Your articles were allegations and never proved the existence of any confounding variables in any of the of samples used in any of the primary studies. This is how you're disingenuously shifting arguments. But that's not what i asked. I asked how do you know, based on what you claimed, that blacks, whites, and ne asians have the same brain volume? You need to provide actual evidence for your claim.
They were not allegations. They were actual studies, references to studies and email conversations with scholars who actually know what they are talking about who showed, citing empirical evidence, that there is no scientific basis for making comparisons between human populations to claim a racial hierarchy in brain size that determines intelligence. If you have no scientific basis for making the comparison then any statistical measurement is completely useless which renders your question worthless. You're attacking a strawman, shifting the burden of proof and question begging. Like I said, learn a new trick or provide primary studies of your own that reach a different conclusion. I went as far as to highlight in bold key statements in my sources that establish my point. There is no reason for you to demand evidence for my actual position when it is already there. My actual position: "There are no racial hierarchies in brain size. Variation in brain size does not determine intelligence for fully developed, healthy brains within species." - EgalitarianJay02 in post #10 No sources by you in this thread challenge this position and your primary sources for your argument (Rushton and like-minded colleagues) were refuted.
Brain volume is irrelevant to intelligence. Taking the upper-end of the .5 brain size/IQ correlation, that means that brain size explains 25 percent of the variation in IQ between individuals---meaning that 75 percent of the variation is unaccounted for. (Also, the true correlation is .4 so Braun size explains 16 percent of the variance. Useless.) Skoyles' theory explains why brains grew larger when they caused birth complications as well as a woman needing a wider pelvis to birth the baby which in turn would impede our endurance running. https://notpoliticallycorrect.me/2017/03/14/brain-size-increased-for-expertise-capacity-not-iq/ We are 'the running ape', we evolved to be active. https://notpoliticallycorrect.me/2017/03/18/man-the-athlete/ http://www.human-existence.com/publications/Skoyles Human evolution expanded brains expertise not IQ.pdf People with erectus-sized brains can have IQs in the normal range. People with chunks of their brains surgically removed can have IQs in the normal range. https://notpoliticallycorrect.me/2017/05/17/traumatic-brain-injury-and-iq/ So if people can have chunks of their brain taken out and still have IQs in the average/above average range and if people can have IQs in the average/above average range with brains the size of erectus, then brains must have increased for another reason, which---as John Skoyles argues---is expertise capacity. So I took his hypothesis and I fit it to racial differences in brain size. Arctic peoples use more tools than tropical peoples who use fewer. It takes expertise to learn how to craft so many different kinds of tools. https://notpoliticallycorrect.me/2017/03/14/brain-size-increased-for-expertise-capacity-not-iq/ So brain size is irrelevant for IQ in the normal range, studies on microcephalics attest to this. See Skoyles (1999) for a review (linked above).
I never claimed brain volume accounted for the black/white IQ gap, and have repeatedly asked ej to support his claim brain volume is equal for blacks and whites. You should try reading.
I'm not claiming that brain volume is "equal" which is a strawman. I'm saying that because brain development depends on environmental factors and there is no scientific reason to believe race determines brain size or volume there is no scientific basis for comparison. This is a very simply concept to understand and supported by all of the sources I cited.
You literally have said blacks and whites have equal brain volume in this thread. How did you conclude blacks and whites have the same brain volume?
That's a lie. Care to quote me on that? Show us the exact quote. What I have maintained is that there is no scientific basis to make a comparison. I don't consider socially-defined racial categories like Black and White to be biological races. These are umbrella terms based on skin color that don't accurately represent human genetic variation and can't be used scientifically to make generalizations about diverse populations. Also given environmental effects on brain development, differences in skull shape due to climate and the relationship between brain size and body size it is very unlikely that you can aggregate diverse populations and get an equal measurement never mind the problems with actually measuring the brain that are outlined by my sources. When I say there are no racial hierarchies in brain size I am not saying that measurements of brain size are "equal" but rather that race does not determine brain size and variation in brain size within species does not determine intelligence. This is very simple to understand, especially if you've done actual research on the topic. What sources have you actually read that form your opinion on brain size and intelligence? I insist you actually answer that question honestly and stop asking me to defend a claim I didn't make. Otherwise this conversation is over. There's no point in arguing with you if you refuse to understand the position of your opponent.
