Principles of Learning Theory in Equitation

Revisiting the ISES Principles, A.N. McLean, P.D. McGreevy, J.W. Christensen

The following 10 training principles are presented as ‘First Principlesfor all horse training interactions. As first Principles, these stand as non-negotiable obligations for trainers to maintain optimal welfare in trained horses as well as optimal training efficiency. These Principles are presented as further refinements of the original 8 Principles on the ISES website and in peer-reviewed literature (McGreevy and McLean, 2006). 

Training Principle 1 – Take into account the horse’s ethology and cognition

DOES YOUR TRAINING DEMONSTRATE: recognition of Ethology and Cognition?

Ethology is the study of animal behaviour that provides information on how animals have evolved to live. It helps to explain natural equine social structures and behavioural needs. Since horses need the company of their own species and readily form attachment bonds, isolation is detrimental. They have evolved to walk and graze for about 16 hours per day.

Cognition refers to the ways animals process information about the world. Compared to humans, horses’ prefrontal cortex is relatively small, so they may not experience events as we do. They excel at memorising and recognising stimuli that trigger certain responses, particularly those that keep them safe. We must be careful not to overestimate equine intelligence and to say things like “he knows what he did wrong”, especially when trying to justify punishment. Equally, we should not underestimate cognitive abilities by supposing that horses do not have emotions.

WELFARE IMPLICATIONS: Isolation and restricted locomotion and foraging have negative impact on horse welfare. Similarly over- or under- estimating horses’ intelligence also can have negative welfare implications.

Training Principle 2 - Use learning theory appropriately

DOES YOUR TRAINING DEMONSTRATE: the appropriate use of Habituation, Sensitisation, Operant conditioning, Shaping and Classical conditioning?

Habituation refers to the process of response reduction, which can occur after repeated exposure to a particular event or stimulus. Horses are innately fearful of new/unfamiliar things (i.e. they are neophobic) and may react to various stimulus characteristics, such as size/magnitude, novelty, proximity, and sudden appearance or occurrence. Objects that are moving, especially if erratic and/or coming towards them, may be hard for them to identify, even when familiar. 

A range of desensitisation techniques can be used to achieve habituation. Systematic desensitisation, approach conditioning, overshadowing, counter-conditioning, and stimulus blending are some methods of desensitisation. See Table 1 for further explanation and practical examples.

Sensitisation is when the responses made by an individual increase, i.e. become more intense. If an individual experiences a series of arousing attractive or aversive stimuli, sensitisation describes the likelihood that it will respond more quickly or with more intensity to these stimuli in the future. This increased response may generalise to a whole class of stimuli.

Operant conditioning describes training using rewards and punishment. There are 4 subsets (see Table 2 for practical examples): 
  1. Positive reinforcement: is the addition of something the horse values to increase the occurrence of a desired behaviour. Primary positive reinforcers are resources that horses naturally value such as food and gentle touch. Training becomes more efficient if the reinforcement is given immediately at the onset of the correct response. Secondary positive reinforcers can also be used but have to be reliably linked to primary reinforcers. These often take the form of auditory stimuli, such as a clicker or a consistent vocalised sound made when the desired response is performed by the horse.
  2. Negative reinforcement is the removal of something the horse wants to avoid to increase the occurrence of a desired behaviour. Negative reinforcement in horse training often relies on the use of pressure and it should ultimately be very subtle. Pressure motivates horses but the release of that pressure is what trains them. Applying pressure for inter-gait and intra-gait transitions relies on the trainer beginning with a light pressure cue followed by the maintenance, repetition or increase of the pressure and then the release at the onset of the desired reaction. 
  3. Positive punishment is the adding of something aversive after an undesired behaviour has been performed in order to decrease the likelihood of that behaviour occurring in the future. Positive punishment can have negative welfare implications and should be avoided. If used, it should be carefully timed to coincide with the occurrence of the undesired behaviour.
  4. Negative punishment is the removal of something the horse values after an undesired behaviour has been performed in order to decrease the likelihood of the occurrence of that behaviour in the future. Negative punishment is rarely used except for prompt removal of attention or food to suppress a behaviour.
Timing is important for all types of operant conditioning: the reinforcing or punishing stimulus must occur in connections with the targeted behaviour. 

Classical conditioning is the process by which an association is made between two stimuli. For example, the animal is presented with a neutral stimulus (e.g. a visual signal that does not per se elicit a response from the horse) and this is followed by a biologically relevant stimulus (e.g. an aversive stimulus such as pain or a pleasant stimulus such as food or freedom) and the animal links them together. In the future the neutral stimulus is responded to by the horse. In equitation, classical conditioning describes situations where horses respond to light cues or signals given by the rider or handler. When first used, these must be carefully paired with the signal known to already elicit the response for the initial association to occur. For example, a verbal command can be used to slow/stop the horse if the command is paired with a rein signal to which the horse has already learned to slow/stop. After the association has been created the verbal command can be used without the rein signal to stop/slow the horse.

