Saturday, February 15, 2014

Love, Science and the Brain

This Valentines season, I would like to talk about a topic that is very intriguing to most but nevertheless essential in our understanding of the human body. This is something that we always do in our everyday lives but rarely thought of how it actually works and why we felt that way. It is an emotion called Love.

We love because we are fond of that person, wants to care for them and are sensitive to their needs and emotions. There are different ways to express love, depending on the type of relationship you have with that person. But, whether they are your parents, siblings, friends, special friends or your special someone, your body reacts with their surroundings and creates a cocktail of chemicals that would translate to love itself. 

As of the moment, two scientific disciplines have so far attempted to explain the processes that leads to the emotion of love. The fields of Evolutionary Psychology and Neurochemistry. 

Evolutionary Phychology*

Evolutionary psychology has proposed several explanations for love. Human infants and children are for a very long time dependent on parental help. Love has therefore been seen as a mechanism to promote mutual parental support of children for an extended time period. Another is that sexually transmitted diseases may cause, among other effects, permanently reduced fertility, injury to the fetus, and increase risks during childbirth. This would favor exclusive long-term relationships reducing the risk of contracting an STD.

From the perspective of evolutionary psychology the experiences and behaviors associated with love can be investigated in terms of how they have been shaped by human evolution. For example, it has been suggested that human language has been selected during evolution as a type of "mating signal" that allows potential mates to judge reproductive fitness. Miller described evolutionary psychology as a starting place for further research: "Cognitive neuroscience could try to localize courtship adaptations in the brain. Most importantly, we need much better observations concerning real-life human courtship, including the measurable aspects of courtship that influence mate choice, the reproductive (or at least sexual) consequences of individual variation in those aspects, and the social-cognitive and emotional mechanisms of falling in love." Since Darwin's time there have been similar speculations about the evolution of human interest in music also as a potential signaling system for attracting and judging the fitness of potential mates. It has been suggested that the human capacity to experience love has been evolved as a signal to potential mates that the partner will be a good parent and be likely to help pass genes to future generations.[5] Biologist Jeremy Griffith defines love as 'unconditional selflessness', suggesting utterly cooperative instincts developed in modern humans' ancestor, Australopithecus. Studies of bonobos (a great ape previously referred to as a pygmy chimpanzee) are frequently cited in support of a cooperative past in humans.

In Neurochemistry

In the United States, Helen Fisher of Rutgers University has proposed 3 stages of love - lust, attraction and attachment. Each stage might be driven by different hormones and chemicals. 

Three Stages of Falling in Love**

Stage 1: Lust

Lust is being driven by the sex hormones testosterone and oestrogen (estrogen). Testosterone is not confined only to men. It has also been shown to play a major role in the sex drive of women. These hormones as Helen Fisher says "get you out looking for anything".

Stage 2: Attraction

This is the real love-struck phase. People think of nothing else when they fall in love. Might lose appetite or have problems sleeping. They sometimes daydream of being together with the person they love. For family relationships, that also translates to tantrums or a "mini"-depression when they don't see their parents often. 

In this stage, several groups of neuro-transmitters called 'monoamines' play an important role:

Dopamine - Also activated by cocaine and nicotine.

Norepinephrine - Otherwise known as adrenalin. Starts us sweating and gets the heart racing.

Serotonin - One of love's most important chemicals and one that may actually send us temporarily insane.
Discover which type of partner you're attracted to by taking our face perception test.

Stage 3: Attachment

If a relationship is going to last, this is the next phase. It is said that people could not possibly stay in the attraction phase forever, otherwise nothing will be ever accomplished.

Attachment is the bond that keeps couples together in a long lasting commitment when they move on to have children. There a two key hormones released by the nervous system, which is currently thought to have a major role in keeping social attachments:

Oxytocin - This is released by the hypothalamus gland during child birth and also helps the breast express milk. It helps cement the strong bond between mother and child. It is also released by both sexes during orgasm and it is thought that it promotes bonding when adults are intimate. The theory goes that the more sex a couple has, the deeper their bond becomes

Vasopressin - Another important chemical in the long-term commitment stage. It is an important controller of the kidney and its role in long-term relationships was discovered when scientists looked at the prairie vole
Find out how the three stages can feel even stronger for teenagers in love, experiencing first love and first sex.


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