In the US, nearly half of adults are single. A quarter of men suffer from loneliness. Rates of depression are on the rise. And one in four Gen Z adults—the so-called kinkiest generation, according to one study—have never had partnered sex.

In an age of endless connection, where hooking up happens with the ease of a swipe and nontraditional relationship structures like polyamory are celebrated, why are people seemingly so disconnected and alone?

Chalk it up to changing social norms or shifting generational attitudes around relationships. But the bigger issue at play, according to Justin Garcia, is that we just don’t crave intimacy in the same way we used to. “Our species is on the precipice of what I have come to think of as an intimacy crisis,” Garcia writes in his new book, The Intimate Animal: The Science of Sex, Fidelity, and Why We Die for Love. Garcia suggests in the book that intimacy—not sex—is the “the most powerful evolutionary motivator of modern relationships,” but that our hunger for it “has been stifled by and misdirected in today’s digital world.”

An evolutionary biologist and anthropologist who began his career studying hookup culture, Garcia is the executive director of the Kinsey Institute at Indiana University, a research lab known for its pioneering work on sexuality, online dating, and aging. (Sex may in fact improve with age, a recent report found). He’s held the position since 2019, and in that time he has also served as the chief scientific adviser to Match, where he provides expertise for its annual Singles in America survey. In 2023, Indiana lawmakers voted to block public funding from the institute—state senator Lorissa Sweet, a Republican, falsely claimed that Kinsey was studying orgasms in minors—but, the following year, the school’s board of trustees voted to abandon its plans to separate the institute into a nonprofit.

Garcia’s book covers a lot of ground—the “cognitive overload” of dating apps, why humans are wired to be socially monogamous but not sexually monogamous, the science of breakups—but its throughline is how “even in this bewildering era, where moments of human connection are becoming increasingly elusive, the search for intimacy remains the most human of human impulses.”

On a recent afternoon over Zoom, I spoke with Garcia about the biggest misconception about the sex recession among Gen Z, the attack on sexual literacy in the current political climate, and why an AI chatbot won’t save your relationship. It’s all connected, he says.

This interview has been edited for clarity and length.

WIRED: What is the intimacy crisis, and why, as you write in the book, are we on the verge of one?

Justin Garcia: We hear a lot about the loneliness epidemic. The research suggests that loneliness is as bad for your health as smoking a pack of cigarettes a day. Psychological loneliness gets embodied in physical and psychological health. At the same time, there are reports that suggest that the numbers haven’t increased all that much for psychological loneliness. But clearly its impact is more, and more people are paying attention to the impact.

For me, there’s a bigger umbrella. We are suddenly talking about loneliness at the same time that all of us have more connections than ever before. That’s why I call it an intimacy crisis. We have more people available to us, particularly through internet and social media platforms, but the depth of the connections, the quality of the connections, is not there.

You suggest that the intimacy crisis can lead to “unprecedented and stark biological consequences.” In what way?

We’re in a moment where the human brain is taking in so much information and so much of the information is threatening. It’s what’s going on in the news, in Gaza and Minnesota, with climate change, with global economics—I mean, pick any section of the paper, it’s bad news. That weighs on our nervous system. Just as humans’ romantic and sexualized lives respond to environments with how they form relationship structures, they’re also responding to this current environment, which is that there’s a lot of threat going on. When the nervous system gets tuned up into a threat response, that’s not conducive to social behavior and it’s most certainly not conducive to mating. If our nervous system is detecting threats from all this stuff in our environment, that has all sorts of effects on our relationships. And if we don’t have the safety net of deep intimacy, we can’t effectively weather these storms.