In the June 2007 issue of O, The Oprah Magazine , anthropologist Dr. Helen Fisher writes about surveying 500 couples to research the different "love types" that exist. Gayle talks with Dr. Fisher about her findings and the state of love and relationships today.

Overall, people are getting married later in life, and the longer people wait to get married, the more likely they are to stay together, Dr. Fisher says. In addition, both men's and women's roles have changed in recent years, she says. The changing roles are apparent in the four love types that Dr. Fisher says she's discovered. While you can fall into more than one of the four categories, Dr. Fisher says most couples are not the same type. "You fall in love with somebody with certain similarities and certain complementariness," she says.

Here are Dr. Fisher's four personality categories:

• The Explorer: High energy and an active dopamine system are strong traits of an explorer. "These people tend to be risk-taking and novelty-seeking, spontaneous and curious, creative and often very irreverent and very fun-loving," Dr. Fisher says.
• The Builder: This is the kind of person who may be a pillar of society and have a lot of activity in the serotonin system. "A builder tends to be calm, social and popular," Dr. Fisher says. "They like schedules and roles, they like to follow social norms and they are often religious or spiritual. They tend to be more conventional—they are loyal, they have a real sense of duty."
• The Director: Activities in the testosterone system influence the director. "They tend to be direct, focused, analytical—logical reasoning is very important to them," Dr. Fisher says. "They are very good at rule-based systems—everything from higher math to building bridges and understanding computers." Many builders may also have poor people skills but are the most intellectual of all the categories.
• The Negotiator: Both men and women can be negotiators despite the fact that they have a lot of activity in the estrogen system. "They are very good at seeing the big picture—they are very idealistic, very compassionate, altruistic, sympathetic and very imaginative," she says.