Nature VS Nurture

[SliK]

What do you think ultimately determines who we are as people?

1) Are we "tabula rasa" at birth - a blank slate? Do we learn and develop our personalities through experience alone?
2) Are we pre-programmed by our genetics to think and respond in certain ways?
3) Is it a combination of the two? If so, how do they interact and which, if either, is the most dominant?

I've been researching this heavily for the last month and I've just submitted my essay on it. I'd like some input and then I'll share some facts with you.

[viJilance]

I think it's mostly we learn from the things around us, but not entirely. I'd give it about 80/20.

If your family has a history of say- bipolar disorder, assuming it's strictly chemical, then it will be ingrained in your genetics.

But mostly the things that affect as at an early age are what shape us... you know, those vivd moments of overwhelming emotion, when thoughts and memories echoed through your childish imagination for what seemed like eternity (at that time), And everything was so crystal clear. I think that's what makes us mostly who we are.

I'd love to read your essay by the way.

[SliK]

Well you'd be surprised to learn that genetic factors influence us a lot more heavily than you would think.
The essay is to counter 17th century philosopher John Locke's statement that the mind is a blank slate at birth and everything we learn is through experience. It is then focused on Ani-Social Behaviour (ASB) and how it presents in people and why. The root causes of ASB are genetic, with environmental factors playing very little (and sometimes no) influence at all.

i'll post the essay, but it's honestly not my best work. I wrote it all in a day and genuinely ran out of time. All the information contained within it is accurate, but it could have been much better written.

[SliK]

