Just watched part of a speech about love by Biological Anthropologist Dr. Helen Fisher, PhD. She is apparently responsible for Match.com’s system for, well, matching people. This system puts people into 4 categories, much like the ancient humours system or a simplified Myers-Briggs Type Indicator. But unlike most personality types, her groupings are based on the dominant neurotransmitter in a person’s brain, so it sounds very scientific.

However, the subjects aren’t medically tested for their brain type, they just fill out a questionnaire. (Of course, she includes a disclaimer that we all have elements of each personality style within us, but we display the traits of one in a higher degree.) I know that that sounds just as “scientific” as phrenology, but Fisher is also the person that found love in the brain by putting people inside an MRI machine! She has a long, serious history of studying how the brain works, and especially how love works in the brain (it’s basically no different from a drug addiction, according to her research).

Long story short:
After a simplistic illustration of her personality styles by telling us which world leaders fall into her categories, she explains the average romantic choices of all four types. Her results suggest that opposites attract, but only if they are the right kind of opposites. Two of the types prefer their own type, and the remaining two types prefer one another.

Here she is describing her findings to the Digital, Life, Design 2010 crowd:
FORA.tv – Digital, Life, Design 2010: Human Emotion
(Skip to part 6 for the meaty stuff.)

Here’s an extended interview with her at Big Think:
Helen Fisher | Biological Anthropologist and Rutgers University Professor | Big Think