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Social scientist Kasley Killam has always been fascinated by the science of human connection. In college, for instance, she once decided to conduct a personal experiment and perform an act of kindness everyday for 108 days. At the Harvard T.H. Chan School of Public Health, she researched solutions for loneliness. At Google’s health spinoff, Verily, her job was to bring people together to promote social health. “I first came across the term ‘social health’ during my research at Stanford, where I was developing an app around human connection,” Killam says. “Since then all my work has been through the lens of connection.”
Ahead of her keynote speech at WIRED Health later this month, Killam explains why social health has been the missing factor in human health. This interview has been edited for length and clarity.
WIRED: Traditionally, human health has been divided into a physical and a mental component. But you make the case that a third pillar—social health—needs to be introduced. Why is that?
Kasley Killam: The reason why I believe it’s so important to elevate and distinguish social health is because connection has such an outsized impact on our health, yet it’s overlooked and underappreciated. If you look at all the data, it is incredible the extent to which it impacts and determines our health, our happiness, and our longevity. Connection is not some touchy-feely thing; it influences how long we live. Social health deserves to rise from the shadows and stand tall in the spotlight, because it’s much more important than we realize.
In your book, The Art and Science of Connection, you point out that the lack of social connections increases the risk of various diseases, from stroke to dementia. One astonishing finding you cite is that we’re two to three times more likely to die in the next decade if our relationships are lacking, regardless of our mental and physical health. This is comparable in effect to regularly smoking and excessive drinking, being obese and physically inactive. What’s happening to our bodies when we’re lonely that leads to such bad outcomes?
One of the leading theories is this idea of stress buffering. If you think about hunger or thirst, these are different cues that our bodies give us as a helpful way to know that we’re missing something that we need. Loneliness is one of those cues. But when it’s chronic, that becomes a problem. Chronic loneliness, just like chronic stress, ultimately increases cortisol, inflammation, and weakens our immune systems. We need other people in order to survive, so chronic loneliness is literally registered as a threat. In contrast, when you have supportive relationships, that calms down your body and you’re able to manage stress more easily. Connection is a fundamental need that our bodies understand.
You call the current state of our collective social health a public health emergency. Many agree with you: In 2023, the US surgeon general issued an advisory about our epidemic of loneliness and isolation, and the WHO has established a commission on social connection. What do you identify as the root causes for this crisis?
The disconnection is a real crisis that gets talked a lot about. But there’s also overconnection, where we’re actually more connected than ever, but not in meaningful ways. We need to tackle both. There are many factors that have contributed to the status quo, and one we have to call out is technology and social media. That’s something that I’ve become more worried about in recent years. Technology tools need to complement real human connection. But right now, a lot of them are being designed as substitutes or as crutches. AI is one example. Millions of people are using AI as a substitute for a romantic partner or a friend. That worries me a lot.
There are also trends in our work culture: how much we work, how busy we feel. We often prioritize our careers over our relationships, at least in North American culture. And there are other trends, like living alone, which is a risk factor, and people being more transient than ever. I’ve lived in 12 cities and three countries at this point; it’s hard to build a community when you’re always moving.
Of course, we can’t talk about this topic without mentioning the impact that the Covid pandemic also had on our social health.
What surprised me is that our social health wasn’t affected as badly as you might think. Numerous studies showed that, although there was a rise in isolation and loneliness initially, people adapted and were resilient. There was a newfound appreciation for relationships and their importance. A lot of the narrative in the news is that the loneliness epidemic keeps getting worse, but not all the data support that.
One of the really interesting findings was about community resilience. There were studies in the US, but also in countries around the world, like Bhutan and Denmark, showing that the places with strong community ties before the pandemic had fewer cases of COVID-19 and fewer deaths from COVID-19. We need to build up social health proactively so we can rely on it in times of need.
We’re a fan of social health initiatives you describe in your book, like Paris-based Super Neighbors and the idea of “social prescribing,” which links patients to community groups and services, and is a key component of the NHS’s strategy for personalized care in the UK. Are we seeing the start of a social health movement?
Absolutely. Social health is today where mental health was 10–15 years ago; I expect the pace of innovation and the size of this industry to accelerate in the years ahead. There’s a lot that I’m excited about: Connection curricula in schools to teach youth how to strengthen their social muscles, just like gym class teaches them how to strengthen their physical muscles. Cities investing in redesigning shared spaces. And so much more.
I founded the nonprofit Social Health Labs in 2020 and we kicked off with a microgrant program, where every month we gave $1,000 to someone in the US who had an idea for a project to bring people together in their local community. It’s been so inspiring. I admire people who do the hard work of fostering empathy and conversation, bringing people together who live within five miles of each other but had never met before. It isn’t buzzy. It isn’t AI-powered. But it’s real, authentic connection—and it’s what we need.
Hear Kasley Killam speak at WIRED Health on March 18 at Kings Place, London. Get tickets at health.wired.com.
Updated 3-7-2025 11:30 am GMT: A misspelling of Kasley Killam’s surname was corrected.
