Debunking Rushton's Life History Variables

[mr friendly guy]

This is a strawman. All brain size data is suggestive as it is consistent with other parts of the data he collected.

A big brain might not be smart, however am small one have upper limits unless human data processing is aphysical, not that physical limits necessarily is important here.

That said, if homo sapian sapians is actually genetically similar, we shouldn't except major differences in design architecture or average tissue-eneregy/mass efficiency. A bigger brain is expensive energy wise, and if it is not defective it'd better do something or it'd be selected against. There is a correlation between brain size and IQ test results.

If you see someone with twice the muscle mass you'd expect a stronger man, or is your first instinct is that "zomg obviously his muscles are half as efficient and he is weak." It may still be true, but one wouldn't normally assign it high probability.

Comparing it to whale brains is dumb. Neanderthals: less dumb but still weak as that lineage have diverged significantly.

Firstly other people have schooled you on the fact that some of the smartest people ever alive did not have ginormous brains, casting doubt on this theory. They have also pointed out this doesn't seem to hold intraspecies even if it does hold interspecies.

Secondly the fact that you describe "instinct" rather than observation to explain the man with more muscle being stronger already tells me about your non scientific mindset. Ultimately science is dependent on observation. If your observations do not match the theory, then your theory is wrong period. Instinct might tell you that people with bigger brains are smarter, but observations counter that. Instinct might tell you that a person with bigger muscles are stronger, but observation triumphs all. For example a person with Duchenes has bigger muscles than a person without the disease, but the Duchene sufferer does not have the greater physical strength.

[EgalitarianJay]

This is a strawman. All brain size data is suggestive as it is consistent with other parts of the data he collected.

It's not a strawman. Rushton's thesis is that human races evolved to have differences in intelligence and personality because of differences in brain size which affects all of the other variables he mentioned.

DISMANTLING RUSHTON’S r- AND K-THEORY

a. Testability of the theory

In Race, Evolution, and Behavior Rushton presented a modified summary of r- and K life history features (see Table 5). Rushton theorized that the survival of early human migrants from Africa, proto-Mongoloids and Caucasians, necessitated an increased cognitive ability to survive the predictable harshness of the colder climate.4 The additional cognitive ability was achieved through selection for K-related life history features that would have been genetically correlated to features allowing an increase in brain size. Genetic correlation can occur due to either pleiotropy (alleles with effects on multiple characteristics or genetic linkage, resulting from loci impacting both traits being physically linked on chromosome segments).

In Rushton’s interpretation of r- and K-theory, ‘The racial differences in intelligence, law abidingness, health, and longevity . . . seem similarly ordered by r-K theory’ (Rushton, 1995: 214). To be genetically based, therefore, Rushton’s theory requires that loci that influence these traits are physically linked or are populated by alleles that have multiple pleiotropic effects on these characters. He predicts that Orientals or Mongoloids (Asians) should be most K-selected (hence have genetically greater intelligence and the lowest fecundity rates), while Negroids (Africans) are most r-selected (thus should have the lowest intelligence and the greatest fecundity), and Caucasians (Europeans) should be intermediate in these traits. To this end, he reports brain size as the basal factor determining life history traits, including generation time, gestation time, rate of maturity and body size (Rushton, 1995: 230–1).

The central difficulty facing Rushton’s hypothesis is the absence of any evidence supporting the r- and K-continuum within our species. He conveniently skips over elementary procedural points in formulating his argument. For example, he does not ever establish the specific relationship between phenotypic variables he measures and their relationship to differential fitness in the human species. Establishing this relationship is crucial to testing adaptive hypotheses (such as r- and K-selection). For if these traits are unrelated to fitness they will not be acted on by any specific model of natural selection.

Source: What a tangled web he weaves: Race, reproductive strategies and Rushton's life history theory Anthropological Theory 2002; 2; 131

Bigger brains = Smarter People is his primary claim.

A big brain might not be smart, however am small one have upper limits unless human data processing is aphysical, not that physical limits necessarily is important here.

According to anthropological research brain size does not determine intelligence within the species normal range of variation.

