No wonder they're man's best friend! Study finds dogs' personalities often end up mimicking their owners' traits as they change over time

It’s said you can’t teach an old dog new tricks. But, when it comes to personality, it seems dogs continue making progress throughout their lifetime.

A new study has found that dogs’ personalities may change over time – and even tend to line up to match their owner’s.

The findings upend previous assumptions that dogs’ personalities are generally unchanging due to the overall stability of their lives ,according to Daily Mail.

According to the researchers, the results suggest dogs experience personality changes similar to how humans do over the course of their lives.

‘When humans go through big chances in life, their personality traits can change,’ said lead author William Chopik, professor of psychology at Michigan State University.

‘We found that this also happens with dogs – and to a surprisingly large degree.

‘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.

‘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.’

In the study led by Michigan State University, the researcher surveyed owners of more than 1,500 dogs.

This included 50 different breeds, with both male and female dogs aged just a few weeks to 15 years old.

Dog owners were given questionnaires about their own personalities as well as their dogs’, the researchers say.

And, this revealed some similarities.

‘We found correlations in three main areas: age and personality, in human-to-dog personality similarities and in the influence a dog’s personality has on the quality of its relationship with its owner,’ Chopik said.

‘Older dogs are much harder to train; we found that the “sweet spot” for teaching a dog obedience is around the age of six, when it outgrows its excitable puppy stage but before it’s too set in its ways.’

Humans with extroverted personalities tended to rate their dogs as excitable and active, while dog owners with higher rates of negative emotions were more likely to rate their dogs as fearful and less responsive to training.

Agreeable dog owners were often found to have dogs that were less aggressive towards both animals and people.

According to the researcher, the findings tap into the idea of ‘nature versus nurture’ – a concept commonly used in the discussion of human personality.

In future studies, Chopik plans to focus on the effect a dog’s home environment can have on its behaviour.

 ‘Now that we know dogs’ personalities can change, next we want to make a strong connection to understand why dogs act – and change – the way they do.’