Prof Richard Wiseman, of the University of Hertfordshire, conducted an online survey where in he asked almost 2,500 people to fill questionnaires about their characters and those of their pets.
After the survey, he found that many dog lovers, cat owners and even reptile keepers said they shared many of the same traits — such as happiness, intelligence, independence and sense of humour — as their pets.
However, he also found that the longer an animal had been with their owner, the more likely they were to have picked up their characteristics.
"For years owners have insisted their pets have a unique personality," The Telegraph quoted Prof Wiseman, as saying.
"Not only does this work suggest they might be right, it also reveals people's pets are a reflection of themselves," he added.
Almost 50 percent of the respondents to his survey were cat owners, while 31 per cent had dogs, 7 per cent fish, 6 per cent birds and 6 per cent reptiles.
Prof Wiseman found about 20 per cent of pet owners rated their own personality and that of their animals in similar terms.
However, for those who had owned their animal for seven years or more, the chance of them rating their pet's traits as broadly comparable to their own increased to about 40 per cent.
"Similarity promotes liking in humans. Research has shown couples that are like each other stay together longer," Prof Wiseman said.
"Extending this to the animal kingdom, I think it is likely someone who is fun and playful is more likely to go for a dog, for example.
"It's like with married couples. They grow to look like each other and to have similar personalities. It's possible we are seeing a similar effect," he added.
Prof Wiseman's research also showed owners of certain pets appear to share similar personalities.
It was found that fish owners were apparently the most contented, with 37 per cent strongly agreeing that they were happy, compared with 24 per cent of people with cats and 22 per cent of those who had dogs agreeing.
4 out of 10 people with dogs believed they were fun loving compared to just 2 per cent of reptile owners.
Those with cats came out as the most dependable, but also the most emotionally sensitive, while those who kept reptiles were the most independent.