3. Rushton’s cranioracial variation is contradicted by evolutionary anthropology.

Rushton argues that “Mongoloids” have superior, larger brains because in their evolution they had to adapt to a cognitively demanding but predictable cold Pleistocene climate (1997a). An alternative scenario is provided by Brace (1998:112): “the mode of subsistence of all human populations was essentially the same throughout the entire range of human occupation over the past 200,000 years. This was conditioned by adaptation to the selective pressure engendered by the cultural ecological niche. For these reasons, then, cognitive capabilities should . . . be the same in all the living populations of the world.” Brace points out (p. 4) that 100,000 years ago early moderns at Qafza “were making the same tools, hunting the same animals . . . as their Neanderthal contemporaries,” and therefore we can conclude that human cognitive capabilities are distributed in a nonclinal way. Similarly, Dobzhansky and Montagu (1947:112) had suggested that natural selection in human societies favored “maturity of judgment and ability to get along with people.” The complex ability to adapt to relationships within a group was a selective factor operating everywhere. How is it possible that cranial size varies with latitude while intelligence is nonclinal in its distribution? Cranial size is a response to natural selection in a cold climate, while variations in the size of the brain do not determine intelligence within the species-normal range of 1,000–2,000 cm3, especially considering the role of cultural environment.

Source: How “Caucasoids” Got Such Big Crania and Why They Shrank From Morton to Rushton Current Anthropology Volume 42, Number 1, February 2001

So whether we're talking big brains or small brains you cannot determine that a person is smart or dumb based on brain size. Men generally have bigger brains than women yet their IQ scores are virtually identical. Brain size actually decreases with age and while the brain is more susceptible to mental diseases as one gets older people don't get dumber as they age.

That said, if homo sapian sapians is actually genetically similar, we shouldn't except major differences in design architecture or average tissue-eneregy/mass efficiency. A bigger brain is expensive energy wise, and if it is not defective it'd better do something or it'd be selected against. There is a correlation between brain size and IQ test results.

The correlation between brain size and IQ scores is only about 0.33, a moderate correlation at best. There is probably some relationship between brain mass and intelligence but to say that brain size variation within species causes differences in intelligence is unfounded because a common evolutionary history indicates that the brain's function is the same for every individual. The only deviations in intelligence related to genes that one might see are in genetic pathologies (mental disorders and disabilities) that affect the brain and genetic anomalies (natural-born geniuses) that we see in people with exceptionally high intelligence. We know for a fact that exceptionally smart people don't necessarily have large brains because some of the greatest geniuses in history (ex. Einstein and Gauss) have had their brains studied and their brains aren't exceptionally large. The people with the largest brains tend to be tall and large and there doesn't seem to be a correlation between height, body size and intelligence.

If you see someone with twice the muscle mass you'd expect a stronger man, or is your first instinct is that "zomg obviously his muscles are half as efficient and he is weak." It may still be true, but one wouldn't normally assign it high probability.

As someone else said the brain isn't made of muscle. Bigger muscle = stronger man may be the general rule but you're comparing apples and oranges here. More brain tissue doesn't mean more brain power. I think the efficiency with which the brain processes information is affected by neuron density which can vary regardless of brain size and ofcourse environmental factors affect brain function including pre and post natal nurturing environment, external stimuli and avoiding brain trauma (don't take blows to the head if you want your brain to stay healthy).

Comparing it to whale brains is dumb. Neanderthals: less dumb but still weak as that lineage have diverged significantly.

Whales and dolphins may be a bad analogy because they are indeed very different species from humans. The brain size/body mass ratio mentioned by Graves wouldn't be relevant to whale brains. They have such big brains because they need those brains to control the nervous system of their enormous body affording them less brain function for the higher cognitive abilities we see in humans (though they are smart animals). However Neanderthal are a different story. We share a common evolutionary history with Neanderthal via hominids. Our brains tripled in size from a primate ancestor to ancient hominids giving us an extreme brain size relative to body mass. Neanderthal anatomy reflects this evolutionary event just as much as modern humans do but their brains were even larger than ours. They do indeed have a different evolutionary lineage but because they descend from hominids a comparison can be made. Neanderthal were either a different species from Sapiens or a subspecies that had the ability to interbreed. They were very close genetically to us. As Lieberman noted (see quote above) cranial size is a response to natural selection in a cold climate. Neanderthal have such large heads because they lived so much longer than modern humans in the cold climate of Eurasia. There's no evidence that they were the super geniuses Rushton's theory would suggest they must have been.

