Most people think romantic love and sexual desire go hand in hand, and that you can't have one without the other.
But a psychologist who argues that it's not that simple, bases her findings on follow-up interviews with a group of women she's followed for more than a decade. Developmental psychologist Lisa Diamond, PhD, started noticing something interesting about her study group's love lives.
Most of the women identified themselves as non-heterosexual, but several reported falling in love with, and developing sexual desire for, individual men in their lives, says Diamond, a University of Utah psychology professor.
Talking to them, Diamond at first thought the women were mistaken about what they were feeling or were confused about their own sexual orientation.
"The more I started listening to their voices, the more I started to think I was wrong," Diamond says.
Diamond started studying the women's experiences for her master's thesis. She's kept in touch with the participants for more than 10 years, interviewing them individually about their sexual identities, sexual desires and romantic relationships every two years.
After reviewing work by other love researchers and delving into accounts of love and friendship across cultures, Diamond developed what she describes as a biobehavioral model distinguishing love and sexual desire.
In her model, she proposes that sexual desire and romantic love are functionally independent; that romantic love is not intrinsically oriented to same-gender or other-gender partners; and that the links between love and desire are bidirectional.
Based on her model, Diamond thinks it's possible for someone who is heterosexual to fall in love with someone of the same gender, and for someone who is homosexual to fall in love with someone of a different gender.
Diamond's model offers a new interpretation of the implications of the ideas developed by psychologists Phillip Shaver, PhD, and Cynthia Hazan, PhD, who see adult romantic love as similar in certain respects to the infant/caregiver attachment bond, but with attachment and caregiving running in both directions between partners and with sexuality added to the mixture.
While Diamond argues that a person can fall in love with someone to whom they wouldn't usually be sexually attracted to, Shaver sees sexual attraction as one of the three behavioral systems contributing to the blossoming of adult romantic love, making it different from childhood attachments.
Other psychologists such as Pamela Regan, PhD, who studies how adults think about love and sex, say that most people view sexual attraction as an essential ingredient in the development of romantic love, the spark needed to set passion burning.
The links between love and desire
Diamond bases her model on the notion of romantic love evolving from the attachment bond formed between infant and caregiver.
As described in her 2003 article in Psychological Review (Vol. 110, No.1, pages 173-192), her model argues that while the goal of sexual desire is sexual union for the purpose of reproduction, romantic love is governed by the attachment or pair-bonding system, with its goal of maintaining an enduring bond between two individuals.
Sexual desire is driven by the gonadal hormones of estrogens and androgens. Animal research indicates that attachment is mediated by the neuropeptide oxytocin, with a more robust oxytocin-receptor network present in the female brain.
And since romantic love, she hypothesizes, is an outgrowth of infant/caregiver attachment, there's no way to "code" romantic love for gender.
That's because highly dependent infants become attached to the most responsive caregiver present, whether it's a woman or a man, she says.
Diamond also argues that the links between love and desire are bidirectional, because sexual desire can facilitate affectional bonding, and affectional bonding can facilitate sexual desire.
Most people perceive connections between the two experiences. Owing to cultural factors, people are expected to form romantic bonds with people they desire.
But they are not expected to experience novel sexual desires for people they love who are not "appropriate" partners, as judged by society.
An example of the type of relationships that fit in with Diamond's model are the intense friendships developed between girls at boarding schools in the 1800s, called "smashes," and between same-sex individuals in other gender-restricted environments, such as combat units in the military, and college sororities and fraternities.
And because the links between love and desire are bidirectional, developing sexual desires running counter to a person's sexual orientation is possible too.
"It appears to be something everybody is capable of," says Diamond.
Now a psychology professor at University of California, Davis, Shaver helped bring attachment theory to psychology's understanding of romantic love, and sees some aspects of romantic love across a variety of relationships.
While teaching at the University of Denver in the late 1980s, Shaver and Hazan developed a concept of love as being a combination of three different behavioral systems: attachment, caregiving and sex.
Describing himself as familiar with Diamond's work, Shaver says it's possible to see the elements of romantic love in things like the crushes that young children, particularly girls, develop for each other in elementary school.
In such relationships, children become possessive of another person, and can feel some of the anxiety, jealousy and distress at separation experienced by adults in romantic relationships, Shaver says.
"I think you could have one or two of these motivational systems active, and then you'd see a partial form of the full-blown romantic reaction," he says.
But once a person goes through puberty, all three systems come together for many people's experience of passionate love, he says.
"And then a lot of the driving force, even if the person doesn't know it, is sexual," he says.
Romantic love's essential ingredient
Regan's work supports a more familiar understanding of love and desire.
Now a social psychologist at California State University Los Angeles, Regan started out as an English major in college. Her study of sublimated sexual desire was confined to novels such as "Wuthering Heights," and its portrayal of doomed lovers and thwarted desire.
She switched to studying psychology when she found she could study passion and desire full time.
From the years of research she and her students have done studying how people think about passionate love and sexual desire, Regan has concluded that sexual desire is an integral part of heterosexual adults' passionate love.
"Those are definitely connected experiences," she says.
As described in a 1998 article in the Journal of Social and Personal Relationships (Vol. 15, No. 3, pages 411-420), people asked to list the features of passionate love overwhelmingly list sexual attraction as one of its key aspects.
In another study, when presented with information packets supposedly filled out by couples who either said they were "in love" with each other, "loved" each other or "liked" each other, participants rated the couples who said they were "in love" as experiencing the highest levels of sexual attraction, Regan says.
In studies cataloging the experiences of dating couples, Regan found men and women who described themselves as "in love" scored very high on measures of sexual attraction, as presented in an article in Social Behavior and Personality (Vol. 28, No. 1, pages 51-60).
While she thinks sexual desire is a key ingredient to passionate love, Regan says there's a difference between what people find sexually attractive and what they find romantically attractive.
"What turns you on physically is not necessarily what turns you on romantically," she says.
In a curious twist, while both men and women find the attribute of physical appearance as sexually attractive, men misunderstand what women seek, and women misunderstand what men seek, Regan says.
Men think women find a man with resources highly sexually attractive-while women think men find a woman who's stereotypically feminine attractive. The truth is men and women both list physical appearance as the quality that's most sexually attractive.
But the list is more comprehensive for romantic attraction. Both men and women list qualities of kindness, warmth, a sense of humor, sociability, trustworthiness and a stable personality as attributes sought in a romantic partner.
Some attributes make the list for both sexual attractiveness and romantic interest, such as a sense of humor, she says.
Judging from her review of what men and women self-report on their daily levels of sexual desire, Regan says men have a stronger sex drive than women.
She notes that social pressures that approve of an openly expressed sex drive in men, and disapprove of it in women, may influence those results.
- Mikulincer, M., & Shaver, P.R. (2007). Attachment in adulthood: Structure, dynamics, and change. New York: Guilford Press.