• DOI:10.1038/381729B0
• Corpus ID: 4330072

The g factor

@article{Jensen1996TheGF,
  title={The g factor},
  author={Arthur Robert Jensen},
  journal={Nature},
  year={1996},
  volume={381},
  pages={729-729}
}

• A. Jensen
• Published 27 June 1996
• Education
• Nature

and general: a + b = b + a. All algebraic formulas and equations are decontextualized statements. Syllogisms can be decontextualized: Which statement (1 or 2) is false? (1) All Xs are Y; all Ys are Z; therefore all Xs are Z. (2) All Ps are Q; all Ns are Q; therefore all Ps are N. Now notice how much easier equivalent syllogisms seem when they are contextualized: (1) All men are persons; all persons are human; therefore all men are human. (2) All chickens are fowl; all ducks are fowl; therefore all chickens are ducks. A person who is unable to decontextualize a syllogism would most likely declare the following syllogism to be false, although in terms of pure logic (but not experience) it is true: All apples are fruit; all fruits are green; therefore all apples are green. Syllo­ gisms are no longer used in IQ tests, because syllogisms are uniformly easy for persons who solve them by using Venn diagrams. Since knowing or not knowing the ' 'trick'' of using a Venn diagram is the main determinant of passing or failing a syllogism, syllo­ gisms are poor items for an IQ test. Different persons with the same IQ differ much too markedly on "syllogism ability," a difference often attributable to their either having learned or not having learned the "trick" of using Venn diagrams for verifying syllo­ gisms. However, syllogisms would be suitable items in an achievement test, to determine whether a student had mastered the use of Venn diagrams after receiving instruction. 28. Lynn, 1987a, 1987b, 1989, 1990a, 1990b; Lynn & Pagliari, 1994. 29. Schoenthaler et al., 1991. A good, though far from comprehensive, article on the effects of nutrition on IQ (Ricciuti, 1994) offers a somewhat more conservative assess­ ment than the articles by Lynn and by Schoenthaler. Eysenck (1995) discusses the use of nutrients as a means of sudying intelligence differences experimentally. Eysenck and Schoenthaler (1997) provide the most recent and comprehensive review of experimental studies of the effects of nutrition on IQ. 30. Jensen (1997a) reviews much of the recent literature on the effects of the biological environmental factors (including mother-fetus immunogenic incompatibility factors) on mental development. Most of the environmental variance in IQ is attributable to the cumulative effect of such biological factors. Jensen (1996a) replies to an article by Flynn (in the same book) and summarizes the specific environmental factors hypothesized to play some part in the secular rise in IQ. 31. Modern mass-production poultry farms make use of this phenomenon, by keeping chicks under bright electric lighting twenty-four hours a day, to hasten their rate of growth and the time needed to reach their maximum egg-laying capacity. 32. (a) Lucas et al., 1992; (b) Ryan et al., 1991.