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(Return to Quotations Files Index)
Genetic Diversity & Human Equality
The Facts & Fallacies in the Explosive
Genetics & Education Controversy
Theodosius Dobzhansky
ISBN 465-02761-0
Dewey # 155.82 D65
No competent scientist takes the IQ as a measure of overall quality or worth of human being (although a part of the public has been misled into believing this). The possessor of a high IQ may be vicious, selfish, lazy, and slovenly, and a lower IQ may be combined with kindness, altruism, and hard and careful work. Burt (1961) is one of those who claim that "we may safely assert that the innate amount of potential ability with which a child is endowed at birth sets an upper limit to what he
can possibly achieve at school or in afterlife," and that IQ measures this supposedly innate ability. Others deny that IQ testing provides any scientifically valid information, and see in it merely a device used by the privileged classes to maintain their status at the expense of the underprivileged ones. It is unfortunate that the writings of Jensen (1969), Eysenck (1971), and some others are eagerly exploited by racist propagandists, perhaps without consent of the scientific investigators
themselves.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 11
The work of Heber (1960) has already been mentioned. It describes an experiment on ghetto children whose mothers had IQs below 70. Some of these children received special care and training, while others were a control group. Four years after the training period the IQs of the former averaged 127 and those of the latter 90, a spectacular difference of 37 points.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 14
The heritability of IQ in man is estimated from data of the sort summarized in Table 1-1. [N/A] Slightly different estimates are obtained from different varieties of IQ tests, from correlations between relatives of various degrees, and between relatives of the same degree reared together and apart. The available estimates have been carefully reviewed by Thomson (1967), and especially by Jensen (1969). Jensen gives an overall estimate of 0.81 (81 percent). This is a high heritability, as
the list of heritabilities of various traits in different organisms, compiled in Table 1-2, clearly shows. IQ is about as strongly heritable as human stature. Its heritability is much higher than those of egg production in poultry or of yield of corn.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 16
[That table is Not Available because I did not copy it from the textbook. -MN]
There has been so much misunderstanding of the significance of the high heritability of IQ that it is imperative to make clear what this heritability does and does not mean. To begin with, it does not mean that the IQ, or scholastic achievement insofar as the latter is a product of IQ, is not subject to modification by upbringing and other environmental means. The cited works of Heber, Skodak, and Skeels have shown this clearly. Even more basic is that heritability is not an intrinsic
property of a trait but of the population in which it occurs. Consideration of limiting cases makes this obvious.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 17
Therefore, estimates of heritability are valid only for the populations and for the times when the data on which they are based were collected.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 17
| Organism and Trait | Heritability |
| Spotting in Friesian cattle | 0.95 |
| Slaughter weight in cattle | 0.85 |
| Stature in man | 0.81 |
| IQ in man | 0.81 |
| Weight in man | 0.78 |
| Cephalic index in man | 0.75 |
| Plant height in corn | 0.70 |
| Egg weight in poultry | 0.60 |
| Weight of fleece in sheep | 0.40 |
| Milk production in cattle | 0.30 |
| Yield in corn | 0.25 |
| Egg production in poultry | 0.20 |
| Egg production in Drosophila | 0.20 |
| Ear length in corn | 0.17 |
| Litter size in mice | 0.15 |
| Response to light in Drosophila | 0.09 |
| Conception rate in cattle | 0.05 |
| Response to gravity in Drosophila | 0.04 |
Average IQs of fathers and of their children belonging to socio-economic classes from I, the highest, to VI, the lowest.
| I | II | III | IV | V | VI | |
| IQs of fathers | 139.7 | 130.6 | 115.9 | 108.2 | 97.8 | 84.6 |
| IQs of children | 120.8 | 114.7 | 107.8 | 104.6 | 98.9 | 92.6 |
| frequency per 1,000 | 3 | 31 | 122 | 258 | 325 | 261 |
Endless dispute and passionate polemics arise from the finding that the white and black populations in the United States also differ in IQ averages. Assuredly, individual scores are broadly overlapping; many whites score below the black mean, and many blacks score below the white average.
Class and race differences in IQ averages may be ascribed to inequalities in educational opportunities and living standards. This explanation is traditionally favored by most social scientists and by political liberals. On the other hand, the differences may be genetic, which is pleasing to racists and reactionaries, but not espoused by any reputable scientist.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 20
The question is sometimes asked: How do you define "man"? Biologically the answer is simple. All human beings are members of a single species, Homo Sapiens. Though some pathological variants seem to be less than human, they belong to our species. Their genes come from the same gene pool as everybody else's. Inhabitants of the whole world share in the common gene pool of the species. Perhaps no hybrids of Eskimos and Tungus with Hottentots and Aboriginal Australians have ever been produced, but there are unbroken chains of intercrossing of geographically intermediate populations. Assuredly, this does not mean that mankind is a single uniform breeding population, wherein every individual would have equal chance to mate with any individual of the opposite sex anywhere. The population of our species is complexly divided into a variety of subordinate Mendelian breeding populations. In each of these, the probability of marriage within is greater than between populations.
Geographic, national, linguistic, religious, economic, and other factors keep the gene pools of the subordinate breeding populations partly, but probably never entirely, separate. Mendelian breeding populations within a species are more often than not overlapping, which does not make them unreal. The population of New York City has WASPs, Jews, Catholics, and blacks; wealthy, moderately well-off, poor and destitute; educated and ignorant; people of English, Irish, Italian, Greek, and other
ethnic groups, partly preserving their cultural backgrounds. Many individuals belong at the same time to two or more of these subpopulations or "isolates."
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 24
Members of privileged classes like to believe that everybody belongs to the socioeconomic class for which his genes qualify him. The poor live wretchedly; if this is not through their faults, then it is owing to their genetic inferiority. The opulent and the mighty deserve their affluence because their genes entitle them to it. Such views are an abomination, not to the underprivileged alone but to some prosperous liberals as well. In their protest they often go out on a limb, espousing
the indefensible extremist position that the genetic basis of mankind is uniform everywhere, and need not be considered further.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 26
Insofar as achievement is genetically conditioned, social mobility is a genetic as well as socioeconomic process.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 28
A caste system entails inequalities of status as well as of opportunity. It also entails occupational specialization. Each of the numerous castes and subcastes in classical India had a business, trade, or work traditionally reserved to it. The problems of training and allocation of status were thus simplified -- everybody knew from childhood what the source of his livelihood would be, and in what kind of occupation or toil he must become skilled. Of course, one belonged to the caste of one's parents, and had to marry a person of the same caste. One could not be promoted or demoted to another caste, no matter what one's achievements, failures, talents, or incapacities. Upper-caste status automatically carried with it respect and privilege; lower castes and outcasts ("untouchables") were subjected to gross indignities.
The system was revoltingly unjust from our modern point of view, yet it had a plausible-sounding rationale. Bose (1951), no partisan of the caste system, wrote: "The careful way in which the tradition of close correspondence between caste and occupation was built up is clear indication of what the leaders of Hindu society had in mind. They believed in the hereditary transmissibility of character, and thought it best to fix a man's occupation, as well as his status in life, by means of the
family in which he had been born." The same rationale is offered by racists in the United States and elsewhere for the denial of equality to the black caste.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 28
Here is a specimen of Putnam's (1967) specious reasoning: "The relationship as to both employment and welfare which existed for generations between white and Negro families in the South was almost ideal because it was based upon reality. The family took a cradle-to-grave responsibility for the Negro family and the latter repaid the former in faithful service." This idyllic (to Putnam and his like), relationship assumed that the blacks are genetically specialized for work in no capacity
other than as domestic servants. The fatal flaw of all caste systems is that they are built explicitly or implicitly on such assumptions.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 31
The caste system in India was the grandest genetic experiment ever performed on man. The structure of the society endeavored for more than two millennia to induce what we would now call genetic specialization of the caste populations for performance of different kinds of work and functions. Such specialization has not been achieved.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 31
Wastage of talent is, in fact, a fatal vice of all caste and rigid class systems.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 33
A person has two parents, four grandparents, eight great-grandparents, and so on. Continued for some 33 generations, the number of ancestors turns out to be greater than the world population. Of course, this is impossible. Notwithstanding the universality of incest taboos, all our ancestors were more or less distant relatives.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 57
[2^33 Answer: 8,589,934,592 (eight point six billion; whereas the world population
only hit six billion in the year 2000) -MN]
Though this cannot be documented, all humans are relatives.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 57
It is sometimes asked how one defines a human being. Biologically, the answer is simple: any individual is human whose genes are derived from the gene pool of the human species.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 58
Rohrer's Index: body weight divided by the height cubed.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 65
One can only conclude that the degree to which differences in the IQ arrays between races are genetically conditioned is at present an unsolved problem. I fully agree with Bodmer and Cavilla-Sforza that "we do not by any means exclude the possibility that there could be a genetic component in the mean difference in IQ between races. We simply maintain that currently available data are inadequate to resolve this question in either direction."
