Biological Basis of Love
The aim of this essay is to discuss and evaluate a more recent area of neuropsychology, which is the biological basis of attraction. The focus of the essay will be on how certain brain activities in regions of the brain are associated with feelings of attraction in an individual. These forms of attractions can be seen as types of love towards a potential mate and this essay will be targeted at defining what love is and the type of loves there are. The essay will then link these types of loves to neuropsychological research to find the connections between these types of feelings and brain activity.
The research will then be evaluated on its validity and reliability to make a conclusion of attraction being based on these brain systems. The first key to achieving an understanding of what love is on a biological basis is made through defining the meaning of love and how exactly it differs from liking someone. Rubin (1973) felt that liking and loving someone, were completely different systems, where liking was shown to be defined more as a respect, whilst love was also composed of attachment, caring and intimacy as well.
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Rubin developed two scales for this theory and the discriminative validity of this theory was measured from at least a male perspective of liking and loving a woman through these scales (Dermer & Pszczynski 1978), the results suggested that there was a significant difference between the two systems. This however doesn’t entirely help us define what love is, considering there can be many types of love and it makes the idea of love very subjective. Sternberg (1998) agreed with the idea of many types of love and took an in-depth view of the type’s love that attracts us to an individual.
Also similarly to Rubin (1973), Sternberg believed that attachment and intimacy were two of the main types of love as well as passionate love. These three together are said to form consummate love, but separately produce different kinds of love. For example intimacy alone is said to produces liking, whilst passion alone creates infatuation, however together they are said to produce romantic love. According to neuropsychology research by Fisher (2000) some of the types of loves Sternberg has referred to, are said to of been associated with different kinds of brain and hormone activity whilst looking at a potential mate.
Fisher has also described love to follow a certain pattern of stages, which Fisher has called the 3 stages of love. The first Stage is similar to Sternberg’s (1998) passionate love and is represented by Fisher has lust. This stage is described to be driven by hormones such as androgens and estrogens in both genders, these hormones are located in the Gonads and are stimulated from gonadotropin hormones passed down by the circulatory system from the Anterior Pituitary gland, which is located just beneath the Hypothalamus of the brain on the anterior lobe of the Pituary gland (Canadian institutes of health research).
The Pituary gland is not a part of the brain, but it said to be stimulated by the Hypothalamus, which assists in regulating emotion, sexual drives and pleasure and that is located in the Diencephalon section of the brain just below the Thamlus and connecting to the Amygdale that is responsible for emotions like sexual desire (Boree 2009). From using this information and what we know about the brain it can be comprehended that these areas can cause this passionate type of love formed as lust and certain sexual drives to arise from that, which will increase overall general attraction in mates.
The only problem with this is on an evolutionary perspective in terms of sexual selection (Darwin 1859); it will cause a lot of problems. Because it will just lead to loads of mating and may not entirely lead to you finding the more dominant partner or genes, which could cause your child to have a lower chance of survival. This is why females have to be especially picky, due to having a limit on the amount of children they can have in a year, whilst the males not as much, but they would still want to be picky in terms of the parent-offspring conflict (Triver’s 1977) similar to females.
The parent-offspring conflict suggests that having less offspring can be more beneficial considering that providing for many children could damage an individual offspring’s survival rate and end up being counterproductive. This leads to the conclusion that there must be more processes involved than just lust. Beach’s (1976) work with mammals has supported this by looking into mammals induced with androgen and although their sexual activity increased, specific mate favouritism did not increase.
This is where Fisher’s next stage on her 3 stage model (2000) comes in, which she described has specific attraction and can be seen in terms of Sternberg’s (1998) triangular model of love has Romantic Love, being the combination of both intimacy and passion (Initial stage). Fisher (2000) reported that the neurotransmitters Serotonin, Dopamine & Norepinephrine had a predominant change in activity during this phase through past research (Fisher 1998) of newly love struck couples looking at their partners whilst getting their blood flow and brain activity measured from a brain scan off a fMRI.
