Why Stressed Puppies Can Become Fearful or Aggressive Adult Dogs

Source: SC Psychological Enterprises Ltd

One of Freud’s most influential statements was "The child is the father of the man." This was meant to be interpreted as meaning that an individual’s early history of stressors, adversity, and other interactions during childhood shapes the final personality and behavior patterns of the adult he becomes. A huge amount of data confirms that Freud was correct in this assumption. Recently, a new study seems to suggest that we might be justified in coining a variant of Freud’s conclusion, namely, “The puppy is the father of the dog.”

Since Darwin first suggested that most living animals shared common ancestors, it has become increasingly clear that there are many similarities in the psychological processes of different species, particularly among those groups of animals that have somewhat comparable forms and functions. For example, human beings and dogs are both social mammals with similar brain structures and patterns of activity, so it is not surprising to find that they also show similarities in their emotional and cognitive processes. Thinking along these lines, it would not be much of a stretch to suggest that if early stressors can cause later psychological problems in humans, then it would make sense to look for an analogous set of relationships in dogs. This appears to have been the reasoning of Julia Espinosa, lead author of a new study from Harvard’s Department of Human Evolutionary Biology.

Measuring Canine Psychological Characteristics

This study involved 4497 dogs whose owners were asked to fill out the Canine Behavioral Assessment and Research Questionnaire (C-BARQ). This is a behaviorally validated inventory which contains 101 questions through which dog owners are asked to assess the frequency and intensity of various common behaviors that they observe in their dog. This questionnaire was developed in the laboratory of James Serpell at the University of Pennsylvania and has been shown to be a reliable way of measuring the temperament of dogs, including levels of fearfulness and aggression.

An Inventory of Stressors

The research team also measured whether each of these dogs had suffered from seven relatively common stressors which included: physical punishment or corrections; being attacked by a dog or another animal; not having or being separated from a primary caregiver; physical abuse (e.g. being hit or kicked); being intensely frightened by a person; suffering from a serious physical injury (e.g. being hit by a car); or being chained or tethered outdoors for long periods of time. For each of these stressors it was determined whether the dog had experienced such adversity, and if so, the frequency of such incidents and the age at which they occurred.

A lot of additional data was also collected, including the sex, neuter status, breed and size, and descriptions of their living environment, as well as the presence or absence of children in the household.

A Sensitive Period

Although the researchers used a set of complex statistics to analyze their data, their true interests were in the measurements of fearfulness and aggression—which are among the most common reasons that dogs are relinquished to shelters or euthanized. Fortunately, when it comes to these two behavioral characteristics, the general pattern of the findings is clear. The outcome of this study can be summarized by saying that stressful experiences which occur before a puppy is 6 months of age have the greatest impacts, increasing both fearfulness and aggression. The timing is important, and the researchers refer to this early time frame as a "sensitive period," meaning that although stressors occurring later than 6 months can still affect adult behavior, these effects are markedly smaller than those which occur earlier.

It is important to note that the effects of the early exposure to stresses in the environment persist for the rest of a dog's life, regardless of its size, sex, neuter status, or weekly exercise, or the nature of the household it lives in. The greater the number of stressors, and the higher the frequency of their occurrence, the more severe the effect on a dog's behavior.

Breed-Related Genetics Matter

The data analysis also demonstrated that another important factor is the dog’s breed. Some breeds are simply more resilient. For example, early life stressors have little impact on the aggressiveness of Golden Retrievers and Labrador Retrievers. Comparatively, Siberian Huskies and American Eskimo Dogs show massive increases in aggressiveness due to exposure to stress.

The effects of stress are not always the same for fearfulness and aggression in a given breed. Although Labrador Retrievers also showed very little difference in fearfulness after early life stress, Golden Retrievers, whose aggression was not much affected by early adversity, did become more fearful when stressed. As the investigators summarized it: “Our findings establish that breed ancestry and individual experience interact to show fear and aggressive behavior in pet dogs, confirming that socioemotional behavior is shaped by gene-environment interactions.”

The takeaway message from this research is that if you want to increase the likelihood that you will have a fearless and friendly dog, you should make a strong effort to shield your puppies from harsh treatment and strong stressors, especially during the first six months of their life.

Copyright SC Psychological Enterprises Ltd. May not be reprinted or reposted without permission.

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