Socialization at appropriate developmental stages are critical for creating well-adjusted adult dogs and is important for the prevention of aggression and biting, in particular.

Proper socialization or “desensitization” involves teaching a dog not to overreact to novel stimuli in the environment. The objective of socialization is to expose the puppy to new situations, people and other animals at a comfortable pace for the puppy, while avoiding  potential for eliciting a negative reaction in the maturing dog.

Undersocialized dogs overreact to fairly innocuous stimuli such as certain noises and new people. Desensitization should be performed in small increments through making positive associations with stimuli that the puppy may have been sensitized to.  However, overexposure to new stimuli in the environment can sensitize a puppy, creating a negative association for otherwise innocuous stimuli. Such improper socialization can induce fear and ultimately aggression in the mature dog.

Some breeds are more suspicious than others, such as working dogs used to guard people and property.  These dogs may need more help with socialization than just increasing their exposure to various stimuli., This is also the case for some individual dogs from breeds that are known to be easy to socialize.  Additional socialization may also be required for dogs raised in isolation or in large breeding facilities. Shelter dogs and strays that are lucky enough to be adopted may also require extensive socialization.

The Optimum Socialization Period is between birth and the time the puppy reaches five months of age.  It is more than acceptable to permit multiple people to gently handle a nursing neonate.  In the event that a puppy does become frightened by something, the owner should refrain from trying to soothe the animal, which may exacerbate the imprinting of fearfulness. Rather the owner should redirect the puppy’s attention to a toy or treat and revisit the exposure training in smaller increments.

Puppies should be introduced to as many people as possible. They should also be introduced to vaccinated adults and vaccinated puppies. Although viral pathogens are dangerous hazards to unvaccinated puppies, there are ample opportunities to socialize dogs under the age of five months to other healthy dogs outside the home.  Far more dogs suffer from improper socialization and neglect than from viral diseases.

The Fear-Imprint Period is from eight to eleven weeks. It is very difficult to extinguish fear imprinting from a negative experience that occurs during this critical socialization period. During this period, which coincides with the time a puppy arrives at its permanent home, the owner should prevent any potential for psychological trauma.

Seniority Classification and Pack Stability become established at ten to 16 weeks of age. Puppies, having been at their permanent home for two to six weeks, spend this period exploring and developing confidence in their new surroundings. This is an excellent time for puppies to take classes and learn basic obedience through positive training. This is also an optimal time for puppies to benefit from socialization.

The Flight Instinct Period is between four to eight months and flight response issues can develop at any point during this time frame.  An owner might yell at the puppy to interrupt some negative behavior and the puppy flees. This ineffective communication is then addressed by the trainer. If a dog has not been socialized or trained prior to this period, other behavior problems may arise.

A Secondary Fear Period may occur at six to 14 months. At this stage of sexual maturation, when puppy fur is replaced with an adult coat and the dog nearly attains full size, a growth spurt can coincide with another period of susceptibility to fear imprinting.  Essentially the puppy can become afraid of things that did not previously induce fear. Again, it is important to continue with proper socialization and avoid overwhelming the dog with novel stimuli.

Puppies mature into adults between one and four years of age.  Maturation rates are dependent upon breed type, breed and environmental factors. Sexual maturation occurs between eight and 15 months of age.  This is when most companion canids are rendered reproductively inactive. Males are castrated and females are spayed. Neuter is the general term for both procedures. In other words “neuter” is a gender neutral term.

At one year of age dogs become more confident and exhibit breed specific characteristics. They still require plenty of enrichment outside the confines of their homes, as well as continued socialization and obedience training.  At three, dogs are more reliable, and trustworthy, but may still be quite impressionable. By four years of age a dog is often settled in a routine and has developed habits and communicative behavior compatible with his or her owners.

Although, dependent on the breed, dogs aged five to 15 years of age generally represent cohorts from midlifers to seniors. Specifically, the senior years begin around seven or eight This is when nutritional requirements may change and accommodations may be needed for hearing loss or compromised sight. Training objectives may also change.

This synopsis is adapted from literature published by the Animal Behavior College.