By Aidan Bindoff on 04/01/2009

The critical period

If you have a new puppy, or are planning to get a puppy, you may have heard about "socialization." It's been established that pups are more likely to grow into stable, well-adjusted dogs if they experience a wide variety of new things at a very early age. Some researchers have even noted a critical period—up to the age of 3 months—when effective socialization is critically important. If your pup misses out on adequate socialization during this critical period, then there is a greatly increased risk of behavioral problems such as fear, avoidance, and aggression later in life.

Birth, breeders, and the early days

Socialization begins right from day one. Puppies begin to learn about the world outside their mother's womb from the moment they emerge from the birth canal. With any luck, the mother will survive the whelping process and will produce more than one puppy. Mom and littermates play an important role in the earliest stages of socialization, laying the foundation for what is to come.

The breeder also plays a role in these early days. More than half of a puppy's critical socialization period will be spent with the breeder. Ideally, the breeder will expose your pup to a variety of sounds, smells, surfaces, and species. This exposure will prove to be a big head start, but exposure doesn't end with the breeder.

When you bring a pup home, you should continue these new experiences, preferably with the guidance of a competent instructor. At a puppy class, your pup will meet other pups in a controlled environment under the watchful eye of someone who knows how to make the best of these experiences. The American Veterinary Society of Animal Behavior (AVSAB) is now officially recommending that socialization take priority over the completion of vaccinations. In the past, there had been debate about when socialization should begin—should pups be exposed to the potential of infectious disease for the sake of socialization? Now there is no question—the risk of infectious disease is many times lower than the risks associated with inadequate socialization in normal populations.

Ideally, the breeder will expose your pup to a variety of sounds, smells, surfaces, and species.

(Editor's note: The AVSAB Position Statement on Puppy Socialization can be found here .)

All of this information could lead you to believe that socialization will only benefit your dog, and that it has no risks. Unfortunately, socialization does carry some risks, but there are strategies that can help you obtain the best results for your puppy.

First impressions matter

Puppies are always learning. What puppies learn in the early days has an enormous influence on the dogs that they become, because it is what they learn first. Puppies certainly don't start off as blank slates—genetics play an important role. Nevertheless, their first experiences with new stimuli shape how dogs respond to those stimuli later on in life. If a pup's first experience with a cat is terrifying, that pup is more likely to be afraid of cats later on in life. Luckily, pups are pups, and tend to brush off most bad experiences! Perhaps it is their playful curiosity? As they get older, they tend to become more wary, so it pays to take advantage of the first three months.

Ideally, aim to expose a pup to all the things that he or she may be exposed to later in life, and try to ensure that these exposures are positive experiences. It's worthwhile to go out of your way in the early months, but don't become obsessive. The aim is to expose a pup to enough things, and have enough positive experiences, that new experiences can be taken in stride at any stage of life.

The aim is to have enough positive experiences that new experiences can be taken in stride at any stage of life.

So how do you make sure these experiences are beneficial and positive?

Conditioning tools

Dogs learn in two ways—they learn by association ( classical conditioning ) and they learn by consequence (operant conditioning). Classical conditioning occurs when a stimulus is paired with something that elicits what behaviorists call an "unconditioned response." When you are socializing a puppy, pairing something in the environment with something the dog already enjoys is classical conditioning. For example, a food treat might often follow when a pup meets children, thereby pairing something good (food) with something in the environment (children). Operant conditioning occurs when a pup learns to do something to get something he wants. An example could be discovering that a food treat often follows when the pup sits and allows children to pet him. Here, food is given as a consequence of sitting and allowing children to pet.

Both types of learning may occur at the same time. A pup can learn both an internal, emotional response and an external, behavioral response to the same stimulus. In order to make a positive association, a pup doesn't have to "earn" food treats, but if the opportunity to reinforce behaviors you like presents itself, take advantage of it!

Food, toys, and games can all be used in both classical and operant conditioning procedures; what's important is that the choice should be something the pup will work for, or something you already know the pup enjoys because he has worked for it in the past. Food is usually the most convenient tool to use, but as you become more familiar with your new pup you might find certain toys or games that the pup particularly likes, too.

It should be noted that dogs will also work to avoid situations that they don't enjoy. For the unwary, the trap here is that you can often reinforce fearful or aggressive behaviors inadvertently, simply by allowing the behaviors to work in a pup's favor. (Certainly this is not to suggest or support forcing a pup to endure situations that he doesn't enjoy in order to avoid reinforcing those behaviors.)

The best advice is to seek professional help from knowledgeable trainers if you notice fearful or aggressive behavior. There is always a path around these situations, a path that doesn't involve reinforcing unwanted behaviors or forcing a pup to deal with situations that he finds stressful (risking irreparable psychological damage).

Emphasizing the positive

When setting up new socialization experiences for a pup, try to set up situations that you have some control over and that are likely to lead to a positive outcome. For example, if you are introducing a pup to an older dog, choose an older dog that you are familiar with and that will not frighten the pup. Choose a safe area so that both animals can play off-leash for a while.

Another good way to introduce a pup to older dogs is to visit an obedience class. Have the pup on-leash and watch from the sidelines. This trip will give the pup the opportunity to see lots of different dogs, all on-leash and working. And, the visit will be a new and different experience for the pup, because he must learn to be around other dogs without being allowed to play.

In situations like the ones above, take steps to ensure that the encounter will be positive, non-threatening, and beneficial. The pup will learn important social skills, and the risks of something going wrong or the pup learning something you don't want him to learn are minimized. It would be inadvisable to go to a dog park where lots of unknown dogs might be playing off-leash, for example. Most of these dogs might be fine, but a bad experience can have lasting effects.

Try this!

Other situations most pups should encounter at an early age include:

Places—car, vet, beach, park, school, shops, friends' houses, crate, public transport, grooming parlor, cafe, obedience club, stairs, hard floors, carpet, gravel, other unusual surfaces (walking over a tarpaulin or a teeter-totter)

People—friends, neighbors, family, children, elderly people, men with deep voices, men with beards, people with colored skin, people in hats, people with wheelchairs or walkers, people who ignore dogs, people who are affectionate toward dogs

Animals—other puppies, other dogs, individual dogs, groups of dogs, working dogs, playing dogs, cats, poultry, horses, livestock

Of course, these are just suggestions. Sit down and think about situations your own pup is likely to encounter during his life, and think about ways to introduce the pup to those situations in a positive and beneficial manner. Be prepared—take some food treats, a favorite toy, leash, clicker , and maybe even a crate or mat in some cases. Another good choice is to invite along a friend with a stable, friendly dog. It is amazing what pups can learn from older dogs, without pet owners ever having to do a thing!

Other winning strategies

If your pup is afraid of something, stay calm. Most of the time curiosity will overcome fear. Keep things positive and don't push the pup. Do use gentle encouragement if you think the encounter will end on a positive note.

Sit down and think about situations your own pup is likely to encounter during his life.

Keep a pup's brain engaged by asking him to perform a simple trick away from something that scared him. Targeting can be very helpful here, too, especially when introducing a pup to new places or surfaces. Very young pups usually pick up targeting very quickly.

Welcoming a puppy into your home is an exciting time of transition. Careful, early exposures and socialization experiences may take a good amount of thought and time, but it's a worthwhile effort to make for a new puppy. A well-planned socialization strategy helps to make your future family life together both positive and rewarding.