This must be wrong. I spend the weekend with two blond girls, manMandrake said:
I previously provided you with referenced comments pertaining to brain volume measurements in rats. Here it is again:Nereid said:
The concept is not abstract. The relationship between brain volume and intelligence has been studied in great detail, using a wide range of techniques. The cause of the relationship is not known, but we don't know why masses attract each other either. That does not mean that gravity is not worth studying.
What parts of the brain do you feel are not related to biology?
No problem at all. I didn't even really notice. Others on this board are far worst.humanino said:
Yes, you did. And I asked you if you could assist readers to understand the extent to which biologists feel that psychometricians are significantly contributing to their understanding of mammalian physiology (should I post your response here too?)Mandrake said:
Nice try
Nereid said:
Yes, and you also pointed out that Jensen doesn't agree with Lynn (as also mentioned by hitssquad). Do you know of any neuroscientists, or other biologists, who have studied the biological variance in the brains of Homo sap.?
Indeed, all parts of the brain would seem to be related to biology, which is partly why I'm quite puzzled that there is, AFAIS, no biological theory of intelligence. Or, to turn up the contrast, that neuroscientists seem to be pretty cool on intelligence (and other objects of psychometricians' desire), cf their intense interest in language; and why two sub-disciplines within psychology don't even seem to acknowledge each others' existence (e.g. how many 'personality psychometricians' quote, or do concurrent research in, 'intelligence'?).
I can do better than that ... I can probably write a fairly succinct algorithm for how to find data sets which will likely have very high correlations among the variables. The Pluto RA/US GDP example took me all of 10 minutes to find and construct, and I deliberately chose it because no one (other than astrologers - I didn't think of thatPhobos said:Oh great, Nereid. You just proved that astrology works.
) would be tempted to see something deep and meaningful in the clear correlation. It shouldn't be hard for any PF member to come up with some quite plausible-looking, highly correlated data sets, particularly with one or more variables that relate to humans, their group interactions, etc.That is a rather poor analogy. Unless you can show that scientists are making up a brain to their own specifications and defining g however they want it and then comparing. But doing a random correlation comparison, which the cranial size to IQ is, you cannot manipulate it the way you did. It's not like the brain and IQ are the researchers own creation which is the case for yours.Nereid said:
Humanino, don't retract your apology, we all need to show respect to each other, even if we disagree.If you like. I don't recall what I wrote.Nereid said:
That was not the nature of your initial question.
At the ISIR conference in 2003, the following people all presented papers that related to brain neurology as it relates to _g_: . Richard Haier, Vivek Prabhakaran, Paul Thompson, Con Stough, Aljoscha Neubauer, and Rex Jung.
I don't understand your observation. What do you think would constitute a biological theory of intelligence? How does that differ from existing models?
What? How did you reach THAT conclusion? I get the impression that you haven't taken the time to read the psychometric literature and that you have not read the gold standard textbook (The _g_ Factor). The entire Haier symposium at the ISIR conference was devoted to this topic. Cool? Huh?
You have mentioned these people on several occasions. I am unaware of their names. Can you tell us who you have in mind? Where do they publish? What are the standard textbooks that they reference? What else can you tell us about them? Thank you.
How fast do you forget ? This is amazing !Mandrake said:
You appear to be unfamiliar with the very large quantity of journal papers that have addressed this subject. They have used a wide range of investigation techniques. The correlation that has been found is quite large and important in comparison with other findings that are accepted as important. You seem to want to dismiss this area of study by implying that it is a fluke or that it has not been seriously investigated. Is that correct? Have you really studied the literature on this topic?Monique said:
There has not been a single assertion here that cranial volume is the only factor determining intelligence. I haven't even seen a comment that claims it determines anything. What has been said is that there is a signficant correlation between brain volume and intelligence. The finding is robust.
And if you did think of such a thing, would it invalidate the MRI measurements? Your comment also seems to imply that the larger brain volumes reported in the literature necessarily imply larger skull size at the time of birth. Is that your belief? Is it true that skull size at birth is proportional to brain volume in adulthood? Since the difference in brain volumes that accounts for the variance is relatively small in adults, why would you extrapolate that this would cause so much increase in size of the head in a baby that it would result in more difficult child birth? Can you give us some verifiable numbers to support your suggestion?
Jensen calls them biological correlates or physical correlates.Evo said:
Inspirations for specific researches are usually explicated in the introduction sections of the corresponding research write-ups. Regarding Jensen's inspiration, he says:
Head size is a relatively-easy-to-measure proxy for total brain size. Total brain size, in turn, is a proxy for the sizes of the specific parts of the brain most associated with g. As we zero in on the parts of the brain most closely associated with g correlations between variance in volume and variance in g grow larger and larger, approaching unity.
