The ubiquity of g

THE

UBIQUITY CR,\&

Institute for Beh~~lorai

Genetics.

Biology

Laboratory.

T. N;\GOSHI

Campus Box 447. co 80309. U.S.;-\.

RONALD Behavioral

OF g

tinlversitb

of Colorado.

Boulder

C. JOHSSON

I I5

Snyder Hall. Universit) HI 96811. U.S.A.

of Hawaii.

Honolulu.

obtained the ,q-loading (unrotated tirst principal-component loading) of each oi the coemtiw ability measures used in the Hawaii Family Study of Cognition (HFSC) for each of the three mijor ethnic gioups (Amcrlcans of European ancestry (AEA). Americans of Japanese ancestry (AJ,A) and homeland Koreans) who took Dart in the HFSC. The degree to which given tests (corrected for reliability) loaded on g was highly correlated wth the association of cognitive t&t scores with the educational and vnerations. wth the degree of occupational attainments of members of both the parent and offsprin, 0 -_ resemblance of spouses and biological relatives, and with the degree to which parental education and occupation predicted otl’sprlng cognitive test performance. For AEA and AJA families ,y was not found to be related to degree of mean within-sibship skew for each cognitive test, but was posikvely correlated with the degree of‘hybrld bigor‘ manifested by otTspring ofcross-ethnic matings. The above results suggest that g. as opposed to the non-g components of intelligence. is more influenced by additive genetx factors. althoueh this is confounded by assortative mating for ,y, but provide only weak support for the hypothesis that y-is more intlurnced by directional genetic dominance. While the correlations were similar in directionality for all groups, they varied conslderably in magnitude. possibly because the groups differed substantially in rn\lronmentsl histories.

Summar)--We

INTRODUCTION

Jensen has presented a number of papers-only some of which will be discussed belou-on the relation of g or ‘general intelligence’ to various other aspects of individual differences. He has presented data suggesting that g (usually operationally defined by him as the degree to which a test loads on the unrotated first principal component in a principal-component or factor analysis of a battery of cognitive tests) is an important predictor of the degree to which a measure is predictive of occupational attainment (Jensen, 1984). He reanalyzed already published data and found a high positive correlation between the first principal-component loadings of the subtests of various cognitive ability test batteries and the degree of Black/White differences in performance on these subtests (Jensen, l983a, 3985b). He has also shown that the degree of inbreeding depression on various subscales of the WISC of offspring of cousin vs non-cousin marriage is positively and significantly related to the g-loadings of those subscales (Jensen, 1983a; see also Agrawal. Sinha and Jensen, 1984). Since the inbreeding depression of offspring of cousin marriage is comparatively slight (between 3 and 4 IQ points) for the WISC as a whole (Schull and Neel, 1965), g must be remarkably sensitive to the efTects of inbreedin, 0 to result in differences in the amount of depression across the subscales of the WISC. The fact that one can predict inbreeding depression from g-loadings suggests that g is more influenced by genetic dominance effects (often associated with ‘fitness’ characters) than is the non-g component of intelligence tests. Taken as a whole, the above evidence has been used by Jensen to support the construct validity of g (and the superiority of the construct over models of intelligence based on specific abilities), the importance of g for socioeconomic success, the strong genetic basis of g and ultimately the idea that g is the major fitness character that has been selected for (and continues to be selected for) throughout human evolutionary history. Based on his research on complex reaction time, Jensen has proposed a ‘neural oscillation‘ model as the physiological basis of g, “a more rapid rate of oscillation between refractory and excitatory phases of the neural processes resultin, 0 in a faster rate of information 201

