What is it about our biology as human being make us fall in love? I read an interesting article recently by Helen Fisher of Rutgers University regarding the emotional systems involved in human mating, reproduction and parenting. It is entitled Lust, Attraction, Attachment.
Ms. Fisher explains that Lust, Attraction and Attachment are three separate emotion states that work together with other bodily systems to facilitate how we meet and stay with our mates. These processes act through the production of chemicals in our brains that include testosterone, estrogen, serotonin, dopamine, oxytocin and several neuropeptides to give us the feelings we experience when we meet someone that we like.
Lust
This is described as the ” sex drive”. It is best described as the emotional state in which one is motivated to engage in sexual behavior with another. This is a drive different from attraction, because it is focused solely on sexual relations, and has been observed in animals to act apart from attraction. An animal may express a sex drive, but they also all show preference to mate with certain individuals, rather than with just anyone.
Studies have shown that middle-aged women and men when injected with testosterone exhibit enhanced sex drives. However, they certainly do not fall in love. In fact, there has been a negative correlation in animal studies that show high levels of testosterone and expression of attachment. In one study, scientists injected male sparrows (who form long-term pair bonds) with testosterone. Afterwards they all abandoned their partners to pursue other females. Human studies have also shown a correlation between high testosterone and unstable marriages . What is interesting is that levels of testosterone decrease in expectant fathers when their children are born, thereby promoting more stability- it is believed.
In mammals, the sex drive tends to be very independent from long-term attachment. Ms. Fisher’s article surprisingly states that although all mammals engage in sexual activity, only “3 % of all mammalian species form a long-term attachment to a mating partner” This is one reason why researchers spend so much time looking a birds when they study long-term pair bonding, and even with birds most do not form bonds beyond the duration of the breeding season.
Attraction
This is the emotion related to “falling in love”. Biologists have observed that this is the state where someone begins “to feel that their beloved is unique; their ‘love object’ takes on ‘special meaning’”. Interestingly, this phenomenon tends to be exclusive, meaning that it is not felt for more than one person at a time, while lust can be. Tests have shown that this state is marked by increased levels of nerepinephrine, which is associated with increased memory for new stimuli. This chemical has also been identified in the imprinting stage characterized by newly hatched geese where they are compelled to follow the first thing they see as their mother.
This emotional state is further characterized by “intrusive thought” patterns, whereby the lover repeatedly and uncontrollably thinks about his beloved. The love-possessed tends to focus his attention on the beloved’s positive qualities and discount the negative. During this stage researchers have found increased concentration of dopamine in the brain; the chemical that is associated with euphoria.
What was fascinating, was that researchers have surmised that passionate romantic love lasts between 6 to 18 months.
Attachment
Attachment is the long-term relationship between mates. It involves the generally activities observed in animals such as defending territory, nest building, mutual grooming and sharing parental chores. “Securely attached men and women also report feelings of closeness, security, peace, social comfort, and mild euphoria when in contact with their partner.” Nueroscientists has observed the presence of vasopressin and oxytocin in mice where increased levels due to the transplantation of a gene increased their affiliative behaviors.
Human attachment is often observed with the pair-bonding in marriage. This human innovation is experience by most people. In the US 93 % of women and 92% of men marry at least once before the age of 49. We also find that 50 % or more of them divorce, most within the first seven years, and the majority of those within 4 years. Ms. Fisher hypothesizes that the natural duration of human pair-bonding is 4 years, and has an evolutionary component. That being that the close attachment of a male-provider was necessary to care for a women who was carrying a small child, but when a child was old enough to be cared for in a communal setting and was able to walk and keep up, that such need was not present. Therefore, the pair would break up. If you read the book Sex a Dawn which I wrote about earlier, you know that this hypothesis is disputed.
Observations
On the whole, I found this article fascinating. If you are interested in the full article, I would be glad to give you the citation.
Keep thinking!