Training Science Articles:
What is Clicker Training?
The Science Behind Learning
Creating Behavior
Eliminating Behavior
Stimulus Control
Building Behavior Chains
The ABCs of horse training
Stimulus Stacking
Dealing with Fear

Putting it into Practice, Ethically:
What is an Aversive?
Over-excited about Food?
Protective Contact
Control vs. Communication
Transition Troubles
Making it a Lifestyle
The Importance of Choice

Dealing with Fear

Make sure to read the article on Stimulus Stacking as well.

There are four basic ways of helping our horses overcome fear. Our goal is not to remove or teach them to ignore their instinct to defend themselves (through the freeze-flight-fight responses), nor to teach them to tolerate every stimuli in the world, but rather to help them build a sense of self confidence and encourage curiosity.

1) Flooding: This is an extremely common method in the horse world. The learner is presented with a prolonged (normally high) level of the fearful stimulus in a situation where escape is limited or not available at all (a round pen for example). The stimulus remains until the fear response is gone.
Advantages: This is an extremely fast method, one session can stop the fear response to that stimuli, multiple sessions can stop a fear response for many things.
Disadvantages: This puts the learner through a great deal of stress, they are extremely overthreshold (and learning can not occur over threshold). They have not learned not to fear the stimuli or become more confident, all they've learned is that there is no escape from the fearful stimuli and their freeze-flight-fight response is ineffective. Many times these fear-responses will return when the learner is no longer contained or when there is a “Stimulus Stack”.

2) Habituation: Prolonged exposure to the (normally low level) fearful stimuli, with easy escape. Gradually accepting the stimuli as safe in their own time. Much like a paddock bordering a road, a horse can run to the far side to feel more comfortable, able to move closer as their confidence increases.

Advantages: This is extremely effective and causes very low or almost no stress in the learner.
Disadvantages: This is a very slow process, things with aversive histories may never be worth their exploration. This requires some natural drive from the horse to investigate or approach, resources may help encourage curiosity. (better grazing near the road for example). If the stimuli become close to neutral it still may be mildly aversive, which could become dangerous in a stimulus stack.

3) Desensitization: Slowly increasing, controlled exposure to the stimuli, can be done at any level of ability to escape. Free, like a large field, Limited, like a round pen, or no ability, like a stall or while tied, the more limited the ability to escape the lower the threshold will become, making it more ideal to work in the largest place possible. The trainer can increase and decrease the level of exposure to the fearful stimuli based on the response by the horse. Usually removing the stimuli when the horse shows signs of relaxed (to negatively reinforce the calming behaviors), and increasing the stimuli as the horse becomes more confident.
Advantages: Works fairly quickly an observant trainer with good timing can make this go smoothly and efficiently without much stress. Doesn't require ever bringing the horse overthreshold.
Disadvantages: It requires an observant, patient trainer as this is easily turned into flooding, more and more so as the ability to escape is limited. We need to remember dealing with fear happens on the horse's time, not ours and take it as slow as needed. It also requires an adequate knowledge of body language and calming signals to be accurate. If the stimuli become close to neutral it still may be mildly aversive, which could become dangerous in a stimulus stack.

4) Counter Conditioning: Repeatedly pairing the aversive stimuli with an appetitive, any primary or secondary reinforcer. This changes the learner's opinion of the stimuli.
Advantages: This works completely, there will be no lingering fear adding to a stimulus stack.
Disadantages: The primary reinforcers may cause extreme conflict in the learner, resulting in stress and hidden emotions. If done too quickly or without taking into consideration the calming signals of the learner you may be hiding fear responses rather than changing their opinion.

As a Clicker Trainer I try to keep my horses' stress to a minimum and work hard never to let them go over-threshold (if I have any control over the situation). My goal is not to teach my horses to hide their feelings or prevent them from expressing themselves like a real horse. Rather, I want to build their confidence and inspire curiosity. I do this by mixing these methods, while I avoid flooding whenever possible, I like to make regular use of all the rest.

When time is not important I like to provide novel stimuli, silly things that could be loved or hated by my horses, provided in a corner of their field for them to explore in their own time. I may have it provide some sort of food reward, but only something moderate-low value, like hay and only while ample food is available, to prevent conflict. They will, over time, habituate themselves to these. I like to vary these up, I have swimming pools, tarps, bottles, buckets, noise makers (like wind chimes or stereos playing low level sounds), anything you can think of.

When there is something I need my horses to be comfortable with sooner rather than later I generally start with systematic desensitization, starting with the lowest possible expression of the stimuli and slowly increasing as the horse becomes comfortable. When the horse is comfortable with the stimuli (close to neutral) I will then begin to counter condition it. I wait until the stimuli is nearly neutral to reduce conflict and reduce hiding emotions. I don't want to give rewards for “looking calm”, when they aren't actually feeling calm, as that would have similar results to punishing fear responses. I like to finish off my desensitizing with counter confitioning, so I can be sure there are no longer aversive feelings in the stimulus and it won't become a part of a stimulus stack.