procejjlng” tJen>en. 195-1. p. I IO). 1lorr recently. Jensen (198ia) has summarlrsd and e~aiuated a number of ditTer?nt theories on the psychometric and ph\siologic,ll bases of y. Jensen’s papers on y raisr‘ a set of qurstions M hich can be readilL tehted using th,- d,lta from the HaL\ail Farnil! Stud> of Cognition (HFSC) in bvhich families (biological parents plus one or more teen-aped or older offspring) Lvert’ tested on a battery of I5 tests of cosnitllc abilit>. The sample included members of the t\co largest racial, ethnic proups in Ha\\aii. .\mericans of European ancestry t.4E.4) and .Americans of Japanese ancestry (AJ.4). as u~ell as ;I sample of homeland Koreans. and Ss provided information on their educational and occupational attainments. Our first report using HFSC data to zct at questions related to 3~ had to do i\ith ethnic group ditTerenccs and Lvithin-ethnic group generational differences in cognitils test scores and the extent to brhich these diff-crences were related to the g-loadings of the cognitive tests (Xaposhi. Johnson, DeFries. Wilson and Vandenberg. 19841). Our ethnic group difierences \\ere not closely ;ljjoci;itsil \\,ith g-loadings. but our generational dityerences were. Lvith generation differences being greater on tests loading higher on ::. Generational differences obtained on the HFSC cognition battery have been found to be large and in opposite directions for AEA vs AJA and AC.4 (Americans of Chinese ancestry) families (DeFries, Corley, Johnson, Vandenberg and Wilson. 19SZ). IVhile other interpretations of our generational data are possible. the results strongly suggest that g is far more influenced by environmental change than the non-g components of intelligence tests, The present report is a further analysis of data from the HFSC to test the follo\+ing questions. (I) The extent to which the Ly-loadings of cognitive tests are predictive of the tests‘ association Lvith the educational and occupational attainments of the parents and offspring of the HFSC. This is a replication of some of Jensen’s ( 1984) analyses reported above. (7) The estent to which the g-loadings of cognitive tests are associated i\ith the degree of spouse resemblance on those tests. Eaves. Heath and Martin (19S1) have recently suggested that assortatiw mating for cognitive ability may be on the basis of a single general factor. This single factor may, in f:tct. simply be education, but education in turn ma! be mostly a function of ,y. (3) The estent to which the g-loadings of cognitive tests are associated with the degree of parent-offspring and sibling resemblance on those tests. Although such familial correlations rellect both additive genetic Lariancc and common family environment, the results of these analyses should be suggestive of the extent to which y is ditTerentially heritable (narrow sense) as compared to the non-g components of intelligence. It is still possible that ,y may bc more inlluencrd by additive genetic factors than non-g, even if Jensen’s (I 98%) findings on inbreedins depression are valid. since the degree of inbreeding depression is solely a function of degree of inbreeding and the summed effects of the eene frequencies and heterozygote deviations from the homoz>,zote midpoint for each locus involved (Falconer. 1981, p. 227). i.e. bvhen many loci are involved. degree of inbreeding depression does not give any direct information as to the relative amount of additive vs dominance genetic variation in a character. Jinks and Fulker (1970. p. 344) estimated from the Schull and Neel (I 965) inbreeding data that as many as 100 loci may demonstrate dominance elects for IQ. (J) The extent to which the g-loadings of cognitive tests are predictive of the association between performance on those tests. Although the parental education and occupation and offspring by correlation bet\veen parental education and occupation and offsprin g cognition is confounded parental cognition and its genetic bases, the results of these anal>,ses could be suggestive of the extent to which g is diffsrentially influenced by environmental fxtors as compared to the non-g components of intelligence. (5) The extent to which g-loadings on cognitive tests are associated bvith the degee of mean within-sibship ske\\, on those tests for families with data on three or more offsprin:. Such deviations from normality \vithin a sibship would be reflective of such non-additive effects as directional genetic dominance. directional epistasis, directional G x E interaction, or directional non-additive environmental influences (Fisher, Immer and Tedin. 1932; Jinks and Fulker. 1970). ‘4 significant negative correlation here would support Jensen’s hypothesis, based on his results for inbreeding depression, that ,q is a fitness character that has been more highly selected for in the past than non-g. with the absolute values of these Lvithin-sibship A significant positive correlation of g-loadings by these non-additi\,e factors than is non-g. skelvs would be indicati\.e that g is more influenced (6) The extent to which the g-loadings of cognitiw tests are associated lvith the degree of

heterosis or ‘hybrid vigor’ on those tests among offspring of cross-ethnic (XEA-XJ.4) matings when compared with the average scores of AEA and AJA offspring of vvithin-ethnic matings. This is the counterpart to Jensen‘s (1983a) analysis on inbreedin, 0 depression (the small coefficient of outbreeding represented by cross-ethnic matin, u is similar in magnitude to the small coethcient of inbreeding in the cousin matings studied by Jensen) and vvould also be indicative of the extent to which g is more influenced by directional genetic dominance than non-g. blETHOD Subjects