I never claimed that brain volume accounted for the whole gap. I claimed that brain size is irrelevant to intelligence and that studies on people with traumatic brain injury prove the point as well. If brain size did mean something for intelligence, how can people with chunks of their brain missing score average or above average on IQ tests? How can people with erectus sized brains score average or above average?
Women have slightly smaller brains compared to men but the differences in IQ are minute. Same for racial differences. A larger factor is nutrition and health pre-natal through adulthood.
Dude, there's a huge difference between brain size differences of few percentage points and a TBI. Why is this so important to you?
Brain volume is also a function of body size, and without greater knowledge whether the brain size differences are uniform between genders as they are between races this point is mostly meaningless.
Do your studies have IQ before and after traumatic brain issue? Was traumatic injury and surgery all regionalized? Not all parts of the brain are equal, and would be important to qualify whether injury to frontal lobe had same effect as other regions. Whites have uniformly larger brain volume than blacks and also roughly equal body size. What is average IQ of people with erectus sized brains? Finding normal IQ people from a subpopulation with a moderate correlation coefficient shouldn't be statistically difficult. Adfitionally, it would also be important to know any structural brain differences and if brain volume is uniformly lower.
Yes IQs were measureed pre-injury. Check out Bigler et al (1995). I'll link the studies on this later. Interesting stuff. Some cohorts show literally a small decrease in IQ after TBI. Hmm... "Was traumatic injury and surgery all regionalized?" I don't recall. I'll get back to you. "Not all parts of the brain are equal, and would be important to qualify whether injury to frontal lobe had same effect as other regions." Good point I'll skim the papers for this information. But the fact that gross brain size can be significantly reduced with little to no change in IQ proves the point. "Whites have uniformly larger brain volume than blacks and also roughly equal body size." I think it's meaningless for Racial IQ Differences. "What is average IQ of people with erectus sized brains? Finding normal IQ people from a subpopulation with a moderate correlation coefficient shouldn't be statistically difficult. Adfitionally, it would also be important to know any structural brain differences and if brain volume is uniformly lower." Skoyles (1999) reviews this evidence. I'll do some research later and see if I can find enough studies on Microcephalics with the brain size of erectus and average them out. However, exceptional scores for people with reduced brain volume---either by birth or injury---show that large brains are not needed for IQs in the modern range.
Like height and weight differences? Hair color? Longevity? Life-time health? Do you think the fact one person's lineage tends to die at age 70 due to heart failure makes them inferior to a person whose family members tend to live to age 80? Do you think a human being's value is summed up solely by their IQ?
"Like height and weight differences? Hair color? Longevity? Life-time health?" We have explanations for that. Brain size differences rest on climate, and as I have argued, capacity for expertise. "Do you think the fact one person's lineage tends to die at age 70 due to heart failure makes them inferior to a person whose family members tend to live to age 80?" No. I think words like 'superior' and 'inferior' when talking about biology are meaningless, undefineable terms. "Do you think human being's value is summed up solely by their IQ?" Not at all. Is there anything in my comments that imply that I believe this?