WELFARE IMPLICATIONS: The misuse of pressure/discomfort has the potential for serious welfare implications.

Training Principle 3 - Train easy-to-discriminate cues

DOES YOUR TRAINING DEMONSTRATE that operant and classically conditioned signals are easily discriminated?

Because of the large number of responses required in horse training, (especially under-saddle), it is important that all signals are as clear and as different as possible to enable the horse to discriminate them. This is important in order to avoid confusing the horse, which can result in undesired behaviours and stress. 

WELFARE IMPLICATIONS: Not using clear and separate signals can lead to confusion and stress and consequently horse responses that compromise performance and rider safety.

Training Principle 4 - Shape responses and movements

DOES YOUR TRAINING DEMONSTRATE: that, for any trained behaviour, training begins by reinforcing basic attempts at the target behaviour and then gradually improving approximations of that behaviour?

It is important to have a plan when training a horse to perform a new response. The horse’s initial responses should be rewarded. As training progresses the horse should only be rewarded for responses that become more and more similar to the ultimate goal.

WELFARE IMPLICATIONS: Poor use of shaping can lead to confusion and responses that compromise equine understanding and performance.

Training Principle 5 - Elicit responses one-at-a-time

DOES YOUR TRAINING DEMONSTRATE: that individual cues/signals are separated in time from each other?

Giving the horse multiple signals at the same time can result in a reduction in responding of any required behaviour. This is because the horse is unable to process two or more signals concurrently as both compete for the horse’s attention. Especially the use of opposite signals (such as acceleration and deceleration) at the same time should be avoided. In the early stages of training, signals should be well separated however eventually they can be given closer together.

WELFARE IMPLICATIONS: The use of opposite signals at the same time can confuse the horse, through weakening the trained link between signal and behaviour/response, and quickly lead to stress and consequently responses that compromise horse performance and welfare, and rider safety.

Training Principle 6 - Train only one response per signal

DOES YOUR TRAINING DEMONSTRATE: that each signal elicits a single response? 

While each response may be elicited by a variety of signals (i.e. rein cue or leadrope) it is most important that each signal elicits only one response. If the same signal is used to elicit more than one response, confusion begins to set in as predictability decreases.  

WELFARE IMPLICATIONS: The use of ambiguous rein and leg signals lead to confusion, stress and responses that compromise performance and rider safety.

Training Principle 7 -  Form consistent habits


When training new responses it is important that the same signals are used on the same part of the horse’s body, or in the same location relative to the horse’s body and that all contextual aspects such as place, equipment and person are kept constant. This is because during the acquisition of new responses, all contextual information is initially included in the array of stimuli associated with the particular response, and maintaining consistency promotes efficient uptake of the associated cue and avoids excessive stress of prolonged training. Once each response is reliably given in response to the signal used, contextual aspects can be gradually removed. Similarly when training inter-gait and intra-gait transitions, consistency in both the delivery of associated signals and the timeframe in which the responses are elicited and reinforced is essential to promote efficient learning and to avoid confusion. 

WELFARE IMPLICATIONS: Inconsistent training can lead to dull responses that compromise understanding and clarity and therefore result in stress and confusion and/or lead the rider to use stronger rather than lighter cues.

Training Principle 8 - Train persistence of responses (self-carriage)

DOES YOUR TRAINING DEMONSTRATE: the continuation of locomotory responses so that the horse learns to ‘keep going’ in speed, line and posture to avoid any need for constant rein or leg signaling and reduce the risk of the horse stopping responding to the signals. This outcome is an important goal in shaping of equitation responses.   

WELFARE IMPLICATIONS: The consequences of a lack of self-carriage range from dull responses to hyper-reactive responses that compromise welfare, performance, and rider safety.

Training Principle 9 -  Avoid and dissociate flight responses

DOES YOUR TRAINING DEMONSTRATE: an absence of flight responses? Flight responses have unique characteristics. They tend to be difficult or even impossible to remove, and may reappear spontaneously. Training processes that involves systematic/deliberate triggering of fear responses should be avoided because fear inhibits learning and reduces equine welfare. 

