The Nature, Development, and Origin of Intelligence - Essay Example

? The Nature Vs. Nurture Debate: The Arguments of Both Sides. Word Count: 2000 The question of whether intelligence and other skills are genetic or instilled by the environment has sparked a controversy for long. The question has lead to the great nature vs. nurture debate amongst psychologists, socialists and others alike. The debate was first initiated by Francis Galton, a cousin of Charles Darwin. Darwin’s publication of his book, Origin of Species, motivated Galton to study heredity, which lead to his questioning the origin of intelligence – whether it was genetic or brought on by environmental factors. The nature vs. nurture debate has been the most controversial in the history of the relatively young science of psychology. Essentially, curiosity about Intelligence and ways to measure it was what established psychology as separate science. Many psychologists have tried to define intelligence in numerable ways. While before many stream-lined definitions of intelligence existed – for instance, Sternberg & Salter define intelligence as ‘the capacity for goal-directed adaptive behavior’ (Sternberg &Salter, 1982, p. 3) while Gardner (1983) defined it as the application of cognitive skills and knowledge to learn, solve problems and obtain ends that are valued by an individual and culture – it has now been agreed that intelligence is multifaceted. This claim takes into consideration the many factors that constitute an individual’s response to and performance on most intelligence tests – for example, culture, spatial reasoning, verbal skills, problem solving abilities, education, etc. This brings us to the validity of Intelligence tests and whether they are an accurate indicator of one’s intelligence. Lorelle Burton states in his book, Psychology: Australian and New Zealand Edition, ‘intelligence tests are measures designed to assess an individual’s level of cognitive abilities compared to other people in a population’. Many distinguished psychologists devised many means to measure intelligence. Theodore Simon and Alfred Binet developed the first intelligence test. This was developed further by Lewis Terman of Stanford University and was called the Terman-Binet Test. The most authentic, accurate assessment of an individual’s intelligence is the Intelligence Quotient (IQ) test, which fairly evaluates cognitive ability and compares it against other individuals in a population. In the context of this paper, intelligence tests are only significant when discussing whether the intelligence they measure is genetic/hereditary or honed and brought on by environmental factors. We come to the core question of this essay: Nature or nurture? Renowned Harvard professor and psychologist, Stephen Pinker in his essay, ‘Why nature and nurture won’t go away’, explains that any given gene will behave differently in response to different environments. Working on this hypothesis he points out that there may then be an environment in which that specific gene might not work at all. Thus, given this mutual relationship between the gene and the environment, he states, ‘it is meaningless to try and distinguish genes and environments.’ This is a position reached by most contemporary scientists. However, this was not so in the past. In his book, The Blank Slate, Pinker relates a study conducted in the year 2000 by psychologist Nancy Segal of ‘virtual’ twins. ‘Virtual twins’, he explains, are the mirror image of identical twins – unrelated siblings, with one or both of them adopted, brought up in the same household and given the same treatment. Their IQ scores, however, barely correlated. One father in the study even said that despite their best efforts to treat them alike, the twins were as different as night and day. This suggests that genetic disposition might have a bigger role to play in contributing to person’s intelligence than the scientists mentioned above claim. This can be further proved by the studies that were carried out on Albert Einstein’s brain which he donated to science after his death. It was found that Einstein had large unusually shaped inferior parietal lobules, which are responsible for spatial reasoning and intuitions about numbers (Witelson, Kigel & Harvey, 1999). According to a recent study of the brains of identical and fraternal twins, it has also been proved that differences in the amount of grey matter in the frontal lobe are not only influenced by genes but account also for the differences in intelligence (Thompson, et al. 2001). This remarkable example shows the extent of the role genes play in determining our intelligence levels and most characteristics. This can be extended upon saying that genes determine the number of neurons we have, the connections between