BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: love

Can Science Explain Love?

Sometimes it’s the greatest feeling in the world. Sometimes it hurts. Although we may never derive a fundamental recipe for it, much of love can be explained by chemistry and biology.

The brain (not the heart!) is responsible for romantic love, which, according to Dr. Helen Fisher at Rutgers University and Katherine Wu at Harvard University, can be broken down into three categories: lust, attraction, and attachment.

Credit: “Hearts” by eflon on Flickr.

Lust is our yearning for “sexual gratification.” This facet of love is grounded in our evolutionary, inherent need to reproduce. Lust is stimulated when the hypothalamus releases “sex hormones (testosterone and estrogen) from the testes and ovaries.”

Whereas lust concerns merely “sexual gratification,” another aspect of love, attraction, encompasses a variety of emotions with regard to a specific person. Attraction leads to the release of the chemicals dopamine and norepinephrine. As anyone whose ever been attracted knows, these chemicals make us “giddy, energetic, and euphoric.” Attraction also stimulates the brain’s reward center, which fires “like crazy when people are shown a photo of someone they are intensely attracted to.” Another hormone, serotonin, is found in low levels in both people with obsessive-compulsive disorder and people those who are experiencing attraction. As a result, scientists have theorized that attraction, and the ensuing low level of serotonin, is responsible for the obsessive infatuation so common in love.

The third aspect of love, attachment, is responsible for intimacy, is a key factor in long-term relationships, and is, of course, mediated by hormones.  The two hormones responsible for attachment, oxytocin and vasopressin, “are found in large quantities during sex, breastfeeding and childbirth,” all activities that are “precursors to bonding.” From this, it is easier to understand the concept of three different aspects of love: the “love” parents feel towards their children is merely the attachment aspect of it, but neither the lust nor the attraction aspect.

Although science can give us a biological basis for it, love, and all of its intricacies, can never be fully explained.

Learning to Love

Photo Credit: Victoria Made Flickr

For years, scientists have believed that the nurture and love we receive from our parents when we are an infant, determines how we are when we are older. We learn very early on to trust and love and the relationship you have with your parents when you are a baby can affect relationships you have later in life. For example, researchers say that a mistreated infant may turn argumentative in stressful situations, while nurtured babies tend to deal with stress more skillfully.

Researchers Simpson, Collins, and Salvatore put babies and their mothers in high-tension situations and then years later researched the babies’ relationships. The researchers found that there is a link between the situations babies are put in and the relationship to the mother, and later relationships and stress management. However, they also found that although there is a link, it is not an extremely strong factor. You can learn to love, trust, and throughout your life, even if something traumatic did happen in your infancy.

Dear Darwin: What Makes Ryan Reynolds “Sexy”?

Photo Credit: Paco Paco Flickr

Now we all know that a big jaw, prominent brow, and bulging muscles are conventionally thought of as attractive features in a man and that large breasts, an hour-glass figure, and big eyes are attractive in women, but have you ever wondered why?

Well the answer lies in an unexpected place: science. According to the Evolutionary Theory of Attraction, what men and women  perceive to be attractive is actually based on adaptational behaviors that traditionally helped survival. Studies show that women look for masculine features such as a defined jaw, prominent brow, and muscular build because these often to reflect physiological and behavioral traits such as strength, aggression, virility, and a strong immune system, which would be advantageous to pass on to offspring and would mean that the man can provide and protect his family.

So while women’s attraction is rooted in a man’s ability to provide for his family, men on the put more emphasis on signs of fertility and youth. The hour-glass figure: large breasts and “child-bearing” hips, and youthful features such as plump lips, a hip-to-waist ratio of 0.7, a face with a high forehead, good skin, and big eyes are signs to men that the prospective mate is fertile and young. Such features helped ensure the male that his genes would be passed on to his offspring. Other factors such as symmetry, especially facial symmetry, is attractive because it means that there are strong genetics at work according to researchers and experts.

Recent studies show that when a woman chooses a mate, often times she must subconsciously choose between a macho man and his more wimpy counterpart depending on her situation. While the macho man has preferential genes to pass on to offspring, these traits often mean tendency to abandon, hostility, and promiscuity. The less masculine man is more likely to provide the stability, love, and care for a family. In fact, according to expert, Dr. DeBruine’s study, a woman’s environment greatly plays into her attraction between these two types of men. In her study on women in countries with poor health standards, women preferred men with more masculine features more than those who lived in more stable and healthy societies. This is a classic example of natural selection because the women look for healthier genes often associated with masculine, macho attractive men.

So that is why we find movie stars like Angelina Jolie, Brad Bitt, and Ryan Reynolds are attractive: evolutionary adaptations meant to help ensure our survival and the successful passing on of genes to offspring. Do you agree with this theory of attraction? And which category would you put yourselves in ladies, those who go after Mr. Sensitive or those who go after Mr. Dangerous?

 

For more on this go to:

http://www.cnn.com/HEALTH/blogs/paging.dr.gupta/2007/10/evolution-of-attraction.html

http://ezinearticles.com/?Male-Female-Attraction—Evolutionary-Theory&id=2236366

http://wilderdom.com/personality/L7-2EvolutionPersonality.html

http://www.economist.com/node/17672806

http://antimisandry.com/chit-chat-main/sociobiological-theories-attraction-11277.html

http://webspace.ship.edu/cgboer/sociobiology.html

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