Flight response behaviours are often accompanied by:
  • Increased HPA-axis activity (raised catecholamine (e.g. adrenaline) and glucocorticoid (e.g. cortisol) levels)  
  • Increased muscle tone – preparedness for flight/escape 
  • Aggression related behaviour 
  • Displacement behaviours and 
  • Behaviours arising from confusion and stress
A horse that frequently shows flight responses tends to be stressed. Frequent and/or chronic stress can lead to one or more of the following:
  • Learning and memory deficits 
  • Compromised immunity 
  • Digestive disturbances 
  • Redirected aggression 
  • Ritualisation of the original behaviours indicative of stress (possibly developing into stereotypies)
WELFARE IMPLICATIONS:  Horse training should not result in flight responses. Stress results in problem behaviours (including escape and aggression). Both acute and chronic stress have a negative impact on horse welfare.

Training Principle 10 -  Demonstrate minimum levels of arousal sufficient for training

DOES YOUR TRAINING DEMONSTRATE: appropriate relaxation? 

Trainers should be able to show that the horse is as relaxed as possible during training. Whilst it is widely agreed that certain levels of physical and mental arousal (e.g. muscle tone and attentiveness) are necessary for learning to take place, it is important these levels are not exceeded resulting in a negative impact on learning, training and horse welfare. 

WELFARE IMPLICATIONS: Whilst insufficient arousal may lead to lack of motivation for learning, excessive arousal may compromise welfare and be related to stress (acute and/or chronic) with associated behaviours such as aggression, flight or learned helplessness).

Table 1. Examples of desensitisation techniques

Technique Description and example
Systematic desensitisation The term refers to a gradual habituation to an arousing stimulus. Systematic desensitisation is a commonly used behaviour modification technique for the alleviation of behaviour problems caused by inappropriate arousal. In a controlled situation, the animal is exposed to low levels of the arousing stimulus according to an increasing gradient, and rewarded when it remains relaxed or shows an appropriate response. An increase in the level of the stimulus is not made until the animal reliably fails to react to the previous level. In this way the technique aims to raise the threshold for a response.

