From Off-Lead, February 1993, pp 12-13)

Humane Socialization Period 7-12 weeks
This is the best time to place a puppy in a new home since he is not ready to transfer his affections from his dam and littermates to his people. From the 7th week to the 16th week, the puppy's attitudes, especially toward people, will be set by what he is taught. From 7-12 weeks the puppy should be given widely varied experiences and meet as many people of all ages and walks of life as possible.

Fear Impact Sub-Period 8-10 weeks
Traumatic experiences during this period may affect him for life. Many dogs fear vacuums, for instance, because they are introduced to them during this time. Vacuum one room at a time when your pup is 8-10weeks. Then stop and leave the "vacuum monster" out where the pup can investigate it between roars.

Seniority Classification Period 12-16 weeks
The pup is cutting teeth and apron strings. Now the pup is trying to figure out who is boss. All biting of human hands, clothing, or of the leash should be discouraged. By 16 weeks, the puppy's emotional makeup is fully developed and cemented for life.

Flight Instinct Period 4 to 8 months
During this period the pup will test his wings. He won't come when called and will, in fact, run away. Just keep him on leash until this passes.

Second Fear Impact Period: 6 to 14 months
Otherwise known as teenage flakiness. In large breeds, this period could extend longer since it is tied to sexual maturity. There is a fear of new situations, or even of old things that appear different to the dog for some reason. Deal with this patiently. The dog should be encouraged to work it out on his own. If anything, it is better to ignore the whole situation than to reinforce the fear by praising dog or petting him while he is afraid.

Young Adulthood 1 1/2 to 2 years
Many dogs will show a rise in their level of aggressions during this time. They may become protective and territorial and may make a new attempt to dominate their owners. Incidents of teenage flakiness may recur.