Dysgenics

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Dysgenics (also Cacogenics) is a term describing the progressive evolutionary weakening or genetic deterioration of a population of organisms relative to their environment, often due to relaxation of natural selection or the occurrence of negative selection.

On the basis of numerous studies carried out over the past few decades, genotypic IQ is estimated to be declining at a rate between 0.57 and 0.9 points per generation throughout the United States. During this time, phenotypic IQ has been rising due to the Flynn effect. The concept appears occasionally in fiction and the popular media.


Contents

Intelligence and Fertility

The scientific community has focused most on declining intelligence throughout the first world; demographic studies indicate that, in affluent nations, women with higher IQs and better education have much lower reproductive rates than women with lower IQs and less education. Because IQ and education are both known to have high additive heritability,[1][2] these reproductive trends have led to concern regarding the future of intelligence in these nations.

Early Research

Some of the first studies into the subject were carried out on individuals living before the advent of IQ testing, in the late 19th century; researchers checked for dysgenic trends by looking at the fertility of men listed in WHO's WHO, these individuals being presumably of high intelligence. These men, taken as a whole, had few children, implying the existence of a dysgenic trend.[3][4]

But more rigorous studies carried out on those alive during the Second World War returned more optimistic results suggesting a slight eugenic trend, or at least the absence of dysgenics with respect to intelligence. The findings from these investigations were consistent enough for Osborn and Bajema, writing as late as 1972, to conclude that fertility patterns were eugenic, and that "the reproductive trend toward an increase in the frequency of genes associated with higher IQ... will probably continue in the foreseeable future in the United States and will be found also in other industrial welfare-state democracies."[5] But reviewers considered the findings premature,[6][7] claiming that the samples were nationally unrepresentative, generally being confined to whites born between 1910 and 1940 in the Great Lakes States. Other researchers also began to report a dysgenic decline in the 1960s after two decades of neutral or eugenic fertility. [8]

In 1982, Daniel Vining sought to address these issues in a large study on the fertility of over 10,000 individuals throughout the United States, who were then aged 25 to 34. The average fertility in his study was correlated at -0.86 with IQ for white women and -0.96 for black women, which Vining argued to indicate a drop in the genotypic average IQ of 1.6 points per generation for the white population, and 2.4 points per generation for the black population. [9] In considering these results along with those from earlier researchers, Vining wrote that "in periods of rising birth rates, persons with higher intelligence tend to have fertility equal to, if not exceeding, that of the population as a whole," but, "The recent decline in fertility thus seems to have restored the dysgenic trend observed for a comparable period of falling fertility between 1850 and 1940."

To address the concern that the fertility of this sample could not be considered complete, Vining carried out a follow-up study for the same sample 18 years later, reporting "the same negative relationship is found between IQ and fertility," although "the overall decline in mean IQ implied by these data is less".[10]

Later Research

Regardless of the methodology employed, later research has generally supported that of Vining.

In 1988 study, Retherford and Sewell found the now well known inverse relationship between IQ and fertility, noting that if children had, on average, the same IQ as their parents, IQ would decline by .81 points per generation. Taking .71 for the additive heritability of IQ as given by Jinks & Fulker,[11] they calculated a dysgenic decline of .57 IQ points per generation.[12]

In a 1999 study Richard Lynn examined the relationship between the intelligence of adults aged 40 and above and their numbers of children and their siblings. Data were collected from the 1994 National Opinion Research Center survey among a representative sample of 2992 English-speaking individuals aged 18 years. Findings revealed that correlations were found to be significantly negative at -0.05 and -0.09, respectively, indicating the presence of dysgenic fertility. Further analysis showed that dysgenic fertility was present only in females. The correlation for females between intelligence and ideal number of children was effectively zero, indicating that, if women had the number of children they consider ideal, dysgenic fertility would be reduced.[13]

