Before you ever bring your puppy home, the breeder should have provided an environment where it was possible for your puppy to begin his socialization to people and experience life, albeit on a limited basis. Locking puppies in the basement or furnace room until someone purchases them is disastrous to their ability to become great family companions. Dogs need to be socialized to people from the beginning, and they need to be underfoot around the house as much as is reasonable. In this way, they are exposed to the sights and sounds of normal family life: They learn the ins and outs of noises, such as dishwashers, vacuums, traffic, children, television, music, and so forth. Without this early exposure, the puppy will never reach his full potential as an adult.
A lack of early socialization literally retards the dog's development, making it harder for him to adjust to a new environment at a later date. Ian Dunbar, a well-known behaviorist, dog trainer, and veterinarian, recommends that dogs meet 100 people before they are twelve weeks old. Although this is a tall order, breeders should be doing their best to introduce their puppies to a wide range of people as early as possible. Educate yourself on puppy developmental dead-lines so that you can ask the breeder appropriate questions.
Providing stimulation — in the way of toys; things to chew on; and things to climb over, around, and through — is crucial, as these activities stimulate the puppy's brain and fosters the beginnings of problem-solving abilities.
Having adult dogs interact with puppies is also an important part of their development. Adult dogs teach young puppies the rules of being a dog, and give feedback on using their mouths gently. Adult dogs will not tolerate puppies biting their sensitive ears or feet for long without disciplining them (gently) or simply removing themselves from the puppies. This is an important lesson for puppies to learn, since it correlates directly to how much mouthing and biting they will do with you. Learning the rules of living with humans while they are still with their littermates makes your job that much easier when you bring your new puppy home.