Daily Social Moments May Shape Long-Term Health and Cognition, New Study Suggests

A psychologist at the University of California has received a $2.55 million grant to investigate a deceptively simple question: whether the small social choices we make each day—calling a friend, showing up to a neighbor's dinner despite exhaustion, staying a few minutes longer in conversation—actually shape how our bodies and minds age.

Susan Charles, an associate dean in the School of Social Ecology, believes that science has been asking the wrong question about social connection. For decades, researchers have treated sociability as a fixed trait, something a person either possesses or lacks. But Charles argues that this misses the real story. The same person who feels surrounded by warmth and community on a Tuesday might experience profound loneliness by Thursday. These daily fluctuations—in how connected or isolated we feel—may be where the health consequences actually live.

The distinction matters because it reframes social interaction from something abstract and aspirational into something concrete and actionable. When you decide to call a friend after work, you are not simply being social. You are triggering immediate physiological responses: a shared laugh eases stress, conversation demands mental effort that keeps your mind engaged, and the consistency of these moments compounds over time. Charles describes this as a ripple effect, where small daily choices accumulate into measurable differences in how our bodies function and how quickly our cells age.

To test this theory, Charles and her team will analyze data from MIDUS, one of the most extensive longitudinal studies in social science. The dataset spans nearly two decades and includes more than 2,900 adults ranging from age 24 to 97. Participants completed nightly phone interviews for a week across three separate waves—in 2002, 2014, and 2023—describing their daily social experiences. Beyond the interviews, they underwent cognitive assessments, provided blood and urine samples, completed physical fitness tasks, and submitted to biomarker testing that measures inflammation, stress hormones, and even the rate at which their cells are aging relative to their chronological age.

Charles plans to examine cortisol, the stress hormone linked to cognitive decline and poor physical health when chronically elevated. She will also analyze inflammatory markers and gene expression profiles, looking for connections between daily social patterns and a phenomenon called inflammaging—the age-related increase in chronic low-grade inflammation now understood to drive cardiovascular disease, diabetes, dementia, and arthritis. The hypothesis is straightforward: if daily feelings of connection or disconnection can move these biological needles, the implications for preventive medicine could be substantial.

The age range of the study is particularly significant. While research spanning nearly a century confirms that social connections matter for people of all ages, Charles is especially interested in how this relationship shifts in later life, when the body becomes more vulnerable. As chronic illness and functional disability become more prevalent with age, she argues, the stakes of social isolation grow higher—and so does the potential benefit of meaningful daily connection. The United States Surgeon General has already declared loneliness and social isolation a public health epidemic, a crisis that accelerated during the COVID-19 pandemic.

Charles sees her research as doing more than documenting a problem. She wants to fundamentally change how doctors, therapists, and public health officials think about social life. Rather than warning people about the dangers of isolation, she wants to reframe the conversation around the power of positive connection. Her ultimate goal is to make social connection a recognized daily health behavior, as concrete and actionable as exercise or diet—something people can measure, track, and deliberately cultivate as part of their routine care for themselves. If the data confirms what she suspects, the message will be simple: the moments that feel most ordinary may be among the most consequential health decisions we make.