About a year ago, in the foothills of Tucson, Arizona, I found myself sitting among a diverse group of eminent psychologists from around the world as they discussed the varieties of human emotional responses and experiences. A short while into the discussion, a young graduate student broke in with a non-sequitur in a way that at once betrayed his tender academic years and prompted a lively change of subject. It all began as a simple question: “How many of the people in this room are married or in a long term relationship?” Unfortunately, the inquisitive student was not adept at managing his passions, and the question sounded vaguely threatening. It obviously contained a hidden agenda--and nobody likes those. Nevertheless, nearly everyone raised his or her hand. It appeared that most of the researchers present were indeed attached.

With that settled, the confusion persisted until, mercifully, the student explained himself. “I’ve been sitting here listening to everyone talk about fear and sadness and disgust and even joy,” he said, eyes wide with fury, “and I’ve waited patiently as you’ve all described how you’ve invested amazing amounts of time and money into studying the minutiae of each of these allegedly basic emotions, and now I can’t help but wonder why no one here has ever bothered to study love!”

At last, we knew what he was going on about. Despite his histrionic bit of theater, the student had a point, and before long, a consensus among the individuals in the room began to emerge, to wit: we don’t study love because we are emotion researchers, and love is not an emotion. The student became fairly apoplectic with shock at this, but the explanations seemed to me to be reasonable, at least at the time. “No one,” someone said, “has a clear idea of what love is.” Another noted that love is too general a term, too much a collection of symptoms, a type of category having more in common with, say, socio-economic status than fear. Finally, someone chimed in with this (or something like it): “The word love is a poetic or literary term. It captures a set of feelings that probably derive from combinations of emotions, from lust to fear to sadness to affection and contentment. We only call it love when these emotions are elicited by people we are driven by biology to procreate with.”

And that was more or less that. Such is the power of a room full of eminent researchers.

Which may only prove that the room wasn’t full enough. Recently, some researchers have begun arguing that love is a specific emotional category. For example, Dr. Helen Fisher of Rutgers University has collected evidence that our brains look very different when we are looking at pictures of our sweethearts than when we are looking at pictures of our close friends. Fisher has argued further that our brains are soaked in different kinds of chemicals depending on the kinds of affiliation-oriented emotions we are feeling. Lust, for example, is associated with testosterone. By contrast, with “love” we are awash in dopamine and norepinephrine--natural stimulants--and our level of serotonin decreases. Serotonin helps us go to sleep, and may keep us from becoming depressed. Serotonin helps us go to sleep, and may keep us from becoming depressed.