Most of us intuitively understand that having positive social interactions is good for us. But when we ask deeper questions, the answers become more challenging to find. Should we tell people who are isolated that they are hurting themselves? And, even if being socially engaged is enjoyable and beneficial, could it really be good for your brain? What is clear is that studies done in very different ways have found the same results: People who develop dementia are less socially engaged in the years before diagnosis than those who do not develop dementia.

I’ll be posting over the coming months about dementia and the science that we know. It’s important to understand how we study the disease and I’ll describe it a bit here. One method, called the epidemiological method, surveys populations and compares people with a problem or disease to those without that condition. To determine whether social engagement might prevent memory decline, for example, a number of studies have compared people with dementia to similarly aged individuals without dementia. Almost all find that in the years before people develop dementia they are less socially active than those who do not develop dementia.

The problem with this approach is the possibility that some other factor besides social engagement led to the risk of developing dementia. There is always the chance, for example, that many diseases causing dementia begin in the brain long before the decline can be detected and that the decline in social activity is the result not the cause of dementia.

Another approach used by scientists is to raise animals such as mice in two different environments, one in which contact with other animals is encouraged and one in which it is limited. Here again, animals raised in the stimulating environment do better on tests of memory when they are adults than those who were socially isolated. This certainly reinforces the idea that stimulating environments improve brain function but it’s a big leap to make recommendations to people based on these studies.

The most convincing evidence of the benefits of being socially active comes from what is referred to as a randomized, controlled trial. In this approach some people get the “treatment” while others do not, and neither the researchers nor the participants know who got which treatment. One long running study, called “Experience Corp,” did just that in relationship to social engagement. Directed by Linda Fried, Dean of the Mailman School of Public Health at Columbia University, the study tested whether training older people to engage and mentor young students would be more beneficial than just encouraging the seniors to do volunteer work of their choice, such as delivering meals or providing transportation.

The results were striking. Those randomized to the student engagement program had many beneficial health outcomes including less frailty, better cognition, and better psychological well-being. Perhaps most surprising of all, those who participated in the engagement program, particularly the men, had an increase in the volume of the hippocampus, the part of the brain that shrinks very early in Alzheimer’s disease and is necessary for the formation of new memories. In the comparison group who had only been encouraged to volunteer, the hippocampus actually shrank! Here, then, is compelling evidence that social engagement is good for your brain—it not only resulted in better reasoning ability and health but actually had a beneficial effect on brain structure.

And just as importantly, the children who participated in the mentoring activity did better on many measures, too. So it is a “win win” for all of us to be socially engaged.  It’s good for our brains and for bringing people and communities together.

Peter Rabins 2016