Love’s dimensions and definitions confound. It’s difficult to name a subject so widely praised and lamented, or a force that has inspired as many conflicts and works of art. Love is mysterious and chemical, a transcendent virtue and an evolutionary adaptation. It moves the hearts of teens and octogenarians and everyone in between. It is, as Martin Luther King Jr. called it, “that strong and powerful element.”
Too often, love is reduced to an emotion: a cousin of affection or a neighbor of infatuation. While love encompasses emotion, it’s also far more than that.
Love is big enough that wrapping a single definition around it becomes impossible.
Only by looking at it from all angles—through the lenses of neuroscience and theology and art and anthropology and biology—can we begin to understand what love is, and what it can do.
Defying neat definition
Dr. Sara Algoe is an expert on love—or at least, on love-related research. A social scientist and professor at the University of North Carolina at Chapel Hill, Algoe studies many sides of love, from romantic relationships to love’s impact on physical health. She also founded and directs The Love Consortium, which tackles the study of love through a collaborative approach. Despite her expertise, Algoe calls herself “agnostic” about which definition of love matters most in the research field. This ambiguity, she says, reflects the state of the field and all the advances yet to be made. It also reflects love’s complexity and the need for a multifaceted research approach.
Algoe founded The Love Consortium in response to this need. Love, she discovered, was an untapped domain in the research field. Sure, social scientists studied plenty of love-adjacent subjects, from conflict in romantic relationships to parent-child attachment. But the construct itself was missing from the literature. Even when psychologists collected data on love, it took too much time for the data to be made available to other researchers. In order to expand and accelerate a deeper understanding of what love is, she realized, scientists needed to collaborate. She founded The Love Consortium to provide “a matchmaking system” for researchers, a digital platform where they can search for and leverage existing data.
When pressed, Algoe offered her current working definition of love: “an other-focused, pleasantly-experienced, self-transcendent motivational state.” But she’s also quick to note the diverse forms of love humans experience, from the passionate love of romance to the dutiful love of family to the muscular love of social activism.
Evolutionary anthropologist Anna Machin is similarly humble when it comes to pinning words to love’s enormity. A researcher at the Department of Experimental Psychology at Oxford University in England, Machin recently published the book Why We Love: The New Science Behind Our Closest Relationships. The book draws together psychology, biology, neuroscience, sociology, and real-life anecdotes to capture love’s impact on human life. Like Algoe, Machin asserts that
“love defies a neat definition because it is a mix of the objective and the subjective, of the biological and social, of the personal and public, and of the conscious and unconscious.”
After spending over a decade immersed in the science behind human love, Machin writes, “rather than becoming immune to its charms, I am increasingly in awe of its complexity and its importance to us.”
Survival of the loving
Along with love’s complexity, Machin and Algoe agree that love plays an essential role in human survival. Romance ballads and rom-coms would have us believe that love is just an emotion: mercurial, dramatic, the source of both ecstasy and despondence. But Machin and Algoe have found that love influences much more than our emotional tides. They argue that it’s necessary for our very existence, both as individuals and as a species. As Machin explains, love is a human need “as fundamental to us as the food we eat and the air we breathe.”
Why We Love opens with an exploration of how love forms the backbone to human survival. “Love stems from cooperation,” writes Machin, “and cooperation is our route to survival.” Humans need other humans in order to live. We need one another in order to reproduce, learn, seek safety, share resources, and raise children—and we rely on social cooperation in order to accomplish all of these essential tasks. Forming and maintaining loving relationships creates a chain of cooperation; when we care for others, other people like us more and are more willing to help us.
The human race continues to exist thanks to our capacity for forming and preserving networks of relationships. Each of our networks can be visualized as a ring of concentric circles, growing larger as the relational ties become looser. The inner circle is formed by our thickest bonds, the kind held together by enduring love: think parents, romantic partners, children, and our closest friends. But we also need to maintain relationships with those in other rings, from friends to colleagues to neighbors. Cooperating with a wide network of people isn’t always easy—which is where love steps in. “At its most basic level, love is biological bribery,” writes Machin. “It is a set of neurochemicals which motivate you to, and reward you for, commencing relationships with those in your life who you need to cooperate with … and then work to maintain them.” These neurochemicals trigger love-like feelings such as warmth, contentment, and even euphoria. Not only do we seek out continued sources of these feelings in the form of new relationships, but the feelings also motivate us to preserve existing relationships. Love, explains Machin, “is the force which motivates us to overcome the difficulties of group living to cooperate at a level unmatched by any other species.”
Beyond collective survival, love also enhances our individual survival rates. It is, in fact, one of the most important factors in our mental and physical health.
“We know from the literature on close relationships that having at least a couple people in your life who are close confidants is health-protective,”
says Algoe. One of her current research projects, funded by the John Templeton Foundation, is called A Scientific Approach to Living in Love: A Framework for the Future. This research focuses on the transformative power of love, and the factors that enhance life-saving human connections. One of Algoe’s recent findings indicates that romantic partners who spend more time together have lower rates of peripheral inflammation, a precursor to cardiovascular disease. This correlation, she says, rests on the idea that humans evolved in the context of being with other safe and trusted people. When our ancestors lived alongside others who they knew to be safe, they could be less vigilant to threats. Their physical bodies could relax from fight-or-flight mode. Today this means that being in loving relationships and spending consistent, in-person time with our loved ones may actually reduce the inflammation present in our bodies.
