love at first sight
You”ve played that game.  You make eye contact and quickly look away.  You”re pretending not to have noticed the other person when really you remember everything.  The way his hair sweeps across his face, the color of his eyes, and whether or not he noticed you too.
When you are attracted to someone, it seems the only factors involved are physical. In reality, your brain, nose and eyes are hard at work.  Subconsciously, that is.
An anthropologist at Rutgers University wrote an article which discusses the “attraction system” humans use to choose a mate.  She explained that this system could also affect romantic love (a relationship based on both emotions and sexual desires).
Normally, the first quality people notice in others is physical appearance.  According to the Time magazine article, “The Science of Romance,” most men are attracted to curves because they show a woman as able to bear children and nurse them. Men with a broad chest and muscles indicate to women that the man is capable of taking care of and providing for them. Women are also more attracted to a deep voice. Studies show that men with deeper voices in the Tanzanian hunter-gatherer community of Hadza fathered more children.
thinking of you
Another factor that is nearly impossible to see, except through functional magnetic resonance imagers (fMRIs), is activity in the brain.  Ms. Helen Fisher, an anthropologist at Rutgers University studied these fMRIs in her article, “Romantic Love: An fMRI Study of Neural Mechanism for Mate Choice.” She found that the brain”s ventral tegmental, which creates dopamine, and caudate nuclei, which is responsible for memory, become active when one sees the person they are attracted to. These areas are associated with the feelings of reward, motivation and pleasure.  In another article, “Romantic love: a mammalian brain system for mate choice,” Fisher writes that activation also occurs in the brain”s nucleus accumbens, which processes dopamine, seratonin, and oxytocin. Oxytocin causes humans to bond and explains parental attachment.  The function of the nucleus accumbens is especially visible in long-term relationships.
In a video titled “The brain in love,” Fisher stated that when love is not returned, you simply work harder to feel that reward in the form of dopamine by becoming more attached to that person.  She even suggests that “romantic love is primarily a motivation system, rather than an emotion.”
romance in the air
Your brain is not the only part of you that is working hard.  When you are attracted to someone, usually their scent lingers, leaving you wanting more.
Mr. Claus Wedekind of the University of Utah”s Department of Biology has researched the importance of pheromones (chemical substances related to smell) to attraction and found that traces of an individual”s major histocompatibility complex (MHC) are found in their scent.  The MHC controls which tissues the immune system will accept as their own, and which they will reject and attack to protect the body.
Humans looking for a mate tend to seek someone who has a unique MHC from themselves.  Wedekind conducted an experiment in which men wore a t-shirt for two nights and women later smelled them, selecting the ones with a different MHC than their own as more “pleasant.”  He hypothesizes that the reason for this is to avoid inbreeding, continually change the makeup of the immune system so parasites do not adapt, and that immune diversity is more disease-resistant.
However, the nose can sometimes mess up.  According to a study by Mr. Stewart Craig Roberts, an evolutionary psychologist at the University of Newcastle in England, the use of birth control could confuse the scent of your possible partner and possibly contribute to divorce.  Some women who marry while on birth control and stop to have children later realize their genes do not match well with their partner”s.
The nose also functions to allow men to subconsciously detect when a female is fertile or ovulating. If this is the case, the male will be more attracted to her because she is able to bear children at the time. According to a study by the journal Evolution and Human Behavior, strippers who are ovulating earn $70 an hour on average, while strippers who are menstruating earn only $35 an hour on average.
taste test
Scent and taste go hand in hand in determining whether a partner suits you. The fact that MHC is also contained in saliva explains kissing.
“Kissing might be a taste test,” said Martie Haselton, an associate professor of psychology at UCLA.
Often, testosterone gets into men”s saliva. Kissing can cause a transfer of this testosterone which could stimulate the female to be more open to greater intimacy.
A study led by psychologist Gordon Gallup showed that women place more emphasis on kissing than men. They use kissing as a way to assess their partner and the status of their relationship.  The study suggested that since women can get pregnant from sex, they tend to be more picky when choosing their partner.
Also, the close proximity of kissing allows you to learn more about your partner.
“At the moment of a kiss, there”s a rich and complicated exchange of postural, physical and chemical information,” Gallup said. “There are hardwired mechanisms that process all this.”
These “hardwired mechanisms” are so primal that humans do not even realize they are using them. When people look for these signs in the opposite sex,they aren”t just looking for love, but to continue the human population.
