Imagine the thinking side of your horse’s brain as a big muscle. The more you use a muscle, the stronger it gets. Let’s say I went to the gym every day for a year, and I lifted weights with my right arm. At the end of the year, my right arm would be bigger and stronger, and it would be more useful to me. Now, let’s say that after that year I quit going to the gym. What would happen to my arm then? Every day my arm would get weaker, flabbier and less useful. Pretty soon, I wouldn’t be able to do as much with the arm as I used to. That’s the way you need to look at the thinking side of your horse’s brain. It’s like a big muscle, and the more you exercise and use it, the more proficient it will get. The less you use it, the weaker and less useful it becomes.