Sometimes a number of unpleasant events are paired or associated with a person or animal which can intensify the fear response. This can occur, for example, with a bad experience with a small child, which then makes the dog fearful of all small children, or from a fight and subsequent injury caused by another dog. Dogs are impressionable, and through the effect of 'single event learning,' one negative or traumatic experience may induce fear or phobic responses that generalize to many similar situations. The brain is adult-like by 8 weeks of age and negative or traumatic experiences are likely remembered into adulthood. Similarly, dogs should be socialized with different breeds of dogs and other animals to prevent fear or phobic responses. To prevent fears and phobias, dogs need to be adequately socialized to a variety of people, such as the elderly, adult men and women, teenagers, and children.

Without adequate positive interactions with people and other animals during this time, dogs may develop fear and phobic reactions. Lack of exposure can be just as detrimental as a negative experience. Socialization is an important aspect of raising a puppy. The socialization period is a sensitive period of development which occurs from 3 to 12 weeks of age, whereby dogs learn to communicate with animals and people and to adapt to a variety of environments. There may have been limited or minimal exposure to people and/or other animals when the dog was young. There are many reasons why dogs can develop a fear or phobic response toward people or other animals including: Why is my dog afraid of people and/or other animals? For more information on fear and phobias, also see the handout on “Fears, Phobias, and Anxiety in Cats and Dogs”.

Pathological fear of dogs called