Example: The horse is fearful of aerosols. As a first step a handler brings an aerosol close to the horse and strokes it on the body with the bottle (no spraying). This is to habituate the horse to the visual characteristics of the aversive stimulus. When the horse shows no avoidance responses, a next step is to stand some meters from the horse and spray in the opposite direction, preferably with water, i.e. a fluid with no smell. This is to gradually habituate the horse to the aural characteristics of the aversive stimulus. The handler gradually steps closer to the horse, and when the horse shows no responses to the handler standing next to it and spraying in the other direction, the handler can gradually spray closer to the horse. Before spraying directly on the horse’s coat, the handler should stroke the horse with a hand and spray gently on the hand. At all stages, it is important to ensure that the horse is only rewarded for appropriate responses, i.e. the aerosol should be removed or spraying terminated when the horse stands still. Positive reinforcement (e.g. food, wither scratching) can be used as an additional reinforcer for appropriate behaviour. 
Counter-conditioning To “condition” means to train, and “counter” means opposite. Counter-conditioning refers to training an animal to show a behaviour (e.g. eating) which is counter to the one that the trainer wishes to eliminate (e.g. flight), i.e. producing an incompatible response to a stimulus that is expressed in preference to the undesired response. This can be done by forming an association between the feared stimulus and a pleasant stimulus so that the fear-eliciting stimulus comes to predict something good to the horse. As soon as the horse observes or encounters the fear-eliciting stimulus, we introduce something that produces a pleasant emotional reaction (e.g. food). Over many repetitions, the animal learns that whenever the fear-eliciting stimulus appears, something pleasant happens. Eventually, the process produces a neutral or positive emotional reaction to the sight of the previously feared or disliked event, person, place or object. This technique is widely used in combination with systematic desensitisation. By ensuring that the preferred behaviour is more rewarding, the animal learns to perform the new behaviour when exposed to the problematic stimulus.
  Example: A horse becomes anxious when it hears the bell before the competition, which compromises good performance. Through counter-conditioning, positive outcomes such as a food reward or termination of work are associated with the sound of the bell so that it becomes a predictor of a positive event. Once the horse shows a neutral or positive emotional state at the sound of the bell, it will no longer be tense before a competition. 
Overshadowing Overshadowing describes the phenomenon whereby habituation to the least salient stimulus takes place when two or more competing stimuli are presented concurrently. In the practical setting of horse training, overshadowing provides an effective method of desensitising horses to aversive stimuli such as clippers, needles or other invasive procedures. These aversive and invasive procedures frequently elicit a withdrawal response in the horse. Similarly, when a horse learns to respond to lead rein signals of forward or reverse, they are initially acquired because they too produce a withdrawal response, which through the refinement of further training, diminish to light lead rein cues.  Therefore outcompeting the withdrawal response elicited by the clippers through the use of the lead rein cues of forward and reverse can be a useful overshadowing protocol. The horse must therefore be reliably trained to step forward and back from lead rein cues via operant conditioning. Overshadowing differs from systematic desensitisation and counter-conditioning principally because of the use of the lead rein mobility responses.  
  Example: The horse is needle–shy and when it sees the person approaching with the syringe it becomes hyper-reactive and pulls against the handler’s lead rein pressures in its attempts to escape. The needle pricking the horse’s skin also induces a severe flight response.  The solution in terms of overshadowing involves the horse being trained to step back and forward from lead rein pressure so that the horse’s reaction is elicited from the lightest of lead rein cues. Next the person with the syringe approaches the horse with the syringe and as soon as the horse displays even the smallest of fear responses, the person with the syringe stops and remains immobile so that the distance between the horse and the syringe stays constant. The horse is then signalled to step back one step and perhaps then forward a step. Initially the horse is delayed and its reaction to light pressure is ignored because his attentional mechanisms are overshadowed by the syringe so the handler then increases the motivational pressure of the lead rein so that in a few repetitions the horse is now responding to light signals of the lead rein. The horse’s fear reaction to the syringe has, at this distance, decreased. The syringe is now brought closer to the horse and as soon as the horse shows the slightest fear reaction, the process is repeated. This process continues until the horse’s response to the syringe has diminished. Positive reinforcement at each increment enhances the acquisition of the lowered arousal. These lead rein signals and their associated mobility responses soon achieve stimulus control of the horse’s locomotion and thus overtake the syringe or clippers for salience. The less salient stimulus either no longer elicits or greatly diminishes withdrawal from the original, more salient stimulus. The procedure however is most successful if the process is begun at the lowest levels of arousal.
Approach conditioning This method exploits the natural tendency of horses to explore and approach unknown objects, in combination with systematic desensitisation. The horse is stimulated by the rider or handler to approach the object of its fear, which is retreating as the horse approaches. The horse may then be signaled to stop before it reaches its fear threshold, so that the object retreats even further. The horse is then signaled to catch up. As soon as the horse slows its approach it is deliberately stopped and this is repeated until the horse becomes as close as possible to the object. The method has been successfully applied to horses that are afraid of tractors and diggers, motorbikes and trams. 
  Example: the horse is fearful of tractors, motor bikes or trams and attempts to escape, in order to lower its fear. However if the process is reversed whereby the horse approaches the retreating machine, this can have the opposite effect: its fear is lowered because the machine itself escapes. This technique has been used in training police horses. In best practice, when the horse closes in on the machine it is stopped, thus allowing the machine to increase its distance from the horse. The horse is then stimulated to approach again and each time it draws closer to the machine before it is stopped. Stopping the horse apparently increases its motivation to approach. This is continued until the horse actually makes contact with and investigates the machine.
Stimulus blending The method uses a stimulus to which the horse has already habituated to systematically desensitise the horse to the original fear-inducing stimulus. The fear-inducing stimulus is applied gradually at the lowest threshold of fear simultaneously as the known, non-fear-inducing stimulus is applied, and then systematically increased in intensity. For example a horse may be afraid of aerosol sprays but unafraid of being hosed. The aural and tactile characteristics of the aversive stimulus (e.g. aerosol) are gradually mixed with the habituated one (e.g. the hose) making identification of the formerly aversive one difficult and perceptually different. The old benign stimulus can then be diminished and finally terminated after which the horse will show habituation also to the new stimulus.
  Example: the horse is fearful of aerosols. In this technique, a stimulus to which the horse has already habituated is used to blend with the problem stimulus. If the horse is used to hosing on its body, the aerosol is introduced during hosing and on the hosed patches of skin. The sound and feeling of the usual water on the horse’s body will blend with the novel sound and tactile feeling of the aerosol, making it less distinct. The hosing can then be terminated while the spraying continues.
Adopted from From McLean & Christensen, 2016. The application of learning theory in horse training. Appl. Anim. Behav. Sci. (in press)

Table 2. The quadrant of reinforcement and punishment
  Reinforcement Punishment
  Increasing the likelihood or intensity of a behaviour Decreasing the likelihood or intensity of a behaviour
 Negative (Subtraction)
The removal of an aversive stimulus to reward a desired response.
The removal of a desired stimulus to punish an undesired response.
  Example: Rein tension is applied until the horse stops and the removal of the tension rewards the correct response.
Example: The horse paws and so food is withheld.

 Positive (Addition)
The addition of a pleasant stimulus to reward a desired response.

The addition of an aversive stimulus to punish an undesired response.
  Example: The horse approaches when called for and receives a carrot to reward the response. Example: The horse bites and receives a slap on the muzzle.