The Science of Social Connections

Social connections are a fundamental human need— as vital for our survival as food, water, and shelter. Throughout human evolution, our ability to rely on one another, form groups, and function as a community provided a clear survival advantage. Consequently, we are biologically wired for connection and social bonding: our brains anticipate closeness with others, and even our reward system—responsible for reinforcing beneficial behaviors—is activated in social settings. Although technological advances in recent decades make it possible to live with minimal face-to-face interaction or communication with others, our deep-seated need for connection remains unchanged.

When we think about what it means to be healthy, we typically focus on physical and mental aspects. Asked how to maintain good health, most people would mention regular exercise, a balanced diet, proper hydration, adequate sleep, and avoiding harmful habits like smoking. In recent years, there has also been growing awareness of the importance of mental health, with more people seeking psychological support upon need or using practices such as meditation to maintain emotional balance and inner calm.

But experts stress that our social well-being is just as crucial to our health. They argue that, just as we actively care for our bodies and minds, we should also invest in the social dimension of our well-being by forming meaningful connections with those around us, maintaining them, and strengthening our ties to the community. As early as the 1990s, American sociologist Corey Keyes highlighted the critical role of relationships in an individual’s overall well-being. Keyes introduced the concept of social well-being,which describes how people perceive the quality of their relationships with others and their sense of belonging within their community.  This perspective is echoed in the World Health Organization’s constitution, which defines health as a state of physical, mental, and social well-being.

=Our social well-being is just as vital to our health as the physical and mental aspects. A group of people standing and conversing with one another | Studio Romantic, Shutterstock

Millions of People Alone

Despite the well-established importance of social connection, evidence suggests that we are becoming increasingly isolated. In the United States, people are spending more time alone, engaging less with friends and family, and reporting fewer close relationships. Notably, the number of individuals who say they have no one to confide in has also increased. The COVID-19 pandemic likely intensified this trend, with health professionals voicing concern - even at the height of the crisis - about the mental and physical toll of prolonged social distancing measures.

In a 2023 report  U.S. Surgeon General Vivek Murthy described social isolation and loneliness as a growing epidemic. The distinction between the two lies in perspective: social isolation refers to the objective state of having few social contacts or interactions, while loneliness is the subjective experience of feeling disconnected or lacking meaningful social relationships. Murthy, echoing the views of many experts, stressed that “the structure, function, and quality of our relationships with others—is a critical and underappreciated contributor to individual and population health, community safety, resilience, and prosperity.”

Social isolation is on the rise. A woman looking out from behind a curtain | KieferPix, Shutterstock

As Harmful as Smoking

According to the report, which draws on numerous studies in the field, social connections have a significant impact on both health and life expectancy. Social isolation and loneliness are risk factors for a range of adverse conditions, inducing cardiovascular disease, dementia, stroke, depression, anxiety, and even premature death, affect mortality in a manner comparable to smoking up to 15 cigarettes a day.
The report also explains how social relationships influence our health across biological, psychological, and behavioral dimensions. Physically, social ties can affect the cardiovascular, immune, and digestive systems. For instance, low levels of social support have been linked to elevated inflammation—an underlying process involved in many chronic diseases.

On the other hand, strong social connections promote positive psychological states such as a sense of meaning, safety, resilience, and hope. They also help reduce psychological stress: social support enables us to better cope with stressful situations and mitigates their effects on our well-being. In addition, social relationships are associated with health-enhancing behaviors, including maintaining a balanced diet, engaging in regular physical activity, and getting sufficient sleep.

Of course, the three dimensions of health—physical, mental, and social—are deeply interconnected. Social health can both contribute to and be influenced by physical and mental well-being. For instance, regular physical activity not only boosts physical and mental health but also makes it easier to form and maintain social ties.  Similarly, psychological therapy can enhance both mental and social functioning, while social relationships in turn, promote physical, mental, and social well-being.

 Social connections affect not only our emotional well-being but also our heart, immune system, and digestion. A group of young people enjoying a meal together at a restaurant | Nejron Photo, Shutterstock

The Social Brain

Many studies have explored the relationship between social well-being and personality traits. Among other findings, social well-being has been found to be positively associated with the Big Five personality traits—a widely accepted model in psychology that evaluates personality across five core dimensions: extroversion, agreeableness, conscientiousness, neuroticism, and openness to experience. A 2019 study even found a link between social well-being and brain structure: social well-being was found to be associated with neuron density in the frontal lobe, a region involved in emotional regulation and social cognition.  According to the statistical analyses conducted by the researchers, the traits of neuroticism and forgiveness directly accounted for the association between structural differences in these brain regions and social well-being.