them and hence, how fast we process information and how well we respond to different situations. To understand this, we must first realize the genes do not guarantee that behaviors or intelligence levels will not change. They only go so far as to ensure that those characteristics exist; change in those characteristics, however, are reliable on a number of variables. Joseph Henry, in his book ‘The Great Brain Debate’, writes about the hereditary nature of schizophrenia. He explains that the schizophrenia is often classified as an outcome of a certain type of gene. He goes on to point out that while this has been known for some time, there is also evidence to show that the likelihood of schizophrenia in identical twins increases with the onset of schizophrenia in one twin. This implies that while twins share the same genetic code, the chances that one twin will get schizophrenia increases if the other twin is schizophrenic. The impact of this environmental factor shows the strength of the arguments of those belonging to the nurture camp. On the link between IQ and genetics, he writes about Richard Bouchard’s famous Minnesota twin studies (1979). The results of the study indicated that the variance in IQ due to genetic variation was significantly high (60 – 70 percent) while previous studies had suggested somewhat lower values (40-50 percent). However, it is of importance to note that Bouchard’s results were obtained from middle-aged adults. This fact is rendered interesting due to recent findings that suggest that the correlation between IQ and inheritance increases with age. This brings to light an important point – the affect of age on and relationship with IQ. At a certain age, have we acquired ‘wisdom over the years’ or are we more prone to displaying our natural intelligence? Also, does the IQ of young children have a stronger relationship with environmental factors than with genetic variables? Does this imply that once the body and the mind have experienced most kinds of environments, the effect of the environment becomes weaker compared to that of genes? Considering the evidence provided by all aforementioned psychologists, you question the validity of the nurture theory. Despite the conclusion the above incidents point to, many leading psychologists have refuted the nurture theory for their insistence of the fact that the human being is a blank slate. Judith Harris, in her book, ‘The Nurture Assumption’, refutes the claim of the nurture camp. She explains that for the nurture assumption to work, the hypothesis that parents impart cultural knowledge to their children must be valid. Harris further goes on to explain that in a foreign environment where parents do not speak the local language, children are more likely to pick up the language of their playmates than gain fluency in their parents language. On the other hand, Stephen Jay Gould, Richard Lewontin and the other signatories of the “Against Sociobiology” manifesto wrote, ‘We are not denying that there are genetic components to human behavior. But we suspect that human biological universals are to be discovered more in the generalities of eating, excreting, and sleeping than in such specific and highly variable habits such as warfare, sexual exploitation of women and the use of money as a medium of exchange.’ (Allen, etal. 1975) The famous anthropologist Ashley Montagu wrote, ‘Apart from the instinctoid reactions in infants to sudden withdrawals of support and to sudden loud noises, the human being is entirely instinctless…..man is man because he has no instincts, because everything he is and has become he has learned…from his culture, from the manmade part of his environment, from other human-beings’ (Montagu, 1973). The distinguished psychologist, Stephen Jay Gould dismissed the notion of imperious genes claiming that the human brain was not designed to function in a definite way. Hudson (1960) conducted an experiment on an indigenous African people, the Bantu tribe. He designed an interesting experiment that aimed to highlight cultural differences in perception. He came up with a number of pictures that utilized relative size as a cue to depth, and many other perception cues. He discovered that an ability to read these cues was related to education and the extent of exposure to European civilization. Bantu individuals who had been educated in European schools or who were more familiar with European culture saw things as Europeans did, whereas those with little schooling or education tended to see things differently. Here, we ask ourselves another question: Is intelligence ‘learned’? Is there any such thing as an intelligent illiterate person – one who is naturally intelligent, but not lettered? Does schooling really make us see and think differently? Scribner (1979) questioned whether logic and problem-solving abilities were innate or instilled by an education. He designed an experiment to figure out why illiterate people failed to answer correctly to verbal problems. Uneducated peasants were asked to explain irrational problems to syllogism problems and they persistently answered either with evidence personally known to them or refused to answer the question based on the fact that they did not know anything about the matter, ignoring the conditions presented to them. For instance, to a problems such as “All children like candy; Mandy is a child; does Mandy like candy?” The most likely answers were ‘How would I know whether Mary likes candy? I don’t even know the child!’ or ‘Maybe she doesn’t like candy. I’ve known children who didn’t.’ Many psychiatrists have taken the middle path, such as Joseph Henry who has along with his arguments been mentioned above. They have argued that it is impossible to isolate the effects of the environment from that exerted by the genes. Judith Harris, in her book ‘The Nurture Assumption’, talks about the direct genetic effects and indirect genetic effects. The direct genetic effects are those that are, directly a result of your genes – good looks, timidity, etc. The indirect genetic effects are those that are caused by the direct genetic effects – that is, you are popular because you are good looking, you are an introvert because you are timid. Thus, even if the environment provided is the same for all children, it would have a different impact on each child due to the direct genetic effects. This statement thus aims to substantiate the claim that intelligence and other characteristics are not related to either genes or the environment. This brings us back to the beginning of this essay where I had quoted Stephen Pinker stating the same. This is also stated by Matt Ridley in his book, Nature via Nurture. He asserts that while genes sow the seeds of characteristics and determine our intellectual ability, they do not control the way we behave or develop. In response to unique stimuli, they can even give us a new set of characteristics. ‘They are both cause and consequences of our actions,’ he writes. Many have slammed this last group of psychologists as adopting the ‘safe, appeasing path’. However, for me, it this last group whose arguments hold the most validity. To adhere to either camp will only ensure the unnecessary continuity of the debate when the answer, I believe, is obvious. Genetic effects are not beyond modification; they only establish a range of characteristics a person may or may not exhibit, depending on the environment. This leads to the conclusion then that one’s performance on IQ tests and hence intelligence depends largely on the kind of education the person receives and the environment a person grows up in as well as the innate capacity for learning, endowed at conception. While both the behaviorists and empiricists present valid arguments, I find that the third path weighs out the arguments of both sides carefully and presents a comprehensive understanding of our behavior. References. Allen, E, et al. (1975, November 13). Against Sociobiology. The New York Review of Books. Bouchard, T. J., et al. (1990, October 12). Sources of Human Psychological Differences: The Minnesota Study of Twins Reared Apart. Science, 250, 223 -228. Downling, John E (2004). The Great Brain Debate: Nature or Nurture? Washington, DC: Joseph Henry Press Gardner, Howard (1993). Frames of Mind: The Theory of Multiple Intelligences. Basic Books. Gould, Stephen Jay. Biological potential vs Biological determinism. Ever Since Darwin: Reflections in Natural History. Stephen Jay Gould, ed. New York: Norton. Harris, Judith, & Pinker Steven (2009). The Nurture Assumption: Why Children Turn Out The Way They Do. Free Press. Hudson, W. (1960). Pictorial depth perception in sub-cultural groups in Africa. Journal of Social Psychology, 52, 183-208. Montagu, Ashley, (ed.) (1973). Man and Aggression. Oxford University Press. Pinker, Steven (2004). Why Nature and Nurture Won’t Go Away. Daedalus Fall Issue, 133(4), 5 -17. Pinker, Steven (2002). The Blank Slate: The Modern Denial of Human Nature. Penguin. Nature via Nurture: Genes, Experience and What Makes Us Human. Matt Ridley 2003 New York: HarperCollins. Scribner, S (1979). Modes of thinking and ways of speaking: Culture and Logic reconsidered. R. O. Freedle, ed. New directions in discourse processing. Norwood, NJ: Ablex Pub. Sternberg, R J, ed (1982). Handbook of Human Intelligence. Cambridge University Press. Thompson, Paul M. et al (2001). Genetic Influences on Brain Structure. Nature Neuroscience, 4, 1253 – 1258. Witelson, SF, Kigar, DL & Harvey, T (1999). The Exceptional Brain of Albert Einstein. Lancelet, 353, 2149 – 2153. Read More