In the 1947 song "Nature Boy," songwriter Eden Abhez posits, "The greatest thing you'll ever learn is just to love and be loved in return" [source: Sing365]. Four years earlier, the psychologist Abraham Maslow published his book, "A Theory of Human Motivation," which included his famous hierarchy of needs. In the middle of this hierarchy, above physical needs like safety but below esoteric needs like self-esteem, lies our need for love and belonging -- the need to love and be loved in return.
While Abhez and Maslow may have disagreed exactly on how important love is to the human experience, both knew that love is one of the most crucial aspects of being human. Where Abhez was content to simply note its importance, Maslow included love as something humans are motivated to have or achieve. Love is a motivating goal for humans, and our behavior can be explained by our attempts to achieve this goal.
Research supported Maslow's hierarchy for decades. In 2005, a groundbreaking study using functional magnetic resonance imaging (fMRI) was published. The study, conducted jointly by researchers at three universities, found visual evidence that supports Maslow's view of love as motivation.
The human motivation system is linked to the reward system in the brain. Once we achieve a goal, the brain releases dopamine into a region of the reward system called the nucleus acumens. We experience this as a profound sense of pleasure and excitement -- the types of sensations one associates with the experience of romantic love.
In the 2005 study, researchers found that when 17 young participants were shown a photo of the person they loved, regions of the brain responsible for motivating and rewarding began to function. In other words, the study found that romantic love motivates people, and the motivation toward this goal -- loving and being loved -- is fueled by the brain's reward system [source: APS].
The imaging also showed that while the emotional centers of the brain were active, no distinct pattern of emotions was followed. This finding counters the longstanding view that love is based in emotion; instead, it seems that love springs from our goal-seeking behavior and that the emotions we attach to it come second to our motivation.
But the question remains: Why do we love?
Evolution and Love
This question of why we're equipped to love has already been answered via evolutionary theory: We love because we're meant to reproduce. Species continue through reproduction, and continuation of the species is paramount in evolution. Since mating is the ultimate goal, then feelings of romantic love are merely a vehicle toward this goal. Yet, the 2005 study found that the areas that cause sexual arousal in the brain aren't fully active as people fall in love. The two regions overlap, but the experiences aren't the same [source: APS].
This doesn't disprove the idea that love exists to foster reproduction, but it certainly raises new questions. Specifically, why do we continue to feel love even after we've reproduced? The current answer is also based in evolution: The combination of reward and attachment lead to a lasting addiction for a particular individual -- our partner.
Because of the association with reward motivation and its attendant releases of dopamine, that initial rush of romantic love resembles addiction rather than emotion. Over time, however, other neurotransmitters may play a larger role in forming long-term attachment that lasts beyond our reproductive years.
The chemicals vasopressin and oxytocin help humans and about 3 percent of other mammal species to experience lasting, monogamous love. These two chemicals are associated with our ability to form memories of others and help us recognize other people. They're also released, along with dopamine, during sex.
This combination of dopamine (which induces feelings of pleasure), oxytocin (which is associated with feelings of attachment) and vasopressin (which also promotes attachment and also allows social recognition) leads to a learned behavior where we actually become addicted to our mate [source: Economist]. Regardless of whether it's the sight of the person we're in love with or the injection of some drug, if both trigger similar releases, humans can experience both similarly and become addicted as well.
These same chemicals may also play a role in familial love, like that between a parent and child or among siblings. The chemical oxytocin, for example, plays a role in parental bonding. It's released in mothers during childbirth, and it plays a role in the production and release of breast milk [source: Johnson].
We experience love, then, to foster the relationships that may lead to reproduction and to maintain relationships with the offspring borne from those relationships.
- Aron, Arthur. "Why do we fall in love?" Discovery Health. Accessed August 30, 2010. https://health.howstuffworks.com/relationships/love/why-do-we-fall-in-love.htm
- Economist. "I get a kick out of you." February 12, 2004.http://www.oxytocin.org/oxytoc/love-science.html
- EurekAlert! "Brain network links cognition, motivation." August 19, 2010. http://www.eurekalert.org/pub_releases/2010-08/wuis-bnl081910.php
- Gusatella, Adam J., et al. "Intransal arginine vasopressin enhances the encoding of happy and angry faces in humans." Biological Psychiatry. June 15, 2010. http://www.biologicalpsychiatryjournal.com/article/S0006-3223%2810%2900243-X/abstract
- Johnson, Steven. "Emotions and the Brain: love." Discover. May 2003. http://discovermagazine.com/2003/may/featlove
- Pettifor, Eric. "Beyond dichotomies: health and values in Maslow's holistic dynamic theory." Personality and Consciousness. Accessed August 30, 2010. http://pandc.ca/?cat=abraham_maslow&page=beyond_dichotomies
- Sing365. "'Nature Boy' lyrics." Accessed August 30, 2010. http://www.sing365.com/music/lyric.nsf/Nature-Boy-lyrics-Nat-King-Cole/ADF31EF29958DA5948256AF1000B59DE
- The American Physiological Society. "Love really is 'all in your head,' though intense romantic love looks more like the brass ring than a bouquet of roses." May 31, 2005.http://www.the-aps.org/press/journal/05/9.htm