This has also been reassessed and supported by more future research through the uses of fMRI by Aron, Brown and Fisher (2005). The brain scans showed a similar change in the hormone activity as well as a higher activity in the Right Ventral Tegmental brain region and the right caudate nucleus, which were extremely active whilst subjects looked at photo’s of their partners, which makes sense considering that they are both a part of the dopaminergic reward pathways (Aron et al 2005).
The Ventral Tegmental Area is located in the Mesencephalon part of the mid brain and it’s connected to other parts of the dopaminergic reward pathways such as the Prefrontal Cortex, Nucleus Acumbens, Hippocampus, Substantia Nigra, Basal Ganglia (where the Caudate Nucleus is located) and the Striatum as well as the Hypothalamus. The Prefrontal Cortex is the region where thoughts and actions are planned towards internal goals, which means that this area could be sending signals to the VTA to create Dopamine to induce attraction in a potential mate.
The VTA has also got many tentacle-like axons, which releases dopamine in many regions in the brain including the Caudate nucleus and the Dopaminergic rewards pathways as well as other local pathways. The Dopamine stimulation in these pathway areas creates a concentrated motivation to attain a reward (Fisher 2004a). The Caudate Nuclues and VTA have also been associated with general arousal (Aron et al 2005; Shultz 2000) as well as the high feeling when on addictive drugs like cocaine (Fitzgerald, Gruener & Mtui, 2007).
This can be the same reason why people become increasingly happy, aroused and exhilarated when they are thinking of their partner and even so excited that they can’t sleep. The second hormone Fisher (1998) found is called norepinephrin, which is also known as noradrenaline. This hormone originates in the Locus Coeruleus and the Lateral Tegmental (Kalat 2009) and it is believed to lead to an excitation effect in most of the brain and in overlapping areas of the Dopaminergic reward pathway as well as the Amygdala, , Cingulum & Cingulate Gyrus, which is responsible in remembering emotionally charged events.
The effect of this hormone is that it influences the reward system by exciting the area along with causing states of alertness and arousal. This increased activity in this hormone is a good explanation on why the heart contracts faster during attraction or meeting a potential mate, which is due to pure noradrenalin pumping through the blood. This area however is associated with stress, so it is hard to believe that such a negative association of stressful fight and flight responses would lead to a positive outcome.
Also Bartels & Zeki’s (2000) study of 17 subjects deeply in love, looking at partner’s pictures, shows deactivations in areas such as the Amygdala and posterior Cingulate Gyrus, which are associated with norepinephrin, that is suggested to produce calmness within the individual. This could explain why more major areas didn’t show up in Fisher’s (1998) FMRI scan due to deactivation in these areas, to settle down feelings of fear and stress, whilst still trying to excite the body.
Bartel et al (2000) also found activations in the Anterior Cingulate Cortex, which involves reward anticipation and emotion, so it does support Fisher’s theory that love is an activation of motivational systems. The third and final significant hormone difference Fisher (1998) found was a decrease in Seretonin levels. Low levels of Serotonin is said to produce a loss of appetite, sleeplessness and it is also said be related to obsessive compulsive disorder (Fisher 2007).
These kinds of symptoms could have a positive effect on attraction because you are no longer thinking about other basic needs such as sleep and food, so it could lead to a pure focus on the potential mate, which will increase attraction. The Serotonin pathway overlaps the Dopamine pathway by stimulating areas such as the Hippocampus, Nucleus Accumbens, but from the Ralhe Nuclei it goes down the brain stem into the body and this type of stimulation can cause an appetite for food.
It can also affect the prefrontal cortex, so this could be why Bartel’s & Zek (2000) found areas in the prefrontal cortex deactivated, despite the prefrontal cortex being a reason why dopamine levels could be so high in the first place. This summarizes Fisher’s (1998) second stage of love and now brings us to the last and final stage of love, attachment, which is supported by Sternberg’s (1998) idea of Consummative love.