--Dr. Theodosius Dobzhansky, Genetic
Diversity & Human Equality, pg 91
Assume for the sake of argument that some part of the average difference between the IQs of blacks and the whites is genetic. Would it follow that the blacks are an inferior and the whites a superior race? Would it be a vindication of the racists in Alabama, South Africa, and elsewhere? Certainly not. Two basic facts refute the racists: the broad overlap of the variation curves for IQs and other human abilities, and the universal educability, and hence capacity for improvement, however
that be defined.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 91
Although the existing races of man differ in many respects...yet if their whole organization be taken into consideration they are found to resemble each other closely in a multitude of points....The same remark holds good with equal or greater force with respect to the numerous points of mental similarity between the most distinct races of man. The American aborigines, negroes, and Europeans differ as much from each other in mind as any three races that can be named; yet I was incessantly
struck, whilst living with the Fuegians on board the 'Beagle,' with the many little traits of character, shewing how similar their minds were to ours; and so it was with a full-blooded negro with whom I happened once to be intimate.
--Charles Darwin, quoted in Genetic Diversity & Human Equality, pg 91
The cardinal distinction between mankind and all other forms of life is that man's adaptedness depends primarily on his cultural rather than on his genetic inheritance.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 93
Celestial phenomena are calculable and predictable, provided that one has discovered the precise and eternal laws which they obey. Biological and psychological phenomena are less predictable, but only because they are much more complex and the laws governing them are yet to be discovered.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 103
Human cultural evolution influences mankind's genetic endowment, and vice versa. In recent years there have been publicized some alarmist views asserting that human genetic endowment is in a process of degeneration, and predicting dire consequences for the future. This matter cannot be adequately discussed in this book; I believe that the dangers have been exaggerated, and in any case the situation is not beyond possible control.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human
Equality, pg 110
If there is no evolution, then all is futility -- human life in particular. If the world evolves, then hope is at least possible.
--Dr. Theodosius Dobzhansky, Genetic Diversity & Human Equality, pg 113
Nothing makes sense except in the light of evolution.
--Theodosius Dobzhansky
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Physical Anthropology and Archeology
Volume 1: An Introduction to Anthropology and Archeology
Third Edition
Dorsey Press
Victor Barnouw
ISBN 0-256-02000-0
Dewey # 301 B262, pg 299 - 309
Race Defined and Questioned:
A race may be defined as a human population whose members have in common some hereditary biological characteristics that differentiate them from other human groups. Putting it in more genetic terms, a race is a breeding population that differs from others in the frequency of certain genes. Membership in a race is determined only by hereditary biological traits and has no necessary connection with language, nationality, or religion, although language, nationality, and religion often act as isolating mechanisms that may maintain to some extent the distinctiveness of a racial group. There is no such thing as an Aryan race, a French race, or a Muslim race.
Some anthropologists even argue that there is no such thing as race at all; "races" in their view, are merely products of human imagination and reason that correspond to no reality in the world of nature. [...]
One reason these writers reject the race concept is that there is no agreement among physical anthropologists about how many races there are.
Early Notions About Race:
An early attempt at racial classification was made by Linnaeus, who first classified man as a primate. Linnaeus distinguished some subdivisions of the human species, of which four were based on geographical areas -- American, European, African, and Asiatic -- while others were more fanciful, such as an alleged Homo monstrosus, and Homo ferus or wild man, suggested by speechless wild children who had sometimes been found wandering in the woods of Europe. A later taxonomist, [...] rejected the latter two categories and added a fifth geographical variation, Malayan. These were the first leading racial classifications; many more were to be drawn up in succeeding generations.
Racial variations were often interpreted as degenerations from a primordial type. Both Blumenthal and Buffon believed that Adam and Eve were white, Oliver Goldsmith argued that white was the original natural color of man. Goldsmith thought that proof of this lay in the fact that the babies of other races were born light skinned. In the late 18th century, Samuel Stanhope Smith asserted that humans had originated, fully civilized and white, somewhere in Asia, but some offshoots had developed dark skin due to the effects of heat. A contemporary, John Hunter, claimed that savage living conditions generally led to dark complexion. On the other hand, James Cowles Prichard, in 1813, asserted that Adam had been a Negro, and that in the process of civilization, man had been slowly turning white. Although these theories differed from one another, a common thread that ran through them all was the conviction of white superiority held by the white theorists.
Those who followed the monogenetic tradition of descent from Adam and Even had to account for the racial diversity which had developed since. Not all thinkers accepted this view, however. Some 18th century writers believed that different races were the products of separate acts of creation. Voltaire, who held polygenetic views, thought that Negroes were not capable of achieving an advanced civilization. Some American defenders of slavery held that blacks and whites were separate species. An obvious weakness of this notion was that the two races could interbreed and produce fertile offspring. Nevertheless, there were several proponents of what came to be know in Europe as the "American School," founded by a physician and anatomist, Samuel George Morton. Between 1830 and 1851, Morton acquired a collection of 968 skulls from different parts of the world. He developed certain standard measuring practices involving about a dozen separate measurments, including that of the cranial capacity. Skull measurements of this sort became standard procedure in the physical anthropology of the rest of the 19th century and the early decades of the 20th. Members of the American School thought that Negroes and whites belonged to separate species and that Negroes were inferior to whites. But despite their implicit support for slavery, polygenetic views did not prevail in the South, since they challenged biblical authority. Fundamentalists could find support for the inferior position of blacks in Noah's curse on his third son, Ham, whose descendants were destined to be the servants of servants. This was believed to refer to the Negro race.
Skull Measurement:
Racial prejudice took a new turn in 19th century Europe; it sought scientific justification. By measuring skulls or estimating cranial capacities, some 19th century scholars tried to find evidence for the superiority of whites. It is curious that some of the first work of this kind had an intra-European scope and was concerned with trying to demonstrate the superitority of either broad- or narrow-headed persons. Paul Broca, who founded an anthropological society in Paris 1859, believed that city dwellers had rounder, broader heads than people who lived in the country and that round-headed Frenchmen of Gallic ancestry were superior to narrow-headed Nordics. An opposing view was held by Otto Ammon, who believed that narrow-headed Nordics were essentially superior to broad-headed Europeans of Alpine stock. Ammon measured the skulls of army recruits in Baden and found that men from the city of Baden tended to have narrower heads than those from the rural districts around the city. This led him to conclude that there is a selective migration of the more intelligent and adventuresome narrow-headed persons from the countryside to the city, leaving behind on the farms a plethora of peaceful, dull-witted, broad-headed peasants.
It was unfortunate for Ammon's theory that an Italian scholar, Livi, found just the reverse situation in southern Italy, where the rural population around Naples turned out to be prevailingly narrow-headed, while a higher incidence of broad-headed persons was found in the city of Naples itself.
[...]
There is no longer a school of thought that champions the broad-headed or narrow-headed person as superior. It is nice to know that a racist view can become extinct. At the time, however, such views were taken seriously. [...]
The notions of Broca, Ammon, and De Lapouge may seem funny to us now, but there was a serious consequence in their head measuring activities. Racist thinking now sought scientific justification. Broca, Ammon, De Lapouge, and others used methods that were held to be scientific and thus brought the question of racism into the arena of science. Moreover, after the publication of Darwin's Origin of Species and the growing acceptance of the idea of evolution, a new type of sanction for the notion of white supremacy appeared. Some writers argued that the whites were the most highly evolved and least apelike of the various races and had the largest skulls and brains.
Franz Boas in The Mind of Primitive Man and Otto Klineberg in Race Differences countered these arguments. If one selects certain traits for comparison, they pointed out, a case may be made for the whites being more highly evolved than the Mongoloids or Negroids; but it depends upon the traits selected. If one chooses other traits for comparison, Negroids may be seen to be less apelike than whites or Mongoloids. In their dark pigmentation, prognathism (facial protrusion), receding forehead, and low, broad nose, the Negroes seem to be more apelike than the other two major racial groups. But Negroes have some traits that show them to be less apelike than Caucasoids and Mongoloids: in particular, the thickness of their lips. Man differs from the other primates in having everted lips in which the mucous membrane can be seen as a continous red line. The Negroes have the thickest, most everted lips among present-day racial groups. Their hair is also least apelike, for tightly curled or kinky hair is not found among apes and monkeys. The whites are the most apelike of the three major racial stocks in having more body hair and more of a brow ridge than either Negroes or Mongoloids. However, one cannot say that one of these three groups is [more or less highly] evolved.