A total of 1816 families (658 I individuals) (both biological parents and their teen-aged or older offspring) took part in the HFSC [see DeFries. Johnson, Kuse. McClearn. Polovina. Vandenberg and Wilson (1979) and Wilson, DeFries. McClearn. Vandenber,. 0 Johnson, Mi and Rashad (1975) for descriptions of the HFSC] in Hawaii. The present report is limited to the two largest racial/ethnic groups tested in Hawaii. Americans of European ancestry (AEA; 926 families) and Americans of Japanese ancestry (AJA; 368 families). The HFSC battery was also translated into Korean and administered to 209 sets of Korean parents and their offspring in Korea (see Park, Johnson. DeFries. McClearn, Mi, Rashad, Vandenberg and Wilson, 1978. for a description of the Korean sample). Only one offspring was tested in nearly all of the Korean families and hence, we do not report analyses of sibling correlations or within-sibship skews for our Korean sample.

The fifteen tests that make up the HFSC cognition battery are listed in Table I, along with their g-loadings (loadings on the unrotated first principal component) and their coefficient r (Cronbach, 1951) reliabilities. As described in Nagoshi et al. (1984a) the g-loadings were highly congruent across all groups, so the y-loadings calculated for the entire sample were used in all analyses. One test, Social Perception, was administered to the Korean families in order to keep administration procedures constant, but was deemed to be too highly culturally loaded to be scored. As can be discerned in Table I, the reliabilities are generally quite high for all groups. The g-loadings of the various tests, as well as the various correlations, within-sibship skews and group differences involving those tests, were all corrected for test reliability before calculating the associations between the y-loadings and the test statistics (see Jensen, 1983b. 1985b; Nagoshi et al., 1984a).

Table

I. Cognitive

tests. g-loadmgs,

reliablli~lss.

wthln-rlbship

skew

and

‘hybrid

vigor

WIthIn-sib>hip Rehnblliry e-loading

Test Primary

,M+zn~l

Abilities

O.Xi

0 58

0.73

-1.17

- 2.26

0 56

0 74

071

-0.21

0.60

0 56

0 YY

0 92

-019

0.14

001

0.55

0.96

0 95

0.58

0.76

0.1 I

0.46

0.89

0 s9

0 51

- 0.20

0.63

0.71

0.79

0 16

-0.41

0.0-l

0.64

0.88

0 87

0 25

-0.93

0.06

0.30

0 62

0 76

-091

-0

0 O?

0.75

0.72

0 17

-016

-0.33

Patterns

0.69

0.92

091

-

I.25

-

Board

0 65

0.8-l

0 85

0 06

-

0.53

O.SI

0 38

0.65

0.69

0 7-l

0.86

(Immcdralt klenul

for and

Memory Pedigrees Hidden

ETS

Form

recall) lest)

of Social

Perceplmn

‘From

Johnson

scorr

marriages

-0

02

0 65 -0

-

33

3x

0.13

I.1x

0 23

I .-l2

0 14

0.40

0.38

I.?Y

0.23

0 x5

- I 09

-0

83

0.30

cr ul. (1975) r, rrl. (1977).

unstsndxrdized

.V = II3

0.07 -0.00

Matnccs.

iorm

Wilson

“[Mean

EndIngs

Comparrsons

‘From ‘(Mean

and

Pro_eressi\e

modified

0.22

(ET%

(a rrasonin_r

Test

0.21

dots’).

Serwce

(dclaycd

Number

Rawn’s

.tnd

RoMons

P!vlA

Whwman

by Vandenberg)

form TestinS

Visu;ll

Paper

(‘lines

0.05

Rotauons

(wing

Mulriphc~tion

Bqmninps

Card

ETS

group

Mnzcs

Word ETS

recall)

IN)

Sheppard-Metzlrr

shorenrd

wgoP

0.96

(a fluency

Educarional

Hybrid

AJ .A

AEA

0 34

Things

ElIthorn

,kw‘ Korean’

0.71

Memory

Subtracuon

AJA’

(PMA)

Vocabulary Vwal

(moddied

.AEA.

