The trainer was hoping to train this pup for Therapy work, so he chose to develop this aspect of the dog s personality. Each time the pup approached a stranger in a friendly manner, the trainer rewarded her lavishly. Not surprisingly, the pup grew into an exceptionally outgoing, social dog. The raw genetic material was there all along, what the trainer did was simply build on what was already there. Each dog has a personality, which is different than temperament.
Personality is developed through interaction with other living creatures, primarily humans.
Pups who are raised in enriched environments tend to have well developed personalities, with maximum emotional range and depth. Dogs who have been kenneled too much often have a flatness to them, they lack the animation and expression we like to see. Thus, socialization and early handling really do count, not because they can change temperament, but because a good handler can build on the innate traits that are already there. And, socialization is part of personality development. Good early handling will make a strong dog even better and bring the weaker dog up to the extent to which the dog is capable.