Scientists already know that canines and humans release the love hormone known as oxytocin when they are together.
"We have pretty good evidence that dogs actually love their humans," said US neuroscientist Dr Paul Zak, who conducted the study.
In the study completed for the upcoming BBC Documentary "Cats vs Dogs", Zak took saliva samples from 10 cats and 10 dogs prior to a 10-minute playtime session with their owners.
According to the results, a 57.2 per cent increase of the hormone oxytocin was found in dogs; whereas a 12 per cent increase of the hormone was found in cats.
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"From this sample it is true to say that these dogs love their owners five times more than the cats do," Zak was quoted as saying by catchannel.Com.
"I was really surprised to discover that dogs produced such high levels of oxytocin. The dog level of 57.2 per cent is a very powerful response.