AEA

ullhln-slbship

fxml~cs.

of otTsprmg

31 AJA from

skew)

r\EA-AJ.4

(.V = 203311 in SD

(mean

ulthln-bIbshIp

SD’)

for

AEA

and

AJA

iamllw

havmg

dt Icat

3 otiaprxng

tested:

iamilw.

unlls.

mlned

marrqes

(,V = 6311 -

[man scox oi ofLprtng

from

wlhin-sthnlc

group

.AE.A and AJA

The correlations of c0gnitiL.c measures with .-1\E.4 ‘lnd .?.J.-\ educational .Ind occupLitional attainment [occupational att,llnment quuntltied using Duncan‘s Sutlonal Opinion Rsssarch Council (NORC) rating system (Reiss. Duncan. Hatt and Xorrh. 13hl )] for the HFSC parents arc from data analyzed as part of a report by Johnson. Xagoshi . .Ahern. L\‘ilbon. DeFries. \lcClearn and Vandenberg (1983~1). The comparable Korean data (occupational data for fLtthers oni). since bvomen rarely \\orked outside of the home in the pro\inclal capital \\hsrc testing took place) are from Johnson and Xagoshi C1385). The educational and occupational attalnmsnts of AE.4 and AJA HFSC ofi‘spring \vere obtained in a follow-up mail-out quzstionnalrz to HFSC families. with data obtained on 561 offspring. and are described in Naposhi. Sch\iittsrs. Johnson and .-Ihsrn (I9YJb) (anal>xs are limited to those 121 AE.4 and II2 .AJ,-\ otTspring 25 gr of age or older). Spouse correlations. parent--otTsprin, a correlations and sibling intraclass correlations for the .AE.A and AJ.A Ss are from DeFries et nl. (1979). Korean parent-child correlations are from Park ct (11. (1975). bvhile Korean spouse correlations are from Johnson. DeFries. Park. XClcCle,irn. hli. Rashad. L’andenbsrg and Wilson (1977). Correlations of parental educational and occupational attainment with offspring cognition are from Johnson and Saposhi (I 9SS). Mean within-sibship ske\vs for each cognitive test ivere calculated separately for the I I3 cIE.+I and 34 AJA families haking 3 or more tested offsprin, ~7bl calculating the mean unstandardized

then standardizing it by dicidin, ~7it bv the cube of the mean Lvithin-sibship standard dcbiation (Fisher CI (I/.. 1932). These mean within-sibship skews arc presented in Table i. Sixty-three HFSC offspring came from AEA~AJA cross-ethnic marriages. .-\lthough their father’s and mother’s mean NORC ratinps and years of education bvrsrc‘virtually identical to the average of all AEA and AJA father’s and mother’s NORC and education. the mean first principa-component score for these offspring ~~3s 0.26 SD above the mean first principalcomponent score of AEA and AJA of‘sprin g from Lvithin-ethnic marriages. sugpesting a ‘hybrid \.igor’ due to outbrerdin g effect. Differences [in SD units; see Jensen (1983b. 19Y5b) for the standardization procedure] bet\\,een the cross- and within-ethnic offspring groups for each of the cognitive tests are also presented in Table I.

RESULTS

The correlations between the g-loadings of the tests and the magnitudes of: (I) the correlations of the different tests M.ith educational attainment; (2) the correlations of the dItf_erent tests Lvith occupational attainment (NORC code); (3) spouse correlations on the tests; (4) parent otTspring correlations on the tests: (5) sibling intraclass correlations on the tests; (6) the correlations of of parental parental education with offspring performance on th e tests: and (7) the correlations NORC with off-spring performance on the tests are presented in Table 7. Given an effective ,V of only 13 (Korean) or IS (AEA and AJA) tests for these correlations. it is not surprising that they \‘ary considerably in magnitude. but it is notable that they are all positive, Lvith 35 of the 61 with the mean correlations reaching statistical significance. The correlations of g-loadings tvithin-sibship skews shown in Table I Lvere essentially zero (r = 0.05 for AEA families, r = -0.01 v,+th the absolute values of the mean for AJA families). while the correlations of g-loadings Lvithin-sibship skews Lvere of slightly higher but non-significant mayituds (v = -0.39 for AEA positive correlation families. I’ = -0.1 1 for AJA families). There was an almost signiticant (r = 0.4, P = 0.10) betkveen the g-loadings and the degree of ‘hybrid \.isor’ manifested on the cogniti1.e tests by offspring of AEA-AJA cross-ethnic matings. To control for possible outlier effects, given the small .C~s, Spearman ps ivere also calculated. producin, 0 highly similar results. DISCCSSION At a minimum. the present results are strongly supportive of the construct validity of g: s US opposed to non-,? does seem to be comprised of a distinct set of important. related abilities (perhaps

