Dog personality changes as dogs age, but in predictable ways

If your dog seems like a different animal than it was as a puppy, you are not imagining it. Research from Michigan State University found that dog personalities change over the course of their lives, often in ways that can be predicted.

The study

Psychologist William Chopik surveyed the owners of more than 1,600 dogs from about 50 breeds. The work was published in the Journal of Research in Personality.

The dogs ranged from a few weeks old to around 15 years old, with a roughly even split between males and females.

Owners described their dogs’ personalities and behavior, and also answered questions about their own personalities.

A sweet spot for training

One of the clearest patterns concerned trainability. Older dogs were harder to train than younger ones.

The study pointed to around the age of six as a good window for teaching obedience. By then a dog has outgrown its excitable puppy phase, but it is not yet too set in its ways.

Fearfulness and anxiety, on the other hand, showed little change with age.

Dogs reflect their owners

The research also found that dogs tend to resemble their people.

Owners who described themselves as extraverted reported more excitable dogs. Owners with more negative emotions reported dogs that were more fearful and less responsive to training.

Agreeable owners rated their dogs as less fearful and less aggressive toward people and other animals.

Dogs that had attended obedience classes tended to show more positive traits throughout their lives.

Nature and nurture

Some traits appear to be rooted in biology and are hard to change. Yet the environment matters too.

According to the university, a dog adopted into a loving home with regular walks can become more relaxed and sociable over time.

Because the study relied on owner reports, it captures how people see their dogs, which may be shaped partly by their own personalities.

What it means for dog owners

The findings echo research on humans, whose personalities also shift gradually across adulthood.

For owners, the message is encouraging. A dog’s character is not fixed at birth. Patience, training and a stable, caring routine can help shape the companion your dog becomes.