Love (scientific views)

Biological sciences such as evolutionary psychology, evolutionary biology, anthropology and neuroscience have begun to explore the nature and function of love. Specific chemical substances such as oxytocin are studied in the context of their roles in producing human experiences and behaviors that are associated with love.

Evolutionary psychology
From the perspective of evolutionary psychology the experiences and behaviors associated with love can be investigated in terms of how they have been shaped by human evolution.[1] For example, it has been suggested that human language has been selected during evolution as a type of "mating signal" that allows potential mates to judge reproductive fitness. Miller described evolutionary psychology as a starting place for further research: "Cognitive neuroscience could try to localize courtship adaptations in the brain. Most importantly, we need much better observations concerning real-life human courtship, including the measurable aspects of courtship that influence mate choice, the reproductive (or at least sexual) consequences of individual variation in those aspects, and the social-cognitive and emotional mechanisms of falling in love." Since Darwin's time there have been similar speculations about the evolution of human interest in music also as a potential signaling system for attracting and judging the fitness of potential mates. It has been suggested that the human capacity to experience love has been evolved as a signal to potential mates that the partner will be a good parent and be likely to help pass genes to future generations.

Neuroscience
Studies in neuroscience have involved chemicals that are present in the brain and might be involved when people experience love. These chemicals include: nerve growth factor, testosterone, estrogen, dopamine, norepinephrine, serotonin, oxytocin, and vasopressin. Adequate brain levels of testosterone seem important for both human male and female sexual behavior. Dopamine, norepinephrine, and serotonin are more commonly found during the attraction phase of a relationship.[citation needed] Oxytocin and vasopressin seemed to be more closely linked to long term bonding and relationships characterized by strong attachments.
The conventional view in biology is that there are two major drives in love — sexual attraction and attachment. Attachment between adults is presumed to work on the same principles that lead an infant to become attached to his or her mother or father– or both.
The chemicals triggered that are responsible for passionate love and long-term attachment love seem to be more particular to the activities in which both persons participate rather than to the nature of the specific people involved.
Helen Fisher, a leading expert in the topic of love, also adds lust to the experience of love. Lust exposes people to others, and is the initial passionate sexual desire that promotes mating, and involves the increased release of chemicals such as testosterone and estrogen. These effects rarely last more than a few weeks or months.

Role of the limbic system
In A General Theory of Love, three professors of psychiatry from UCSF provide an overview of the scientific theories and findings relating to the role of the limbic system in love, attachment and social bonding. They advance the hypothesis that our nervous systems are not self-contained, but rather demonstrably attuned to those around us and those with whom we are most close. This empathy, which they call limbic resonance, is a capacity which we share, along with the anatomical characteristics of the limbic areas of the brain, with all other mammals. Their work builds on previous studies of the importance of physical contact and affection in social and cognitive development, such as the experiments conducted by Harry Harlow on rhesus monkeys, which first established the biological consequences of isolation.

Brain imaging
Brain scanning techniques such as magnetic resonance imaging have been used to investigate brain regions that seem to be involved in producing the human experience of love.

Source:
http://en.wikipedia.org/wiki/Love_(scientific_views)