In 2004 Richard Lynn and Marian Van Court attempted a straightforward replication of Vining's work. Their study returned similar results, with the genotypic decline measuring at 0.9 IQ points per generation for the total sample and 0.75 IQ points for whites only.[14]

Fertility and Education

Another way of checking the negative relationship between IQ and fertility is to consider the relationship which educational attainment has to fertility, since education is known to be a reasonable proxy for IQ, correlating with IQ at .55;[15] in a 1999 study examining the relationship between IQ and education in a large national sample, David Rowe and others found not only that achieved education had a high heritability (.68) and that half of the variance in education was explained by an underlying genetic component shared by IQ, education, and SES.[16] One study investigating fertility and education carried out in 1991 found that high school dropouts in America had the most children (2.5 on average), with high school graduates having fewer children, and college graduates having the fewest children (1.56 on average).[17]

Birth Control and Intelligence

Among a sample of women using a reliable form of birth control, success rates were related to IQ, with the percentages of high, medium and low IQ women having unwanted births during a three-year interval being 3%, 8% and 11%, respectively.[18] Another study found that after an unwanted pregnancy has occurred, higher IQ couples are more likely to obtain abortions [19]; and unmarried teenage girls who become pregnant are found to be more likely to carry their babies to term if they are doing poorly in school.[20] Conversely, while desired family size is apparently the same for women of all IQ levels,[21] highly educated women are found to be more likely to say that they desire more children than they have, indicating a "deficit fertility" in the highly intelligent.[22] In her review of reproductive trends in the United States, Van Court argues that "each factor - from initially employing some form of contraception, to successful implementation of the method, to termination of an accidental pregnancy when it occurs - involves selection against intelligence." [23]

International Research

Although most of the research into intelligence and fertility has been restricted to individuals within a single nation (most of them living within the United States), Steven Shatz has recently extended the research into dysgenics internationally; he finds that "There is a strong tendency for countries with lower national IQ scores to have higher fertility rates and for countries with higher national IQ scores to have lower fertility rates."[24]

The Flynn Effect

If it is true that the genes underlying IQ have been shifting, it is reasonable to expect that IQ throughout the population should also shift in the same direction, yet the reverse has occurred in recent decades, a phenomenon known as the Flynn effect. However, as pointed out by Retherford & Sewell, genotypic intelligence may fall even while phenotypic intelligence rises because of environmental effects (e.g. better schooling, nutrition, television, and so on).[25] The Flynn effect has increased IQ scores as much as 15 points throughout the first world, but some researchers claim that this trend now shows signs of reversal, which would be consistent with the reported dysgenic declines to IQ becoming visible when the environmental mask of the Flynn Effect is removed.[26] [27]

The Dysgenic Fallacy

While it seems obvious that differential fertility would result in a progressive change in IQ, Preston and Campbell have argued that it is a fallacy that applies only to closed subpopulations. They argue that as long as child IQ can be higher or lower than that of the parents, an equilibrium is established, and that in the case of endogamous mating in IQ subgroups, a differential fertility change of 2.5/1.5 to 1.5/2.5 (high IQ/low IQ), causes a maximum shift of four IQ points. For random mating, the shift is less than one IQ point.[28][29]

James S. Coleman however contends that Preston's and Campbell's model depends on assumptions which are unlikely to be true and argues that that their dismissal of the "common belief" in the case of IQ is unfounded.[30]

History of the term

According to the Oxford English Dictionary, the term "dysgenic" was first used as an adjective as early as 1915 by David Starr Jordan to describe the "dysgenic effect" of World War I. He believed that fit men were as likely to die from modern warfare as anyone else, and war was seen as killing off only the physically fit male members of the population while the disabled stayed safely at home.[31][32]

In the 1930s, Julian Huxley, who later became the first director of UNESCO, was concerned by dysgenics[33] and described eugenics as "of all outlets for altruism, that which is most comprehensive, and of longest range".[34]

