I have obviously been reading too much evolutionary biology lately. Reading through this very interesting paper by John Hobcraft I came across this intriguing paragraph:
Our emotions play an important part in any long-term relationship. A ‘good’ partnership can successfully meet many of our basic needs for sex, for nurture, and for intimacy (Panksepp, 1998). On the other hand intimate partnerships are too often associated with emotions of fear, disgust, or anger (Fiske 2004). Demographers need to engage with neuroscience and gain a better understanding of the role of emotions in relationships (see also Massey 2002). Moreover, we need to pay attention to some emergent suggestions that pair-bonding and love generate lasting changes in brain structure (Young 2003). In other words, the key importance of feedback loops in relationship formation and breakdown need to be included in our consideration.
"emergent suggestions that pair-bonding and love generate lasting changes in brain structure" hmmm, I thought. So I dug out the reference and went looking for Young:
Young, L.J. 2003. The neural basis of pair bonding in a monogamous species: a model for understanding the biological basis of human behavior, in K.W. Wachter and R.A. Bulatao (eds.) Offspring: Human Fertility Behavior in Biodemographic Perspective. Washington D.C.: National Academy Press.
where I found:
Studies of voles have produced an exciting hypothesis that suggests pair bond formation is regulated by the same brain regions involved in the actions of drugs of abuse. These so-called reward circuits are regions of the brain that regulate feelings of pleasure and reward. These regions are activated by a neurotransmitter called dopamine, which is increased in the brain after taking cocaine and amphetamines. Those experiencing love of-ten report feelings of euphoria when intimate with their partners, and these feelings are often reported as being similar to being “high.” There is some scientific evidence that these reward circuits may in fact be involved in the psychobiology of love. One study examined brain activation in people while viewing photographs of someone to whom the subject reported being deeply in love. Brain activity was also determined while these same subjects viewed photographs of other familiar individuals. The authors reported that viewing photographs of their lovers elicited brain activation that was remarkably similar to that seen in other studies after drug consumption (Bartels and Zeki, 2000). This suggests that perhaps similar neural circuits are used to facilitate pair bonding in voles and humans. Perhaps the saying “love is an addiction” has biological support.
The biological basis of the pair bond in humans may change with time. In the early years of a relationship, love is experienced as an incredibly intense sensation that often drives the behavior of the individual. People experience a euphoria that may be similar to that experienced by drugs of addiction, and this experience undoubtedly has a specific neurochemistry underlying it. The individuals in these relationships are consumed by thoughts of being with their partner, often at the expense of other relationships. However, often in later years of a marriage, the nature of this bond changes and becomes less visceral and more a relationship of codependence. Perhaps for our primitive ancestors, the transition between these two types of love, which would occur after the offspring of the relationship are less dependent on the mother, would mark the dissolution of the relationship.