Horse training approaches should involve the principles of learning theory (the principles of how all organisms learn), and consider motivation, associative learning, reinforcement, punishment, shaping, and habituation. In addition, horse training should consider equine ethology (the study of the horse’s natural behavior), so that we use stimuli similar to those that horses naturally respond to, and reinforcers that they find reinforcing. This seems needlessly complicated, but that’s how the world works. In fact, basing our training on learning theory and ethology simplifies everything. Without understanding these fundamentals, we enter a world of accidental results and mythological explanations of those results. And that is today’s world of equestrian coaching.
Natural horsemanship favors the use of reward in daily interactions with your horse. Traditional horsemanship is more prone to using aversive influences, such as bits, spurs, and whips, but tries to disguise them as “aids”, “moving away from pressure”, etc. Is one approach better than the other? The answer to this question might hinge on the training techniques used, not the language we use. Your horse would choose to live in a world in which positive reinforcement was the norm. So would you. But would he learn better with positive reinforcement than with the other options? Positive and negative feedback have somewhat different roles. Both improve performance, but positive feedback is important to maintain a desired behavior, while negative feedback is most useful in adjusting current behavior.
Bits, spurs, and saddles are all potential sources of injury, and thus of pain. As pain warns us of pending injury, a horse that feels pain from a bit or spurs or a saddle is in the process of being injured. The pain or injuries from these “aids” won’t be obvious at first — at least to us, but over a period of time the injuries may show themselves.
Bits and spurs are tools that provide more control over a horse, and riders universally favor more control. Wishful thinking helps us believe that something so useful for our needs is not something that is hurting our horse. Riders will tell you that the way they use bits and spurs doesn’t injure their horse, or cause it pain.
You might ask whether a horse would be so willing to allow a rider to mount them if the bit hurt so much. As McGreevy and McLean have noted, “It is by no means certain that horses connect pressure in the mouth with the rider. They have not evolved to expect that another animal can apply pressure to the inside of the buccal cavity via a piece of metal.”