Physical desire is a necessary stop on the path to love, but not all lustful encounters escalate to levels of falling in love. Helen Fisher, Rutgers University anthropologist and leading authority on the subject, has conducted extensive research and experiments to get to the bottom of the biological purposes and differences between lust and love.
Brain in Lust
Lust refers to the desire for sexual gratification, and is primarily driven by high levels of the hormones estrogen and androgen, says Fisher. While lust is necessary to initiate the pursuit of a mate, it is not always followed by the process of falling in love, nor is lust always directed exclusively at the object of a person’s love. According to Fisher, people may feel a sex drive response to any individuals other than those they are romantically attracted to. On the other hand, she also warns that engaging in sex can initiate the mechanisms that fuel attachment whether two lustful individuals intend a long term relationship or not, as the hormones secreted during sexual intercourse stimulate the drive for romantic bonding and closeness.
Motivators for Lust
Fisher believes that the neural circuitry associated with lust evolved as a biological motivator for people to pursue any genetically compatible partner at all to mate with. In males, the sex drive is more constant and heavily influenced by visuals, while the female sex drive is more intense and greatly stimulated by romantic words and fictional images.
Brain Falling in Love
Falling in love, or the second stage of love which Fisher refers to as attraction, is primarily driven by high levels of dopamine and heightened activity in the brain’s caudate nucleus. The caudate nucleus is regarded as the brain’s reward system, which indicates that love is not so much an emotion as it is a motivational drive, compelling people to seek the affections of a particular partner. The presence of dopamine in the brain is associated with new environments and highly focused attention -- which is why falling in love is characterized by euphoric, exhilarated, energetic, anxious, sleepless, obsessive states of mind for the enamored individuals concerned. The same elevated hormones, neural circuitry and states of mind associated with falling in love are also associated with cocaine abusers. However, by the time couples arrive at love’s third and final stage, attachment, new hormones -- oxytocin and vasopressin -- take over the process and the obsessive elation calms.
Motivators for Love
Fisher believes that the neural circuitry associated with falling in love evolved as a biological force to lead romantic partners to exclude other love interests and conserve time and energy required for mating by directing it toward a specific genetically-suitable individual until offspring have been conceived. Men’s attractions tend to stem more from physical appearance, while women are more likely to find themselves attracted to men based on financial, educational, occupational and financial status. Unlike unions driven by lust, Fisher found that people actually falling in love view sex as secondary to other factors defining their relationship, with 64 percent of respondents reporting they disagreed that sex was the most important part of their relationships.
- "Archives of Sexual Behavior"; Defining the Brain Systems of Lust, Romantic Attraction, and Attachment; Helen E. Fisher, Ph.D., et al.; October 2002
- McMan's Depression and Bipolar Web; The Brain in Love and Lust; John McManamy; January 2011
- "Time"; Biology: Your Brain In Love; Helen Fisher; January 2004