Daily Bruin

Analyzing love in human relationships can be difficult because love is often approached as an abstract concept. However, by taking a deeper look into the psychology, physiology and evolutionary history of love, one can gain a clearer understanding of the complex science of romantic relationships.

Who do we love?

People tend to feel initially attracted to individuals whose behaviors are compatible with their own during conversations, said Benjamin Karney, a professor of social psychology at UCLA. He said personal interactions matter more for romantic attraction than idealized qualities such as profession or an educational background.

“When we are talking to somebody, what matters is how they make us feel, and this has nothing to do (with) the sort of qualities you find in a list,” Karney said.

Biologically, humans tend to look for mates who will both pass on healthy genes to offspring and be involved in the child rearing process, said Martie Haselton, a psychology professor. Unlike many species, which release their offspring into the wild as soon as they are born, human children rely on their parents for food and safety for years. Haselton said people tend to fall in love with those who demonstrate loyalty, intelligence and other traits associated with good parenting.

“Because humans have long-term pair bonding, we select this particular mate, and the state of love narrows our focus to one mate rather than considering potentially endless alternatives,” she said. “This probably helped us initiate reproduction and care for offspring with the help of another person.”

Since love evolved to facilitate biparental care of offspring, individuals also tend to look for people they will be compatible with in the long term, Haselton said.

“That’s why it’s a very uneasy feeling when you start to fall in love with someone,” she said. “If you’re focusing in on this one particular person and (it) doesn’t work out, it’s going to be painful.”

Some animals’ reproductive behavior is heavily controlled by hormones, she said. For example, certain species of rodents will only reproduce when they release certain hormones. Haselton said hormones do not strictly control human reproductive behavior the way they do in other mammals.

However, just prior to ovulation when fertility is higher, women tend to prefer male traits that could indicate fertility and good genes, she said. They also make a more noticeable effort to attract partners through self-grooming and choice of dress around this time in the reproductive cycle, studies show.

Why do we love?

Evolution can help explain the adaptive benefits of romantic relationships. Certain responses to falling in love, for example, contribute to the health of offspring.

Haselton and her colleagues studied women who had just entered new relationships. Several months later, they examined the blood of those who had fallen in love and those who had not. They found the women who had fallen in love had stronger antiviral responses. This protects the woman’s health and and may protect her child’s health if the relationship results in pregnancy according to a recent study.

“This makes sense because viruses are socially transmitted,” Haselton said. “In addition, these physiological changes were consistent with preparation of the body for successful pregnancy.”

Robert Bilder, a clinical psychology professor, added love causes distinct responses in the brain which prepare couples for long-term relationships. He said studies show that when humans feel lust, they use the deeper, more primal parts of the brain. When humans fall in love, however, they use higher-level processes that are associated with long-term planning and inhibition control, Bilder said.

“Love really supports the enduring, future-directed, sustaining power of attachment,” Bilder said.

Bilder added that these brain systems associated with long-term planning can be described as a higher-order representation of lust, an attachment that helps to support people’s interactions and survival as a species. This combination of higher-level and primal attachment helps explain why humans fall in love, he said.

While many researchers have studied the genetic basis of love, the process is extremely complex and research is still in its early stages, Bilder said. Most well-studied human behaviors are half-heritable, meaning our observable cognitive and personality traits, including those involved in love, can be half explained by structural genetics, Bilder said. While it is still unknown which genes govern complex problems such as love, it is possible to identify which traits associated with love can be inherited and controlled by hundreds or thousands of genes, he said.

What happens when we love?

While love can sometimes seem abstract, the process of loving another person produces distinct hormonal responses, Bilder said. Oxytocin, a hormone known for its role in social bonding, is often dubbed the “love hormone.” Oxytocin plays a large role in many types of attachments, Bilder said.

He said studies demonstrated that prairie voles, a highly social species, secrete large amounts of oxytocin. Studies with montane voles, a less social species, show they produce less oxytocin. This indicates oxytocin plays a role in how affiliative members of a species are with one another, Bilder said.

“(Montane voles) are loners who don’t hang out in the same way prairie voles do,” he explained.

However, Bilder said a strict emphasis on oxytocin oversimplifies the role of hormones in love. Almost all hormones, including testosterone, estrogen and numerous endorphins, are involved in the physiological response to love. These hormones play a large role in people’s reward systems, he said.

“The positive attractive aspects of other members of the species are ultimately mediated by these reward systems,” he said.

Once people fall in love, they also try to maintain this feeling of intimacy, said Gerald Goodman, a clinical psychology professor at UCLA. Staying in love with another person requires the development and maintenance of intimacy with another person, Goodman said. Intimacy results from making risky disclosures, in which one shares personal details about one’s life, he said.

“All relationships are essentially nothing more than a series of conversations,” he said. “If you want to become close to someone, you begin to disclose to them.”

Goodman added in order to maintain intimacy, a couple must focus on honesty, acceptance and empathy. Relationships thrive when couples avoid deception and emphasize open communication, he said.

Maintaining relationships also requires communication during stressful periods, Karney added. It is important to keep a relationship healthy by nurturing it, similar to how someone would maintain their own physical health, he said.

“Pay attention to your circumstances and your partner’s circumstances, especially if your relationship is going through a challenging period,” Karney said. “People who are attentive to stress in their partners’ lives keep their relationships healthy.”