Psychology is the study of all human behaviour, using scientific method such as experimentation, observation and measurement to collect and compare data (Michell, 1997). However, before the advancement of science, philosophers tried to explain human behaviour using rational theories rather than empirical evidence (Subhani & Osman, 2011). John Locke is one such philosopher who argued that the mind is a blank slate – “Tablua Rasa” – at birth. He proposed that everything we think and every action we make is based solely on experience. This essay’s focus is on scientific studies concentrating on the role of genetics, specifically in anti-social behaviour (ASB), which suggest that nature works via nurture to shape our personalities. The lines of evidence that will be used in this essay are twin studies, adoptive studies and molecular genetics. These studies demonstrate higher correlations in personality traits as genetic similarity increases (Viding, 2004). Subsequently, personality differences in genetically similar or identical individuals are attributed to environmental factors (Viding). The relationships between environmental and genetic factors are established by comparing Monozygotic (MZA) twins with Dizygotic (DZA) twins. If MZA twins appear more similar in a trait there must be a genetic influence on that trait (Viding). These lines of evidence create a strong case against Locke’s argument and support the theory that nature plays the primary role in ASB.
Philosophy was once the primary study of human behaviour and explores the same issues that modern psychologists are interested in today. Dishion and Patterson’s (2006) study defined ASB as behaviour that falls outside of established social norms. Examples of ASB are behaviours that are irresponsible, aggressive, impulsive, deceitful or harmful (Bree, Svikis & Pickens, 1998). John Locke was a 17th century philosopher who argued that humans acquire knowledge, and develop personalities, via our senses and a process of reflection (Subhani & Osman, 2011). The term “tabula rasa”, which Locke uses to describe the mind at birth, was coined by the influential Greek philosopher Aristotle in 384BC. Aristotle also argued that the mind is a blank slate at birth (Subhani et al.). As with any field of study, Locke was influenced by the work of others before him. Therefore it is no surprise that he took a philosophical approach to the issue using the best methods of analysis available at the time. However, most of the evidence that philosophers once deemed valid, such as intuition, is not accepted in current academic circles (Cath, 2012). Over time, methods of testing a hypothesis were continually improved to ensure the accuracy of each experiment. In addition to this, the technology available in Locke’s time meant there could be no insight into the role genetics play in behaviour. Due to the heavy reliance of intuition and other such abstract methods of measurement, psychologists have disregarded these “armchair judgements” made by philosophers, such as Locke, in favour of more scientific methodologies (Cath, 2012). These out-dated practises, coupled with no knowledge of genetics, resulted in Locke’s very limited understanding of human behaviour. (Zembroski, 2011).
Twin studies have shed much light on the role genetics play in ASB. By studying genetically identical individuals it is possible to establish a correlation between genetic factors and behaviour. This counters Locke’s theory as genetics are in play well before birth and can potentially determine an individual’s behaviour, with environmental factors playing a very limited role in shaping the human psyche (Burton, Westen & Kowolski, 2012). There are now over 30 twin studies of the environmental and genetic effects on ASB. These studies have found considerable heritability in ASB traits among children and adolescents, with genetic factors accounting for up to 50% of variances (Eley, Lichtenstein & Moffitt, 2003). Findings from such studies strongly suggest that familial resemblance during adulthood is only slightly influenced by shared rearing environments (trait correlation on a single variable is about 0.03) and affects relatively few behavioural dimensions (Bouchard, Lykken, McGue, Segal & Tellegen, 1990).
The Minnesota study of twins raised apart established that around 70% of differences in Intelligence Quota (IQ) are linked to genetic factors (Bouchard et al.). This challenged views of individual differences in social attitudes at the time, which focused on nurture as the primary influence of IQ differences and therefore ASB (Bouchard et al.). The most important conclusion that Bouchard et al. makes is that genetic factors play a substantial role in behavioural variability. This was established by obtaining the IQs of MZA twins raised apart which were then analysed and compared with results of prior MZA twin studies. Results were consistent with previous studies performed by Newman et al., Juel-Nielsen and Shields (as cited by Bouchard et. al.). In Koenan, Caspi, Moffitt, Rijsdijk and Taylor’s (2006) study of 1,116 five year old twin pairs and their family it was reaffirmed that the genetic factors which determine IQ play an important role in ASB. It has also been found that genetics are most influential in those who engage in life-course persistent ASB (Blonigen, Carlson, Krueger and Patrick, 2003). Life course persistent ASB is defined as young individuals (up to 5 years of age) who develop ASB and consistently engage in ASB throughout their life (Blonigen et al.). Alternatively, those who engage in adolescent-limited ASB, a common form of ASB that only presents in children and adolescents, usually do so because of environmental factors such as peer pressure (Eley et al.). Although environmental factors do have a heavy influence on ASB in adolescents, this is a common stage of development for most people that is eventually grown out of (Eley et al.). ADHD is a condition that results in broad spectrum of anti-social behaviours. These behaviours generally present in childhood and are an example of life course persistent ASB. Studies using kinship pairs indicate that 80% in the variance of ADHD is genetically influenced (Beaver, Sak, Vaske & Nilsson, 2010).
ADHD has also been heavily tested in adoption based studies (Beaver, Nedelec, Rowland & Schwartz, 2010). Like twin studies, adoption studies look at an individual in a situation where opposing genetic and environmental factors are at work. In Carodet and Stewart’s (1991) adoption study of attention deficite/hyperactivity/aggression and their relationship to adult antisocial personality they concluded that ADHD has its roots in the delinquency and criminality of a child’s biological parents. Children of parents with an arrest record have between a 0.5 and 0.72 probability of being arrested, as opposed to 0.30 in those without a genetic risk factor. By studying odds ratios it can be calculated that those with genetic links to criminality have an increased risk of being arrested by a factor of up to 4.5 (Beaver, 2011). In several adoption studies carried out over the last decade it was discovered up to 80% of the variance in anti-social phenotypes is attributed to genetic factors with most of the remaining variance being attributed to shared environment (Mason and Frick, 1994; Miles and Carey, 1997; Rhee and Waldman, 2002; Arseneault et al., 2003 as cited by Beaver et al., 2010). When Eley, Lichtenstein & Moffitt (2003) compared data from both twin studies and adoption studies they found a very high similarity in results, despite different limitations in each. By confirming results using a different method of testing, the results of each study design are supported (Eley et al.). Some studies, such as O’Connor and Deater-Decker et al.’s (1998) adoption study (as cited by Eley et al.) have found that an association between negative parenting and child ASB was environmental, not genetic. However, an overwhelming number of studies show that persistent ASB as the child matures is genetically influenced (Moffitt, 1993).
To better understand the way genetics work, molecular genetics map the human genome and attempt to establish a trait for a specific gene or allele (Li & Lee, 2010). To further establish the relationship between genetic and environmental risk factors scientists use molecular genetics to try and determine specific alleles responsible for ASB (Li & Lee). Although no gene has been pinpointed as the cause of antisocial behaviour, much research has been conducted on the issue and has shed some light on the role individual genes play. Men with the high activity MAOA allele located on the X chromosome have a statistically higher probability of committing ASB (Gokturk, Schultz, Nilsson, Knorring, Oreland & Hallman, 2008). However, in a landmark study in the involvement of genotype in the cycle of violence in maltreated children, strong evidence was found that the low activity MAOA allele is an indication of anti-social behaviour only when coupled with childhood maltreatment (Caspi et al., 2002). Only 12% of Caspi et al.'s sample group had the low activity MAOA allele coupled with a history of childhood maltreatment but they accounted for 44% of all criminal activities within the sample and 85% of them displayed ASB of some kind. There have been several follow up studies that have replicated these findings (Haberstick et al., 2005; Huizinga et al., 2006; Young et al., 2006 as cited by Beaver et al., 2010). Although much research has been conducted in the field of molecular genetics, results are still vague. As such, some claim it to be too unreliable as it is still unable to assign genes to specific kinds of behaviour (Bondy, 2011). Although this is true, enough research has been conducted to show strong correlations between certain alleles and general patterns of behaviour. This research provides strong evidence against Locke’s view that ASB can only be developed through experience.
When John Locke described the human mind as a blank slate at birth, he was using only his thoughts and the influence of his peers to formulate his hypothesis. Advancements in science have allowed researchers to gain a better understanding of human behaviour, with a particular focus on ASB. Each line of evidence presented in this essay is enough to shed doubt on Locke’s argument. As McCarten’s (2007) study concluded, life course persistent ASB reflects temperamental traits with a biological basis. She concludes that difficult temperaments result from interactions that promote and sustain ASB between a person and their environment (McCarten). Twin studies, adoptive studies and molecular genetics have established strong links between ASB and genetic factors. Combined, they are enough to disprove Locke’s theory that ASB is gained only through experience.

