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Personality Changes Over Time

Updated: Mar 14, 2023

Original post The Fascinating Way Your Dog's Personality Changes Over Timeby Dr. Karen Shaw Becker on Healthy Pets


Research into the relationship between dogs and their humans continues to reveal fascinating insights. Very recently, a study published by Michigan State University suggests that dogs’ personalities change over time, and further, our interactions with them play a role in these gradual changes.


“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,” William Chopik, Ph.D., professor of psychology and lead study author, explained in an MSU news release.


“We expected the dogs’ personalities to be fairly stable because they don’t have the wild lifestyle changes humans do, but they actually change a lot. We uncovered similarities to their owners, the optimal time for training and even a time in their lives that they can get more aggressive toward other animals.”


Largest Study to Date Looks at Changes in Dogs’ Personalities Over Time

The study, published in the Journal of Research in Personality, is among the first, and is the largest to date to evaluate changes in dogs’ personalities. The researchers developed an extensive survey comprised of questions about dogs’ personalities and behavioral history. The survey was answered by owners of over 1,600 dogs of 50 different breeds, ranging in age from a few weeks to 15 years, including a similar number of males and females.


The survey questions incorporated five aspects of dog personality: fearfulness, aggression toward people, aggression toward animals, activity or excitability and responsiveness to training. The owners also answered a survey about their own personalities.


Important Takeaway: Obedience Classes Are Linked to More Positive Personality Traits Throughout a Dog’s Life

The researchers discovered, predictably, that younger dogs are more active and excitable than older dogs, and the decrease in activity level occurs gradually and steadily over the course of a dog’s lifetime. The trait of aggression toward both people and other animals peaks in 6- to 8-year-old dogs, with both younger and older dogs showing lower levels of aggression of either type.


When it comes to responsiveness to training, the researchers found the trait increases steadily from puppyhood and peaks between the ages of 6 and 8, at which time it begins a gradual decline.


However, the decline occurs no more rapidly than the rise from puppyhood to middle age, suggesting that it is indeed possible to “teach an old dog new tricks.” One personality trait that rarely changes as a dog ages, according to the researchers, is fear and anxiety. However, they also report that dogs exposed to obedience classes tend to be less fearful overall.


“Exposure to obedience classes was associated with more positive personality traits across the dog’s lifespan,” said Chopik. “This gives us exciting opportunities to examine why personality changes in all sorts of animals.”


Outgoing and Agreeable Owners Rate Their Dogs More Positively

Since the MSU study measured dog personality traits that aren’t shared by humans, the researchers’ observations of how “dogs resemble their owners” is, in my opinion, not especially enlightening or helpful. From the MSU news release:

“Extroverted humans rated their dogs as more excitable and active, while owners high in negative emotions rated their dogs as more fearful, active and less responsive to training. Owners who rated themselves as agreeable rated their dogs as less fearful and less aggressive to people and animals."


"The owners who felt happiest about their relationships with their dogs reported active and excitable dogs, as well as dogs who were most responsive to training. Aggression and anxiety didn’t matter as much in having a happy relationship,” Chopik said.


As dog behavior expert and author Dr. Stanley Coren points out in his Canine Corner blog in Psychology Today, dogs and humans share at least four personality traits (agreeableness, extraversion, openness and neuroticism), and hopefully, future researchers will look at those traits in dogs to see if they change with age, as they do in humans


8 Ways Your Dog’s Behavior May Change as She Gets Older

Most pet parents are aware that their dog will change physically as she gets up in years, but many aren’t prepared for the behavior changes that can accompany aging.


Needless to say, any change in your pet’s normal behavior should be discussed with your veterinarian, because animals often express underlying physical problems through a behavior change. For example, a painful hip or back can result in one or more of the behaviors listed below.

  1. Aggression — Along with an age-related reduction in hearing, eyesight and sense of smell, your dog may startle more easily, and in some dogs, this can result in unprovoked aggression. The situation will require some sleuthing on your part, with the help of your veterinarian, to understand the specific causes or triggers of the behavior so a treatment or behavior modification protocol can be implemented.

Enrolling in positive training classes (obedience, nose work, agility, etc) through the 8-year mark when aggressive behavior potentially peaks is a great way to help keep a dog’s interactions with other humans and animals controlled, positive and relationship-oriented. Significant behavior changes may also require the help of a veterinary behaviorist, and I encourage you to contact one sooner rather than later if your older dog is having episodes of unprovoked aggressive behavior.

  1. Anxiety — Dogs who are anxiety-prone as youngsters and adults (for example, those with noise phobias or separation anxiety) often become more so as they age.