During World War II the United States had difficulty training low-IQ military recruits; this led Congress to ban enlistment by those from the lowest 10 percent (an IQ below 80) of the population. [35]

In 1963, Weyl and Possony asserted that comparatively small differences in average intelligence can become very large differences in the very high I.Q. ranges. A decline in average psychometric intelligence of only a few points will mean a much smaller population of gifted individuals.[36]

In his 1965 article "Roman Culture and Dysgenic Lead Poisoning" Colum Gillfallen argued that lead used by Romans in plumbing and cooking utensils poisoned the water and food of the Roman elite, causing the decline of the Roman Empire.[37] In 1985, the Gillfallen paper was refuted by Needleman and Needleman. They agree that lead poisoning from cooking utensils was potentially hazardous. However, measurements of lead from bones of Romans and other peoples provide no evidence that the fertility of the Roman elite was adversely affected.[38][39]

The term fell out of use after eugenic thought lost popularity in the 1940s, and when used again by William Shockley (a Nobel laureate in the field of electronics) in his controversial advocacy of eugenics from the mid 1960's until the early 1990's; he and his theories were unfavorably portrayed in the press. [40]

Dysgenics: Genetic deterioration in modern populations is the title of a 1996 book by the psychologist Richard Lynn, in which he argues that intelligence in Western nations has been decreasing due to dysgenics and that China may overtake the West due to continued deterioration of intelligence in the Western nations, especially the USA. The book received several favorable reviews.[41][42]

Robert K. Graham in 1998 argued that genocide and class warfare, in cases ranging from the French Revolution to the present, have had a dysgenic effect through the killing of the more intelligent by the less intelligent, and "might well incline humanity toward a more primitive, more brutish level of evolutionary achievement."[43]

In fiction

Cyril M. Kornbluth's 1951 short story The Marching Morons is an example of dysgenic fiction, describing a man who accidentally ends up in the distant future to find out that dysgenics has resulted in mass stupidity. Mike Judge's 2006 film Idiocracy has the same premise, with the main character signing up for a military hibernation experiment that goes awry, taking him 500 years into the future. While in the short story civilization is kept afloat by a small group of dedicated geniuses, their role has been replaced by advanced automated systems in Idiocracy.[44][45]