Jensen is an emeritus professor of educational psychology. For many years there was a question in Jensen's country, the United States, as to why the Blacks of the country were not achieving educationally, socially and professionally at the same levels as those of the Whites of the country. Being an educational psychologist, Jensen decided that the question lay within his professional realm of scientific inquiry and so he inquired into it. Jensen explains this in Miele 2002 (p113):
Inter-population differences in head size may constitute useful evidence for evolutionary theorists, including evolutionary psychologists:
Mine was a cautionary statement about biology.Mandrake said:
This is very much trivial. Anybody expects the ability of a neural network to increase if one doubles the size of the lattice. In a mathematical analogy, take a polynomial and try to fit a set of points with it. If you double the order of the polynomial, you double the number of points which can be fitted. This is a poor analogy, since the combinatorics in the lattice are non-linear. However, it amounts to pretty much the same thing.BlackVision said:
This does not answer my question. This has never been peer reviewed nor do I expect it would ever appear in Intelligence.Nereid said:
Really? So you're stating one will have a difficult time determining which is more intelligence. Dolphins or flies. Wolves or salmon.
Perhaps a little common sense.
Because there is actually a dispute that in the path of human evolution, intelligence has increased? That the enormous growth of cranial size in the path of human evolution has had no impact on the intelligence of humans? You're trying to make it as though there is a controversy in an area which does not have one.
Neanderthals could of very well been more intelligent. It wasn't their lack of intelligent that caused them to be extinct. Modern homosapiens also came very close to extinction itself.
BV, it appears that you are not familiar with the skills the Neanderthals are known to have possessed. Archaeological digs of Neanderthal sites clearly show what they were capable of.BlackVision said:
I am quite aware of the acheivements of the Neanderthals. They have made several advances but not near as far as modern homosapiens. But that does not necessarily portray them as less intelligent. Any more so than the fact that most technological advances coming out of Europe instantly qualifies them as the most intelligence race. I've read several theories to why Neanderthals did not make the advancements that homosapiens did. The main one being that Neanderthals did not travel long distances as often as homo sapiens sapiens did. Maybe partly due to their heavier limbs. This caused less interaction with other Neanderthals and less exchange of ideas than with Homo sapiens sapiens.Evo said:
Thanks for some great reading hitssquad!hitssquad said:
If you have it handy, could you give us some idea of the range of the reported correlations?Mandrake said:
I have no idea where one would find the range or reported values. The only parameter that matters is the actual correlation, based on the best presently available methodology. The usual numbers are around r = 0.40 to 0.43.Nereid said:
Proxies for brain size show the effect very well, but obviously include factors that disconnect the proxy from brain volume.
You can easily compile a lot of information by using a search engine and the Internet. Aside from that, you might want to read some of the best psychometric textbooks.
bd1976 said:
If you're referring to the nice stamp collection of 'biological correlates', then that hardly constitutes a 'biological theory.'Mandrake said:
I'm still looking; so far all I've found is a very few results on the relationship between personality and intelligence (none). I'm still flabbergasted that two groups, both psychologists, both calling themselves psychometricians, apparently don't use tools developed by the other group, ignore each other's work, even though the seat of everything they study - the human brain - is the same! It's almost as if condensed matter physicists were ignorant of the work of plasma physicists.
Mandrake said:
BlackVision said:
We had some interesting discussion on this while you were away SelfAdjoint (welcome back by the way); Moonbear and Mandrake both posted some interesting results (in Social Science, IIRC), and I did some simple arithmetic. The net is that these fMRI results seem to be quite confusing; the mechanism of intelligence remains quite elusive.selfAdjoint said:
There wasn't a large episode that caused a mass extinction for Neanderthals like it happened for the dinosaurs. At one point Neanderthals had higher mortality rates than birth rates which continued generation after generation that slowly but surely they disappeared off the face of the Earth.Phobos said:
The human population was bottlenecked at one point no? I recall that from somewhere. If anyone has more info on this please share among us. I could be wrong though.
You raise an interesting point Mandrake ... the research that shows a correlation between brain volume and _g_, was that done with young adults? young children? To what extent did the researchers tap into other research, on changes in brain volume of Homo sap. from birth to adulthood? To what extent did these brain volume studies attempt to measure the volumes of the different brain structures?Mandrake said:
So we would put these in our 'Jensen stamp album'. Some of the stamps we'd put in our 'dluoG stamp album' (physical or biological characteristics NOT apparently correlated with _g_) might be:hitssquad said:
I don't know if the 'prove' is Jensen or hitssquad; however, a) as this is science (and not maths), the correlates don't *prove* anything; b) the stamps in the 'dluoG album' suggest that Monique's observation is spot on.