The sensitive period for socialization is a very important time in the lives of kittens and puppies. This is when their brains are especially receptive to learning about the kind of social world they will live in as they get older.

The Sensitive Period for Puppies

In puppies, the sensitive period begins at 3 weeks and goes on until about 12 or 14 weeks. Our knowledge of this period comes from classic experiments that involved isolating puppies during this time. We don’t know exactly when the sensitive period ends, and it may end at slightly different times depending on the breed.

This means two things for people who get puppies.

First of all, because part of the sensitive period occurs before the puppy comes to live with you, it’s important to ensure you get a puppy from a breeder or rescue where the puppy is in a home environment and getting socialization already.

Puppies acquired from pet stores are more likely to have behaviour problems such as aggression, and one reason could be that they are missing those early socialization opportunities because the environment they are born into is typically not a home environment.

An early socialization program for puppies means they are less likely to have behaviour problems such as body sensitivity and separation-related behaviours as adult dogs.

Second, it means you have to be prepared to continue socialization during those first few weeks the puppy is with you.

Waiting for Vaccinations

Sometimes people want to wait until their puppy has had all its vaccinations before beginning socialization. This is understandable, but unfortunately it means they miss this important period.

Because the leading cause of death of young dogs (under 3) is euthanasia due to behaviour problems, rather than infectious diseases, the American Veterinary Society for Animal Behaviour recommends that puppies start puppy class at 7-8 weeks of age.

Puppies should have one set of vaccinations before the first class, and should also be dewormed.

Choose your puppy class with care to make sure the dog trainer will use reward-based methods. Classes should include socialization opportunities with people and play with the other puppies, not just basic obedience.

Puppy class usually lasts 6 weeks, and one study suggests that a one-off puppy party does not have as many benefits.

Remember it’s your job to take care of your puppy and ensure those experiences are positive. If other people want to pet your puppy, be sure to give your puppy a choice.

Why is it called a sensitive period?

You may also have heard people refer to a critical period for socialization. A critical period means that if the right exposure doesn’t happen during that window, the abilities will never be developed. It has a sharp beginning and end, and is most likely controlled by genetics.

In contrast a sensitive period has a more gradual onset and offset, during which time the brain becomes more sensitive to the right kinds of experiences, and then towards the end of the period it becomes less sensitive. Exposure to stimuli during this time affects the developing brain and may also increase plasticity.

Of course puppies and kittens don't have identical experiences, and perhaps different kinds of exposures will affect the brain in different ways, but work towards the same goal.

Plasticity of the brain means that it may be possible to still develop in some ways if these exposures happen later than they should have, even if the development will never be quite the same.

It is difficult to define the beginning and end of these periods, although research on neurological development is providing a lot more information.

Early brain development is so important because it provides the scaffolding for further development later in life – something that also applies to human babies.

Reproduced with the kind permission of Zazie Todd, PhD. See more of her brilliant work at Companion Animal Psychology.