See also

External Links

References

Cited

  1. ^ Rowe, David C. (1999). "Herrnstein's Syllogism: Genetic and Shared Environmental Influences on IQ, Education, and Income". Intelligence 26(4): 405-423. 
  2. ^ Neisser et al., Ulric; Boodoo, Gwyneth; Bouchard, Thomas J. Jr.; Boykin, A. Wayde, Brody, Nathan; Ceci, Stephen J.; Halpern, Diane F.; Loehlin, John C.; Perloff, Robert; Sternberg, Robert J.; Urbina, Suzanna (1996). "Intelligence: Knowns and Unknowns". American Psychologist 51(2): 77-101. 
  3. ^ Huntington, E., & Whitney, L. The Builders of America. New York: Morrow, 1927.
  4. ^ Kirk, Dudley. 'The fertility of a gifted group: A study of the number of children of men in WHO'S WHO.' In The Nature and Transmission of the Genetic and Cultural Characteristics of Human Populations. New York: Milbank Memorial Fund, 1957, pp.78-98.
  5. ^ Osborn, F. (1972). "The eugenic hypothesis". Social Biology 19: 337-345. 
  6. ^ Osborne, R. (1975). "Fertility, IQ and school achievement". Psychological Reports 37: 1067-1073. 
  7. ^ Cattell, R. B. (1974). "Differential fertility and normal selection for IQ: Some required conditions in their investigation". Social Biology 21: 168-177. 
  8. ^ Kirk D (1969). "The genetic implications of family planning". Journal of Medical Education 44 (supplement 2): 80-83. 
  9. ^ Vining Drj (1982). "On the possibility of the reemergence of a dysgenic trend with respect to intelligence in American fertility differentials". Intelligence 6 (3): 241–64. PMID 12265416. 
  10. ^ Vining, Daniel (1995). "On the possibility of the reemergence of a dysgenic trend with respect to intelligence in American fertility differentials: an update". Personality and Individual Differences 19 (2): 259–263. 
  11. ^ Jinks, J. L., & Fulker, D. W. (1970). Comparison of the biometrical, genetical, MAVA and classical approaches to the analysis of human behavior. Psychological Bulletin, 73, 311−349.
  12. ^ Retherford RD, Sewell WH (1988). "Intelligence and family size reconsidered" (PDF). Soc Biol 35 (1-2): 1–40. PMID 3217809. 
  13. ^ Lynn R (1999). "New evidence for dysgenic fertility for intelligence in the United States". Soc Biol 46 (1-2): 146–53. PMID 10842506. 
  14. ^ Lynn R (2004). "New evidence of dysgenic fertility for intelligence in the United States". Intelligence 32 (2): 193-201. ISSN 0160-2896. 
  15. ^ Neisser et al., Ulric; Boodoo, Gwyneth; Bouchard, Thomas J. Jr.; Boykin, A. Wayde, Brody, Nathan; Ceci, Stephen J.; Halpern, Diane F.; Loehlin, John C.; Perloff, Robert; Sternberg, Robert J.; Urbina, Suzanna (1996). "Intelligence: Knowns and Unknowns". American Psychologist 51(2): 77-101. 
  16. ^ Rowe, David C. (1999). "Herrnstein's Syllogism: Genetic and Shared Environmental Influences on IQ, Education, and Income". Intelligence 26(4): 405-423. 
  17. ^ Bachu, Amara. 1991. Fertility of American Women: June 1990. U.S. Bureau of the Census. Current Population Report Series P-20, No. 454. Washington, D.C.: Government Printing Office.
  18. ^ Urdry, Richard (1978). "Differential fertility by intelligence: the role of birth planning". Social Biology 25: 10-14. 
  19. ^ Cohen, Joel (1971). "Legal abortions, socioeconomic status and measured intelligence in the United States". Social Biology 18(1): 55-63. 
  20. ^ Olson, Lucy (1980). "Social and psychological correlates of pregnancy resolution among adolescent women: a review". American Journal of Orthopsychiatry 50(3): 432-445. 
  21. ^ Vining, Daniel (1982). "On the possibility of the reemergence of a dysgenic trend with respect to intelligence in American fertility differentials". Intelligence 6 (3): 241-264. 
  22. ^ Weller, Robert H. (1974). "Excess and deficit fertility in the United States". Social Biology 21 (l): 77-87. 
  23. ^ Van Court, Marian (1983). "Unwanted Births And Dysgenic Reproduction In The United States". Eugenics Bulletin. 
  24. ^ Shatz, Steven (2008). "{{{title}}}". Intelligence 36 (2): 109-111. 
  25. ^ Retherford, R. D., & Sewell, W. H. (1988). "Intelligence and family size reconsidered." Social Biology, 35, 1−40.