If you don't like the Neanderthal example there's also the Ona people of Tierra Del Fuego who also lived in cold climate, also have exceptionally large heads yet are incredibly impoverished. They are as human as any other group yet their cultural development (a variable of Rushton's) does not reflect his predictions of larger brains meaning smarter people.

A smarter objection would be environmental factors can effect development that lead to smaller brains and low IQ results. We actually know malnutrition can do this, though other stuff is far more iffy.

That's also possible. Brain size can be effected by environmental factors. But it is a fact that brain size does not determine intelligence at least not normal brain size.

[Channel72]

There's no evidence that they were the super geniuses Rushton's theory would suggest they must have been.

I think Neanderthals are a potential fulcrum point for racial mythology - they were likely blonde haired, or lighter skinned - and their larger brains make it tempting for racists to imagine them as some kind of Nordic master-race, especially since their DNA is not found in modern Africans.

But the reality is that Neanderthals were most likely either equally intelligent as H. Sapiens, or possibly a bit dumber. The Aurignacian culture of H. Sapiens which ultimately replaced Neanderthals (either through war or interbreeding) clearly showed signs of being more advanced in terms of culture (they produced art and musical instruments). Also, despite their larger brains, Neanderthals were less "encephalized" than H. Sapiens, meaning the ratio of brain mass to body mass is less than H. Sapiens.

[Zixinus]

I actually noticed before but forgot to comment, so apoligies for not mentioning this before.

The reproductive advantage of successful murderers in the jungles of new guinea (from "the world until yesterday") in capturing resources and women provides a selection pressure towards aggressive traits. The same traits might not have worked as well in civilized areas with central authority imposing a monopoly on violence and harshly punishing those that fail to conform. It is suggested that places with long history of civilization have "self domesticated" and thus shifted personality traits. We know from domestication that given changed selection pressures, traits can change significantly in this time frame. (this from "10000 year explosion")

Then you have a very weird idea of civilization. In past feudal societies one good way to rise on the social ladder was to become a warrior. There are historical figures that managed to rise from lowly commoner to rich noble. As there is a creation of a warrior-class would select for the most aggressive, the most physically able to do violence and survive it. So you would think that "civilized" people would actually be more aggressive. And even if you weren't a warlord, general security for an honest commoner was spotty at the best of times, so the ability to do violence if necessary would not be selected against. Yes, there were laws in some places that told that the peasantry cannot carry weapons but that did not mean they never had to fight. Today's security that you can life over half your life without getting into life-threatening violence is a modern phenomenon.

Unless your idea of "aggressiveness=sociopath".
In which case, such traits should be selected against in general throughout human history, even in hunter-gatherer societies. Rape is a common feature of warfare, even tribal warfare, but rape isn't the best reproductive strategy. Especially compared to a strategy that involves actual courtship. A raped woman alone can provide a worse upbringing than a father-mother couple (a father is an important factor in the survival chances of children due to his protection, as J. Diamond notes in another one of his books). That is not to mention that rape is more dangerous as you have to fight the target and trough her relatives.
What's more, such extremely high levels of being prone to violence would work against the entire species if it were the norm. People need to trust and work with each other. Even hunter-gatherers hunt and gather in groups. Agriculture requires even greater cooperation and tolerance for each other.

[SWPIGWANG]

Science and accumulation of knowledge is about observations. Good data that one can extrapolate from is useful even if there is no good theory behind them. (for example quantum mechanics) "Debunking" theories but not data doesn't do very much. That is like saying that "we see this in reality, but does it work in theory?"

Ultimately science is dependent on observation. If your observations do not match the theory, then your theory is wrong period. Instinct might tell you that people with bigger brains are smarter, but observations counter that. Instinct might tell you that a person with bigger muscles are stronger, but observation triumphs all.

However observation have shown that people with bigger brains are generally smarter at 0.3 correlation, and people with bigger muscles are usually stronger.

Better measurements exists of course, you can measure intelligence and strength directly. If you do so, you'd get pretty much "racist" results as much of the best jobs in the modern economy requires things that is correlated with IQ test and education and a minority is bad at it.

