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Oveshadowing, the most useful training tool you could learn this year!

This is the full version of the article printed in the March 2010 issue of Horses and People Magazine.

Overshadowing is a technique we have developed at the AEBC to habituate horses to objects and situations they find scary or aversive to be correct. It is based on the scientific principle that when the horse is receiving two or more stimuli at any one time, one of them will overshadow or override all others. Overshadowing applies to people as well! As much as we like to think we can do two things at once, the truth is we can only concentrate on one at a time.

Typically the horse will concentrate on and respond to the stimulus he finds “scariest” (most aversive is the correct term). Horses are flight animals and become easily frightened, so it is not surprising that there will be many situations where the horse can become controlled by something other than the human handler.
For example: your horse is parking perfectly until someone turns the clippers on, at which time he focuses all his attention on the terrifying object, tries to run away, and does not respond to your stop signals anymore.

The solution is to habituate the horse to the clippers (or whatever he finds frightening), but how can we do it when he responds with so much fear and we lose control?

In order to habituate the horse to anything, the first thing we need to do is stop him from running away. Traditional methods typically involve immobilizing the horse using force of one kind or another, for example using hobbles, ropes, crushes, a twitch, etc. An extreme example would be lying the horse down and preventing him from getting up. Regardless of the questionable ethics, the problem is that using force you are only ever lucky if it works, and there is a great potential of increasing rather than decreasing the horse’s level of fear and putting everyone in a dangerous situation.

This overshadowing technique  is an effective, safe and humane way to habituate the horse to any situation or object he finds aversive. Since there is something overshadowing your signals (the clippers for example), the task should be to reverse the effect, that is make your signals overshadow the clippers. Through re-training stop, step back and go in a very controlled way while the frightening object approaches, your horse can learn to be more controlled by your lead signals than by the scary object. In a short time, he will habituate to it, and in a few sessions he will actually lose his fear, in such a way that after overshadowing you won’t even need to restrain him in that situation.

Before you start:

At the AEBC we have used this technique to re-train hundreds of horses who were scared of a myriad different things or situations, from clippers to race barriers, and this technique has always worked and can be adapted to any situation, as long as you always adhere to a few principles:

  1. The responses we use to overshadow the scary situation are those that delete flight and tension  – stop, step back, and head control. We will use these in a very controlled manner (one step forward-release, stop- release, one step back-release etc) so it is essential to train these responses thoroughly in neutral situations to obedience level (where the horse responds immediately to light lead rein signals) before using them to overshadow. (See Parts 1 to 6 of Elsa’s Setting Good Ground Rules training series).
  2. Above all you must not flood or overwhelm the horse, for example get the scary thing so close to him that you have no hope of controlling him, because apart from creating a dangerous situation, your failure to control him will actually reinforce his fear and flight behaviour is likely to get worse. Progress must be achieved very gradually, and this is done by breaking down the situation into stages and re-training the horse at whichever stage he starts to be controlled by the object or situation. If this happens to be 70 metres away, that is where you would begin. This will ensure you keep the horse’s fear level at a minimum, and will help you achieve relaxation quickly.
  3. Work in a safe area, a yard, large stable or wash bay for example, with safe non-slip footing and at least one wall so you can stand next to the horse and don’t have to worry about him moving sideways (it is simpler for the handler to step in forward/back without having to worry about him moving sideways). Always wear a helmet, gloves, appropriate clothing and footwear.
  4. Have an assistant. One person (the more capable trainer) handles the horse, and the assistant handles the “scary thing” (clippers, spray bottle, hose, etc). For safety reasons, both handler and assistant must always be working from the same side and communicate all the time. Once again the handler must be capable and experienced in training a horse in hand to obedience level.
  5. Use a halter, bridle or a stallion bit (preferably a rubber coated one (only ever use stallion bits with a straight mouthpiece, as curved mouthpieces are too severe and could cause tongue injuries). Practice training in hand with this equipment until your horse responds calmly and obediently to light lead signals. You can also carry a dressage whip, or have one handy in case you need to reinforce your stop/go signal.
  6. Stand on the nearside facing the horse (in the same position we have explained before for all other ground work training – lead rope in the left hand and if using an whip, have it in the right hand held as if it were holding a tennis racket (i.e facing in-front of you, not behind you) keeping the wall on the horse’s right side.

