Interesting column at Better Humans by James J. Hughes. A biological approach to thinking about love and sex:
Not just lust, but the amorphous ball of feeling called “love” itself is a biochemical phenomenon, amenable to manipulation. In Anatomy of Love, anthropologist Helen Fisher summarizes research arguing that love is composed of three biochemical process. The first process, driven by testosterone, is lust. The second process, infatuation, is controlled by dopamine, norepinephrine and phenylethylamine — amphetamine-like chemicals that produce feelings of euphoria. The lust and infatuation chemicals peak after a year, and for the lucky few relationships that survive their decline a new biochemical response emerges based on oxytocin, vasopression and endorphins, which produce feelings of intimacy, trust and affection.
(via Three River Tech Review)