Previous research by Ainsworth, Blehar, Walter & Wall (1978) has shown this type of love does exist through the use of assessing relationships of mothers and babies. However Fisher felt that this was an important part in loving a partner seeing it gives a sense of calmness and stability to allow for the upbringing of offspring, because it would not be any good if the human race fell in and out of love constantly, but it needs to remain stable to an extent.
One of the differences noted on a neuropsychological level of attraction and attachment is the Vasopressin and Oxytocin level’s which have been reported to be higher (Aron, Brown & Fisher 2006) in people who have been in a longer relationship compared to that of earlier ones. Oxytocin levels is a powerful hormone that is released by men and women during orgasm and it is released in the Nucleus Acumben, which is in the Dopamine pathway.
Vasopressin has similar properties and it is released in areas such as the medial Amygdale, which is in the Noradrenalin pathway. These two neurotransmitters are very important in attachment and when Voles had a drug that repressed Vasopressin their usual monogamous relationship deteriorated (Lim & Young 2004). Aron et al (2006) also found that Oxytocin and Vasopressin levels may interfere with Dopamine and Noradrenalin pathways. Thus allowing the couple to relax and stabilize considering having a bodily high for decades would not be very healthy.
Another difference between the two stages is that Nerve Growth levels have shown to be significantly higher in subjects who were in an early relationship compared to a longer relationships (Emanuele, Politi, Bianchi, Minoretti, Bertona & Geroldi 2006). Nerve Growth cells are made of a crystal knot structure of beta strands and are said to help maintain the sympathetic and sensory system. This leads to a conclusion that they decrease later on due to the Vasopressin and Oxytocin inhibiting the other hormones, thus leading to a decrease in this area.
Another important finding Fisher (2004b) found is that there was a slight difference in gender between brain activities when looking at a photograph of a partner. Men had a slight bit more activity in the temporal lobe which allows the integration of visual stimuli. Whilst women had areas of memory recall, have an increase in activity. This again could be due to evolution reasons, with men needing to look for youth, to find a fertile to pass on the gene, whilst women need to be picky to find a dominant male and this may need to be assessed over many occasions.
The essay concludes that it has met its aim by finding the activity in the regions of the brain that are associated with feelings of attraction in an individual, which were displayed by the difference in activity through Field’s (1998) 3 stage model of love. This model gives great insight and it even explains why certain unevolutionary events occur such as long-term relationships in homosexuality, considering that orgasms alone can produce Oxytocin, which will lead to a need to attachment as well as other neurotransmitters that will cause attraction.
The validity and reliability of Fields model was very valid and reliable due to the huge support from other studies, apart from Bartel et al (2000), which results kind of, contradicts the theory of the Dopamine reward pathway, due to his data showing deactivations rather than activations in these areas. However seeing this is a new area it may be interesting to dig deeper why areas such as the Pre-frontal Cortex is deactivating when it should be the initial activation.
Ainsworth, M. D. S., Blehar, M. C., Waters, E., & Wall, S. (1978). Patterns of Attachment: A Psychological Study of the Strange Situation. Hillsdale, NJ: Erlbaum. Aron, A. & Brown, L.L. & Fisher, H.(2005). Romantic Love: An fMRI study of a neural mechanism for mate choice. Journal of Comparative Neurology, 493: pp58-62. This study was able to support Fisher 1998 by doing a similar study, which assisted in giving the study reliability as well as more data to support the neutransmitters effecting certain pathways. It also highlighted that the VTA and the Nucleus Caudate were two very important areas in activity during the attraction phase. Aron, A. & Brown, L.L. & Fisher, H.( (2006) Romantic Love: A Mammalian Brain System for Mate Choice. In “The Neurobiology of Social Recognition, Attraction and Bonding,” Keith Kendrick (Ed),Philosophical Transactions of the Royal Society: Biological Sciences. 361:pp.2173-2186 Bartels, A. & Zeki, S., (2000) The neural basis of romantic love. Neuroreport, 11 (17): pp.3829-3834. This study contradicted Fisher’s (1998) theory of how a reward system works somewhat, to a certain extent, but in a way it poses new question to answer for the future of why those areas on the dopamine pathway shutdown.
