Caucasians are inherently more intelligent than African Americans

Just to be clear to all the readers, Con and I have agreed that IQ is intelligence, for the purposes of this debate. And, inherently means genetically influenced. Also, even though it only refers to "Caucasians" in the debate title, we have also agreed that this debate is about "Caucasian Americans". So, what I have to do in this debate is show that Caucasian Americans have higher average IQs than African Americans, and that this is influenced, at least partially, by genetic factors. I only need to show that it is partially influenced by genetic factors. Con needs to show that genetic factors play no role in Caucasian Americans having higher average IQs than African Americans. After all, if genetics play any role in the higher IQs observed in Caucasian Americans, then Caucausian Americans are "inherently" more intelligent. To be clear, we are talking about averages. It is obvious that there are individuals and groups within the African American population that are more intelligent than individuals and groups within the Caucasian American population. There are also groups and individuals within the African American population that are more intelligent on average than the entire Caucasian American population. However, the claim I am defending is that the average IQ of the entire Caucasian American population is higher than the average IQ of the entire African American population. When I refer to "whites" and "blacks" in this debate, I am referring to Caucasian Americans and African Americans. So, without further adieu, I begin my arguments. IQ Gaps that are ObservedThe IQ gap between blacks and whites in the USA is well known and widely accepted. The debate on this topic is not really over the existence of this gap, but it is instead over the cause of this gap. Still, I feel compelled to bring up this gap, just for the sake of clarity. The gap observed is about 15 points. Whites average about 100 IQ. Blacks, on the other hand, average about 85 IQ [1]. I would hope and assume that my opponent would not dispute the existence of this widely acknowledged gap and would only argue the cause of this gap. I will know make the arguments for why I think these gaps have genetic influences. IQ is Heavily HeritableGiven that is widely accepted that a black-white IQ gap does exist, it is also relevant to look at how heritable IQ is. The evidence is overwhelming that it is very heritable. IQ, like most other traits, gets more heritable with age. So, in younger children, genetics matter less for IQ than genetics matter for 17 year olds. In 1996, the American Psychological Association gave a heritability estimate of about .45 for children and about .75 during and after adolescence. In 2004, a meta analysis of reports in Current Directions in Psychological Science gave an overall estimate of around .85 for 18 year olds and older [2]. The evidence is overwhelming that IQ is very heritable. Since the black-white IQ gap is evident for people in adolescence or later, the high heritability in adolescence and later is the relevant figure here. The Improbability of Genetics Not Playing a RoleGiven the magnitude of the black-white IQ gap (about 15 points) and the heritability of IQ in adolescents and adults (somewhere from .75 to .85), it is highly unlikely that genes play no role in IQ. It would take virtually all blacks being severely malnourished and addicted to drugs and virtually all whites being well fed and drug free for this gap to be entirely the result of these environment influences. While it is true that blacks are somewhat more likely to be malnourished and are slightly more likely to be on drugs, the differences here are not nearly enough to explain the gap. Malnourishment is extremely rare in all races in the USA, and drug use is only slightly higher among blacks (8.5% of whites have used a drug in the past month versus 9.7% of blacks) [3,4]. Given these realities, the idea that environment influences explain the entire black-white IQ gap is simply implausible. The Black-White IQ Gap is Larger on More G-Loaded (Genetically Influenced) TestsIf there were genetic influences on the black-white IQ gap, we would see parts of IQ tests that are more genetically influenced have larger gaps than parts that are less genetically influenced. In fact, this is exactly what is observed. The black-white IQ gap is larger on the more genetically influenced Backward Digit Span test than it is on the less genetically influenced Forward Digit Span Test [5,6]. The fact that the black-white IQ gap is more pronounced on more genetically influenced tests lends a lot of support to the idea that there are genetic influences on the black-white IQ gap. Differences in Brain SizeThere is a correlation between brain size and IQ of about .40. Larger brains have more neurons and synapses and process information faster. Like all correlations, this does not always mean larger brains mean more intelligence. But, as a general rule, larger brains do suggest more intelligence. Whales, for example, have larger brains than humans, but humans are still more intelligent. But, whales are still intelligent animals and an overall correlation exists. The 0.40 correlation of IQ and brain size is only within the human species. So, it is relevant that whites have larger average brain size than blacks and also higher IQs. It is also relevant that east asians have larger brain size than both whites and blacks and higher IQs than both whites and blacks [5,6]. This final element to this adds strength to the notion that brain size does matter for intelligence with human races. This adds more strength to genetic influences mattering for the black-white IQ gap. Minnesota Transracial Adoption StudyThe famous Minnesota Transracial Adoption Study looked at individuals, some with two black biological parents, some with two white biological parents, and some with one black biological parent and one white biological parent, who had been adopted into upper middle class white families. So, the environments were somewhat similiar for all of these groups. If genetics did not matter for the black-white IQ gap, we would expect IQ to be somewhat similiar for these different individuals. At age 17, the IQs of each of these groups had their IQ measured. The adopted children with two black biological parents scored an average IQ of 89, the adopted children with two biological white parents scored an average of 106 IQ, and the adopted children with one biological white parent and one biological black parent scored an average of 99 IQ. So, to summarize, pure white children scored an average of 106, pure black children scored an average of 89, and half white and half black children scored an average of 99 [7]. So, despite being raised in white upper middle class families, the black-white IQ gaps remained. This would suggest that genetics do matter for these IQ gaps. Granted, there are flaws with this study, but it is the only study that I know of that looked at kids at an old enough age for genes to fully express themselves for intelligence. Other studies typically looked at kids at too young an age to truly estimate the impact of genes. This are my first round arguments. I look forward to my opponent's response. [1] . http://en.wikipedia.org...[2] . http://en.wikipedia.org...[3] . http://www.heritage.org...[4] . http://oas.samhsa.gov...[5] (for the actual study) . http://psychology.uwo.ca...[6] (for a summary of the study) . http://www.news-medical.net...[7] . http://en.wikipedia.org...