Why You and Your Best Friend Really Are of One Mind

New research shows that you may be sharing something way cooler than a friendship necklace with your bestie — your memory bank.

A best friend is someone you can share most anything with. Your deepest secrets, fears, hopes and dreams. You’ve experienced life’s grand moments together, your first concert, a broken heart and graduation day.

But now research is showing that, without even knowing it, you may share something that biologically ties the two of you together. And it’s way cooler than a “best friends” necklace, it’s science.

The transactive memory system (TMS) are repositories of knowledge shared between two or more people. Can’t remember that person you went on a terrible date with a few years ago? Just tap into your TMS, because there is a chance your BFF does and could even recall certain details you’ve completely forgotten (or chose to push out of your mind).

The TMS has been studied in romantic and work relationships (commonly known as “groupthink”), but a new study published in the Journal of Social and Personal Relationships looks at the memory in the context of friendship, specifically best friends.

As part of the study, people answered questions about their relationship with their best friend, such as how loyal they were, how long they’d been friends and whether they thought their friend had credible knowledge of them or knows them well.

“We found that the longer they were friends, the stronger these transactive memory systems were in the friendship,” Nicole Iannone, a professor of psychology at Penn State University and lead author of the study, told the Atlantic. “And then trust was really important: The more trust you have in your friendship, the stronger your transactive memory system was.”

Because having a TMS with someone means trusting one another and being psychologically and emotionally close (not to mention having integrated lives), friends that showed a stronger TMS connection were almost a tribute to the legitimacy of their friendship. They reported having perceived their friendship as being of higher quality.

Maybe there is a way to determine who your best friends are. Let’s just hope they measure up.

The report also studied the two different structures of TMS — differentiated and integrated. In an integrated TMS, friends share similar knowledge so they can validate and help remind each other of events. In a differentiated TMS, they have knowledge of different things, which can be a real lifesaver in moments of memory lapse.

Interestingly, the researchers found that in mixed-gender best friendships, TMS was more differentiated, while in same-gender best friendships, it was more integrated.

Because you share an encyclopedia of your life’s knowledge with your BFF, there’s nothing the two of you can’t do! (Now if only you’re best could Freaky Friday for you at your next job interview.)

What Do YOU Think?

Share a story about a time your BFF helped you remember something important. Do you think you know everything you need to know about your bestie? If not, it may be time to study up!