Helen Fisher, the Rutgers anthropologist who wrote "Why We Love," has a new book out. It's based on her work with Chemistry.com, a dating website that's an offshoot of Match.com.
Chemistry.com purports to add an analysis of what you could call one's neurochemical tone to the usual mix of interests, needs and wishes that dating sites typically use.
Fisher has then used the anonymous aggregated information gathered from all these Chemistry.com users to study her hypothesis that there are four types of people.
Dividing people into types is, of course, nothing new. These categories can provide a useful framework for thinking about relationships, whether or not they have all that much congruence to one's dominant neurochemical.
In any case, this Time interview is an interesting read.