New York, May 17 (IANS) Don't be surprised if your mother sometimes calls you by the name of your pet dog. It only shows how integral the dog is to the family, suggests new research that has found that wrong name due to the slip of the tongue is usually plucked from the same relationship category.

Friends call each other by other friends' names, and family members by other family members' names. And that includes the family dog, the researchers said.

Among people who know each other well, the wrong name is usually plucked from the same relationship category, the study found.

"It's a cognitive mistake we make, which reveals something about who we consider to be in our group," said one of the study authors David Rubin, professor at Duke University in Durham, North Carolina, US.

"It's not just random," Rubin said.

The study, based on five separate surveys of more than 1,700 respondents, appeared online in the journal Memory and Cognition.

In addition to mixing up sibling for sibling and daughter for son, study participants frequently called other family members by the name of the family pet -- but only when the pet was a dog, the researchers found.

Owners of cats or other pets did not commit such slips of the tongue.

The researchers were surprised how consistent that finding was, and how often it happened.

"Our study does seem to add to evidence about the special relationship between people and dogs," lead author Samantha Deffler, PhD student at Duke University noted.

"Also, dogs will respond to their names much more than cats, so those names are used more often. Perhaps because of that, the dog's name seems to become more integrated with people's conceptions of their families," Deffler explained.