Take a few minutes to think about how you train and keep your horse.
Does your horse obey to gain something appetitive or to avoid something aversive?

Do you abide by the LIMA principles?
Do you know what the humane hierarchy looks like?
Do you understand the 5 Domains of animal welfare?
How can you tell whether your horse is “happy”?

I don’t have all the answers but they are worth thinking about next time you are with your horse. Negative reinforcement is what most people use but it must be understood and used appropriately until you learn how to train without aversive stimuli. There are other components of how we all learn and they are worth exploring. Of course punishment is a last resort and only to be used if we are in a dangerous situation with an insufficiently trained horse.
Not every one will want to change and if you consider your horse happy with what you ask then you may not even understand the reason to change or even to learn more.
The more tools we have in our tool box the better trainers we will be.
There may be some cognitive dissonance too as we learn new ways of doing things, we try to rationalise why we do what we do.

The key is to learn about equine body language and the signs of appeasement and calming behaviours. Once seen they can’t be unseen and pop up all the time – watch videos and analyse the horses reactions. Know the signs of a distressed horse, learn what eye wrinkles mean and tight lips and chins. We all need a little adrenaline rush to get us going but too much and a horse way over his/her emotional threshold is not a good sign. Nor is it healthy for the horse, horses are very good at disguising how they feel.

LIMA principles

Language Signs and Calming Signals in Horses

The 5 Domains of Welfare

Research into how horses may hide stress

Negative Reinforcement

Negative Reinforcement

It may well be that – at this moment in time – it is not possible to use only positive reinforcement in equine training.
If people wish to compete in mainstream equestrian events then they will need to use -R unless they retrain or train from scratch everything with +R. There may well be a time when the horse world catches up with other animal trainers in the use of +R.
It isn’t something that many positive reinforcement trainers talk about and talking about -R on some Facebooks groups gets you banned. However we must know how -R works and how it can affect the horse.
If we work on the LIMA principles of using the Least Intrusive, Minimally Aversive stimuli to train behaviour and apply behaviour modification programs then I think we are doing well.

Negative is just a mathematical notation – so subtracting something to reinforce a behaviour. Of course if we remove something the horse likes and wants that can be construed as negative punishment if the behaviour decreases, as it may well do if the horse can’t get what he wants.
 So to be reinforcing the stimuli removed must be something the horse wishes to avoid, so an aversive stimuli. The removal of the stimuli is felt as a relief to the horse and can be very light leg and rein and weight aids. So the leg is conditioned to mean forward and is reinforced by the removal of the aid.
Negative reinforcement does trigger different neurotransmitters and hormones than those triggered in positive reinforcement. Using Jaak Panksepps 7 emotional systems, that all mammals share, we can see which system is at work in any quadrant. 
So with +R we see the SEEKING system in action in a positive way – horse learn to solve problems, they are empowered to share in their learning. The PLAY system is important too as horses learn through PLAY just as other mammals do e.g human children.
So what system is -R using?
 If we use another behavioural model – Paul Gilberts 3 Circle Model – we can see that using an aversive stimulus to form a behaviour is in the THREAT circle. Panksepp would be the FEAR system, this does not have to be all out flight but aversive enough for the horse to want to avoid the stimulus.

diagram of the 3 circle model of emotional regulation

Of course we need to achieve homeostasis of the emotional systems as soon as possible by removing the aversive stimulus and also by putting the behaviour on a command – so the horse can avoid any escalation. So in any training session the horse can be in the RED zone but we need to get him back in the GREEN zone. Horse stuck in the RED zone can become hypervigilant – if the HPA axis is triggered then cortisol is released and this takes a long time to dissipate, so a little bit of adrenaline keeps them motivated but too much and it tips into distress rather than eustress.

Positive reinforcement works on the DRIVE or SEEKING system, but we can also get horse stuck in this mode too – so they get frustrated if reinforcement isn’t forthcoming or we are slow with reinforcement.
 Whatever we use whether +R or -R we need to understand what is happening and how we can use them for the good of the horse.

Difference between a cue and a command?
A cue is used in +R training to tell the horse reinforcement is coming. In -R we use the word command as the horse rarely has a choice – so often it is a “to it or else” scenario, the horse performs the behaviour to avoid any escalation of an aversive stimulus.

Paul Gilbert

Jaak Panksepp

HPA axis