Dogs’ personalities can change to reflect similar changes in their owners. Which means your midlife crisis could have life-changing consequences for your dog.

“When humans go through big changes in life, their personality traits can change. We found that this also happens with dogs—and to a surprisingly large degree,” said William Chopik, PhD, MS, assistant professor of psychology at Michigan State University and lead author of a new study that shows dogs, like humans, can go through predictable personality shifts over the course of their lives.

“We expected the dogs’ personalities to be fairly stable because they don’t have wild lifestyle changes [like] humans do, but they actually change a lot,” Chopik said.

Chopik and his team surveyed more than 1,600 dog owners. The dogs included more than 50 different breeds, and ranged in age from a few weeks to 16 years old. About half were pure bred.

The owners were asked to rate their own personalities, their dog’s personality, and answer additional questions about their dog’s demographic and behavioral history.

The researchers were looking at three major areas: chronic health problems, biting history, and relationship quality. They found that dogs’ personalities can predict life outcomes in all three areas.

The researchers measured five canine personality traits using the Jones personality taxonomy for dogs:

• Fearfulness: a dog’s general anxiety and fearfulness toward people, other dogs, new environments, and handling by owners and others (e.g., veterinarians and groomers)
• Aggression toward people: a dog’s general and situational aggression
• Activity/excitability: a dog’s general level of excitability, playfulness, engagement, and companionability
• Responsiveness to training: a dog’s trainability and controllability(e.g., will the dog leave food alone when told to?)
• Aggression toward other animals: a dog’s aggression and dominance toward other dogs and perceived prey (e.g., squirrels)

The researchers wondered if, just as human personality informs human health outcomes, dog personality might be linked to dog health outcomes over time. Researchers asked owners to indicate whether their dogs had any of the following health problems: deafness in one or both ears, blindness in one or both eyes, arthritis, hip or other joint dysplasia, and other disability). Thirty percent of dogs had at least one health condition.

Certain predictable patterns emerged.

For example, highly aggressive dogs, especially those aggressive toward people, were more likely to have bitten a human; dogs highly responsive to training were less likely to have done so.

But the only significant personality trait predicting chronic health conditions in canines was activity/excitability—dogs who were more active/excitable had fewer chronic health conditions, as did dogs who were younger. One possibility is that older and/or inactive dogs may be more likely to develop health conditions (e.g., obesity) that might predict the onset of chronic illness. 

Another suggestive finding is that dogs who are responsive to training by their owners may also avoid health-harming behaviors (e.g., eating foods they shouldn’t or running away or going somewhere dangerous). The authors point out that variation in adaptive behavioral patterns and personality have also been found to be related to longevity and health in nonhuman primates.

Researchers also found a surprising correlation between dogs’ personalities their owners’.

Owners high in extraversion rated their dogs as more active/excitable; owners high in agreeableness, conscientiousness, or open-mindedness rated their dogs as less fearful, more active/excitable, and less aggressive toward people and animals, as well as more responsive to training; owners high in negative emotionality rated their dogs as more fearful and active/excitable, and less responsive to training.

Owner agreeableness was associated with higher relationship quality. Owners report higher relationship quality if their dogs are more active/excitable and more responsive to training. Female owners report higher relationship quality with their dogs. Owners of older dogs also report higher relationship quality.

In general, younger dogs showed a lot of the same impulsiveness we see in human youth. Specifically, younger dogs were more active/excitable, less aggressive toward people, more aggressive toward other animals, and less responsive to training compared to “middle aged” (around six to eight years old) and older dogs. There were no age differences related to fearfulness in dogs. 

Chopik plans to continue his research into dogs’ personalities by examining how the environment an owner provides their dog might change the dogs’ behavior.

“Say you adopt a dog from a shelter. Some traits are likely tied to biology and resistant to change, but you then put him in a new environment where he’s loved, walked, and entertained often. The dog then might become a little more relaxed and sociable,” Chopik said. “Now that we know dogs’ personalities can change, next, we want to make a strong connection to understand why dogs act—change—the way they do.”

Just don’t take your dog on that trip to Cabo. Whatever life-changing event you experience down there, it’s likely to change him too, soon enough.

Photo credit: © iStock/Veronika7833