Friends Make You Smart

Three years after Christine McCleary’s father died, she started noticing changes in her mom, Stella. A typically active woman who always had lots of friends, Stella started skipping church services, which was out of character for her. She stopped wearing makeup and didn’t always remember to launder her clothes.

Sign up for AARP's Health Newsletter.

Not only that, Stella, 86, began spending more and more time alone in her apartment and often couldn’t remember what day of the week it was. McCleary was no longer sure that her mom, who lived thousands of miles away, was remembering to eat regular meals.

Social engagement can benefit memory and cognitive function. — Photo by Ralf Nau/Getty Images

“We knew that things were going downhill,” says McCleary, 56, but the final straw came during a frantic phone call. “She thought my father was there, and he’d been dead at the time for three years. That made us say, hey, she can’t be living on her own anymore.”

So Stella moved from her longtime home near Pittsburgh to a senior residence in Reno, Nev., close to McCleary and her husband. Stella went from having maybe two social interactions a week to living in a building with more than 200 of her peers. Within a month she was applying blush and wearing jewelry. She started playing bridge every week and walking three miles a day.

Her conversations became animated again. “It was like the clock was turned back four years,” says McCleary’s husband Larry, 59. “You could tell she enjoyed getting up in the morning.”

New research suggests that Stella’s turnaround may have been integrally tied to her level of social activity and engagement. Many scientists now believe that social interaction is key to maintaining good mental health and warding off diseases like dementia and Alzheimer’s. Many recent studies document the positive effects of social interaction. Although researchers are not certain what happens in the brain to produce the positive effects seen among the more socially engaged, it appears clear that close relationships and large social networks have a beneficial impact on memory and cognitive function as people age.

In a study of 2,249 California women published in the July American Journal of Public Health, researchers reported that older women who maintained large social networks reduced their risk of dementia and delayed or prevented cognitive impairment.

By interviewing the women over the course of four years, researchers accumulated data about the size and closeness of their social networks. Researchers asked the women questions such as “How many people can you rely on for help?” and “How many people can you talk to about private matters?” They also tallied the frequency of visits, phone calls and mail from family or friends the women received.

The results showed that women with the larger social networks were 26 percent less likely to develop dementia than those with smaller social networks. And women who had daily contact with friends and family cut their risk of dementia by almost half.

“If you stay connected, you have a better shot,” says Valerie Crooks, clinical trials administrative director at Southern California Kaiser Permanente Medical Group and lead author of the study. “Whenever we have even the most basic exchange, we have to think about how to respond, and that stimulates the brain. There are people who are outliers, who have two very close relationships and are fine cognitively. But people who have three or more relationships tend to do better.”

Crooks and her colleagues suggest that one reason for these findings may be that social networks facilitate healthy behaviors — like joining a walking group, tennis team or bowling league.

A number of observational studies have shown that exercise reduces or delays the onset of pathological changes in the brain that lead to cognitive impairment. And the first clinical trial showing that physical exercise may improve cognitive function among those who suffer mild impairment was published in the Journal of the American Medical Association in September. Exercise, particularly along with social interaction, is believed to stimulate the formation of brain synapses, enhance blood flow in the brain and increase the formation of nerve cells.

Next: Why does social interaction make a difference? >>