Positive reinforcement training may be helpful in curbing anxiety-related behavior in your dog, and it certainly can’t hurt as long as you don’t get too focused on results. It’s important to realize that just as you’ve dealt with some level of anxiety in your pet for years, you should expect and plan for amplification of those issues as she ages. Again, fun and social classes are a great way to help manage anxiety-based behaviors and build trust.

  1. Destructiveness — Sadly, some dogs become destructive as they age — a situation that can be quite disturbing for family members. You might lose a cherished belonging or two at this stage of your pet’s life, or she might turn her destructive urges on herself.

Some older dogs develop pica (eating nonfood objects) for the first time. Others seem driven to lick, suck or chew their own body parts, those of family members or household objects. Digging and scratching can also become a problem. Many of these behaviors can be boredom-based, so maintaining daily environmental enrichment is super important.


Once again, it’s important to talk with your veterinarian about any destructive tendencies your dog develops to rule out an underlying physical cause. Meanwhile, you’ll want to dog-proof your home and belongings, and ensure your pet has plenty of appropriate raw bones and chews to gnaw on, but only when you’re around to supervise.

  1. Hypersensitivity, fears and phobias — If your senior pet has deteriorating vision or hearing, even his own home can become a frightening place. Pets thrive on routine and consistency, and this goes double for aging companions who are having trouble navigating even familiar terrain.

It’s important at this stage of your dog’s life to keep his environment consistent. Don’t arbitrarily move his food or water bowl, his crate, his bed or his toys. Try to avoid rearranging the furniture in your home. Mealtimes and potty walks should be consistent from one day to the next, as well as exercise and play time.

If your dog is becoming more sensitive to normal household or neighborhood sounds, play background music or keep the TV on to mask noises.

  1. Inappropriate elimination — If your older dog seems to have forgotten his housetraining, there are a number of potential causes, none of which involve deliberate disobedience. The first order of business is to make an appointment with your veterinarian to rule out any underlying disease process. Once that’s done, you’ll need to investigate other possible causes for inappropriate elimination, including decreased mobility, needing to go more often or less control over his bladder or bowels.

Initial steps you can take to resolve the problem include taking him outside more often to eliminate, and/or introducing/re-introducing him to a crate. It’s also important to recognize the difference between urine dribbling, over which your dog has no control no matter how often he goes outside, and urinating.

  1. Nighttime restlessness — Some older dogs develop a problem sleeping through the night. Age-related issues that can cause this change include loss of vision or hearing that affects sleep quality, the need to relieve himself more often, or an increased response to noises that never bothered him before.

All dogs, including senior and geriatric pets, need age- and condition-appropriate exercise each day. If your dog gets some exercise already, try increasing the time he spends playing or taking walks. If he doesn’t get much exercise, start safely increasing his daily activity level. The goal is to tire him out physically, so he’ll be more likely to sleep at night.


If your dog needs midnight trips outside to relieve himself but is otherwise healthy (as confirmed by your vet), he may be taking in too much water before bed. Try removing his water bowl after dinner, and ensure he gets an opportunity to relieve himself right before you retire for the night.

Let your dog sleep in your bedroom. Sleeping near his humans should help ease any anxiety that is contributing to his nighttime restlessness.

  1. Compulsive behavior — These are repetitive behaviors your dog may perform over and over, for no apparent reason. They can include constant licking (usually of a particular body part like a paw), which can result in hot spots. Other behaviors include repetitive tail chasing, spinning, jumping, pacing, “air biting” and staring blankly into space.

If a thorough workup by your veterinarian shows no medical cause for your dog’s obsessive behavior, she may be doing it to relieve feelings of anxiety or conflict. One way to try to break the cycle is to simply stop her as soon as she begins the behavior, by speaking calmly to her and petting or massaging her. If the behavior is potentially dangerous or harmful and you don’t feel you can manage it on your own, talk with your integrative veterinarian or a veterinary behaviorist.

  1. Vocalizing — Excessive vocalizing is more common in older cats than dogs, but if your dog is growing more “talkative,” it can be unsettling because as her guardian, you want desperately to understand what she needs from you.

An increase in vocalizing can be caused by the disorientation that comes with a decline in cognitive function. It can also mean your dog isn’t hearing things as well as she once did, or that she’s in pain. If your veterinarian has ruled out an underlying medical condition, try training your dog to respond to a gentle verbal cue such as “Quiet” or “Shhh,” and reward her lavishly for her efforts.

However, keep in mind it’s possible she doesn’t realize she’s making noise, in which case she’s not likely to learn a verbal command to be quiet. If that’s the case, you’ll just need to distract her when she vocalizes by speaking quietly and reassuringly to her.

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