/sci/ - Science & Math

There are many physical properties of the brain that are associated with greater intelligence. More intelligent brains show faster nerve conduction, less glucose utilization in positron emission tomography [PET scans], faster reaction times, faster inspection times, faster speeds in general, greater circumference and volume, smaller standard deviation in reaction times, greater variability in EEG [electroencephalogram] measures, shorter white matter T2 relaxation times, and higher gray-white matter contrast with magnetic resonance imaging [MRI] (Miller, 1994d). The thickness of the three outer layers (the supragranular layer) of the cerebral cortex (the six outer layers), increases from lower animals to man (Corballis, 1991, p. 67). The supragranular layer is 15% thinner in blacks than in whites (Vint, 1934). The nerves in blacks are reported to be larger (Burmeister, 1853).

The prefrontal area typically constitutes 29% of a man's brain (Herrick, 1956, p. 385). The human neocortex is over three times as large as expected for a primate matched for body size (Passingham, 1982). Compared to Caucasoids and Mongoloids, in Negroids the back of the brain is more developed and the front less developed (Broca, 1858, cited by Rushton, 2000a, p. 106; Bean, 1906; Levin, 1997, p. 105). This is noticeable in the more sloping forehead of Negroids and the length of their skull. Vision is processed in the back of the brain, hearing at the side, and planning and abstract thought at the front. Blacks have better hearing than other races (Murphy, 2006). Thus, a brain that is more devoted to one of these functions than to others will have a greater mass of brain tissue in that area and the skull shape will be expanded in that area.

Hybrid vigor is a myth.

Anti-whites have argued that people of mixed race are in some ways superior to people of unmixed race, and therefore race-mixing is desirable. This seems inconsistent with their position that there are no significant genetic differences between races, but anti-whites are not strongly committed to consistency.

Here is the reality. The greater the genetic distance between two individuals, the greater is the incompatibility of their alleles.

The mating of people with dissimilar genes often results in health problems in the offspring due to the failure of genetically-programmed incompatible biochemical or physiological pathways, a phenomenon known as "outbreeding depression."

Mismatched alleles in mongrels often leads to autoimmune diseases, such as arthritis and multiple sclerosis, where the immune system inherited from one parent attacks the proteins made from the other parent's DNA.

There are rearrangements, inversions, and duplications in the human genome that differ among the races and may cause incompatibility. There are also some non-genetic costs of race-mixing, such as cultural incompatibility and the spread of a disease that one of the parent populations is immune to but the other is not.

The size of the Negroid brain is significantly lower in volume than the Mongoloid or Caucasoid brain. The size of its frontal lobes are small and uncomplex, and the brain as a whole shows an unimpressive, moderate degree of fissuring (Lynn, 2006a, pp. 210-211; Rushton, 2000a, pp. 130, 133).

Converting brain volume into the number of neurons, Mongoloids average more than half a billion more neurons than Negroids (Rushton, 2000a, p. 133; Broom, 1918, p. 63-79; Howells, 1948, p. 118; Galloway, 2005, pp 31-47). East Asians (Han Chinese, Koreans, and Japanese) have the highest ratio of brain to body mass, but the record for brain size goes to Russian writer Ivan Turgenev, at 2012 gms (Corballis, 1991, p. 66). The heritability of brain size is about 0.9 (Lynn, 2006a, p. 67).

The ridges (gyri) between the groves (sulci) at the surface of the brain greatly increase the surface area of the cerebral cortex, the outer layer of the cerebrum. Since the cerebral cortex processes information, increased brain fissures increases the percentage of the brain that is cerebral cortex and should increase intelligence without increasing the volume of the brain, although this is difficult to establish quantitatively (Baker, 1974, p. 432). Negroids and some retarded people have fewer convolutions (fissures) in the cerebral cortex of their brains, where abstract thought is performed (Broca, 1858, cited by Rushton, 2000a, p. 106).

There are many physical properties of the brain that are associated with greater intelligence. More intelligent brains show faster nerve conduction, less glucose utilization in positron emission tomography [PET scans], faster reaction times, faster inspection times, faster speeds in general, greater circumference and volume, smaller standard deviation in reaction times, greater variability in EEG [electroencephalogram] measures, shorter white matter T2 relaxation times, and higher gray-white matter contrast with magnetic resonance imaging [MRI] (Miller, 1994d). The thickness of the three outer layers (the supragranular layer) of the cerebral cortex (the six outer layers), increases from lower animals to man (Corballis, 1991, p. 67). The supragranular layer is 15% thinner in blacks than in whites (Vint, 1934). The nerves in blacks are reported to be larger (Burmeister, 1853).

The prefrontal area typically constitutes 29% of a man's brain (Herrick, 1956, p. 385). The human neocortex is over three times as large as expected for a primate matched for body size (Passingham, 1982). Compared to Caucasoids and Mongoloids, in Negroids the back of the brain is more developed and the front less developed (Broca, 1858, cited by Rushton, 2000a, p. 106; Bean, 1906; Levin, 1997, p. 105). This is noticeable in the more sloping forehead of Negroids and the length of their skull. Vision is processed in the back of the brain, hearing at the side, and planning and abstract thought at the front. Blacks have better hearing than other races (Murphy, 2006). Thus, a brain that is more devoted to one of these functions than to others will have a greater mass of brain tissue in that area and the skull shape will be expanded in that area.

Race differences in average IQ are largely genetic
http://www.news-medical.net/news/2005/04/26/9530.aspx

Thirty Years Of Research On Race Differences In Cognitive Ability
http://psychology.uwo.ca/faculty/rushtonpdfs/pppl1.pdf

What If The Hereditarian Hypothesis is True?
http://www.udel.edu/educ/gottfredson/reprints/2005hereditarian-hypothesis.pdf

Is it Really Because of Culture?
http://www.gnxp.com/MT2/archives/004064.html

Mainstream Science on Intelligence: An Editorial With 52 Signatories, History, and Bibliography
http://www.udel.edu/educ/gottfredson/reprints/1997mainstream.pdf

Population Differences In Brain Morphology and Microstructure Among Chinese, Malay, and Indian Neonates
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0047816