,) U”‘

0 50

0 1s”’

0 ih’

0 50 0

‘1j”.

I) S4”*

0 39

0 35”’ 0 13 0.71” 0 90”

0 66.

0 55. 0 6’)” 0 jY’ 0 76”.

II 33 I) -I?

-

0 ‘6

0 76”’

0.37

ItSI***

0 26

I).fl7*

O.59*

0.~8”’

0.16

0 26 0.55’

0.14 -

0 699’

0.57’

II 74’.

under the control of some single underlying mechanism) associated with a distinct pattern of developmental factors. While some of the present findings are highly confirmatory of Jensen’s work and conclusions on the nature of g, other findings suggest the importance of complicating factors not considered by Jensen. The degree to which tests load on g is highly predictive of the degree to which they are correlated \vith educational attainment (mean r = 0.63) and occupational attainment (mean r = 0.57). This is a striking confirmation of Jensen’s (1984) analyses. indicating that g may be the major ability factor in present-day socioeconomic success and, hence, the need to understand what it consists of and the nature of its development. In support of Ea\,es er ul.‘s (1983) hypothesis, spouse correlations for cognitive abilities seem to be based largely on g (mean r of g-loading with spouse resemblance = 0.63). Since. as indicated above, g is highly correlated with educational attainment, it is still reasonable to believe that assortative mating for ability is largely the result of assortative mating for education. although Ahern, Johnson and Cole (1983) have reported a secular trend toward less assortive mating for education in recent years. The degree to ivhich a test loads on g was found to be substantially related to the magnitude of parent-offspring correlations (mean r = 0.54) and, to a lesser degree, of sibling correlations (mean r = 0.13) on those tests, suggesting that the narrow-sense heritability ofg is higher than that for the non-g components of intelligence. possibly because of greater assortative mating for g than non-g. Also of note is that. since siblings, as opposed to parents and offspring, share dominance as Lvell as additive genetic variance, if g as opposed to non-g was more influenced by dominance genetic factors. then g-loadings should have been more highly correlated with the sibling than Lvith the parent-offspring correlations on the cognitive tests. Such was not the case. This result,