Brain Size and Morphology:
Racists have sometimes made the claim that whites have larger or more advanced brains than nonwhites. Comparative studies have sometimes shown slight differences in cranial capacity between racial groups, but these do not seem to be significant. One comparative study of the cranial capacities of whites and blacks gives the mean capacity of 1,179 white male skulls as 1,517.49 cc, and that of 661 black male skulls as 1,467.13 cc. Thus, the white skulls are larger, but the difference between the two series is only 50.36 cc. Some series of nonwhite skulls have yielded larger cranial capacities than the white series with which they were compared. [...]
It must be kept in mind that in many of the non-European groups the stature is smaller than that of whites. An increase in head size accompanies growth in stature. Since diet affects stature, the more favorable nutrition of European and American whites may affect brain size, but this would not necessarily indicate greater intelligence on their part. Many outstanding persons have had quite small brains. Within the normal human range, mere size is not an indicator of intelligence.
Some American racists have argued that whites have more highly developed frontal lobes than blacks do and that the brains of whites how more fissuration and sulcification. Robert Bean is cited for an early study (1906) in which he claimed that Negroes tend to have smaller frontal lobes than whites. A later study by Fanklin P. Mall did not confirm Bean's findings. He separated the brains of about 100 Negroes and whites into three groups according to the richness of their convolutions. The brains of the whites wre not found to be more complex. Mall also weighed the frontal lobes of all the brains. He found that the brains of Negroes were somewhat lighter than those of the whites, but the Negro frontal lobes were relatively as heavy. Mall (1909) emphasized the great variation to be found among the brains of both racial groups. J.H. Kohlbrugge has written: "The comparison of convolutions and sulci does not present constant racial differences. . . . Each variation can be found in different races if one has enough data. . . . Among a group of brains belonging to different races, no one is capable of distinguishing one which corresponds to an Australian from a European, nor one of a genius from that of a man of average intelligence."
Still another work on brain morphology cited in racist literature is F.W. Vint's The Brain of the Kenyan Native. The reason this brief article is referred to in such publications is that Vint, who made a study of 100 brains of Kenyan natives, concluded, among other things, that the pyramidal cells of the supragranulated cortex are smaller in the brains of Kenyan natives than in the European brains described by von Economo. Racist writers who have made use of these findings consider it to be significant that the African Negro brains studied had thinner supragranular layers of the cortex than European brains. But these writers ignore some qualifications made by Vint himself. He pointed that his collection of brains came from individuals who, while alive, were generally of poor physique. Vint wrote: "The high incidence of spirochetal diseases, yaws, and syphilis, must be taken into consideration in any deduction drawn from the finding in this series of brains." The racist writers who cite Vint's study make no reference to this caveat. Moreover, none of the 100 brains came from members of the "so-called educated class." [...]
Intelligence Testing:
In current racist literature, much is made of the fact that whites generally do better than blacks in intelligence tests given in the United States. This fact has long been known, but the most generally held interpretation among psychologists and other social scientists is that the poorer performance of blacks on such tests reflects poorer educational facilities for blacks and a more generally depressing, inhibiting social environment. IQ scores do not reflect native intelligence. Many studies have shown that when childrend are moved from orphanages to satisfactory foster homes the IQ scores often shoot up. And IQ scores may also drop if the individual's environment is restrictive and unrewarding.
Klineberg has shown that an individual's performance on intelligence tests is affected by many factors besides intelligence, such as familiarity with the language in which the test is given, motivation, rapport with the investigator, and level of education. He showed that northern blacks did better than southern blacks in intelligence tests given to army recruits in World War I. For that matter, northern whites also did better than southern whites. Evidently these differences reflect more adequate educational faciities in the North. What is more, some groups of northern blacks did better than southern whites. Indeed, on the Beta tests, the blacks of Ohio did better than the whites of 27 other states.
In a much debated article, "How Much Can We Boost IQ and Scholatic Achievement?", Arthur R. Jensen claims that efforts in compensatory education such as the Head Start program have failed to raise the level of scholastic performance among blacks; their inability must therefore be due to a genetic deficiency in intelligence. Some of Jensen's critics have replied that most programs in compensatory education have not been effectively administered; their alleged failure need not imply any genetic inadequacy on the part of blacks.
Jensen and other writers with a racist orientation assert that, when blacks and whites of comparable status and educational level are tested, whites still come out ahead. But in what sense is status comparable? Negroes were slaves little more than 100 years ago [this text was written in 1977 --MN], and in the intervening years they have faced barriers of poverty and prejudice. [...]
In an article criticizing the Jensen article, C. Loring Brace and Frank B. Livingstone draw attention to reported effects of malnutrition on IQ, which should affect many lower-class American blacks. Jensen is able to dismiss this variable by claiming that there is little extreme malnutrition in the United States -- a debatable point. Brace and Livingstone also comment: " ... we fail to see, after pointing out that enviroment can change IQ by as much as 70 points, [how] he [Jensen] can make the statement that 'in short, it is doubtful that there is any significant environmental effect on IQ.'"
To understand the low IQ scores and the high rates of divorce, delinquency, and crime among American blacks, often cited by racists, we must look at social environment and past history of the American black, including the years of slavery and their aftermath, years of poverty and prejudice. One need hardly invoke race to account for such phenomena.
It is striking that despite the prejudices they have encountered, American blacks have often been outstanding in the fields where they have been accepted, especially in literature, music, the entertainment world, and athletics.
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Exploding The Gene Myth:
How Genetic Information Is Produced and Manipulated by
Scientists, Physicians, Employers, Insurance Companies,
Educators, and Law Enforcers
Ruth Hubbard and Elijah Wald
Beacon Press
ISBN 0-8070-0418-9 (cloth)
ISBN 0-8070-0419-7 (paper)
Dewey # 174.9574 H876
To formulate eugenic policies, it is necessary first to label certain physical or mental traits and social behaviours as aberrant and then to assume that they are transmitted biologically from parents to their children. Such labels can easily be exploited for ideological and political ends. An extreme example is the invention of drapetomania, a hereditary mental disease said to be prevalent among black slaves in the South, which manifested itself in an irresistible urge to run away from their masters.
There is no evidence whatsoever for the biological nature or genetic transmission of many of the traits that eugenicists said were inherited. Take the label "feebleminded." Class, race, ethnic, and linguistic difference have often led to people's, and especially children's, mental capacities being judged lower than average. Many instances of slow or arrested mental development have their origins in infectious diseases or physical, psychological, or social traumas and hence are not inherited biologically, though members of the same family may share them because they share those experiences.
When we come to such labels as "alcoholism" or "pauperism," difficulties of assigning causes are compounded by problems of description and definition. How much does one have to drink to be an alcoholic? How poor does one have to be, and for how long, before one is a pauper?
Even where diagnosis is relatively unambiguous, the eugenic approach only confuses and obscures the issues. In the early part of this century, pellagra, a chronic condition characterized by skin eruptions, digestive and nervous disturbances, and eventually mental deterioration, reached epidemic proportions in parts of the southern United States. Many people believed it to be infectious in origin, like syphilis. Charles Davenport and his colleagues agreed, but argued that by virtue of genetic predisposition pellagra is acquired preferentially by certain kinds of people. With uncanny precision, Davenport specified that "when both parents are susceptible to the disease, at least 40 percent, probably not far from 50 percent, of their children are susceptible."
Around the same time, Joseph Goldberger, an American epidemiologist, showed that pellagra results from a lack of vitamin found in grains and fresh vegetables, which he called the pellagra preventive (or PP) factor. His PP-factor was later renamed nicotinamide or niacin and identified as a member of the vitamin B complex. Although Goldberger published his findings in 1916, nutrition programs that could have prevented many cases of pellagra were not instituted until the beginning of
the New Deal in 1933. The conservative Republican administrations of the 1920s, averse to spending money on health and nutrition, were supported in their inertia by the assertions of Davenport's adherents that pellagra was hereditary and could not be remedied by said programs.
--Exploding The Gene Myth, pg 16-17
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Living With Our Genes
Dean Hamer & Peter Copeland
ISBN 0-385-48583-2
Dewey # 155.234 H214
. . . human DNA differs from chimpanzee DNA by only 1 or 2 percent; your DNA and a chimp's are at least 98 percent the same. Yet this seemingly "fine print" of DNA instructions is the reason humans can do calculus, compose poetry, and build cathedrals, while chimps pick bugs off each other and eat them.
--Living With Our Genes, pg 19
The Bethesda Confirmation
The only one way to prove that a gene directly affects a complex charasteristic like novelty seeking is to look within families. This is because families are homogeneous racial and ethnic units; and by looking at children raised in the same household, the effect of different environments -- including parenting, and the social and cultural background -- is minimized.
My laboratory at the National Institutes of Health in Bethesda, Maryland, had been gathering just the right data to test the Israeli findings. During the several years we had collected DNA samples and personality questionnaires from a broad range of people who had vounteered for studies conducted at the National Cancer Institute and, in collaboration with Johnathan Benjamin and Dennis Murphy, at the National Institute of Mental Health. The best thing about our subjects was that they included families, mostly pairs of brothers, not genetically unrelated poeple like the subjects in the Israel study.
Would the Israeli link between novelty seeking and D4DR hold up in our very different group? We had the DNA samples and results of a similar questionnaire to the one used in Israel. The rest was mathematics.
When the computer finished comparing the DNA with the scores for novelty seeking, the results were almost identical to the Israel study. People with long versions of the D4DR gene scored on average 0.4 standard deviations higher for estimated novelty-seeking scores than did people with the shorter versions. Because our study population was considerably larger than the Israeli population -- 315 subjects versus 124 subjects -- the results were statistically even more convincing. [...]
So now we knew the result could be replicated, but was it real? Was the D4DR gene directly related to the difference in novelty seeking, or was it just a spurious association [...]?
The critical experiment was to look at the families. We focused on those in which one sibling had a long gene and the other had a short gene. If the theory was correct, then the brother with the long version should score higher for novelty seeking; but it the theory was wrong, then there'd be no difference inside the families. In other words, if the theory was wrong, stockbroker Charles O'Rourke could score high for novelty seeking and his brother Michael O'Rourke could socre low, but their forms for the gene would be the same. That would mean genes weren't responsible for making Charles a hard-charging windsurfer and Michael an aspiring elementary school teacher.
When the comparison was completed, the result was clear. Charles had a long version of the D4DR gene, whereas Michael had a short version. The same was true of the other pairs of brothers and siblings. The difference was statistically significant, even larger than the difference between all long-gene and short-gene individuals. Even though these brothers were dipped out of the same gene pool and grew up in the same environment, they were different in a recognizable way, and their genes for the D4 dopamine receptor were different as well.
The complete agreement of the two studies was all the more impressive in view of their differences. The subjects came from different ethnic groups: Ashkenazic and Arabic Jews versus non-Jewish Caucasians, Hispanics, Asians, and African Americans. They came from different lands and cultures. Even the type of questionnaires used was different. The concordance of results indicated that the D4DR gene was affecting something fundamental about human nature -- not just something peculiar about one specific population, or something limited to one particular way of measuring personality.
After these results were published, another research group found the D4DR was not related to novelty seeking in a small group of Finnish subjects. However, because the Finns are an unusual gentic isolate, it's not clear how relevant this finding will be to populations at large. Recently another group, working in Canada, confirmed the association between the D4DR gene and positive emotions, which is one aspect of novelty seeking, and moreover discovered a connection between the gene, the
personality trait, and the density of gray matter in one particular region of the brain.
--Living With Our Genes, pg 43 to 46
And of course genes aren't everything. The behavioral genetics studies show that that environment -- meaning everything that isn't inherited -- is as least equally important in harm avoidance. Exactly what the important environmental factors are, however, isn't clear. Kagan has evidence that inhibited infants whose parents encourge them to fend for themselves are more likely to lose their shyness as they grow up than are infants who are mollycoddled. But up bringing can't have very much of an overall effect because twin studies show that shared environment, which includes general parenting style, has almost no statistically discernible effect on harm avoidance.
Scientists aren't even sure which unique life experiences are important. One unique experience -- and one that most people consider positive -- is falling into a lot of money. But even a windfall of money isn't enough to tip the scales of anxiety, research has found. Edward Diener, a psychologist at the University of Illinois, found that lottery winners are no happier a year after hitting the jackpot than were before. The same is true with many of the factors that we usually associate with contentment; getting married, having a family, or a job promotion have only minor effects on happiness.
Equally surprising is that negative events, such as divorce, losing a spouse, getting fired, or even suffering a spinal cord injury, have only minor correlations to depression. Typically such events, either the good ones or the bad ones, make people happier or sadder for a few weeks or months, but within a year their mood had returned to the previous level. This has led some researchers to propose that the brain has a set point for happiness just as the body has a set point for weight.
The combination of influences explains why there are exceptions to the genetic rule. For example, Russell, 41, has the long version of the gene and should score low for harm avoidance, yet he scores in the top 10 percent. [...] On the other hand there is Daniel, a middle-aged man who has the short version of the DNA and should score high for harm avoidance. Yet he scores in the lower 10 percent [...].
Both men are proof that DNA is not necessarily destiny and that character traits can override genetic predisposition.
--Living With Our Genes, pg 83 to 84
Bipolar disorder is more than just sever harm avoidance. The brain mechanisms are not yet understood, but what is clear is that bipolar disease has a strong genetic component. It runs strongly in families, and systematic studies have shown that the parents and siblings of manic depressives have a 10-fold increase in disease rate. Not surprisingly, it also runs in twins: the identical twins of a manic depressive has nearly a 40-fold increase of having the disease.
Obviously environment is also important for bipolar disorder, although we aren't sure what about the environment matters. The best evidence that environment is important is that rates of bipolar disorder have increased subtantially during the previous 20 years and that the age of onset is getting younger. Something appears to be changing in the way we live that is increasing the rate of manic depression.
--Living With Our Genes, pg 85
Disentangling the role of genes and environment in a trait as complex as criminality is not simple. Because children are both the genetic and environment products of their parents, it's difficult to establish the cause of behaviour. The same parents provide the genes and the environment, making it hard to see which is more important and how. The most useful method is to study children who are separated from their biological parents shortly after birth and are brought up by genetically unrelated parents. If the child turns out to be more like his biological parents, genes are clearly involved. If he grows up more like the people who raised him, environment is the key. This kind of experiment happens all the time. It's called adoption.
The most comprehensive adoption experiments in the United States have been conducted by Remi Cadoret and his colleagues, who have studied more than 1,000 Iowa families during the past twenty years. They compared the biological children of parents in trouble -- with the law, alcohol, or getting along with others -- to the biological children of parents without such problems. All the chidren were separated from their biological parents at birth or with a few days and were adopted by families with no blood ties. The basic qeustion is: are the adopted children more like their biological parents -- who contributed the genes -- or more like the parents who reared them -- who contributed the "environment"?
The answer is neither and both. For the children with non-problem genes the home environment made little difference. Even if the new parents got divorced, abused alcohol or drugs, or had other problems, the children turned out the same as kids raised in good homes. Some turn out good and others got in trouble, but the ratio was normal; it didn't change because of their home life. In other words, when the genes were good, the rearing environment didn't matter that much.
--Living With
Our Genes, pg 96 to 97 [Continued to quote below. -MN]
When the genes were bad, however, the home environment meant the difference between success and failure. When the home environment was bad, the children who inherited problem genes were at risk. In these households, the level of childhood and adolescent aggression was dramatically increased. Measures of bad behaviour such as lying, stealing, truency, and school expulsions were up by as much as 500 percent. Some of these children turned out fine, but the ratio of bad kids to good kids was
skewed. Aggressive and antisocial behaviour increased dramatically only in children with both "bad genes" and bad homes. That shows that what is being inherited is not bad behavior or aggression, but rather a genetic sensitivity to the environment. The genes didn't make them antisocial; the genes made them vulnerable. A bad seed planted in good soil had a decent chance. A bad seed planted in bad soil withered. Humans by nature respond well to nuture, but they also respond to its
absence.
--Living With Our Genes, pg 97
. . . serotonin is thought to be a key player in depression, anxiety, hostility, and other facets of the temperament trait known as harm avoidance. The relationship makes sense if depression is regarded as a form of anger or bad feeling about oneself, while aggression is viewed as anger toward others. Serotonin's job is to make people feel bad; it's the brain's punishment chemical.
--Living With Our Genes, pg 103
The question of whether genes play a role in aggression and crime is tremendously controversial. Yet even the most vocal critics, those convinced that only bad environment produce bad people, can't deny one simple biological fact. The most important single factor in whether a person is violent or aggressive is determined by just one chromosone, the Y, which assigns gender.
The statistical evidence is overwhelming. Men are charged with five times as many aggravated assaults as women, ten times as many murders, and 86 times as many rapes, according to the U.S. Department of Justice. In all history, wars have been waged mostly by men. Aggression today doesn't just get men killed, it also makes them rich and famous. Professional sports are dominated by men, especially men who can channel their strength toward a specific goal. And what do other men like to do? Watch violence on television or in stadiums.
Martin Daly and Margo Wilson, who studied murder around the world for their book Homicide, didn't want to be misled by the social and physical dominance of men in most cultures, so they compared rates of men killing men to women killing women. They went to American cities, African villages, towns in India, and communities in Scotland. Every place they looked, the answer was the same. Males commit more murders than females.
The most impressive finding was that the relative rate of male-to-female homicide remains constant even as the absolute rate varies. In other words, although there is much more killing in an American city than in rural Wales, the same percentage of the murders are committed by men.
--Living With Our Genes, pg 107
Inmate X
So far there is only one gene linked to violent behaviour in humans. The clue that led to its discovery came from a man we'll call Inmate X, the single most important individual in the entire debate over the biology of crime. Inmate X was truly a prisoner of his genes, in fact, of just one gene.
Born in Holland, Inmate X was 23 when he was convicted of raping his sister. He was transferred to an institution for psychopaths, where he was described as quiet and easy to handle. In spite of this, fights occurred with other inmates. He was working in the fields one day and became upset when a supervisor told him to work harder. Inmate X stabbed the warden in the chest with a pitchfork.
A relative of Inmate X visited a doctor because she wanted to have children but was worried about her family history. She told the doctor that Inmate X wasn't the only one with a problem in her family. When she was younger, her own brother used to force her to undress at knife point. Another male relative had tried to run over his boss with a car. Two other male relatives had committed arson. Then there was a male relative who exposed himself, and another who was a voyeur. The problem of boys bothering their sisters was so common that some of the girls had fled their homes.
Her frightened inquiry led to a long scientific study of this single family. The bad behaviour of the men varied widely, but there were common threads. All eight of the men closely studied were either mildly mentally retarded or borderline. The typical IQ score was 85. The one to have completed primary school was also the only one with a regular job. All eight had repeated outbursts of aggressive, sometimes violent behaviour. They were described as shy and withdrawn and often had no friends. A seeminly minor thing could set them off, and their response usually was way out of proportion to the provocation. They were especially likely to be aggressive during periods of one to three days when they slept little and complained of night terrors.
The problems with the woman's family stretched back for at least five generations. Thirty-five years before, one of her ancestors had done his own investigation. He visited all the men in the family and found that nine of them were retarded. Five additional cases emerged later. Inmate X himself had three affected brothers and two affected nephews, both of them related through sisters. Then there was his affected cousin, who was the son of his mother's sister. A maternal grandaunt's son was affected. So was a great-granduncle on the same side of the family. So were three sons of maternal great-grandaunts and two of their nephews through a sister. All together there were 14 men who showed the characteristic syndrome.
The family seemed to be suffering from a mysterious disease. The symptoms were retardation, aggression, and bad behaviour. The victims were certain males; other men in the family were happy and healthy. Not one women in the family had ever shown any sign of the disease.
It took a Dutch geneticist, Hans Brunner, to see the pattern. All the troubled males were related through their mothers. There was not a single instance of an affected father having an affected son. Whatever was making these men bad was passing through the females in the family, yet always sparing the women.
Brunner suspected the X chromosome, which is one of the two sex chromosomes. Males have an X chromsosome and a Y chromorsome, whereas femalse have two X chromosome. Therefore a male always receives his X chromosome from his mother, never from his father. This means that traits that are controlledd by genes on the X chromosome are always passed down to sons from their mothers, which was exactly the pattern seen in the family of Inmate X. Typically such traits are expressed more frequently in males that in females because males have no "good" copy of the gene to mask the "bad" copy, whereas females have an extra "good" copy of the gene on their other X chromosome. This how many X-linked traits, such as colour blindness and one type of hemophilia are inherited.
Based on this clue, Brunner and colleagues set out on the arduous task of precisely mapping the gene, isolating it, and figuring out exaclty what it did; what type of protein it made and how it functioned in the brains. They analysed the DNA from family members to see if there were any genetic signposts, called markers, that were linked to the syndrome. The trial and error paid off when they discovered that all the rpoblem men had one variation of a particular marker, and the healthy men had a different flavour. The responsible gene was none other than that for monoamine oxidase A, one of the enzymes that breaks down serotonin -- already a suspect of violent behaviour.
Brunner and company soon showed that Inmate X and four of his troubled male family members all had exactly the same mutations in the monoamine oxidase A gene: a single base change that told the cell machine not to produce the enzyme. Twelve of the healthy men in the family did not have this mutation. The odds of that happening by chance were less than 1 in 1000. The enzyme that was supposed to break down the serotonin was dead in the violent men, and there were filled with a natural toxic waste.
The discover of the "crime gene" generated headlines around the world and prompted criticism from scientists who refused to believe that something so simple -- even simpler than the mechanism that determines blue eyes or brown eyes -- could turn men into monsters. Doubters said the mutation alone could not cause such a personality change, that other genes must be involved, or it was something in their childhoods.
The doubt lessened when mice were engineered with the same mutation: they became crazed killers. Mice with a knockout for the monoamine oxidase A gene bit and attacked other mice without provocation. When they mated they squeezed their partners harder than other mice, and their partners squealed louder than other females. Soon the mutant mice were covered with scars from fighting and had red patches where the hair had been torn out by the roots.
Even this evidence wasn't enough for the critics, who continued to attack Brunner as a "biological determinist" and other nasty names. Sadly, the most important finding was largely ignored in all the commotion. Shortly after the discover of the mutation in the Dutch family, scientists looked for the same change in a large number of DNA samples from a variety of people with mental problems, including violent criminals. Not one of them had the mutation, which was so rare that it's been called an "orphan mutation."
What this means is that the monoamine oxidase A mutation cannot be used to explain all human violence and crime, or even a substantial percentage of it. In fact, that was never the claim. What Brunner found was the source of abnormal behaviour in just a single family, not in the population at large. What is important about the discovery is that it confirms the role of one particular aspect of brain chemistry -- the monoamine system -- in the biological part of aggression. It doesn't say
anything about the environmental component which takes a different kind of research.
--Living With Our Genes, pg 116-120
Of all the things that determine whether people will be violent, aggressive, and antisocial, the most important is neither genes nor parenting style. The most important factor is not the type of brain a person has or whether they were abused as children. What matters most is geography.
The people in the inner cities are the same genetically as the people in rural areas, yet urban crime has spun out of control. We are the same genetically as the Nazis, yet we like to think of ourselves as more civilized. The level of crime in American cities, or the crimes against humanity in Bosnia, Rwanda, or Nazi Germany, can't be explained one bit by genetics, because genes don't change that fast. It's hard to say what is the cause of urban crime, or of genocidal atrocities, but it sure
isn't biology.
--Living With Our Genes, pg 123
This Is Your Brain On Drugs
Kicking an addiction may be a matter of character or will power, but getting hooked in the first place is not. Addiction is not necessarily a sign of mental weakness, a lack of character, a symptom of psychopathology, or even a social disease. Rather, addiction is a disorder of the brain induced by chemicals that modify behaviour. People become addicted to drugs for one simple reason: the drugs change their brains.
Perhaps the most convincing evidence about how addiction works come from studying animals. If rat are given the choice of pushing a lever the delivers cocaine or another lever that delivers food and water, the start off pushing both levers about equally. But within a short time, they ignore the food and water and go straight for the cocaine every time. They will continue to do this until they die. Just like human addicts, they sacrifice their own welfare for the reward that coaine gives to their brain. Rats, mices, and other laboratory animals can also be taught to administer themselves amphetamines, morphine, alcohol, nicotine, and just about any other drug you can imagine. If they fail to get the drugs, they go into painful withdrawal, so they keep on pushing the lever -- until they die.
Although individual drugs work differently on the brain, the major addictive substances share one mechanism: they activate the nucleus accumbens, the brain's reward center. This is the part of the brain that recognizes a new drug and says, "Hey, I like that." When the drug stops appearing, it says, "Something's wrong here." When drug-addicted animals were tested with PET scans, their brains showed a hot spot of metabolic activity directly over the nucleus accumbens. The hottest area of all was the outer shell of the nucleus, a region that connects directly to the limbic region, the seat of emotions. The drugs were acting on the connector between the midbrain and forebrain, the perfect place to link good feelings to specific behaviour. This is where the brains says, "If it feels good, do it."
To figure out what cocaine was doing in rat brains, minature probes and samples were inserted into the shell of the nucleus accumbens and sample were taken before, during, and after drug use. Of the many signal molecules present in the brain sap, only one was specifically elevated: dopamine, the "pleasure chemical." Moreover, when the dopamine fibers were intentionally damaged in addicted rats, they stopped taking drugs. This showed that it was the brain's own dopamine -- activated by the cocaine -- that was stimulating the rats.
The addicted rats illustrate how pointless it is to argue about whether drug addiction is environmental or genetic, a social disease or a medical problem. Obviously, their drug use was 100 percent environmental: cocaine is not produced by the body; it has to be ingested. If the rats hadn't been exposed by drug-pushing scientists, they never would have become hooked. On the other hand, once the rats had their first taste of cocaine, they became physiologically and biologically driven to keep using it. The need for cocaine became as strong, and finally stronger, than the need for food. It wasn't the scientists who kept the rats hooked; the rats were betrayed by their own brains. The rats didn't live in especially bad neighborhoods, they weren't abused as babies, they weren't members of an oppressed minority, they weren't depressed about being unemployed. The rats became drug addicts because the drugs rewired their brains.
Human brains work the same way.
--Living With Our Genes, pg 136 to 138
Coolidge Effect
President Calvin Coolidge is not usually though of as a major contributor to sexuality research. Nevertheless his name is associated with an important phenomenon. The story is that Coolidge and his wife were inspecting a government farm. While the president was off somewhere, Mrs. Coolidge observed a rooster with a hen in the chicken coop. "How often does he do that?" she asked. "Dozens of times a day," said the guide. "Please mention this fact to the president," said Mrs. Coolidge. Later, when the president passed the chicken coop, he was told of the roosters' prowess. "Always with the same hen?" the president asked. "Oh no, a different one each time," said the guide. The president said, "Please tell that to Mrs. Coolidge."
The Coolidge Effect is the interest of males in a variety of sexual partners, and it is well documented in humans. According to Sex in America: A Definitive Survey, a large and careful study from the University of Chigaco, the typical American male has six sexual partners over a lifetime, while a woman has two. Those numbers are mathematically impossible, unless there is a hidden minority of women who sleep with many men, but they certainly reflect what men would like to be true.
--Living With Our Genes, pg 176 to 177
The traditional way of measuring orientation is the "Kinsey Scale," [...]. The Kinsey scale is a yardstick from 0, for exclusive heterosexuality, to 6 for exclusive homosexuality. The numbers in between represent various degrees of bisexual behaviour and fantasy. Probably the best way to measure sexual orientation [...] is to measure at least four different things: attraction, fantasy, behaviour, and self-identification. A person's total score is the average of the four areas. So a man who
has slept only with women but admits to occasional fantasies about men would score between 0 and 1 overall.
--Living With Our Genes, pg 183
Measuring Intelligence
The discoveries of the role of specific genes in long-term memory and map making were possible because scientists were able to come up with tests that isolated those particular types of thinking. The key to the experiments was to be able to measure very specific and narrow facets of cognition that could be recognized in experimental animals. For years, however, the most common measure of thinking in humans has been for the most complicated function of the the brain -- general intelligence -- and the measure of it the least specific -- the IQ test.
Long before neurobiology, or even before science, people recognized individual differences in intelligence. We have always measured each other for intelligence, and we have informally created our own standards. [...]
Coming up with a reliable, quantifiable measure of intelligence has been much harder. In fact, there isn't much scientific agreement on a definition of intelligence. Lewis Terman, the pioneer in intelligence research during the 1920s, called intelligence "the ability to think abstractly." David Weshler, who developed his own widely used intelligence test in 1944, defined it as "the capacity to understand the world and the resourcefullness to cope with its challenges." In 1982 Robert Sternber and William Salter called intelligence "a person's capacity for goal-oreinted adaptive behaviour."
None of these definitions is encompassing enough to include all the different forms of intelligence, nor specific enough to indicate what is and is not included. For example, the ability to slam on the car brakes is clearly goal-oriented adaptive behaviour, where the goal is to stay alive, but not what we normally think of as intelligence. Thus psychologists have fallen back on a purely operational definition of intelligence: intelligence is what's measure by an IQ test.
Intelligence tests were invented because the French school system was too crowded. The year was 1905 and the French government had just made education compulsory for all children. As a result the classrooms were overflowing. Teacher were, in many cases for the first time, encountering children who weren't capable of keeping up with the standard curriculum. The government wanted to set up special classes to help these children, but no one was sure how to identify them objectively.
The answer came from Alfred Binet, the leading French psychologist of his era. Binet and his collaborator, Theophile Simon, devised a test to sort out the children of average intelligence from those below normal, which became the predecessor of modern IQ tests. The test consisted of 30 questions in order of increasing difficutly. For example, an easy question was to point to the nose, eyes, and mouth; and intermediate question was to name four colors; and a difficult question was to make sense of a jumbled sentence. Binet reasoned that all children follow a similar path of intellectual development but some progress slower than others; i.e., they are "retarded." Thus, but comparing a child's test score to his or her chronological age, teachers could determine the child's ability to profit from the standard curriculum or from special education. The simple test did prove to be a reliable predictor of a child's success in the French school system.
A few years later, the German psychologist L. Wilhelm Stern formalized Binet's concept of mental age into the "intelligence quotient," or IQ, which is simply the ratio of mental age to chronological age multiplied by 100. The formula is designed to give an average IQ of 100 for the population at large. For example, a five year old who performs as well as an average seven year old has an IQ of 140, while a ten year old who can only answer the same number of questions as most eight year olds has an IQ of 80. Because intellectual development does not proceed indefinitely, IQ tests for adults use broad age groups rather than exact chronological age. Since then many different IQ tests have been developed to measure aptitude rather than actual achievement or learning. The tests emphasize abstract thinking, such as comparing the areas of two geometric figures, rather than specific knowledge such as knowing a particular equation.
It's clear that different people have different types of mental abilities. [...] But it's also clear that people who are particularly bright tend to be good at many different types of mental activities, while less bright people rarely excel at any. IQ tests reflect this diversity of skills by asking different types of of questions. When the scores from thousand of IQ test are analyzed, two results emerge. First, there is a cognitive ability factor, called the "g-factor" or simply g, which cuts across all the different types of intelligence measure by an IQ test. People who are high on g tend to do well on all aspects of the test, while those who are low on g do not fare as well across the board. Second, there are specific areas of mental expertise that are partially but not completely distinct, such as word fluency, numerical calculation, spatial visualization, memory, and so on. So overall intelligence depends on a combination of general ability (g) and specific expertise.
Although the significance and usefulness of IQ tests are passionately debated, one point should not be lost: IQ tests do what they were originally intended to do, they predict a person's ability to perform in school. In study after study, IQ is the single best predictor of school performance. Although many other factors, such as socio- economic status and parental occupation play some role, there is no better predictor of a child's grades or how far he will proceed in his education. Nor
should this be surprising since much of education advancement depends exactly on the sort of skills measured by IQ tests. To a certain extent, IQ tests are simply measuring the ability to take tests.
--Living With Our Genes, pg 213 to 217
Obviously IQ tests cannot measure the full range of human intelligence; it's hard to imagine any test that could. They are also culturally biased; even the smartest English speaker is going to fail an IQ test in Chinese. Cultural bias is not as evil as some critics suggest, however, because one measurement of intelligence is the ability to understand and adapt to the environment, including culture, there have been criticisms that IQ tests are prejudicial and that it would be unfair to ask a
city resident questions about farming or to quiz an American about the Chinese language. The well-designed tests, however, do not measure the accumulations of facts but the ability to think, and the tests themselve are constantly being evaluated and used on different cultures and in different languages. Nor are IQ tests a measure of a person's worth, but then they were never intended to be. Despite the objections and the limitations, the tests do measure something that relates to different
types of mental ability, that has real-life consequences, adn that differs in a cohesive way from one person to another.
--Living With Our Genes, pg 217
. . . it is these experiments designed and carried out by behavioural geneticists that provide the best evidence for the environment's role in IQ. When social minded psychologists have tried to measure the effects of the environment without controlling for genetics, such as by comparing test scores with the number of books per household, they have never been able to conclusively prove that environment plays any role at all.
The experiments do not, however, what what about the environment matters. Some of the best evidence comes, sadly, from orphanages where children received little human contact or stimulation. The classic experiment of this type was started in the 1930's by H.M. Skeels, who studied children in an Iowa orphanage who had been classed as mentally retarded and were receiving almost no human attention. Thirteen of these children were moved into a separate institution and placed in the care of
foster mothers who spent much of their time nurtuting the children. Within just four years these children had gained an average of 30 IQ points, a remarkable increase, whereas 12 other children who remained in the orphanage lost 20 IQ points. Twenty years later the differences remained. Most of the children who received individual care graduated from high school and became self-sufficient, whereas most of those who grew up in the orphanage were either still institutionalized or not
self-supporting. What's really amazing is that the children who were moved were placed in an institution for mentally retarded adults; the foster mothers were themselves mentally retarded. So, it's not necessary to be a genius to help a child's mental development. What is important is love and human contact.
--Living With Our Genes, pg 220 to 221
The connection between genes, environment, and IQ has become enmeshed in one of the bitterest scientific feuds of our times: the role of race in intelligence. In the United States, Asians as a group score about 3 IQ points higher than whites, who in turn score about 15 points higher on average than blacks. What's controversial is not that such group differences exist, but what they mean.
First of all, it's important to emphasize that these are only average differences. There is a great deal of overlap between the groups, and all the races show the same broad range of IQ scores. For example there are as many Asians who score lower than the average white or black, and many African Americans who score higher than most whites and Asians. This means that knowing a person's race is not a good predictor of his or her IQ. There are also regional differences in IQ scores, and for that matter in ability to play basketball -- but that doesn't mean you can judge how smart a person is, or how good a free throw shooter, by asking what state he's from.
Nevertheless, there is still the puzzling issue of a substantial point spread in average IQ values. One theory is that the difference is genetics. This theory was most recently brought to national attention, and intense emotional reaction, by the 1994 book The Bell Curve by Charles Murray and Richard Hernsteing. They began with two facts: individual differences in IQ scores are substantially heritable and race is heritable. From there, they deduced that racial differences in IQ scores must also be genetic.
Their argument is fundamentally unsound because it confuses individual differences, which is what twin studies and other genetics methods measure, and group differences, which can't be addressed by those methods.
--Living With Our Genes, pg 223 to 224
Direct evidence for the importance of environment to racial differences in IQ comes from an adoption experiment described by Sandra Scarr and Richard Weinberg in the 1970's. They studied 99 African American children who were adopted from poor black households into white middle-class households in Minneapolis. The average IQ of these adopted children was 106, which was highter not only than the average black IQ but also than the average white IQ. The researchers estimated that being brought up in a relatively privileged environment contributed about 16 points to the IQ scores -- just about the size of the difference between average IQ scores for whites and blacks in the United States.
Racial mythology is such a powerful force that it may itself push down IQ scores. Claude Steele and Joshua Aaronson administered a difficult verbal test to black and white students at Stanford University. They told some of the subjects that they were taking a test of intellectual ability, thus presenting the black students with the threat of fulfilling the stereotype about race and intelligence. The other students were told that the test was simply a laboratory problem- solving task that
had nothing to do with with intelligence, thus making the racial stereotype irrelevant. For the white students it made no difference what type of test they were taking. But for the black students, merely the idea that the were taking an intelligence test lowered their scores by more than 25 percent -- a margin even larger than the black-white difference in IQ scores. As Steele and Aronson comment, "Compared to viewing the problem of Black under- achievement as rooted in something about the
group or its societal conditions, this analysis uncovers a social psychological predicament of race, rife in the standardized testing condition, that is amenable to change . . . "
--Living With Our Genes, pg 225 to 226
Part of the reason that The Bell Curve was so controversial is that if IQ is genetically fixed at birth, why should society bother with Head Start or other programs to help black children? If they aren't going to get smarter, why throw good money at bad genes?
This is another example of not understanding how genes work. A person's genes are entirely in place at conception, but they aren't all switched on. Humans are designed to develop slowly and cannot do so without the help of other people. Fetal development follows an orderly, predictable path, as does childhood. Milestones such as puberty must occur precisely on time or the child does not develop properly. Different genes are constantly dimming and brightening, switching on and off, and
responding to a changing environment. The genes that control the development of the brain, and thus IQ, are no exception. This is why the power of genes to shape IQ changes over time.
--Living With Our Genes, pg 226 to 227
The genetic influence on IQ increase with age through adulthood. Matthew McGue and colleagues have examined data from a large number of twin studies involving subjects between the ages of 11 and 88. As the twins progressed from adolescence to middle and old age, the heritability of IQ increased from about 50 percent to as high as 80 percent. Meanwhile the effect of the shared environment dropped from being very important to close to zero, which might be expected as the twins moved away from home, parents, and shared schools.
Thus, IQ develops dynamically, not statically. Environment is most important early on, while genes become most important as we mature. This finding was reinforced by the observation that the extent to which a child's future IQ score can be predicted from its present score increases over the same period. A likely interpretation is that the environment for infants and young children is almost completely provided by their family, while as people mature they become more responsible for creating
their own environment. For example, how much a child is read to is determined by its parents, but how much an adult reads depends only himself or herself. There is an early window when much can be done to maximize IQ, but that window closes with time.
--Living With Our Genes, pg 227 to 228
Finding genes for retardation, language disorders, or reading problems likely will be easier than finding genes for overall genetic in average people. Robert Plomin, one of the leaders in the field of behavioural genetics, has begun an ambitious project to collect DNA samples from a large number of children, ranging from genius to somewhat below average. He plans to test the sample with a series of genes likely to have soemthing to do with neural functioning. Although Plomin's experiment is
well designed, it success will depend on something that isn't yet well known: the genetic architecture of IQ. While we know that IQ is substantially heritable, we don't know how many genes are involved. For example, if IQ is 50 percent heritable and there are 10 major genes, then each gene would have a 5 percent effect, not huge, but detectable using a few hundred subjects. But if there are 100 or 1,000 genes, then each would account for only 0.5 to 0.05 percent of the difference from one
person to the next, an effect so small that it would be difficult to detect and understand even using thousands of subjects.
--Living With Our Genes, pg 234 to 235
We spend our lives thinking about aging, but how we regard the process depends upon our place along the time line. Children count the weeks until their birthdays, and young people can't wait until they are old enough to drive, or drink, or stay out late. In our twenties we are invincible and oblivious to passing years, until the thirtieth birthday. Women, especially, hear the loud ticking of biological clocks as their reproductive years come to an end. Middle age sneaks up on us as we
continue to push ahead our idea of what constitutes "old." We compare our acheivements to those of other people until one day we realize that there are a lot of people who are younger and more successful. Priorities change, our bodies make more demands, and at some point memories of the past outnumber plans for the future. Suddenly we are old. And then we die.
--Living With Our Genes, pg 273
The best estimate of how strong a genetic role there is in longevity comes from a twin study. In a group of 2,872 Danish twin pairs born between 1870 and 1900, the age of death was closer for identical twins than for fraternal twins, showing a genetic effect. But it was not a terribly strong effect: the heritability of longevity was estimated to be at 26 percent in males and 23 percent in females. Most of the variance in how long people lived was explained by those seemingly random factors unique to the individual and not shared within the family. Even that moderate heritability of & is probably spread out among many, many different genes. By one estimate, 70 percent of the 100,000 or so human genes have an influence on life span. That would make 70,000 "aging genes," far too many to study conveniently, especially since there has been so little raw data -- only a few generations of people -- generated since the science of genetics began.
Not everyone has been put off by the difficulty of finding genes for aging. In 1976, when Michael R. Rose was a graduate student in genetic at the University of Sussex in England, he started his "family" in a few milk bottles. He filled the glass bottoms with nutrients and inhabited them with 200 fertilized female fruit flies. After five weeks, the flies were at the end of their reproductive "years." Rose colled the eggs from those few were still healthy and fertile, and bred a new generation. He waited five more weeks and again took the eggs from the oldest breeding flies. He kept repeating the process, each time selecting the progeny only of the longest lived flies. Just as he's hoped, at each new generation the selected flies lived a tiny bit longer than their ancestors.
Today, Rose is the proud father of a million flies, and they are still breeding, each time being selected for longevity. Rose now has 50 research assistants to help him with project at the University of Irvine in California. The amazing thing is that the current generations of flies are living twice as long as the founding flies, and they keep living longer. If these were humans they'd be living to 140 years old. Rose calls his 120-day wonders, "Methuselah flies."
--Living With Our
Genes, pg 276-277
Currently, most mental health experts analyze personality using very unsophisticated tools: their eyes and ears. They listen to patients, compare their symptoms with those of recognized syndromes, and make a "diagnosis." Only it isn't a diagnosis at all because it doesn't say anything about the underlying mechanism or origins of the problem. It's just a description: a matching of the patient's complaints to complaints that other people have described.
In the future, a person who complains of depression or anxiety could have a DNA test to check the serotonin genes. People with compulsive behaviour such as gambling, drinking, drugs, or promiscuous sex, would be checked for dopamine genes. Eating disorder or obesity? Look at the genes for leptin, the leptin receptor, and its targets. A new technology calle DNA chips, under development by a biotech firm called Afymatrix, will make an entire DNA blueprint as easy to read as a supermarket bar code.
