In the twentieth century, formalized dog training originated in military and police applications, and the methods used largely reflected the military approach to training humans. In the middle and late part of the century, however, more research into operant conditioning and positive reinforcement occurred as wild animal shows became more popular. Aquatic mammal trainers used clickers (a small box that makes a loud click when pushed on) to "mark" desired behavior, giving food as a reward. The change in training methods spread gradually into the world of dog training. Today many dog trainers rely heavily on positive reinforcement to teach new behaviors.
Dog intelligence is exhibited in many different ways, and a dog that might not be easy to train might nonetheless be quite adept at figuring out how to open kitchen cabinets or to escape from the yard. Novice dog owners need to consider a dog's trainability as well as its energy level, exercise requirements, and other factors before choosing a new pet. Very high intelligence is not necessarily a good thing in a companion dog, as smart dogs can require extensive daily mental stimulation if they are not to become bored and destructive.
Unless you plan to keep your dog outdoors--and few of us do because it's not recommended--you'll need to teach your dog where to eliminate. Therefore, house training (also called housebreaking or potty training) is one of the first things you need to work on with your dog. Crate training can be a very helpful part of the training process. This includes house training as well as many other areas of training: