Unfortunately, in the dog and horse training worlds there has been a fair amount of misunderstanding and misapplication of the scientific principles and terminology of animal learning. So your question offers an opportunity to explain these very important principles and their implications.

In learning science, habituation refers to a progressive decrease in one’s response to exposure to a stimulus over time. In the horse world, we most often think of habituation as that to nonharmful stimuli to which horses innately and almost reflexively react. With repeated exposure below the threshold for escape or panic, the horse’s response to the stimulus decreases gradually and may disappear, such that we might say the horse is “getting used to it.”

I recently observed this when watching a 24-hour video of a horse. The horse was brought to a new facility and placed in a stall, which happened to be right next to a very noisy thermostatically controlled heater. The first couple of times the heater kicked on, the horse startled and retreated to the far side of the stall, where he froze in an alert posture, staring in the direction of the fan. Over the 24 hours, his response to the heater turning on became less and less noticeable, such that after about 12 hours I could not tell from his behavior alone that the heater had kicked on. So this horse habituated to the heater motor noise and vibration.

Well-done, judiciously paced introduction to a wide selection of circumstances is the ideal goal with any horse. With a horse of a naturally mellow temperament, systematic habituation to all sorts of situations can lead to what we call a “bombproof” horse. The horse reaches a point where his initial reaction to a completely new stimulus seems muted compared to that of other horses, and habituation to each successive stimulus or situation may become much more efficient. This is especially important for kids’ horses, police horses, and therapy horses.

As we all know, repeated exposure to nonharmful stimuli does not necessarily lead to habituation. In fact, the opposite response, called sensitization—an increased rather than decreased reaction—can occur. The initial innate response to the particular stimulus could have been fairly neutral, but because of circumstances and associated events, fear and anxiety lead to an increased response. In a training context, the goal would be to introduce the stimulus or situation in a measured way, below the escape -threshold, so as to best facilitate habituation and avoid sensitization.

Should a horse become sensitized, trainers can perform a behavior modification procedure called systematic desensitization to get back to baseline innate reaction and then hopefully get going in the desired direction of habituation, reduced reaction, or no reaction.

The common horse examples of sensitization requiring systematic desensitization are the aversions horses so easily develop to procedures such as clipping, veterinary treatments, and trailer-loading. This skill or art of achieving habituation and avoiding sensitization involves instantly recognizing the subtle signs of comfort vs. fear and simultaneously adjusting the pressure and/or adding positive distractors/reinforcers so as to keep the horse below the threshold for escape behavior or panic.

Learned helplessness refers to a state of significantly reduced response resulting from the animal’s inability to affect its condition or environment. In the context of negative experiences, the -phenomenon results from repeated exposure to unavoidable, inescapable painful or fear-inducing stimuli or situations. The animal essentially shuts down behaviorally, no longer trying to escape or avoid, and enters a state of behavioral depression. Learned helplessness can be situation-specific, but most often in psychology the term learned helplessness is used to describe a generalized “shutdown” or depression and apparent inability to act.

We know a lot about this phenomenon in many animal species, as scientists have used animals as research models for studying human psychopathology (mental and/or behavioral disorders), including the testing of psychopharmacological interventions for anxiety and panic disorders, phobias, and depression. Learned helplessness is a psychopathological condition. In addition to depression, it can lead to behaviors such as unpredictable bizarre “acting out,” self-mutilation, inability to learn and work, stereotypies (repetitive behaviors that serve no function), and health effects such as gastric ulcers and suppressed immune function.

So you are right, I think most of us would agree that learned helplessness is not a good state of welfare for our horses. And although practices deliberately aimed at producing such a state still exist in certain segments of horse training, I like to think these days that fewer and fewer horses are exposed to training with learned helplessness as an intended objective. Such techniques include severely restraining the horse (hog-tying or burying in grain or sand tanks) and then presenting the overwhelming stimulus until the horse submits. In learning science, this “sink or swim” approach is called flooding and is not recommended as a humane training method. The practice known as imprint training, in which a newborn foal is restrained and forced to tolerate/submit to human handling, is essentially intended flooding.

But, unfortunately, many training practices meant to habituate or to desensitize can easily go wrong and result in varying degrees of learned helplessness. These include methods that incorporate injudicious negative reinforcement (application of pressure until the horse yields) without ample positive reinforcement (rewards when the horse does the desired behavior) to maintain motivation and/or that depend heavily on restraint or incorporate punishment.

Many classically trained behaviorists working with horses worry that some popular clinicians and equine educators promote methods that put the less-skilled horse owner or handler at risk of inducing learned helplessness. When trying to use negative reinforcement alone to gain a horse’s compliance with mildly aversive procedures, for instance, one can easily sensitize the horse, essentially teaching escape and avoidance behaviors. This happens a lot! For example, some clinicians teach negative reinforcement techniques to tolerate ear clipping, injections, oral medication administration, etc. This can be done, but it requires extraordinary skill. The timing must be perfect, and if you can’t ride out expected escape behavior, you can very quickly create a wreck. Also, breeds and individual horses within breeds, as has been shown for many species, appear to vary in their ability to handle these methods and inadvertent training mistakes. For example, a Quarter Horse or Standardbred is more likely able to handle negative reinforcement and punishment than the typically more sensitive Thoroughbred or Arabian.

Decades of scientific research document all these learning phenomena that, for the most part, have yet to be introduced to equine education. For example, there are 10 characteristics of habituation, each with very interesting and useful animal training and welfare implications. Behaviorists working with horses recognize these characteristics in their subjects. Hopefully, with increasing interest in learning science, equine educators, trainers, and veterinarians will more fully embrace and teach scientific learning principles. So again, thank you for bringing this up.