While sifting through mountains of love-related research, Machin encountered a similar result:
We know what the important things for a healthy life are: exercise, a balanced diet, not smoking and maintaining a healthy weight. That’s it. We have survival cracked. But a seminal study carried out by psychologist Julianne Hold-Lunstad and her colleagues in 2010 would beg to differ.…she concluded that being within a supportive social network reduced the risk of mortality by 50 percent.
Fifty percent. As Machin points out, that places supportive, loving relationships on par with quitting smoking as a factor for longevity. It means love is a more important factor when it comes to our physical health than maintaining a healthy weight. Since Hold-Lunstad’s seminal study, many other researchers have arrived at the same conclusion: “that having good-quality social relationships (known as social capital) is the most important factor in your health, happiness and life satisfaction.”
Love’s transformative power extends beyond social cooperation and individual health. Beyond mere survival, love helps us flourish as a society. To understand love as a force for collective change, we can turn to the work of theologians and social activists.
In a 1957 sermon titled “Loving Your Enemies,” Martin Luther King Jr. spoke to the power of love for social transformation. The sermon was drawn from Jesus’s Sermon on the Mount in the Gospel of Matthew. This passage records one of Jesus’s most difficult commands—to love your enemies and do good to those who curse you—a command with which King was intensely familiar through his work in nonviolence and racial justice. “Far from being the pious injunction of a utopian dreamer, this command is an absolute necessity for the survival of our civilization,” King said. “Yes, it is love that will save our world and our civilization, love even for enemies.”
Love, according to King, is essential not just to the survival of individuals, but also to the survival of civilization.
Societies fall when they repay hate for hate. But by acting with love toward our enemies, humans can break the cycle of destruction.
Force begetting force and hate betting hate, King said, is “a descending spiral, ultimately ending in destruction for all and everybody,” he said. “Somebody must have sense enough and morality enough to cut off the chain of hate and the chain of evil in the universe. And you do that by love.”
In his sermon, King distinguished fiercely between like and love. “It’s significant that [Jesus] does not say, ‘Like your enemy.'” Like is akin to affection: a sentiment, an emotion. Feeling affection for one’s enemy is unlikely and perhaps not even advisable. But love reaches far beyond positive emotion or easy affection. It is a muscular and difficult virtue. It requires action and risk, as those who fought for the rights of Black Americans in the 1960s demonstrated. And while the kind of love that Jesus and King spoke about is difficult, it also possesses redemptive power. Loving one’s enemies, King preached, “eventually transforms individuals.”
In this sermon, King told a story about Abraham Lincoln’s political enemy, Edwin Stanton. For years, Stanton campaigned against Lincoln, slandering him in public and trying to undermine his work and political momentum. Lincoln ignored him. When Lincoln was elected president, the time came for him to choose his cabinet. To everyone’s surprise, Lincoln named Stanton as his Secretary of War. When his advisors asked why, Lincoln replied: “I find that he’s the best man for the job.” Stanton went on to lead the Union to victory and serve loyally at Lincoln’s side. Following the president’s assassination, Stanton’s words were one of the most powerful tributes to the president. He said of Lincoln, “Now he belongs to the ages.” Lincoln repaid Stanton’s cruelty with dignity and forgiveness, and this love changed Stanton. A transformed individual contributed to the transforming of a society.
This truth also bears out in social science. Research shows that witnessing other people’s kindness can influence a group for the better. When we see someone acting in a loving way, it makes us more interested in being friends with the loving person, more likely to support them, and more willing to go out of our way for them. Witnessing love in action even influences how we view the recipient of love: “[When I] see Person A be loving toward Person B, not only does my perception change of Person A, but also even the value of Person B,” Algoe explains. This is what Algoe calls “compassionate” or “enacted” love, as distinguished from the passionate love of romance or the duty-bound love of parents to children. “It’s very different from love as an emotion,” she says. “And it’s a really important aspect of love and the love experience that we need to disentangle.” Compassionate love has a ripple effect beyond the interaction of two individuals and directly influences those around them. It has the power to collectively raise up a group. It can lead to more kindness, more pro-sociality, and better working together in a society.
A new frontier
Love is biological bribery and evolutionary adaptation. It’s essential for collective survival and individual health. Yet none of this diminishes its transcendent power. Each of love’s functions are one part of a multifaceted whole, like a gemstone with many faces. To understand the many sides of love and its bedrock role in human life, we need the perspectives of poets and social scientists, ministers and activists, anthropologists and musicians.
One of the most exciting things in the science of love is how much we still have to learn. Particularly when it comes to compassionate or enacted love, the kind that can transform people and change societies, there’s a whole frontier of science to explore. “This idea of loving your enemy or being committed to the humanity of other people is something that I think we need a lot more work on,” says Algoe. “That’s where I think the really exciting work is left to be done.”