Don't just stop at "love". Now we gotta find out just why we feel love.
According to howstuffwork.com love is a survival instinct used to generate a bond between the two mates to ensure that they can successfully procreate and raise a new generation. The mechanism for this is a mixture of a few different chemicals. Oxytocin, which, according to the wikipedia article, does this:
- Inducing maternal behaviour Sheep and rat females given oxytocin antagonists after giving birth do not exhibit typical maternal behavior such as grooming towards newborns. Conversely, virgin sheep females show maternal behavior towards foreign lambs upon cerebrospinal fluid infusion of oxytocin, which they would not do otherwise.
- Thought to induce pair bonding in people. Levels of oxytocin are found to be higher amongst people who claim to be falling in love. It is also thought to mediate other forms of pair bonding such as friendship and family relationships as given above. Reduction of sociophobic behavior was shown after treatment with oxytocin.
- Nasally administered oxytocin appears to generate trust in humans. In a 2005 study, it was shown that in a risky investment game, experimental subjects given the hormone displayed what the researchers deemed "the highest level of trust" twice as often as the control group who were given placebos. The same experiment with the subjects told that they were interacting with a computer showed no such reaction, leading to the conclusion that oxytocin was not merely affecting risk-aversion (Kosfeld 2005)
Oxytocin is the main chemical responsible but according to the article other neurotransmitters such as dopamine, epinephrine (adrenaline), norepinephrine (noradrenaline), and testosterone and estrogen play a role in love as well.
So, looking one level deeper we find tha twe love in order to fulfill our evolutionary instinct to procreate and perpetuate the species. The question is, do we stop here, and chalk the reason to live up to fulfilling our instincts? Or can we look deeper and find a reason why we are given evolutionary instincts before?