The clicker and its usefulness depends on the fact that animals learn by association. The sound of the click means nothing to start with, but when your dog notices that every click is followed by a small natural tasty FourFriends treat, he/she begins to pay close attention to that click. FourFriends Tuna or Chicken Twist Bite are excellent for this purpose. Remember to reduce the amount of food given at meal time to compensate for the treats used in training.