If everyone had the same test scores and achievement we wouldn't be discussing this at all. What is going on is that there is a difference in measurement and a number of hypothesis is raised to explain it.

The brain size issue is like Galileo's observation of Jupitor's moons and using it to support his world view of the Earth orbiting the sun. It is not direct proof, however it is consistent with the model used to comprehend a different issue.

There's nothing that would explain why Africans have a unique selection pressure that selects against brains that are "too big" and "too powerful." So there's no reason to expect them to develop such brains, or for the reverse to happen in other lands.

There is unlikely to have selection pressure for stupidity (until now, where high IQ people have lowest fertility) however there are other selection pressures, including tissue cost. The genome is also a unrefactored mess where selection pressure to kidneys may require a changes to the jaw and all that. There might be selection pressure in completely unrelated things that indirectly led to lowered intelligence. We do not have a good view of things from a gene's point of view, and it is hard to know what trade offs is involved.

Now, that is not to say this claim naturally targets Africans like in the r-k theory (even fast life cycle benefit from intelligence). That said, intelligence differences due to environment selecting different things would not be surprising. There are also other possibilities, like novel mutations that hasn't had enough time to spread throughout the population, like lactose tolerance, or simply increases in genetic errors (some claim societies with high cousin marriages have ~5 points less IQ) and things like that.

some reference:
http://www.pnas.org/content/111/36/13010.abstract
"We find that the brain’s metabolic requirements peak in childhood, when it uses glucose at a rate equivalent to 66% of the body’s resting metabolism and 43% of the body’s daily energy requirement, and that brain glucose demand relates inversely to body growth from infancy to puberty. "

http://www.nytimes.com/2008/05/06/scien ... d=all&_r=0
selection against intelligence

Lieberman's article: How “Caucasoids” Got Such Big Crania and Why They Shrank: From Morton To Rushton Current Anthropology Volume 42, Number 1, February 2001

I do not disagree with the criticism on Rushton, however that criticism does not rule out significant biological variation due to environment. Rushton have choosen a crude line to divide the "races" when traits are likely to be specialized to specific environments, for example Tibetan high altitude adaptation. http://en.wikipedia.org/wiki/High-altit ... _in_humans (note this took only 3000 years, plus admixture with archaic hominins)

If significant biological differences exists, then most population divisions, even if not sensible, it likely to capture a part of that and see difference in mean.

Men generally have bigger brains than women yet their IQ scores are virtually identical. Brain size actually decreases with age and while the brain is more susceptible to mental diseases as one gets older people don't get dumber as they age.

I'd say demantia would lead to poor test results. If smaller brains means increased vulnerability mental illness then one would see a skew in performance.

Then you have a very weird idea of civilization. In past feudal societies one good way to rise on the social ladder was to become a warrior. There are historical figures that managed to rise from lowly commoner to rich noble. As there is a creation of a warrior-class would select for the most aggressive, the most physically able to do violence and survive it.

A "standing bandit" called the state have low incentive to actually hurt the peasants, and every incentive to have workable relations use threats and rewards to manipulate them for taxes. Every minute anyone in the your domain is fighting is time they are not producing wealth for you to tax. If you kill the peasants, then there is no one to tax. In Europe after the black death, there is actually a surplus of land so more subjects = more wealth and power.

A roving bandit, someone who is not settled, have no relations with those robbed and no reason to limit violence as a roving bandit can just move somewhere else after killing the newest set of victims.

Of course, these are a form of "just-so" stories. Someone has gone through the effort of collecting the data however:
http://en.wikipedia.org/wiki/The_Better ... Our_Nature

The Pacification Process – Pinker describes this as the transition from “the anarchy of hunting, gathering, and horticultural societies ….to the first agricultural civilizations with cities and governments, beginning around five thousand years ago,” which brought “a reduction in the chronic raiding and feuding that characterized life in a state of nature and a more or less fivefold decrease in rates of violent death.”

The Civilizing Process – Pinker argues that “between the late Middle Ages and the 20th century, European countries saw a tenfold-to-fiftyfold decline in their rates of homicide.” Pinker attributes the idea of the Civilizing Process to the sociologist Norbert Elias, who “attributed this surprising decline to the consolidation of a patchwork of feudal territories into large kingdoms with centralized authority and an infrastructure on commerce.”