  26. ^ Teasdale, Thomas; Owen, David R. (2008). "Secular declines in cognitive test scores: A reversal of the Flynn Effect". Intelligence 36 (2). 
  27. ^ Lynn, Richard (2008). "The decline of the world's IQ". Intelligence 36 (2). 
  28. ^ Preston SH, Campbell C (March 1993). "Differential Fertility and the Distribution of Traits: The Case of IQ" (fee required). The American Journal of Sociology 98 (5): 997–1019. Retrieved on 2008-04-22. 
  29. ^ Lam D, Campbell C (March 1993). "Comment on Preston and Campbell's "Differential Fertility and the Distribution of Traits"" (fee required). The American Journal of Sociology 98 (5): 1033–1039. Retrieved on 2008-04-22. 
  30. ^ Coleman JS (1993). "Comment on Preston and Campbell's 'Differential Fertility and the Distribution of Traits'" (fee required). The American Journal of Sociology 98 (5). 
  31. ^ Jordan, David Starr (2003 (Reprint)). War and the Breed: The Relation of War to the Downfall of Nations. Honolulu, Hawaii: University Press of the Pacific. ISBN 1-4102-0900-8. 
  32. ^ McNish, Ian "David Starr Jordan on the Dysgenic effects of dysfunctional culture," Mankind Quarterly. Washington: Fall 2002.Vol.43, Iss. 1; pg. 81
  33. ^ Huxley, Julian (1936). "Eugenics and Society". Eugenics Review 28 (1): 24. Retrieved on 2007-09-25. 
  34. ^ Huxley, Julian (1936). "Eugenics and Society". Eugenics Review 28 (1): 11. Retrieved on 2007-09-25. 
  35. ^ Gottfredson, Linda S.. "The General Intelligence Factor". Scientific American. Retrieved on 2008-06-12. 
  36. ^ Weyl, N. & Possony, S. T: The Geography of Intellect, 1963, s. 154
  37. ^ Gillfallen, S. Colum (1965, Jan-Mar). "Roman Culture and Dysgenic Lead Poisoning". The Mankind Quarterly 5 (3): pp. 131-148. ISSN 0025-2344. 
  38. ^ Needleman, Lionel; Diane Needleman (1985). "Lead Poisoning and the Decline of the Roman Aristocracy". Classical Views 4 (1): pp. 63-94. ISSN 0012-9356. 
  39. ^ Grout (October 10 2006). "Lead Poisoning and Rome". Encyclopaedia Romana. James. http://penelope.uchicago.edu/~grout/encyclopaedia_romana/wine/leadpoisoning.html. Retrieved on 2006-04-30. 
  40. ^ "William Shockley 1910 - 1989". A Science Odyssey People and Discoveries. PBS online. 1998. http://www.pbs.org/wgbh/aso/databank/entries/btshoc.html. Retrieved on 2006-11-13. 
  41. ^ Loehlin JC (1999). "Dysgenics: Genetic Deterioration in Modern Populations, reviewed by John C. Loehlin" (fee required). Annals of the American Academy of Political and Social Science. 
  42. ^ Vining DR (1998). "Dysgenics: Genetic Deterioration in Modern Populations, reviewed by Daniel R. Vining, Jr." (fee required). Population Studies. 
  43. ^ Graham, Robert K. "Devolution by revolution: Selective genocide ensuing from the French and Russian revolutions," Mankind Quarterly. Washington: Fall 1998.Vol.39, Iss. 1; pg. 71
  44. ^ Mitchell, Dan (2006-09-09). "Shying away from Degeneracy". The New York Times. http://www.nytimes.com/2006/09/09/business/09online.html. Retrieved on 2008-06-29. 
  45. ^ Sailer S (2006-10-06). "The Morons Shall Inherit the Earth". The American Conservative. http://www.isteve.com/Film_Idiocracy.htm. Retrieved on 2008-06-29. 

General

  • Thomas W. Teasdale and David R. Owen (2005). "A long-term rise and recent decline in intelligence test performance: The Flynn Effect in reverse." Personality and Individual Differences 39(4), pp 837–843.
  • Shockley on Eugenics and Race: The Application of Science to the Solution of Human Problems Scott-Townsend, 1992
  • Dysgenics Genetic Deterioration in Modern Populations, Richard Lynn, Praeger Publishers, 1996
  • Galor, Oded and Omer Moav: Natural selection and the origin of economic growth. Quarterly Review of Economics 117 (2002) 1133-1191. [1]
  • Hamilton, W. D. (2000) A review of Dysgenics: Genetic Deterioration in Modern Populations. Annals of Human Genetics 64 (4), 363-374. doi: 10.1046/ j.1469-1809.2000.6440363.[2]


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