Beach, F. A. (1976). Sexual attractivity, proceptivity, and receptivity in female mammal. Hormones and Behavior, 7, pp.105-138. Boeree. C. (2009). The emotional nervous system. Available: http://webspace.ship.edu/cgboer/limbicsystem.html. Last accessed 20/05/2012. Canadian institutes of health research. The brain from top to bottom. Available: http://thebrain.mcgill.ca/flash/i/i_04/i_04_cr/i_04_cr_peu/i_04_cr_peu.html. Last accessed 20/05/2012. Darwin, C. (1859). The Origin of Species. J. Murray: London. You +1’d this publicly. Undo
Dermer, M., & Pyszczynski, T. (1978). Effects of erotica upon men’s loving and liking responses to women they love. Journal of Personality and Social Psychology , 36, pp.1302-1309. Emanuele, E., Politi, P., Bianchi, M., Minoretti, P., Bertona, M., & Geroldi, D. (2006). Raised plasma nerve growth factor levels associated with early-stage romantic love Psychoneuroendocrinology, 31 (3), pp 288-294. This was a great source it provided me with one of the key elements to describe the difference between the stages of attachment and attraction, which was the Nerve growth and this supported the idea of Oxytocin and Vasopressin’s interfering (Aron et al 2006) with the neurotransmitters. Fisher, H.E. (1998) Lust, attraction, and attachment in mammalian reproduction. Human Nature 9: pp.23–52.
This was probably one of the most useful sources that I used to achieve my aim in my essay and the 3 stage model of love was the core of the essay. I used this source to relate to Sternberg’s (1998) triangle of love and how these types of loves can be used in the 3 stage model. It was very well supported by other studies and many studies also referenced it. Fisher, H.E. (2000). Lust, attraction, attachment: Biology and evolution of the three primary emotion systems for mating, reproduction, and parenting. Journal of Sex Education &Therapy 25, pp.96-104.
Fisher, H. E. (2004a). Biology: your brain in Love. Available: http://www.time.com/time/magazine/article/0,9171,993160-3,00.html. Last accessed 20/05/2012.
Fisher, H. (2004b). Why We Love? The Nature and Chemistry of Romantic Love. New York: Henry Holt and Company.
Fisher, H. & Thomas, J. A. Jr., (2007) Lust, Romance, Attraction, Attachment: Do the side-effects of serotonin-enhancing antidepressants jeopardize romantic love, marriage and fertility? Evolutionary Cognitive Neuroscience. Platek, S. M., Keenan, J. P. & Shakelford, T. K. (Eds.), 245-283, Cambridge: MIT Press.
Fitzgerald, M. J. T., Gruener, G. & Mtui, E. (2007). Clinical Neuroanatomy and Neuroscience. 5th Edition, New York.
1. You +1’d this publicly. Undo Kalat, J.W. (2009) Biological Psychology (10th Ed.). Belmont: Wadsworth Cengage Learning. This was a very useful source in understand where and what everything was in the brain and it was used to help me come up with my own theories such as the prefrontal lobe cortex starting of the Dopamine pathway due to its function of planning to achieve internal goals. Lim, M. M. & Young, L. J. (2004) Vasopressin-dependent neural circuits underlying pair bon formation in the monogamous prairie vole. Neuroscience, 125 (1):pp. 35-45.
Rubin Z (1973). Liking and loving: An invitation to social psychology. Holt, Rinehart and Winston. Schultz, W., (2000). Multiple Reward Signals in the Brain. Nature Reviews Neuroscience 1, pp.199-207. Sternberg, R.J (1998) The Triangle of Love. New York: Cambridge press. I found this a very interesting source to use because it fitted perfectly with Fishers 3 stage theory and helped explain the types of love that there was and it was supported very well with the neuropsychological data Trivers, R.L. (1974). “Parent-offspring conflict”. Am. Zool. 14:pp. 249–264.