Socialization, as it pertains to dog training, is a very important part of the development of a well-rounded, calm and obedient dog. Socialization includes introducing your dog to new people, events, places and other animals in a safe and non-threatening way so that the dog becomes comfortable in any situation. This is important because a dog that is relaxed and comfortable is not going to become possessive or defensive, which are the two triggers for dog aggression.
All dogs, regardless of their size, only have two responses when they see something new that they deem to be a potential threat. They can either run away or stand and fight, either or neither may be a good option considering the particular circumstance. Most dogs with a submissive type personality choose the run away option while dogs with a more dominant temperament choose the stand and fight result. If a submissive dog wants to turn and run but is cornered, he or she will result to plan B, which is responding with aggression. Dominant type dogs or dogs that are highly possessive or territorial will automatically start barking and approaching in an aggressive stance to establish that this is their area or item.
Neither one of these behaviors is what owners want their dogs to typically use. Most owners would prefer that the dog stand calmly and think through the issues, ending up at a peaceful and non-aggressive type response. In reality this is simply not something that the average dog can do as they are designed to respond to instantaneous situations, not engage in problem solving. What owners can do is provide their dogs with a safe place to experience a wide range of things so that these events, animals, situations and activities become non-threatening. Once the dog can associate a positive or non-threatening response with something new, they no longer respond with those fight or flight responses.
The unfortunate aspect of owners with toy dogs is that they often don't allow their dogs to experience these events as other larger dogs would. Granted a toy breed puppy may be very tiny, however they still need to have routine chances to experience the world around them. What many owners do is isolate and shelter their toy dogs, picking them up or keeping them away from other dogs and pets to avoid any perceived potential injury to the puppy or young dog. This teaches the toy dog that other things in their environment including other animals and strange dogs are to be avoided and even defended against. As the toy dog matures he or she becomes more isolated and less likely to know how to greet and interact with other dogs. The owner, in turn, senses the dogs mounting defensiveness and protectiveness and continues to pick the toy dog up or isolate them, completing a vicious downward lack of socialization cycle.
Ideally owners of toy dogs need to provide appropriate socialization starting as early as possible when it comes to interacting with other dogs. It is very reasonable for owners of toy puppies to be concerned with allowing full sized breeds, even puppies, to rough and tumble play with their very small puppy. Many breeders of toy dogs can recommend trainers or associations that work specifically with toy breeds, which allows safe and suitable interactions. It is also important to realize that puppies of any breed are typically not aggressive. This means that even larger puppies will not respond with aggression towards smaller puppies, especially if you select already socialized larger puppies. Keep in mind that many of the toy breeds are dominant temperament dogs and will soon become the alpha leaders, despite their diminutive size.
The second mistake with regards to socialization that many owners of toy breeds make is to reward aggression towards other people. Toy breeds have been bred for centuries as companion pets and as such they may bond very closely with one person in the family, typically the person that cares for them and spends the most positive time with the puppy and later with the dog. Often toy breeds tend to see their "person" as a possession and become very territorial of other people touching or getting too close. While this may be cute, it is really very serious and can result in biting and other types of aggression of the dog towards other people. A lapdog that snarls, growls or shows their teeth towards a person in the family should be immediately put on the floor and ignored for bad behavior. If they sit calmly on your lap and allow the other person to approach they should be allowed to stay and be rewarded with attention.
Socializing your toy dog from an early age means they will always be welcome, even in situations where you might not expect to see dogs. Even airlines are now allowing small dogs to fly in the cabin with their owners, but they have to be secured in a specific type of carrier and very well behaved. Many restaurants, hotels, shops and even entertainment venues will allow toy dogs that are in carriers to come on the premises, but again only if the dog's behavior is appropriate.
Lastly, toy dogs are not, by nature, yappy or snarly dogs. With proper socialization and routine training a toy breed can be a satisfied, happy and very friendly breed. It is up to the owner to provide the situations and opportunities for this to occur. With incorrect treatment a toy dog can become just as aggressive and vicious as a large breed, which has lead to the poor reputation that some toy breeds have.
For first time dog owners considering a toy breed it is important to work with a breeder, trainer or animal behavioralist that can help you adjust your training to accommodate the needs of your toy breed puppy. Look for puppy obedience classes and training programs geared to small and toy breed dogs if you have a concern about your puppy interacting with larger dogs. It is far less effort and time to get it right the first time rather than having to retrain and correct problem behaviors after they develop.