Socialization - Social training or Trusting the pack leader?

There are two main views of what it takes to get your dog to be able to handle challenges, such as meeting other animals, dogs of all shapes, ages and both sexes, babies, children, cars, etc. One is simply that if your dog trusts you, it will not get scared unless you get scared, since you are the pack-leader and the dog believes you can handle anything. The other view is that the dog needs to get used to different animals, dogs, cars etc, while still young and if the dog has good experiences with of all of the things mentioned above, none of them will be a problem when the dog is grown up.
Well what do I think.. well, non of them are wrong. If your dog trusts you it will do everything you ask of it. But isn't socialization of the puppy exactly that, that you show the puppy that no matter what situation you're in or no matter who/what you meet you remain calm and happy. So I guess the views are just two different ways to describe the same thing.
What about you being the "pack-leader"? Some people have left this way of thinking altogether, they claim that being a "pack-leader" means that you train your dog with corrections instead of rewards. I don't agree, and I think the term "pack leader" has a much deeper meaning. It all comes down to trust. If you act calm and like you can handle everything, you act like a pack leader. If you on the other hand seem insecure or even afraid of something, the dog will not view you as a reliable protector and will either be scared itself or try to take on the role of protector, or pack leader. Does this mean that it "wants to take over and be boss"? No, definitely not! It just tried to do what it thought you wanted it to do! But back to the subject of socialization. 
I once read an article about a guy that had a Laponian herder, he claimed that socialization was just nonsense, that the dog just had to trust him in order to handle new and challenging situations. The way he had gotten his dog to trust him was putting the dog in a number of different situations and showed the dog that it could always count on his support and that he himself always remained calm. Which is just another way of describing socialization... He did have one point though, the dog did not have to have experienced exactly every situation it could ever happen to experience, during its training/socialization, in order for it to be able to handle it. Just like we can, a dog can learn to generalize, meaning it can learn that similar (but not identical) situations can be handled the same way. To take one simplified example, it is enough for the dog to learn that when a car comes passing by,  it should stay by your side. It doesn't have to learn that it has to stay by your side for every type of car, red/blue/grey.., sedan/station wagon/SUV and so on. It can generalize from having seen a few examples.


Effects of lacking socialization
I read in another article, about problem behaviors in dogs, that the typical dog that was referred to dog psychologists was male, 1-1,5years old, castrated and had been bought from breeder (or re-homed) after 12 weeks of age.  So why is this the archetype of problematic dog? Well, to start with the gender, males are more difficult to handle simply because they are in general tougher and because of testosterone also more prone to aggressive behavior.
Castrated then? Shouldn't castration take away the testosterone and hence the problematic behavior caused by it? Well I guess that was the point of the castration, but the procedure was most likely done too late to affect the problematic behavior. You see, dogs learn behavior. And when a behavior is learned, such as "when I see a dog, I bark at it", it won't matter what caused this to begin with (testosterone/territorial behavior). If removed from home territory or castrated, the dog will still bark whenever it sees another dog.
Then to the age of the dog. Sometime when the dog is between 6 months and 1 year old it will hit adolescence. This means that the sex-hormone concentration in the body will increase, altering behavior and physical development. As going to the dog psychologist probably isn't the first thing the dog owner tried (castration...) there is a slight time lag between initiation of problem behavior and first counseling at the dog psychologist. It is also possible that the delay is caused by the fact that the dog isn't at it's strongest when adolescence start, so it is easier to handle it in the beginning, as the dog grows it becomes increasingly harder to handle it.
And then the part that brings us back to socialization. The age at which the dog left the breeder to go to its new (and hopefylly last) family. What is it about the time between 8-12 weeks old that makes it so important to get the puppy at this age? Well, this is the time in the puppy's life when it learns what is "normal". For example, if you live in an apartment where people are walking up and down the stairs outside of your door all day, and you get the puppy when it is 8 weeks old, it will learn that this is normal and stop caring about it (if you show it that you don't care about the noise and ignore the dog or even correct it when it barks/growl at the noise). If you on the other hand get the dog when it is 3 months old (approximately 12 weeks old) or older, and it used to live in a house on the countryside, these noises will affect it and you will have a much harder time getting the dog to ignore it. The same goes for everything else that will be "normal" for the rest of the dogs life.
So, does this mean that a dog will not be trainable after 12 weeks of age? Of course it doesn't mean that! It will only be harder, but far from impossible. You just have to be aware that you might have to put some extra energy and time into it.

So what should you do to prevent the problems? Below is a series of pictures to illustrate some of the things you should try to expose your dog to before 12 weeks of age, or if you start later, maybe the dog has to be exposed to it more times before it stops being stressed about it. And remember, the training never stops, a dog will only be good at doing stuff it does every day, or at least often.

Meeting different animals, and walking on roads with cars, there is a lot to learn here for the two 4-months old Siberian husky puppies.

It is important for all dogs, and especially dogs that will be around children, to meet children of different ages. Scott, 2 years old, is not very used to kids, but handles it a lot better now than he did a year ago.

Meeting smaller and bigger dogs than yourself is important, Scott 2 years old Danish Swedish Farmdog, and Vida 4 months old Siberian husky.

Playing with other dogs is good socialization, but only if it doesn't get out of hand, it is important that the dog learns to be calm around other dogs too. Here are 3 young dachshunds at a dogshow in Tromsø June 2011.

Learning to greet each other and interact with the opposite sex is also important, here two Labrador retrievers at a dogshow in Tromsø June 2011.

For fully grown male dogs to be able to interact and play like Scott (2 years old) and Casper (1,5 years old, Basset Artésien Normand) does here, they need to be very good at communication between dogs. This is something all dogs need to work on!