Train by reward, not confrontation
Should you train your dog by ‘showing it who’s the boss’? Is it true that the dog will otherwise conclude that it’s the boss?
According to zoologist John Bradshaw (author of Dog Sense – How the New Science of Dog Behavior Can Make You A Better Friend to Your Pet), this whole idea of hierarchy is a misunderstanding. While many trainers believe that the dog perceives us as another dog, there is no actual evidence for this. Dogs do not by nature want to control us. In fact, the opposite is probably true. As domesticated animals, they probably have a need for us to control them.
So the rule is: Yes, train dogs to behave well from an early age, but use positive, reward-based training, not harsh, painful or frightening methods.