The technique of “marker” training comes from Ivan Pavlov’s “classical conditioning”. In my training, when a dog accomplishes the task that I set for them, I indicate success by saying “yes”. That indication is followed by some type of reward (I.e. food, verbal praise, touch, toy). When a dog fails at maintaining appropriate behavior or failing to complete a task that he understands, I indicate failure by saying ‘no”. That indication is followed by some form of consequence (i.e. leash correction, verbal reprimand, psychological pressure, taking something away, touch). By using this technique consistently, the dog will associate his actions as being approved or disapproved based on the reward that follows “yes” and the consequence that follows “no”.