Here's the secret to having a super sharp memory

The answer has something to do with lasting friendships.

Turns out, close friends help not only in creating memories, but also in keeping them alive well past their shelf life.

A new Northwestern Medicine study found that maintaining positive, warm and trusting friendships might be the key to a slower decline in memory and cognitive functioning.

Superagers -- who are 80 years of age and older and have cognitive ability at least as good as people in their 50s or 60s -- reported having more satisfying, high-quality relationships compared to their same age peers, the study reported.

"You don't have the be the life of the party, but this study supports the theory that maintaining strong social networks seems to be linked to slower cognitive decline," said senior author Emily Rogalski.

Participants answered a 42-item questionnaire called the Ryff Psychological Well-Being Scale, which is a widely used measure of psychological well being.

The scale examines six aspects of psychological well being: autonomy, positive relations with others, environmental mastery, personal growth, purpose in life and self-acceptance.

Superagers scored a median overall score of 40 in positive relations with others while the control group scored 36, a significant difference, Rogalski said.

"This finding is particularly exciting as a step toward understanding what factors underlie the preservation of cognitive ability in advanced age, particularly those that may be modifiable," said first author Amanda Cook.

"It's not as simple as saying if you have a strong social network, you'll never get Alzheimer's disease," Rogalski said.

"But if there is a list of healthy choices one can make, such as eating a certain diet and not smoking, maintaining strong social networks may be an important one on that list.

"None of these things by itself guarantees you don't get the disease, but they may still have health benefits."

The study is published in the journal PLOS ONE.

Lead photograph used for representational purpose only. Kind courtesy: Josephine Skriver/Instagram