On the Relative Contributions of Nature and Nurture to Average Group Differences in Intelligence

Abstract

By combining this relation with equation (1) and remembering the equality of N, and Ne, we obtain (2 + x) (1 + x)-'= (m/m) X e2/(h c). (7)The empirical value of the right-hand side is 2.13 and the solution of equation (7) is a value of x slightly above unity. It would just be equal to one if we could put the right-hand side of equation (7) equal to 2.12, thus diminishing its empirical value by half a per cent.Thus, if the equations derived by Eddington and by Sitte and Glaser hold, we arrive at the conclusion that in the state of equilibrium the number of neutrons nearly equals the number of protons. On the other hand, a relation, first pointed out by the author,4 which connects purely atomic constants and which is fulfilled to within an error of about half a per cent, i.e., mp/mX e2/(h c) = 3/ V (8) may be derived from the formulae of Eddington and Sitte and Glaser by assuming the equality of the numbers of neutrons and protons in the equilibrium state. ' A. S. Eddington, Proc. Roy.It has become a more or less accepted commonplace that environmental differences, although having a demonstrable influence upon individual differences in IQ, are less potent than natural differences under the conditions ordinarily met in our urban culture. No wholly satisfactory quantitative estimate of the relative r6les of nature and nurture has yet been possible, but various estimates agree in placing the contribution of nurture under per cent, and probably considerably under. (See references 1 to 5.)* 276 PROC. N. A. S.

The Wilson Effect: The Increase in Heritability of IQ With Age

“…6. Other contemporary adoption studies (Petrill & Deater-Deckard, 2004;Plug & Vijverberg, 2003;Scarr, 1997;Scarr & Weinberg, 1978) as well as much older ones (Burks, 1928(Burks, , 1938Leahy, 1935). For a detailed discussion of these and other earlier studies, see Bouchard (1993), , and Bouchard and Segal (1985).…”

“…The Colorado Adoption Project (CAP), a longitudinal study of adoptive and biological families (Plomin et al, 1997). Other contemporary adoption studies (Petrill & Deater-Deckard, 2004; Plug & Vijverberg, 2003; Scarr, 1997; Scarr & Weinberg, 1978) as well as much older ones (Burks, 1928, 1938; Leahy, 1935). For a detailed discussion of these and other earlier studies, see Bouchard (1993), Bouchard et al (1996), and Bouchard and Segal (1985).…”

Heredity vs. Environment: The Effects of Genetic Variation With Age

“…It was Burks (1938) who first realised the significance of Leahy's data and, reclassifying her own data (1928a) in the same way as Leahy had done, she obtained somewhat similar results.…”

Fitting Problems: Evaluating Model Fit in Behavior Genetic Models

“…Such designs have been used to understand the genetic and environmental influences on virtually every construct on which people vary (Polderman et al, 2015). These individual constructs can range from the benign, such as height (Holzinger, 1929;Rodgers et al, 2019;Silventoinen et al, 2003) to potentially controversial, including intelligence, educational attainment, and economic success (Burks, 1938;Burt, 1966;Hernstein & Murray, 1994;Jensen, 1969;Murray, 1998;Thorndike, 1905). Researchers have used a variety of kinship groups in their biometrical comparisons, ranging from twins (Galton, 1876), different types of siblings (Thorndike, 1905), cousins (Fisher, 1919), and adoptees (Snygg, 1938); this review will focus on twin studies because they are the most popular within this discipline.…”