Doctors won't be the only ones to read this information. Insurance companies, which profit by charging based on risk factors such as smoking, would be very interested in genetic predispositions toward addiction or mental disorders. The military, which today rejects people who took medication as teenagers to control attention deficit disorder, might want to know about genes for rebelious temperament. Employers might be interested in genes for loyalty. Religious orders would be wise to discourage high novelty seekers, while the maker of sports cars would want to target them with ads. Dating services would have revealing new ways to match people. Imagine how excited certain school administrations would be to track students who are bright, troubled, or aggressive.
We will have all new ways to understand people -- and to label them, discriminate against them, or help them. The technology is coming; how to use it is up to us.
--Living With Our Genes, pg 302-303
The problem with germline therapy is that it targets genetic "problems" before they have manifested themselves. If left alone, traits that could be regarded as problems might never develop, or they could turn out to be assets. If it's true that there is a fine line between genius and madness, or between creativity and depression, then we should be careful what we engineer for because we just might get it. A DNA map is not a road map, which shows exactly how to get from one place to the
next. A DNA map offers possibilities and predictions but not certainty.
--Living With Our Genes, pg 308
The uncertainty principle also includes unintended consequences. Even if we know exactly what a gene is for, say baldness, that doesn't mean that neutralizing the gene will cure baldness. Even if it did cure baldness, the gene might also be involved in vision or smell of some other function that we could never have imagined. Consider, for example, what happened when scientists used gene surgery to improve the muscle mass in mice, research that could be of great benefit to people suffering from muscle disorders.
A gene called myostatin controls muscle growth. When the body has a normal amount of muscle, the myostatin prevents the muscle cells from growing any further. Scientists easily knocked out the gene and bred a strain of mice without myostatin, who therefore had no block on muscle production. By six weeks, the mice had developed unusually big shoulders and hips. When they were full grown, their skeletal muscles were two to three times larger than normal mice. Other types of muscle, such as in the heart and intestines, were not changed. The speculated that this type of gene therapy could be used to make leaner, meatier farm animals. Some day it could also be used on humans to treat the loss of muscle that occurs in muscular dystrophy and in some types of cancer and in AIDS.
But there was another totally unexpected result: the muscular mice were wimps, what the scientists politely refered to as "gentler." The big mice were less eager to attack other mice and less likely to react when poked or prodded by human handlers. When Alexandra McPherron, one of the scientists at John Hopkins University who developed the new strain, presented the mice to the world at a new conference, the mice started fighting. McPherron commented matter-of-factly, "The normal one there is beating up the big muscular one."
No one expected a personality change. The only effect on the mice was supposed to be in muscle mass, not in the brain. Everybody thought they knew exactly how mycostatin works on muscle growth, but the gene must have some other still unknown role. Or perhaps taking out that gene changed the expression of another gene, or a hormone, or something else in the body that altered personality. There could be 10,000 steps between muscle mass and a passive personality, but when step 1 is removed
the entire developmental process shifts.
--Living With Our Genes, pg 308 to 309
So what about free will? It's alive and well, and probably genetic. Free will means taking control of your life. This is only possible when you understand who you are. As humans, we are born with instincts to survive, to love, to reproduce. As individuals we are born unique, each of us a variation on the human theme. Genes play an essential role in the overall theme and the individual variations; genes make us human and they make us unique. People cannot be mass produced, even if we
tried. Every individual has too many choices and too many possibilities to ever predict the future. You are born with pen and paper in hand, but you have to write your own story.
--Living With Our Genes, pg 314
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Date: 11-28-98
From: DEADEYE
To: THE AVANTE GUARDIAN
Subj: QUEBEC Language WARS
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De> But seriously, the same Darwinian losing-game is being willingly
De> played by the Anglo population that is remaining to "stand firm"
De> for their linguistic rights: they are being forced to inbreed as
De> well.
TAG> a point of some validity where perhaps the bottom line in
TAG> militaristic terms is that even were the entire anglo population
TAG> in Quebec to implode, there would still be an outside pool from
TAG> which to revitalize the numbers.
While it's fun to bandy Darwinism about as if we were geneticists, (apologies to any of us that *are*) I think it's wrong to make assumptions about the numbers required to ensure viability of a population group. I seem to recall reading that mere tens of thousands, not millions, are all that is necessary to provide genetic variety. The concept that the more the better is correct, but I feel fairly certain that 6 million Québecois are more than sufficient to survive adequately.
Not to mention the recent variants of evolution that have been proposed which suggest that the "dead" or dormant sections of the DNA strand are there for a purpose: the paper the other day mentioned experiments with Drosophila that produced radical mutations merely by mimicking catastrophic environmental changes. "Nature" tried a variety of random metamorphoses in a rapid (much more so than Darwin would have conceived: Stephen Jay Gould must have been elated!) attempt to create an adapted, survivable specimen to counter sudden and extreme attacks by an "environment" gone berserk. Wing shape, size, as well as other organ variants, appeared just as readily as if chemically or radioactively caused.
This brings about the re-examining of the absolute necessity of outside sources of genetically infused diversity, as suggested by Darwin. It would seem that each strand in *every* member of the human species contains backup, emergency supplies of redundant code, ready to enter into the reproductive fray should the going get tough. And some of these codes contain "branches" from up the tree going back to the roots of our evolution. Explains the occasional animal-limbed baby, such as the cloven-hoofed or equine-eared child.
So the French "harming" themselves genetically by isolating themselves overly much, while theoretically sound, is a somewhat exagerated statement. They would probably do fine, or at least as well as other, smaller groups (South American, African, Indonesian etc...tribes) that aren't considered genetically at risk mostly by virtue of their existence not bearing a particularly political stamp.
In any case, I feel the French in Québec are deluding themselves if they think they are any purer-"lained" than other population groups. The nature of the "racial purity" argument is ludicrous at best.
Taking only one case as example (albeit a *choice* case, if I do say so myself!) let us consider some of the implications of the coming ashore of the Normands at Hastings in 1066, which are not to be found in any history texts which *I've* read!
To recap, the almighty British Empire, which Francophones won't let their Anglo neighbours forget, (and cite as source of so much of their troubles) was as yet merely a distant dust mote on the horizons of the English Channel. And it's advent was about to be delayed by some considerable time: the Normands vanquished the Anglo-Saxon inhabitants and submitted them to 200 hundred years of occupation.
Some may remember that in feudal times, the nobility exercised a happy (for them) little prerogative entitled "Droit du Seigneur"...
[...]
...sometimes also referred to as the "Droit de Cuissage," or the right to be the first to "splay the thighs." (while British women are sometimes derogatorily referred to as "Birds," this would inply a wish"bone" of an entirely different nature!) This allowed for the nobility's enjoying not only young and clench-capable pudenda(dums?), at a reduced rate of venereal nastiness given the (supposed) inexperience of said maidens, but also disseminated the noble semen in a prioritarily inseminational manner. (Whewww!)
And this went on for TWO HUNDRED YEARS! Add to that the newly "discovered" fact by science that monogamy is unnatural, not only for we humans, but even for those much-admired-&-used-as-examples-by-moral-arbiters-to-disuade-the-faithful-from-jumping-the-fence birds that "mate for life." So even the non-"seigneured" Brit-birds musta been doin' the horizontal Bour%eacute;e, Gigue, Menuet and Gavotte *once* in a while. (not to mention the occasional Passepied & Saraband‚!...er, Sarabande) And versa-vice by all those strapping Anglo-Saxon stable-boys and chimney-reamers...sweepers ...er, SWEEPS!...on the Mademoiselles of the occupying forces. And all in a time when contraception consisted mainly of the phrase
"Have no fear, my dear, for I am a man of impecable timing, great restraint and moral virtue, and will 'retir‚' as soon as...ooOOOPS!"
So, any claim of lineage extending back to such-and-such a time by either assemblage of descendants is bound to be met with derision, suspicion, and a healthy dose of smirkin' in one's bodkin!
Other waves of conquest surely resulted in similar, if smaller-scaled, adulteration of pedigrees by rampant rape & pillage (notice how the phrase is "rape & pillage," NOT "pillage & rape": indicating what was foremost in the minds of the conquerors) over the rest of Europe and elsewhere.
Therefore the French-Canadian is a mish-mash of genetic sources just as much as all the rest of the planet's denizens. If they want to play the purity card, they had best look South, (the American South) and observe the almighty stench that will ensue as Southern whites are more and more frequently genotyped, (usually for medical reasons) and it turns out the black slaves must'a come in from the cotton fields at least SOME of the time!
Of course, that is still no reason to isolate themselves unnecessarily, because the vital bit of emergency DNA might reside in anyone, anywhere, and mixing more rather than less remains a sound strategy for the survival of the species as a whole.
The problem is that ALL isolationists (Québecois, Bosnian, Palestinian, you name it) percieve the mixing as a dilution rather than an augmentation.
More fool they.
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