Early puppy socialization is critical. Research clearly demonstrates that puppies that grow up in isolation – both from other dogs as well as from a wide variety of humans – have a greater tendency to develop behavior problems later in life such as fear-based aggression. But for many years, dog owners have been advised to keep puppies safe at home for the first four months of their lives, in order to avoid infectious diseases. This puts the owner of a new puppy in a terrible predicament: keep your dog at home and risk psychological and behavioral complications, or take your dog out into the world and risk disease.