Most horse training is negative reinforcement. You kick the horse until it moves forward. You pull on the reins until it stops. Once the horse has learned that the kicking will stop when he moves forward much more subtle cues such as a Walk On’ or just a squeeze of the legs can be substitutes. Positive reinforcement-giving a treat when the animal performs a task is very popular among dog trainers, but not horse trainers. A recent paper found that yearling horses given grain after they stood still learned to stay more quickly, remembered longer and were more friendly to humans than ones taught with no reward.

Positive interactions lead to lasting positive memories in horses,Equus caballus. Carol Sankey, Marie-Annick Richard-Yris, Hélène Leroya, Séverine Henry, Martine Hausberger Animal Behaviour 79 (2010) 869–875