The overshadowing technique:

When faced with a scary object, the horse will become tense and at worst try to flee the situation, you will notice that his responses to your stop, go and step back signals have become heavy or he may not respond at all.   In order to overshadow the aversive stimulus you must re train stop, go and step back until they are light again. Remember to rapidly increase the pressure until you get the response and then immediately release, this way your signals will once again be reduced to light aids. At the point when he is responding to light aids he will no longer be attempting to flee.   At a later stage, and when the horse doesn’t run away but still shows some fear, you can finish the habituation using head control (head down – head up) in the same way. Then you can switch to positive reinforcement so that the presentation of the scary thing is seen by the horse as sign that food is coming. This is called counter–conditioning.


Overshadow the aversive stimulus by re-training stop, go and step back until they are light again


Overshadowing with “head up-head down” works to finish the training when the horse is light but still showing small signs of fear or concern

How to do it:

First check that the go, stop and step back responses are obedient – the horse responds to light lead rope signals taking just one step at a time when you ask. You can also practice getting the horse to take half a step forwards and back repeatedly (moving one front leg only) with no real time gap between the movements. First one front leg, then the other. This is a good way to get him to concentrate fully on your signals.

The assistant approaches first:

While your horse is responding well to light go, stop and step back signals (one step at a time) ask your assistant to start approaching the horse (just the assistant, no other scary thing in sight). If during the assistant’s approach the horse becomes heavier to control – he delays his response to your aid – or shows any signs of fear, tell your assistant to stop at that distance, and train the horse to go, stop and step back until he is at obedience level again. When he is light again, ask the assistant to continue his approach, stopping to re-train at any time the horse shows the slightest heaviness (heaviness means he is starting to focus on the assistant instead of the lead rope). Continue to progress in this way until your assistant can approach and make and maintain contact with the horse’s shoulder area, without affecting your control over the horse’s legs. Don’t hesitate to use whip taps to reinforce your lead rein aids if you need to.

The key is to ensure you achieve obedience level at each stage, that is: the horse responds to light aids without delay.

Remember to give your horse breaks when you achieve an improvement, and to positively reinforce him when he responds to light aids with a “good boy” at the exact moment of the correct response followed every time by a wither scratch.

The overshadowing process continues as the “scary object”  approaches, but in order to avoid flooding, we must break down the task into stages or smaller components. I will explain:
Scary things have “scary stimuli” associated to them – there is a “visual scary” and a “auditory scary”, a “tactile scary” (and probably an “olfactory scary” also), and the way to avoid flooding is break them down and address one “scary” at a time.

In the case of clippers for example, the visual element is the clippers approaching the horse, and moving around close to him – usually with a long electric cable attached. The auditory element is the noise they make when they are working. The tactile element is the vibration when they are in contact with the horse.

So when overshadowing the clippers, you first overshadow the approach of the assistant; then his approach with the clippers visible but turned off, until the clippers turned off can remain in contact with the horse’s body (starting at the shoulder area and moving from there to other parts of his body). After that, you add the noise, overshadowing the approach of the clippers turned on – first turning them on while they are out of sight, and then approaching while they are working, until you can  make contact with his body – maybe run the clippers in the direction of the hair (without clipping) starting in the shoulder area and going further from there. After that you can go further into clipping.

The more stages or components you break the task into, the easier it will be to achieve a steady progress, so in the case of clippers you can also start with a smaller portable set of clippers that have no electric cable, make less noise and vibrate less, and when he habituates to them, introduce and overshadow the bigger, noisier clippers.
During the overshadowing, the handler needs to communicate with the assistant all the time, stopping his approach to re-train the horse to be light and controlled by the lead rein signals at the slightest sign of concern from the horse. Remember that you will have to overshadow both sides of the horse’s body. Then you counter-condition the formerly scary thing into a good thing, by now whenever you present the scary thing, food or caressing follows.

This is basically how it works, it is quite a simple principle and the process is very repetitive. It may seem like it will take a long time at first, but the results are so good that in just three or four fairly uneventful and unexciting repetitive sessions you will find that the horse stops showing all signs of fear and never needs to be restrained in that situation again.
To make this technique work for your own particular situation, all you need to do is plan how to breakdown the “scary” stimuli into small enough components and address one at a time. The list of objects and situations a horse may find scary can be as long as a piece of string!

Following are some examples of how we break down the overshadowing training in different situations.

Remember that you are aiming to achieve obedience to the handlers aids at each stage before going further. You do this by using a light aid first, increasing pressure rapidly to get the response and releasing immediately when he offers and attempt at the correct response. Always reward a light response with positive reinforcement: a “good boy” followed immediately by a wither scratch or food, this is called positive reinforcement.  If you don’t think any of these examples cover your particular situation, or you need some more help or clarification, don’t hesitate to comment here, or email us: admin@horsesandpeople.com.au. We will get back to you with a full explanation.


