Goleman describes the three brain systems at play in the realm of romantic love, each fueled by a different type of brain chemical. The first form is attachment, or support in the form of presence. The second is caregiving, which creates the desire to nurture and protect. The third is sex, which Goleman treats as self-explanatory.

Goleman states, “Each of these three strands connect people in different ways” (189). All three are necessary according to his model of romantic love. If any one of the three is lacking, romantic love is challenged. These systems begin in infancy, guiding the baby to seek care and comfort from others.

An anecdote presents a woman who solicits the notice of a man at a bar by looking at him as she walks past. As he starts to look back at her, she glances away and then retreats. Goleman refers to this as an “approach-withdrawal sequence” (190), in which a woman tests a man’s willingness to pursue her and commit to winning her. Goleman states that flirting in and of itself pays off: Men most often approach women who signal their willingness to engage. Goleman points out that this behavior—smiling, talking animatedly, and making eye contact—is very similar to the behaviors an infant uses to solicit attention from a caregiver.