combined ~iith the results of correlating g-loading Lvith ~iithin-sibship ske\v and \t~th degree of ‘h> brid ligor’. jwgcst that the e~tdence for sreater dlrsctlonal genetic dominance as ;I result of natural election for g as opposed to non-g is weak at best. The finding oi sreatcr 2dditiL.e genetic Lariation for :’ as opposed to non- g noted above corresponds to the results of fumil> and adoption studies indicating the presence of constderable addltiw zenstic Lariation for zenera intelligence [see. for example. Plomin. DeFries and McClearn ( 19SO) for a reviw.]. a reasonable tindinz iT one ajs‘unlt‘j that the {election pressures in present-day society, are qu~re diRerent from the jrllsction pressures on the e\,olution of g, thus ‘freeing up‘ additive genetic \.ariance. LVhlle ,y appears to be under greater additive and perhaps dominance genetic control. those tests that load on g also seem to be most influenced by parental education (mean r = 0.56) and parental occupation (mean I’ = 0.4). confirming our earlier conclusion (Nagoshi CJ[(I/.. 19Xla) that x maq be more influenced by some environmental factors (in this case, the differences in shared family sniironment that is reflected in parental socioeconomic status) than is non-g. .As noted above. ho\vsver. the correlation of parental education and occupation Lvith offsprin g cognitive abilities is confounded ivith parental cognitive ability and its genetic bases. The correlations ot‘gi\en tests \vith parental educational and occupational attainment are highly correlated u,ith the ,r-loadinps of the tests; therefore. it is not surprising that parental education occupation correlates ~bith otfspring performance on these tests to a degree dependent on their loadings on 5. When parent--otTspring resemblance on the cognitive tests is controlled for and the resulting partial correla[ions of parental education and occupation with oft‘sprin g cognitiw abilit>, are used. the correlations with the o-loadings are reduced an average of0.30. but a few still remain signiticant. If these environmental icorrelations are valid. it would indicate that the dsvelopment of g is strongly iniluenced hq the convqencc of shared familial genetic and environmental factors. while non-g cognitive abilities arc more under the intluence of specifk environmcntnl factors. DilTerences across the ethnic groups in the magnitudes of correlations are substantial and bvould not appear to be accounted for solely by instability of the correlations due to the small .V. Environmental circumstances of the three groups \,aried greatly during the years in which the parents were _croLving up and probably still vary to some degree (Ahern et (II.. 1957; Johnson et (11.. 195X1. b; Johnson and Nagoshi, 1985), possibly producin g the ethnic group dit7.erences found. For euamplc. as noted in Johnson and Nagoshi (1985). the Korean parents in the HFSC entered adulthood at a tirne when Korean society was largely non-meritocratic and. hence. correlations of parental ability \\.ith parental socioeconomic attainment and parental socioeconomic attainment i\ith orspring ability are generally lower among the Korean Ss. Again, perhaps the most important conclusion to be drawn from the above findings is that, in accordance w+th the results of Jensen’s many studies, g does appear to have a great deal of validity as a construct with many implications for the study of indii,idual differences. On the other hand, the correlation of,~ with so many diff‘erent aspects of individual differences suggests that its basic components, evolutionary history and developmental bases may be much more complex than is implied in Jensen’s theorizing to date. .-l[,X,ro~~/c,c!~~,rtio~i\--The results rrportcd here are made powble b) a collaboration of :t group 01 In.,sstiytors (G. C. .Ajhton. R. C. Johnson. Xl. P. h11 and .LZ. N. Rashad at the Uni\usit> of Hawail and 1. C. DeFrla. G. E. hfcCleurn. S G Vandenberg and J. R. LC’~lson at the University of Colorado) supported by SSF Grant GB-347N and Grunt HD-06669 I’rom the Sdtional lnst~tute of Child Health and Human Development. LVe‘d Ilire IO thank D. W. Fulkrr and J C. DeFrlej for their comments and suggestions on earlier Lerslons of this manuscript.

REFEREZCES .Azra!+al N . SInha S 5. and Jensen A. R. (1984) Effects of Inbreeding on Raven >latrices. Behu~l Genrr. II. 579-535. .Ahern F Xl.. Johnson R C. and Cole R. E. (1983) Generational diferences in spouse simiiarlry In educational attalnmenI B~~kll I GWWI. 13, 95-98. Cronbach L. C1951) Coeficient alpha and the Internal structure of tejtj, ~‘.r~,~l~~,n~etri~~[~16. 297.-331. DeFries J. C . Johnson R C.. Kuse A. R.. ,LlcClearn G. E.. Polovlna J Vandenberg S G. and Wilson J. R (1979) Farnil? resemblancr for speuiic cognlti\e abiliria. BC/UK/ Gmr~. 9, 23 43. DeFries J. C.. Corlry R. P., Johnson R. C . Vandenberg S. G ,lnd \+‘llson J. R. (1982) Sex-by-yner;ltion and ethnic group-by-ncneratlon Interactions in the Hawaii FarnIl\ Stud\ of Cognlilon. Bc/wL./ Gerwr. 12, 223 231). Eaxrc L. J : Gtxth .A C and \lurtln N. G. (19X.4) .A not; on th; generalized eff‘ects ol assortatiw marIng. Br~i~crc./ Grnci. II, 37 I-376.

The ublqult).