This is for horses that are scared of being hosed with water, and it is a great way to introduce young horses to this experience. First overshadow the visual stimuli with the hose turned off, have your assistant approaching with the hose, and moving around. Then turn the hose on and spray away from the horse, overshadow any reaction to the noise/sight before touching the horse with the water. Once the horse is relaxed, you can allow the water to make contact with the front legs, fan the stream of  water out in such a way that the water will remain in contact even if the leg moves. If the horse is afraid of the water, chances are he will try to move away and he will be heavy to correct, if he moves back you must immediately step him forward, if he moves forward or sideways you must immediately step him back. Make sure especially in the first few steps that you don’t allow the horse to remove the water from the leg. Continue stepping forward and back until the responses become light.  Once the horse has habituated to this you can start to gradually move the hose to other parts of his body in the same way.


Horses quickly learn to be scared of sprays by moving away and successfully creating distance between themselves and the spray bottle,  some become quite reactive about it. Prepare a spray bottle by filling it with clean water, so you are not wasting expensive products. Start by overshadowing the visual element of the spray bottle approaching and then making contact without spraying. Second, overshadow the noise and sight of the spray while spraying away from the horse, gradually approach the spraying towards the shoulder. When he is relaxed, move on to spraying the shoulder. As with hosing he will try to move away and you must immediately correct this, don’t allow him to change the distance between himself and the spray bottle as this will reinforce his fear. Once the horse is habituated to the feel of the water spraying on his shoulders you can gradually move to other parts of his body.


This is for horses that object to having certain parts of their body touched, such as wither, stifle area, rump etc. some people refer to these horses as “ticklish” but they can become habituated easily with overshadowing. This also includes “girthy horses”.( head shy, and hind feet are dealt with a little differently). First overshadow the approach of the assistant. The assistant then makes contact with the shoulder, if the horse is ok with this then move the hand toward the sensitive area, keep the hand in contact with that area and overshadow any reaction until the horse is light. When the horse is ok with the hand there,  move the hand closer to the sensitive part, again overshadow with steps forward and back as soon as he shows any concern. Continue moving the hand towards the most sensitive part until the horse is completely habituated to being touched there. At a later stage, when the fear signs are mild, you can also overshadow with head up and head down.


Again, horses learn to be scared of having their heads handled by raising their heads and successfully creating distance from the handler’s hand. Some then develop a strong fear association with the visual element of the hand approaching, and because of this we find it very useful to start by using a damp towel over the hand. To deal with head shy horses it is important to have trained head control thoroughly beforehand. Once again start overshadowing the hand/towel approaching, first with stepping forward and back and when he is light, with head up and down. Once you have contact you need to ensure the hand/towel remains in contact and progress to more difficult areas carefully and gradually. Once the horse has habituated to the towel, you can start to move your hand out of it in stages. You may need to be quite athletic to keep your hand in contact with the horse’s head once you start! Remember that allowing him to change the distance between himself and your hand will reinforce his fear.


For horses that kick with their hind legs when being handled, we use hosing in the way I described above. This is quite a safe way to start, and you can use steps forward and back, fanning the water so it stays in contact with the hind leg as he steps forward and back, then moving on to head up head down when he is light. After that you can use a long whip, one which is sturdy enough to maintain an even contact, and gradually get closer and closer until you feel confident enough to touch the leg with your hand. You must be aware that the horse could revert back to what he has practiced before, and try another kick during the training, in which case the handler should increase the backwards pressure rapidly and release as soon as he responds, then continue to step back and forward.  At this stage the horse may also start to ‘threaten’ to kick or not keep his leg completely still. A small vibration backwards on the lead rope should delete this, if it doesn’t, make the horse do a complete backwards step.  Then once he is calmer you can repeat the raising and lowering of his head to continue overshadowing.

Kicking is a dangerous response, and it is imperative to maintain excellent communication between assistant and handler in this case, so you can stop and overshadow at the slightest sign of fear. Make sure both handler and assistant are on the same side at all times as the assistant who will be focusing on the hind legs, will not be able to read the flight reactions of the horse.


Start in the same way, by overshadowing the approach of the assistant towards the shoulder then making contact with it and moving up towards the neck. We find it easier to inject taking a fold of skin from the neck rather than use the “tap-tap-whack the needle in” approach – the feel of holding the fold of skin probably overshadows the prick of the needle, and you can overshadow with stepping forwards and backwards, while you hold the skin. Be sure to keep the training short, and take lots of breaks, rubbing the horse’s neck to make him as comfortable as possible. We find that once the horse accepts you taking a fold of skin, the actual injection is no longer a problem.
-Elsa Willans Davis