Relationship between aggressive and avoidance behaviour by dogs and their experience in the first six months of life

Short Synopsis: The researchers looked at the histories of dogs who came to a vet for problems with fear or aggression. The researchers excluded any dogs whose histories before the age of 6 months were unknown, because the goal was to see how early life experiences and behavioral problems were related.

The dogs were divided along 3 main criteria:

  • Those raised in domestic (inside the home) environment as young puppies versus those raised in non-domestic environments (kennels, sheds, shelters, outdoors)
  • Divided by the age they were acquired by the owners
  • ivided by whether or not they’d been exposed to a busy urban environment between the ages of 3 and 6 months.

The researchers found that:

  • Puppies raised in non-domestic environments were more likely to show avoidance behaviors and aggression towards unfamiliar people.
  • Puppies not exposed to urban environments between the ages of 3 and 6 months were more likely to show avoidance behaviors and aggression towards unfamiliar people.
  • Puppies from non-domestic environments who were rehomed BEFORE the age of 8 weeks were a bit less likely to be aggressive towards unfamiliar people than puppies who left that environment later in life.
  • Aggression in veterinary contexts was correlated with being raised in a non-domestic environment, but not with lack of urban exposure as a 3- to 6-month-old.
  • Aggression towards familiar people was only weakly correlated with a non-domestic puppyhood environment. If you excluded the dogs that were aggressive towards unfamiliar AND familiar people, the effect disappeared entirely.
  • Dogs were slightly more likely to be aggressive towards other dogs if they weren’t exposed to an urban environment as 3- to 6-month-olds, but otherwise there wasn’t an effect for dog-dog social skills.

In conclusion, to quote from the abstract:

“These results support the suggestion that there is an association between a dog’s early environment and the development of fear-related behavioural problems (Serpell and Jagoe 1995). The provision of a rich social, and stimulating physical, environment, by both breeders and owners, during the first six months of a dog’s life, appears to be associated with a reduced incidence of some kinds of problem behaviour, and may therefore be of general benefit to canine welfare.”

Authors: D. L. Appleby, J. W. S. Bradshaw, and R. A. Casey

Publication: Veterinary Record

Publication Date: April 2002

Applies To: early life experiences, aggression

Sample Size: 820 dogs

Limitations/Drawbacks: only looked at dogs who had severe enough behvavioral issues to see a vet for the problem.


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