There are explorations into how this "civilizing" process may have influenced genetics and caused the industrial revolution.
http://www.amazon.com/Farewell-Alms-Eco ... 0691141282

[Zixinus]

A "standing bandit" called the state have low incentive to actually hurt the peasants, and every incentive to have workable relations use threats and rewards to manipulate them for taxes.

You are confusing my point. You are talking about government not hurting the peasantry, while my arguments was against the idea that nobody would hurt the peasants. Violence had a general presence in the past even for the average person.

A roving bandit, someone who is not settled, have no relations with those robbed and no reason to limit violence as a roving bandit can just move somewhere else after killing the newest set of victims.

And hence why peasants needed to defend themselves. They may not have had dedicated weapons by law, in some places, they were hardly unarmed and defenseless. The use of agricultural tools as effective improvised weapons has a long history. Bandits of various kinds were not anomalies but regular events. Threats also came from animals, other peasants, various nomads, mercenaries searching for work, groups of thieves that would steal crops, etc. Warfare, which was fairly constant, was also a factor because pillaging or raiding your enemy's economic producers was a common strategy.
This is not even to mention the various group conflicts that could occur between communities, populations or even villages. Lords would do their best to discourage this, but they still happened. Being a peasant was not a constant of idealic hard work. Violence was not the main event, but it did occur and its threat was a constant.

There are explorations into how this "civilizing" process may have influenced genetics and caused the industrial revolution.

Genes do not make steam engines. The right economic, social and technological conditions do. The book you point to argues about cultural conditions being a significant driving factor, not necessarily genetics.

[EgalitarianJay]

Science and accumulation of knowledge is about observations. Good data that one can extrapolate from is useful even if there is no good theory behind them. (for example quantum mechanics) "Debunking" theories but not data doesn't do very much. That is like saying that "we see this in reality, but does it work in theory?"

Well that begs the question, is Rushton's data good? Graves has argued that his data is questionable for the most part and unreliable for testing his evolutionary hypothesis. An objective observer would consider his research to be "bad science" or pseudoscience given the fact that his theory is invalid and his methodology is unsound.

The brain size issue is like Galileo's observation of Jupitor's moons and using it to support his world view of the Earth orbiting the sun. It is not direct proof, however it is consistent with the model used to comprehend a different issue.

The brain size issue is an attempt to find a biological basis for IQ differences. What causes these differences? Rushton believed that genetic differences caused biological differences in brain size which in turn causes differences in intelligence.

Since that theory was proven wrong the argument over brain size becomes a red herring.

I do not disagree with the criticism on Rushton, however that criticism does not rule out significant biological variation due to environment. Rushton have choosen a crude line to divide the "races" when traits are likely to be specialized to specific environments, for example Tibetan high altitude adaptation. http://en.wikipedia.org/wiki/High-altit ... _in_humans (note this took only 3000 years, plus admixture with archaic hominins)

If significant biological differences exists, then most population divisions, even if not sensible, it likely to capture a part of that and see difference in mean.

If you read the article you will see that Lieberman outlines why significant biological differences do not exist. There is some genetic differentiation between human populations but it can not account for the racial differences that Rushton claims exist.

I'd say demantia would lead to poor test results. If smaller brains means increased vulnerability mental illness then one would see a skew in performance.

I don't think there's any relationship between brain size decreasing with age and mental illness. I think age itself simply makes a person more susceptible to certain diseases including mental illness. The point is that brain size decreasing with age is a natural phenomena that doesn't affect the intellect of the elderly which is why you still see mentally sharp professors in their 60s and 70s.

[Terralthra]

Science and accumulation of knowledge is about observations. Good data that one can extrapolate from is useful even if there is no good theory behind them. (for example quantum mechanics) "Debunking" theories but not data doesn't do very much. That is like saying that "we see this in reality, but does it work in theory?"

Ultimately science is dependent on observation. If your observations do not match the theory, then your theory is wrong period. Instinct might tell you that people with bigger brains are smarter, but observations counter that. Instinct might tell you that a person with bigger muscles are stronger, but observation triumphs all.

However observation have shown that people with bigger brains are generally smarter at 0.3 correlation...

No, it hasn't.