Reference list

Beaver, K., Nedelec, J., Rowland, M., & Schwartz, J. (2012). Genetic Risks and ADHD Symptomatology: Exploring the Effects of Parental Antisocial Behaviors in an Adoption-Based Study. Child Psychiatry & Human Development, 43(2), 293-305. doi:10.1007/s10578-011-0263-0

Beaver, KM., Sak, A., Vaske, J., & Nilsson, J. (2010). Genetic risk, parent child relations, and antisocial phenotypes in a sample of African-American males. Psychiatry research, 175, 160-164.

Blonigen, D., Carlson, S., Kreuger, R., & Patrick, C. (2003). A twin study of self reported psychopathic personality traits. Personality and Individual Differences, 35(1), 179-197.

Bondy, B. (2011). Genetics in psychiatry: Are the promises met?. World Journal Of Biological Psychiatry, 12(2), 81-88. doi:10.3109/15622975.2010.546428

Bouchard, T., Lykken, D., McGue, M., Segal, N., & Tellegan, A. (1990). Sources of human psychological differences: the minnesota study of twins reared apart. Science, 250(4978), 223-250.Michell, J. (1997).

Burton, L., Westen, D., & Kowolski, RM. (2012). Psychology: Australian and New Zealand Edition (3rd ed.). Brisbane, Australia: John Wiley & Sons.

Carodet, RJ., & Stewart, MA. (1991). An adoption study of attention deficite/hyperactivity/aggression and their relationship to adult antisocial personality. Compr Psychiatry, 32, 73-82.

Caspi, A., McClay, J., Moffitt, T.E., Mill, J., Martin, J., Craig, I.W., Taylor, A., Poulton, R. (2002). Role of genotype in the cycle of violence in maltreated children. Science, 297, 851–854.

Cath, Y. (2012). Evidence and intuition. Episteme (Cambridge University Press), 9 (4), 311-328.

Eley, T., Lichtenstein, P., & Moffit, T. (2003). A longitudinal behavioural genetic analysis of the etiology of aggressive and nonaggressive antisocial behaviour. Development and Psychopathology, 15(2), 383-401.

