Loneliness is something we’ve all experienced from time to time. It’s defined as perceived social isolation. Chicago-based neuroscience researcher John Cacioppo has spent much of his career exploring the social nature of the human brain, and loneliness has been a main focus for him. In a Q&A with the University of Chicago, Cacioppo described how the perception of social isolation alone can trigger a physiological reaction:

“Much of what goes with loneliness—behaviorally, physiologically—is so deep that we’ve got it in our genes….Loneliness is a mechanism that’s in place because we need, as a social species, to be able to identify when our connections with others for mutual aid and protection are being threatened or absent. If there’s no connection, there could be mortal consequences. Those are threats to our survival and reproductive success.”

When loneliness continues for an extended period of time, it can make individuals vulnerable to physical and mental health problems. Cacioppo estimates that one fifth of Americans experience chronic loneliness, severe enough to be a major source of unhappiness.

Let’s make the focus of this holiday season human connection. Reach out and invite your neighbor over for a meal. Volunteer at a homeless shelter and sit and talk with the residents. Call your estranged sibling to check in to see how they’re doing. Human connection is a powerful tool, one that can cause physiological changes within us.