Nature vs. Nurture: "Rationality"

Pro Case:C1: Con is correct to say that I should have supported my speculation with evidence, so I admit that those specific points are no longer as relevant. However, he then claims that the Flynn effect was most likely caused by improved nutrition and medicine, which is probably true, but clearly supports the idea that environmental influences have a large impact on the expression of intelligence.With that being said, our education system has declined, in the United States at least;"Over the past 30 years, one country after another has surpassed us in the proportion of their entering workforce with the equivalent of a high school diploma, and many more are on the verge of doing so. Thirty years ago, the United States could lay claim to having 30 percent of the world’s population of college students. Today that proportion has fallen to 14 percent and is continuing to fall. While our international counterparts are increasingly getting more education, their young people are getting a better education as well. American students place anywhere from the middle to the bottom of the pack in [student] achievement...in the advanced industrial nations."-2006 Report by the National Center on Education and the Economy’s New Commission on the Skills of the American Workforce. [1]And, on the other side of Con's response, he is right that the environment hasn't become less stimulating. To the contrary, it has become too stimulating in many ways. Mainly through the increasing ubiquity of "smart" technology and Internet-use. Greenfield writes, "Already, it's pretty clear that the screen-based, two dimensional world that so many teenagers - and a growing number of adults - choose to inhabit is producing changes in behaviour. Attention spans are shorter, personal communication skills are reduced and there's a marked reduction in the ability to think abstractly." [2] Also, Richtel reports that, "Scientists say juggling e-mail, phone calls and other incoming information can change how people think and behave. They say our ability to focus is being undermined by bursts of information." Also, that, "While many people say multitasking makes them more productive, research shows otherwise. Heavy multitaskers actually have more trouble focusing and shutting out irrelevant information, scientists say, and they experience more stress." [3]So Con's claim that environmental factors don't play a large role anymore is demonstrably false. They are probably more relevant than ever.C2: Con makes a basic implementation assumption here that isn't necessarily correct. Simply because twin studies and neuroplasticity research both exist doesn't imply that they would have been combined yet, as the latter is much newer than the former, and twin studies take time. To answer his question about the similarity of MZ twins raised apart, consider a pair of twins who are both slightly taller than average. How much more likely is it that they would both be matched to an environment where they were encouraged to play basketball? It would clearly be much more likely than in the case of a pair of twins slightly shorter than average. This goes for IQ as well, with the difference being that IQ can be, and is, increased or decreased by environmental factors such a study habits, or lack thereof. People with even slight genetic advantages or disadvantages tend to be matched to environments where those tendencies are reinforced. [4]Con here ignores the fact that my evidence showed large, short-term changes in I.Q. to be associated with specific brain changes that likely developed from specific changes in individual environments.Moreover, meditation has been demonstrated to improve attention, focus, stress management, impulse control and self-awareness, even in relatively inexperienced meditators. These clearly relate to the definition of conscientiousness. [5]Physical exercise has been demonstrated to produce similar effects, as well as enhancing overall brain function. [5][6]Also, studies have shown specific, brain-training tasks to improve unrelated measures of fluid intelligence. [7]C3: Con makes another implementation assumption here, since what proof does he have that Head Start employs the same techniques as the abecedarian project? Furthermore, his argument is somewhat of a strawman, as I never cited the abecedarian I.Q.s, but only their later-life success rates as measured by college graduation, employment rate, and use of public assistance.I did cite the improved I.Q.s of Norwegian schoolchildren from increased education, which weren't measured until they were 19, 3-5 years after the extra school, which shows that the improvements lasted, and which Con never addressed.C4: Con is right that there is a difference between the variability between oneself and others. However, I argue that what matters to anyone is the relative amounts to which their own intelligence is affected by their genes and by their environment. Clearly this study demonstrated that the latter leaves a lot of room to work with in terms of changing one's own I.Q.Con's punnet square is simply wrong. If IQ had 4 genes, there would be 64 genotypes. Perhaps he meant 4 alleles, but that would still be 16 genotypes, not 4. Either way, intelligence is a multifactorial trait influenced by many genes, along with the environment.To address his point though, for one thing, I.Q. can change by much more than 8 points, as much as 20 points or so in a short timeframe, as I have already demonstrated. Second, the Scottish study also showed that the I.Q.s in old age correlated to the I.Q.s in youth by a factor of only about 0.62. This shows that they are related, of course, but also shows that they can, and do, change much more than Con implies. Especially when you consider that the first tests were done at age 11, when the children were already past their most neuroplastic, early-life stage. [4][8]Con Case:R1: Traditional twin studies are based on correlations, which do not equal the level of causation, and estimations of heritability, which are not totally reliable, nor are they supported by direct, biological evidence. Conversely, Deary performed another study which tracked specific genes in order to discover the genetic variance of IQ between people. His conclusion? The genetic variance of IQ is between 40-50%. Which means that environmental variance is between 50-60%, and that it is, on balance, more important in 'determining' IQ. [9][10]R2: Con's own numbers here, along with my evidence that traits that comprise conscientiousness can be neurologically-altered, show that on balance, it is influenced more by environment than by genes.R3: For one, if Con wanted me to only argue for one type of "environment," he should have clarified that before the debate began. Second, I agree with him that "unique" environment is mostly personal choice regarding activities, habits, etc. Third, my own case, however, has shown that shared environment does have measurable effects on IQ. Finally, a dual example for his request is the prevalence of technology.[1]http://www.doczonline.com...[2]http://www.dailymail.co.uk...[3]http://www.nytimes.com...[4]Restak, Richard. Think Smart: A Neuroscientist's Prescription for Improving Your Brain's Performance. New York: Penguin, 2009. Print.[5]http://scopeblog.stanford.edu...[6]http://www.thedailybeast.com...[7]http://www.nytimes.com...[8]http://www.nature.com...[9]Cummings, Michael. Human Heredity: Principles and Issues. 9th ed. Belmont: Cengage, 2009. Print.[10]http://www.webmd.com...