What physiological changes can explain the honeymoon phase of a relationship?
Gary W. Lewandowski, Jr., associate professor of psychology at Monmouth University and co-editor of www.ScienceOfRelationships.com, replies:
Ah, the honeymoon stage—that magical time when your partner is still perfect and you are very much in love. This period features high levels of passionate love, characterized by intense feelings of attraction and ecstasy, as well as an idealization of one's partner. The strong emotions associated with passionate love have physical manifestations, such as butterflies in the stomach or heart palpitations. Recent research has begun to explore how these feelings manifest in the brain and in one's physiology.
Using functional MRI, investigators have identified several brain regions associated with feeling love. Individuals who experience passionate love (typically brought on by pictures or thoughts of the beloved) show greater activation in the caudate nucleus, important in learning and memory, and the ventral tegmental area, central to emotional processing. Both brain areas tend to be rich in dopamine, a neurotransmitter associated with reward and motivation.
Another study found that when women who were madly in love thought about their partner, instead of a friend, they exhibited elevated levels of the stress-buffering hormone cortisol.
Researchers have also examined how experiencing passionate love can influence an individual's brain chemistry. One study revealed that recent lovebirds had higher levels of nerve growth factor (NGF), a protein that aids in the development and functioning of neurons, than people who were single or in long-term relationships. The authors speculated that elevated NGF levels might increase a person's feelings of euphoria or connection. When measuring cortisol and NGF levels 12 to 24 months later, they found that differences between the passionate love group and the others had disappeared.
These findings suggest that romantic love is an arousing but stressful experience. These physiological changes are short-lived, perhaps because we become acclimated to our partner with time. Although the ardor may diminish, do not lose faith—research shows that some couples can sustain these honeymoon period feelings throughout their relationship by challenging each other with new activities, such as biking or dance.