Feb 142010
 

For a while a conundrum has been playing with my thoughts. It all started one chilly but sunny Saturday, during an ordinary training session, whilst training a horse that for the purposes of this article we will call ‘The Pony’. It was nearing the end of the session when The Pony tripped over a protruding root an came very close to stand on my foot. In an effort to preserve my foot I quickly asked the horse to move back with a little pressure on the chest. A fairly benign act in response to which The Pony quickly ceased stumbling toward my vulnerable metatarsals and politely backed away. The training session continued without incident but a question remained in my mind.

Pressure and release is a commonly used method of horse training, within equestrian literature it is often cited as a simple but effective use of negative reinforcement. Whether it is a pressure on the chest of a horse to ask for a reverse, the use of the head collar to lead the horse, a gentle pressure on the reins to ask for a halt or the use of advance and retreat to approach a nervous horse, it is almost impossible to avoid the use of negative reinforcement in training. However until the incident with The Pony it had never occurred to me that positive punishment maybe an inextricable part of negative reinforcement. Can negative-reinforcement occur with out positive punishment? The Pony had be negatively reinforced for reversing away from me by the release of pressure, but it had been the addition of the pressure which had prevented further advancement.

Negative reinforcement is defined within all behaviour literature as the removal of an unpleasant or aversive stimulus in response to a wanted behaviour to reinforce the behaviour, and thus encourage the behaviour to reoccur in the future. This is a definition that most people are familiar with. However, the training incident with The Pony made me think – in order for something to be removed it must have been applied at some point in the past. For the aversive stimuli to be removed to reinforce a behaviour it must at some point have been applied. The addition of an aversive stimulus is the definition of positive punishment, the effect of positive punishment is that it reduces the likelihood of the behaviour it is a consequence of occurring in the future. Pressure on the chest of The Pony prevented further forward advancement towards my foot, so is it that I positively punished the forward movement? And as an extension of this thought, is it that every use of negative reinforcement begins with the use of positive punishment?

This is may seem like a conundrum based in the semantics of academic definitions but the practical consequences of positive punishment being inextricable from negative reinforcement are not dismissible. The most important practical consequence of positive punishment is that it discourages the behaviour it is associated with from occurring again. When applying the negative reinforcer, be it pressure or the advance of advance-retreat training, we must be careful that the behaviour it is being applied to is unwanted or the positive punishment would diminish a desired behaviour. The training should thus ensure that the negative reinforcer is attended to with regards to not only the timing of its release but also it’s application, this will ensure that wanted behaviours are not punished.

The problem of positive punishment being inextricable from negative reinforcement and the two training methods not being mutually exclusive is one that has impacts on training which could effect the psychology of the horse, the effectiveness of the training and the welfare of the horse. Punishment has been correlated with side effects which are important to our training of horses and must be understood to preserve the horse’s well being within training. Although this article is not the place to detail the problems and side effects of punishment I will briefly outline the most important ones below.

  • Punishment teaches only what not to do and does not suggest a more appropriate behavioural replacement for the one being punished.
  • Punishment can invoke emotional reactions in horses, such as fear or aggression. These reactions are more likely with physical punishment. In order to avoid these reactions, any punishment applied should be sympathetic to the horse’s personality i.e. how reactive they are and also to the situation. Positive punishment and negative reinforcement are both based in use of stimuli which are to a greater or lesser extent unpleasant for the horse, such as pressure, and as such it must be ensured that the horse is not stressed by the punisher in order to ensure emotional reactions are not experienced.
  • Pain-elicited aggression can be induced if painful physical punishers are used. Pain can heighten a flight/fight response and cause aggressive reactions in the horse as they try and escape the threat of pain, therefore positive punishers which cause pain should never be used in training.
  • Anxiety caused by punishment can actually impair the horse’s ability to concentrate and learn effectively. Extremes of emotion inhibit the brains cognitive abilities and thus impair attention.
  • Learned helplessness is a condition induced through the incorrect use of punishment. Learned helplessness occurs when the horse feels they cannot avoid punishment over a sustained period of time. The horse learns that any attempts to escape are futile and thus the horse will not attempt to escape or avoid the punishment, even once an escape or avoidance method is offered.
  • Avoidance behaviours – if the horse learns to associate a person or situation with punishment, the horse may logically try to avoid that situation or handler.
  • It is also possible for horses to selectively suppress the punished behaviour until punishment is less likely, either when the punishing handler is no longer present, or when the horse believes that it is less likely to be punished for the behaviour.
  • Punishment can reduce the horse’s interest in their work, if a horse is punished the horse’s motivation will be diminished and thus the horse is less likely to participate willingly in training.

If negative reinforcement by its definition begins with a positive punishment these problems that are associated with punishment are consequently also a problems intrinsic to the use of negative reinforcement. It is therefore essential that they are considered carefully if negative reinforcement is to be used in training. The application of the negative reinforcer must follow the rules of applying positive punishment if side effects are to be avoided in the horse.

The rule of applying punishment to avoid side effects are as follows, the punishment must be –

  • Immediate
  • Consistent
  • Never painful
  • Never dealt in anger
  • Specific to targeted unwanted behaviours and not delivered randomly or accidentally.
  • Never used during confusion

Obviously each horse has their own tolerance levels for different stimuli. An aversive stimulus for one horse may not be unpleasant for another. However given that negative reinforcement is based upon the release of an aversive stimulus, it is highly likely that the stimulus use as a negative reinforcer could also be a positive punisher for the horse. I would be interested to hear if anyone could think of a training scenario in which the negative reinforcer when applied could not be considered a positive punisher because I must admit I could not think of one.

To finish this article I would like to say that I don’t believe that we can avoid the use of negative reinforcement in training but any part of training that uses aversive stimuli, i.e. negative reinforcement or positive punishment should be carefully considered with regards to the strength of the stimulus and its application.

By Emma Lethbridge

www.emmalethbridge.com

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