Gokturk, C., Schultze, S., Nilsson, K. W., Von Knorring, L., Oreland, L., & Hallman, J. (2008). Serotonin transporter (5-HTTLPR) and monoamine oxidase (MAOA) promoter polymorphisms in women with severe alcoholism. Archives Of Women's Mental Health, 11(5/6), 347-355. doi:10.1007/s00737-008-0033-6

Li, J., & Lee, S. (2010). Latent class analysis of antisocial behaviour: interaction of serotonin transporter genotype and maltreatment. Journal Abnormal Child Psychology, 38(6), 789-801.

Moffitt, TE., (1993). Adolescent-limited and life course persistent antisocial behaviour: a developmental taxonomy. Psychological review, 100, 674-701.
Quantitative science and the definition of measurement in psychology. British Journal Of Psychology, 88(3), 355-383.

Subhani, I. M., & Osman, A. (2011). Human mind is a tabula rasa. Interdisciplinary Journal Of Contemporary Research In Business, 3(3), 1173-1176.

Viding, E. (2004). On the nature and nurture of antisocial behaviour and violence. New York Academy of Sciences, 1036, 267-277.

Zembroski, D. (2011). Sociological theories of crime and delinquency. Journal of Human Behaviour in the Social Environment, 21(3), 240-254.

[viJilance]

"they concluded that ADHD has its roots in the delinquency and criminality of a child’s biological parents."

Interesting read, pretty well written in my opinion.

I'm still a bit skeptical as there are many factors to take into account when conducting these studies, but it definitely has tickled my curiosity quite a bit. I definitely can look at the other side of things now with a bit more of an open mind, but it hasn't changed my view on it, it only makes me want to look deeper.

Let me know when you get on it by the way, good luck.

[SliK]

It's hard to argue with twin studies as MZA twins are biologically identical. They share 100% of their genetic makeup. So any differences in personality must be environmental. Having said that, the fact that they score very similarly across a broad range of personality tests despite no shared environment and no interaction with each other over the course of their entire lives speaks volumes on the influence of genetics.

The essay is average, I'm hoping for 70% haha.

[viJilance]

It's hard to argue with twin studies as MZA twins are biologically identical. They share 100% of their genetic makeup. So any differences in personality must be environmental. Having said that, the fact that they score very similarly across a broad range of personality tests despite no shared environment and no interaction with each other over the course of their entire lives speaks volumes on the influence of genetics.

The essay is average, I'm hoping for 70% haha.

Yeah well I guess genetics has to make up for something, otherwise there'd be no point in multiplying, and we'd all be exactly the same, which isn't the case.

But with how connected society is these days, I can't imagine anybody born after the year 2000 being different..lol...

[SliK]

I think Sociology would be more for you.

[viJilance]

I think Sociology would be more for you.

Makes sense, I took a 3-in-one in high school (psych, anthro, and socio) hated it all because of my teacher. I really should begin learning and challenging myself again....

[SliK]

I thought this topic would go off tbh.

[viJilance]

I thought this topic would go off tbh.

Kids don't read anymore

[UofLCard]

It depends on the case.

[SliK]

It depends on the case.

Are you suggesting there are cases where nature (ie genetics) play little to no roll?

It's hard to know exactly what you mean, because you only posted 5 words...

[PAINKILLƎR]

I'd say it's a combination of the both, genetics being more dominate I would say. Our surroundings and the way we grew up shapes up our personalities. I want to talk on personal experience but I'm afraid it may come off as absurd and kind of embarrassing(for me personally)

[SliK]

I look at personal experience as what shapes us, within the constraints of what our genes allow.

For example, my mother put a heavy emphasis on education and sparked my interest in things when I was young. I think, without her, I wouldn't be as intelligent (not saying I am SO smart or like SUPER intelligent or anything) or have as much of an interest in learning. However, there is no amount of teaching that can change genetics, so if I only have the potential for a 120 IQ there is no way I can get more than that.

So environment plays a part in every single person, but more so in determining how strong/weak certain traits are, not whether or not you have that trait at all.

Hence, Nature via Nurture.