I can't remember if I've posted on this thread already, but I know I've talked about clicker training on other threads and will get up on my soapbox to talk about it here. Sorry for being so repetitive, but this is something I'm passionate about and I hate seeing it go misunderstood to the point of being completely stomped on.
The basic truth is that ALL ANIMALS LEARN THINGS THE SAME WAY. THIS IS A FACT. YES, EVEN YOUR HORSE LEARNS THINGS THIS WAY. NO ANIMAL (NOT EVEN YOUR HORSE) IS ABSOLVED OF THE LEARNING THEORY.
Here is a video of a horse who came to the present owner as a totally unpredictable bag of nerves. This horse was completely rehabilitated and trained using only force-free methods, including the clicker. I really encourage you to watch the whole thing.
Think about how these simple techniques can be applied to "real" horsemanship. Running a figure 8 around the chairs can be expanded into barrel racing, jumping over logs and jumps can be expanded into bigger jumps, the horse is learning to be less fearful of ordinary objects such as chairs and blankets through targeting (touching with the nose), the horse accepts grooming, and knows a multitude of really practical things. All that may look sweet and fun, but have a real purpose in life. Not to mention...how amazing is their relationship??? This is a horse who could not be touched!