'Dogs mirror owners' personalities'
The idea that a dog takes on the personality of its owner has received scientific support.
Researchers in Austria say dogs can mirror the anxiety and negativity of owners.
And dogs that are relaxed and friendly can pass this on to humans, perhaps helping their owners cope with stress.
More than 100 dogs and their owners underwent various tests, including measurement of heart rate and their response to threat.
Saliva samples were also taken to measure cortisol levels, a marker for stress.
The owners were then assessed for the big five hallmarks of personality: neuroticism, extraversion, openness to experience, agreeableness and conscientiousness.
The personality of dogs was also assessed with a questionnaire.
Dr Iris Schoberl, of the University of Vienna, said both owners and dogs influenced each other's coping mechanisms, with the human partner being more influential than the dog.
"Our results nicely fit to experience from practice: owners and dogs are social dyads [a group of two], and they influence each other's stress coping," she told BBC News.
She said dogs are sensitive to their owners' emotional states and may mirror their emotions.
Dogs have lived alongside humans for more than 30,000 years.
Evidence shows they can pick up emotional information from people and adjust their behaviour accordingly.
The research is published in the journal, PLOS ONE.
Follow Helen on Twitter.