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Fslcontr D. S ( IYdI ) Inirodrrtilcrn ,o c)um!~ume Grner~c~. 2nd sdn. Longman. London Fisher R. .L\ . Immer F R and TedIn 0. C1932)The genetxal Interpretdtlon of st;Llstlcsoi the third dsgree in the stud> of quantltatibr InherItaxe. Grrwi~cs 17, 107-123 Jensen ,A. R. (1953alThr r!Tects of InbreedIng on mental ablhty factors Person. !n&[-id 01/j’. 1. 71-Y; tests. InLited address. .4vwr~carl Jsnsen A. R. 11983b) The nature of M’hits-Black dl!Terences on various ps)chomctric Prj choio~ical .4.~.w~~1~1111~11 Conrrnr~rv~, Anaheim. Calif. Jensen A. R (1951) Test \alidlt>: 4 xersus ths specificity doctrine. J. wc. hwl. S/ru‘.r. 7, 93-l 18. Jensen A. R. (19Y5a) The ,y beyond factor anal>s~s. Paper presented in Brtror-.Yahrdu 5_tn1porimr on .\lru.wrtwwn~ cd Tesrinp. L’ni\. of Nebraska. Lincoln. Neb. Jensen A. R. (1985b) The nature oi the Black-White difference on various ps>chometrx tests: Spearman‘s h>pothesis. Beharl Brain Sci. In press. Junks J. L. and Fulker D. W. (1970) Comparison of the biometrical grnetlcal. Xl.-\I’.A. and classical approaches to the analysis of human behavior. Ps~choi. Bull. 73, 31 I-349. Johnson R. C. and Sagoshi C. T (19S5) Parental ablllty. education. and occupation as influences on offspring cognition in Hawaii and Korea. Person. ind~~irl. Dffl: 6, 113123. Johnson R. C., DrFrlcs J. C.. Park J-Y.. McClearn G. E.. MI M. P.. Rashad hf. S.. h’andenberg S. G. and Wilson J. R. (1977) Assortatlve marriage for specific cogmtivc abilities in Korea. Sot. Bid. 23. 31 I-316. Johnson R. C., Nagoshi C. T.. Ahern F. 41.. Wilson J. R.. DeFrirs J. C.. SlcClearn G. E. and Vandenberg S. G. (1983,) Family background. co_emtlve ablht), and personality as predictors of educational and occupatlonal attainment. Sut Biol. 30, 5t%lOO. Johnson R. C., Nagoshi C. T.. Ahern F. Xl.. Wilson J. R.. McClearn G. E., L’andenberg S. G. and DeFries J. C. (I983b) Age and cohort effects on personalit) factor scores across sexes and racial ethnic groups Person. idirrd. Difl: 1. 709-713. Nugoshi C. T., Johnson R. C.. DeFries J. C.. Wilson J. R. and Vandenberg S. G. (I9YJa) Group ditferences and tirst principal component loadings in the Hawaii Family Study of Cognition: a test of the generality of ‘Spearman’s hypothesis‘. Prrw~. tnrlkid. Dif 5. 751-753. Nagoshi C. T.. Schuittrrs S Y.. Johnson R. C. and Ahern F. M (1981b) InHuences on the educational and occupational attainment of otTsprIng of the Hawait Family Study of Cognition. Unpublished manuscript, Behavioral Biology Lab. Uni>erslty of Hav.aii. Honolulu. Hauali. Park J-Y.. Johnson R. C.. DeFrics J. C., McClearn G E. MI M. P., Rashad hl. N.. Vandenberg S. G. and Wilson J. R. (1975) Parent-otTspring resemblances for specltic cognitive ablhtirs in Korea. Behac~l Genes. 8, 33-57. Plomin R.. DeFries J. C. and McClearn G. E. (1980) Beha~iorcd Grnericst n Primer. Freeman. San Francisco. Calif. Reiss A. J., Duncan 0 D.. Hatt P. K. and North C. C. (1961) Occupurions and Social Sfa~us. Free Press. Glrncoe. Ill. Schull W. J. and Neel J. V. (1965) Tilt E/~KI.T o//nhrding in Japanese Children. Harper & Row. New York. Wilson J. R.. DeFrics J. C.. McClearn G. E.. Vandenberg S. G.. Johnson R. C.. Mi bl. P. and Rashad M. N. (1975) Use of family data as ;Lcontrol to assess sex and age dltl’erences in two ethnic groups. Inr. J. Agin,q Hwr~ DU 6. 761-276.