Several studies now show that dogs learn faster, and that training is much more effective when dogs are taught with rewards rather than with aversive training. Aversive training methods use punishment of some sort in training (hitting, alpha rolls, forced down-stays, spray bottles).

A tasty pile of dog treats. Training dogs with treats, rather than punishment, has been found to be more effective. Jane Bowers photo
A group led by Simon Prins, is training police and military dogs in the Netherlands by rewarding desired behaviors and removing rewards for unwanted behavior. They report that they have cut their training time down to one-eighth of the time it originally took and that dogs trained this way handle new situations confidently as they are not afraid to try things.
A one-year study based on detailed surveys with owners of dogs was done by Meghan Heron and colleagues at the University of Pennsylvania. Researchers found that the use of punishing techniques when training dogs tended to increase aggression in the animals substantially.
Rewarding behaviours we want from a dog make the dog more likely to repeat those behaviours. Food is an obvious choice as a reward for dogs, but play is also a great reward for dogs. Dogs whose owners play with them have been found to score higher in obedience tests than those whose owners do not play with them. Play is associated with a reduction in the stress hormone “cortisol”. Playtime with a favourite dog friend is also rewarding. Some dogs find petting and praise very rewarding.
Food rewards should be something the dog really likes (generally dehydrated meats) and should be about the size of a pea. To get the most out of play, keep things positive. Train for just a few minutes at a time and give the dog plenty of breaks. Use humane equipment like flat collars and well-fitting harnesses that do not hurt the dog and long lines to keep the dog safe if you have to train or play in an unfenced area. Avoid using pet-sitters or facilities where aversive methods are used on the dogs.
Dogs who are trained with rewards tend to have more confidence when learning new things and offer behaviors more willingly than those who have been punished. This results in faster learning and a happy dog who is trained more quickly.