When The Brain Scrambles Names, It's Because You Love Them

Enlarge this image Alex Reynolds/NPR Alex Reynolds/NPR

When Samantha Deffler was young, her mother would often call her by her siblings' names — even the dog's name. "Rebecca, Jesse, Molly, Tucker, Samantha," she says.

A lot of people mix up children's names or friends' names, but Deffler is a cognitive scientist at Rollins College, in Winter Park, Fla., and she wanted to find out why it happens. So she, and her colleagues, Cassidy Fox, Christin Ogle, and senior researcher David Rubin, did a survey of 1,700 men and women of different ages, and she found that naming mistakes are very common. Most everyone sometimes mixes up the names of family and friends. Their findings were published in the journal Memory & Cognition.

"It's a normal cognitive glitch," Deffler says.

It's not related to a bad memory or to aging, but rather to how the brain categorizes names. It's like having special folders for family names and friends names stored in the brain. When people used the wrong name, overwhelmingly the name that was used was in the same category, Deffler says. It was in the same folder.

And there was one group who was especially prone to the naming mix-ups.

"Moms, especially moms," Deffler says. "Any mom I talked to says, 'You know, I've definitely done this.'"

It works something like this: Say you've got an armful of groceries and you need some quick help from one of your kids. Your brain tries to rapidly retrieve the name from the family folder, but it may end up retrieving a related name instead, says Neil Mulligan, a cognitive scientist at UNC Chapel Hill.

"As you are preparing to produce the utterance, you're activating not just their name, but competing names," he says. You flick through the names of all your other children, stored in the family folder, and sometimes these competing names win.

Like in the classic scene from the TV show, Friends. When Ross says his wedding vows, he is asked to repeat his fiancée's name, Emily. He says his former girlfriend's name Rachel instead.

Now Ross probably had both Rachel's and Emily's names in his mental folder of loved ones and a mental mix-up ensued.

And it's not just human loved ones that are filed together.

"Whatever dog we had at the time would be included in the string along with my sister Rebecca and my brother Jesse," Deffler says.

So your family dog typically gets filed with other family members. This of course sparks the question — what about your family cat?

"You are much more likely to be called the dog's name than you are to be called the cat's name." Deffler says.

This implies that psychologically, we categorize the dog's name along with our family member's names, according to Mulligan.

"And we don't do that with cats' names, apparently, or hamsters' names or other animal names," Mulligan says.

Maybe that's why we call the dog man's best friend.