This is not to say that most behavioral changes are medically induced.
Tremendous differences exist in temperament and behavior between breeds.
In fact, one of the main reasons an owner selects a particular breed is because of the temperamental and behavioral qualities the breed is supposed to exhibit. For the most part, one can only make broad generalizations and comparisons between breeds about temperament and behavior. For example, Pitbull terriers are probably more aggressive than Shetland sheep dogs. Likewise, Doberman pinchers are probably better at learning obedience commands than a Basset Hound or Bloodhound. Although gross differences and similarities are present, one must never lose sight of the fact that each dog is an individual and will behave as such.