A review of the scientific literature on the relationship between social well-being and brain activity found that both social acceptance and social isolation are linked to the brain’s reward system. One study included in the review involved 23 female participants who were shown a series of images some with social content and others without - while their brain activity was monitored using functional MRI (fMRI). After the imaging session, participants completed questionnaires assessing their levels of loneliness.The results revealed a clear pattern: lower levels of loneliness were associated with greater activation in a brain region involved in reward processing. Participants who reported higher levels of loneliness showed less activity in this area when viewing social images compared to those who felt less lonely. The opposite pattern was observed for images with non-social content: participants who reported higher levels of loneliness exhibited increased reward system activity when viewing non-social content.

This suggests that social interactions may be inherently more rewarding for individuals who feel less lonely, whereas those experiencing greater loneliness may derive more reward from non-social stimuli.

The Impact of Social Media

Social and demographic shifts, declining participation in community groups, and waning trust in societal institutions have all contributed to the growing prevalence of social isolation. Technological advances—and social media in particular—have also played a role in this trend. While social media can help people stay connected across physical distances, could its use also be undermining our social well-being?

In 2017, researchers proposed a model explaining how social media use influences social well-being. According to the model, passive use—such as consuming content without engaging directly with others—can trigger social comparisons and feelings of envy, thereby ultimately diminishing subjective well-being. In contrast, active use of social media —involving direct interaction, such as commenting or messaging—can strengthen social bonds and foster a greater sense of social connectedness, thereby enhancing subjective well-being.

In 2022, the creators of the original 2017 model published a follow-up article with an updated framework. According to the revised model, even active social media use can reduce subjective well-being if it lacks intentionality or focus. For instance, posting to a broad audience without addressing a specific person may reduce a sense of connection, especially if it doesn’t elicit meaningful responses from others. Activities involving negative interactions, such as online bullying or the spread of hate speech, also negatively impact subjective well-being. Regarding passive use, the researchers emphasized that the type of content consumed plays a critical role in its effect on our well-being. Murthy’s report highlights a related study showing that individuals who used social media for more than two hours a day reported feeling significantly more socially isolated than those who used it for less than 30 minutes. These findings underscore the importance of being mindful about how we engage with social media—recognizing that both the content and the context of our usage can significantly shape our social well-being.

 Browsing social media and consuming content without direct interaction with others can lead to comparisons and envy, reducing our sense of well-being. A teenage girl scrolling on her phone | Monkey Business Images, Shutterstock

The Social Dimension of Health

The growing recognition of social well-being has led experts to define “social health” as a distinct and essential component of overall health—alongside physical and mental health. Kalsey Killam, a public health expert and advocate for social health,  argues that when social well-being is treated merely as a subset of mental health, its importance is diminished and not enough emphasis is placed on its role in overall health. She emphasizes the need to raise awareness about the health benefits of social connection, stating, “We need to translate that awareness into action—giving people the tools to be healthier through their relationships and setting up our society in such a way that connection and community are the norm.”

Social well-being, however, is not a one-size-fits-all concept. The sense of connectedness we experience depends on several factors: the number and diversity of our social relationships—such as family size, the breadth of our social circles, and how often we interact with others; the extent to which these relationships meet our needs, including emotional support and help during times of crisis; and the overall quality of our interactions. Positive or negative experiences in these relationships play a key role in shaping our satisfaction with them.

When reflecting on our own social well-being, it can be helpful to consider how we would ideally like our relationships—with both individuals and the broader community—to look, and how they actually look at present. If there’s a gap between the desired state and current reality, it’s worth exploring practical steps to improve our social well-being, rather than accepting the status quo as unchangeable. There are various ways to enhance our social health: for instance, we can broaden our networks by joining clubs, volunteering, or participating in community events, or we can deepen existing relationships by investing quality time with friends and family. The U.S. National Institutes of Health (NIH) also emphasizes that our social habits  play a role in both mental and physical health. To support this, they’ve developed a toolkit outlining specific actions that can help foster stronger social connections and improve social well-being.