How Does Loneliness Lead to Cognitive Decline?

Lonely Man Feeding Pigeons
Credit: Dreamstime

For most of us, we were at our most social during our school years. In fact, according to the Encyclopedia of Human Relationships, young adults spend as much as 25 hours per week with friends, more than any other age group. It is no coincidence that these youthful years also found our minds in their sharpest and most creative state. Though scientists have long suspected a positive correlation between socializing and cognitive ability, recent studies have shed light on the reason why friendships keep our minds sharp.

From grade school through college, we spent most of our days in close quarters with our peers maintaining existing friendships and building new ones. It is during this phase that we engage in a type of "social sampling," in which we expose ourselves to as many different types of people as possible to determine who we best form connections with. But this phase only lasts until approximately age 25, the year in which our number of friendships typically peak.

While marriage is a joining together of two unrelated families and friend groups, the ceremony often marks the beginning of the decline in the quantity of our friendships. Between the birth of children and spending time with in-laws, most marriages pull attention away from friend groups and focus it instead on direct family members. By age 39, the number of friends we interact with on a monthly basis typically drops by nearly 40% and continues to decline as we grow older. While we do not necessarily spend less time communicating with other people, it is the loss of friendship diversity that has a profound impact on our social lives and, consequently, our cognitive health.

Young Kids Making Friends
Credit: Dreamstime

Research has concluded that the friendship experimentation of our formative years engages our minds in an entirely different way than a reliance on existing, comfortable relationships. Upon interacting with someone new, our minds strive to establish personal connections based on mutual interests. We utilize our memories to store personal details about the person before us. We employ our problem solving skills to make the best impression of ourselves and avoid embarrassing gaffes.

In other words, building many friendships activates the neural pathways in our brains, much like exercising a muscle. But as we grow older and the quantity of our friendships dwindles, so does our stimulation of these neural pathways. In this way, our slow decline into social isolation effectively causes our brains to atrophy.

While building friendships is not necessarily as convenient as it was when you spent all your time with your schoolmates, more opportunities exist than ever before to form new relationships and rekindle old ones. Social networks like Facebook make it simple to relocate a long lost friend and pick up where you left off years ago. Just adding a few additional friendships can stimulate the neural connections in your brain and restore the sharp mind you possessed in your youth.



Paul has been interested in medical research since his first organic chemistry class in college. He was a high school biology teacher for 32 years until retiring to spend more time reading, hiking, and camping with his wife and two dogs.

Email Paul at [email protected].


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