YOUR LINK: IV. OBJECTIONS IV.1. SMALL BRAIN SIZE NORMALLY LINKS TO RETARDATION 29. The above individuals are EXCEPTIONS: the presence of a small brain in the overwhelming number of individuals (whether due to early brain removal or microcephaly) is associated with retardation. However, this would be expected. Even if microcephalic brains were capable of normal levels of intelligence, the pathological factors responsible for their abnormal brains not only reduce their size but will usually have other effects (independent of this) on their neural integrity. In the case of hemispherectomy, the prior pathology in the original brain might already have effected the remaining normal brain. Thus, it will be relatively uncommon that brain mass is reduced without a parallel but separate impairment of cognition. IV.2. BRAIN INJURIES DESTROY COGNITION 30. Following accidents and strokes, people show dramatic loss of cognitive abilities. This might be taken to suggest that the brain cannot work with reduced brain mass. However, the damage in these cases is connected with its suddenness. The brain can easily recover from injuries incurred in small stages, but not when they occur all at once (Feeney & Baron, 1986). This is in part because sudden brain injuries are followed by the release of excitotoxins which cause further neuronal loss. In contrast, the brain loss which occurs slowly can pass without notice. For example, asymptomatic meningioma can grow (at an average of 2.4 millimetres a year) into the size of plums -- five in centimetres diameter -- without noticeable effects (Olivero, Lister & Elwood, 1995). Interestingly, even when brain damage is sudden, as with post-traumatic atrophy or focal damage, it can happen with minimal change in measured IQ (Bigler, 1995). IV.3. IQ CORRELATES WITH BRAIN SIZE 31. Although IQ correlates with brain-size, the correlation is modest, the best recent estimate being around 0.40 (Wickett, Vernon & Lee, 1994). The percentage contribution of a 0.40 correlation is 16%, leaving 84% of intelligence to be explained by things other than brain size. Even higher reported correlations of up to 0.51 (Andreason, Flaum, Swayze et al., 1993; Willerman, Schultz, Rutledge & Bigler, 1991) would still leave 74% of the variance unexplained. Moreover, such IQ/brain-size correlations derive from studies on educated people with a restricted range of IQ and brain size, raising methodological problems about their generality (Peters, 1993). It is not known whether the 0.40 correlation found between IQ and brain size likewise holds in extreme cases outside the range tested; indeed, the evidence reviewed above suggests that it does not. Moreover, size would not be expected to increase cognitive competence more than modestly because larger brains have larger neurons and more myelinated axons connecting them (Deacon, 1990). It is perhaps because for this reason that people with larger than normal brains are not necessarily brighter (DeMyer, 1986); indeed, there appears to be a plateau and perhaps a decrease in IQ in the largest brains (Reiss, Abrams, Singer, Ross, & Denckla, 1996). 32. The 0.40 correlation, moreover, does not by itself rule out the existence of outliers. A statistical correlation is, after all, only a mathematical means of describing a data set. Thus, the 0.40 correlation between IQ and brain size is in itself not evidence against the existence of the cases reviewed above. ..... So you post EXCEPTIONS as the rule. And as someone who has Claimed, and Blogged 'Race Realism'... We are seeing some Bizarre and strained environmentalism. ALL of your posts here are Contrary to 'Race Realism.' Again: Devil's Advocacy or Dual Personality? +
Skoyles addressed the objections. You can also eck out Reis et al (1996) referenced by Skoyles who show that there is a plateau, and perhaps even a decrease in IQ in people with the largest brains. Re exceptions: I agree. However as Skoyles argued it shows that people with erectus sized brains can have IQs in the normal range. Think about when brain size increased and then think abour when erectus began controlling fire and the argument will become clear. Re devils advocate or dual personality: I'm just talking other arguments to see how they hold. I am skeptical of g, and I refuted numerous bullshit claims by Rushton. I'm a skeptical hereditarian.
Anomalies need explaining, no? I combined Skoyles hypothesis with racial brain size differences and provided sound and logical argumentation.
Nah, the anxiety is actually on the left. The left overplayed the race card so badly during the Obama regime it means nothing to anyone outside the loony left...
I believe in the reality of race, whether defined by genes or morphology. Therefore I am a race realist. Now, you can seriously reply to my comment.
