I.Q and Human Intelligence

 

 

1. Relationship Between National IQ and GDP per capita

2. National IQ Prediction Based on Racial Composition

3. I.Q Heritability

4. Various Correlations

5. Mean I.Q

6. Impact on I.Q

7. I.Q and Justice

8. Other Diverse Correlations

9. Mean Salary Predicted from National I.Q

10. I.Q and Diseases

11. I.Q and BMI

12. I.Q and Life Expectancy

 

1. Relationship between National I.Q and GDP per Capita

GDP per Capita as a Function of National I.Q

For further discussion of the link between the national I.Q and economic development, see National I.Q and Economy.

The following table shows that there has always been a strong correlation between IQ and GDP per capita, and this since at least the 1500PCN, the two weakest correlations, in 1950 and 1980, correspond to an increase in GDP per capita of oil-producing countries, such as Kuwait, Qatar, and the United Arab Emirates, which has increased their average GDP per capita regardless of IQ

2. National IQ Prediction Based on Racial Composition

Table 9.7. National IQs in Latin America and the Caribbean predicted from racial composition of the populations

3. I.Q Heritability

Ref	IQ HERITABILITY	Correlation
1	Monozygotic Twins reared together	0.86
2	Monozygotic Twins reared together	0,85
2	Monozygotic Twins reared apart	0,74
2	Dizygotic Twins reared together	0,59
2	Siblings reared together	0.46
1	Siblings or Dizygotic Twins reared together	0.45
2	Mid-parent / Child together	0,50
2	Single parent / Child together	0,41
1	Siblings or Dizygotic Twins reared apart	0.40
13	Between Husband and Wives	0,45
17	Between Husband and Wives	0,37
18	Between Husband and Wives in USA	0,33
1	Half siblings reared together	0.20 à 0.30
2	Single parent / Child apart	0,24
2	Adopting parent / Child together	0,20
1	Cousins reared together	0.15
20	Personns without any genetic parenty reared together : during childhood	0,25
20	Personns without any genetic parenty reared together : when adults	– 0.01
19	broad heritability according to age: – Children – in adolescents and young adults – Later maturity	0.40 to 0.50 0.60 to 0.70 0.80

4. Various I.Q Correlations

Ref		Correlation
7	Head size	0,40
8	Level of aggression in primary school	-0,45
9	Social Conservatisme	-0,45
15	Validity predicting Job Performance Rating	0.53
16	Myopia	0.20 to 0.25

5. Mean I.Q 

Ref		QI	% > 100*
4	African-Americans (about 25% of european admixture)	85	16
22	France: Mean I.Q if the father is maneuver	92	30
3	US Prison population	92	30
22	France : Mean I.Q of the child if the father is a farmer	96	41
5	Average European	100	50
22	France : Mean I.Q of the child if the father is a commerical employee	100	50
4	East Asians (China, Korea, Japan, Singapore…)	106	66
22	France: I.Q of the child if the father is a middle manager	107	30
22	France: I.Q of the child if the father is a senior manager	112	78
4	Ashkenazy Jews	115	85
3	University Master Level	115	85
3	Plus hauts diplômés Américains	145	99

* : Percentage of people in the population with IQ> 100 

6. Impact on Mean I.Q (expressed in Wechsler I.Q points)

Ref		IMPACT	% > 100*
10	IQ of hospitalized schizophrenics compared to the corresponding general population (expressed in relative terms)	-31	2
10	IQ of non-hospitalized schizophrenics compared to the corresponding general population (expressed in relative terms)	-13	19
21	IQ of Monozygotic Twins if both are born viable (expressed in relative terms)	-5	37
21	IQ of Monozygotic Twins of which one is stillborn (expressed in relative terms)	0	50
29	IQ of Twins at the age of 5	-5,3	37
29	IQ of Twins at the age of 9	-6	34
24	IQ of 9 year old children who have suffered at least once a year from the parasite G. lamblia (causes diarrhea)	-4	40
24	IQ of 9-year-old children who suffered from chronic malnutrition during the first two years of stunted growth	-10	25
28	IQ of 5 year old children who had cried a lot at 6 and 13 weeks, 6, 9 and 13 months	-9	27
28	IQ of 5 year old children who had a lot of colic at 6 and 13 weeks, 6, 9 and 13 months	0 (pas d’impact trouvé)	50

* : Percentage of people in the population with IQ> 100


7. IQ of Condemned People

Ref	(US) MEAN IQ ACCORDING TO DEEPEST LEVEL OF CONTACT WITH THE CRIMINAL JUSTICE SYSTEM, WHITES MALES	QI	% > 100*
6	None	106	66
6	Stopped by the police but not booked	103	58
6	Booked but not convicted	101	53
6	Convicted but not incarcerated	100	50
6	Sentenced to a correctional facility	93	32

* : Percentage of people in the population with IQ> 100 

8. Various Statistics

Ref	STATISTIQUES DIVERSES CONCERNANT LE QI	CHIFFRE
12	On the crimes committed by educated  children in the USA, percentage of those committed by the IQ between 70 and 100	74%
0	IQ of Baccalaureate if 80% of the population has to get it	88
16	Percent of females exceeding the male median in spatial visualization ability	25%
27	Birth weight: IQ points for 1 kg more, boys	4,6
27	Birth weight: IQ points for 1 kg more, girls	2,8
23	Correlation with economic success (see below)	0,757
25	Correlation with religiosity (percentage of people responding that religion is “very important”)	-0,886
26	Correlation with the suicide rate	Men : 0,36 Women : 0,49
30	Mean IQ when adult according to the age of the first sentence uttered	Before 24 months: 107 24 months: 101.8 After 24 months: 100.6

9. National I.Q and Economic Success

(The National IQ data here come from “IQ and the Wealth of Nations” Lynn and Vanhanen, 2002. Better data has been obtained since then, see National I.Q and Economy).
About 60% of the economic variations between countries are explained by the IQ variations of the population. 3 elements come down the correlation (which, without them, would be even more important):
o  The degree of economic freedom: countries that have lived (or still live) communism are of course much poorer than the others
o  The quantity of natural resources (eg oil in the Middle East)

o  The internal organization of the country: putting the intellectual elite in economic power increases the global wealth of all.

Légende

o   Fitted GDP (FGDP) = “theorical” GDP estimates from National I.Q

o   GDP / FGDP = indicates whether the country is doing better or worse than its IQ suggests

Country	average IQ	GDP	fitted GDP	GDP/FGDP
Hong Kong	107	20 763	19 817	1,0477368
Korea, South	106	13 478	19 298	0,6984143
Japan	105	23 257	18 779	1,2384579
Taiwan	104	13 000	18 260	0,7119387
Singapore	103	24 210	17 740	1,3647125
Austria	102	23 166	17 221	1,345218
Germany	102	22 169	17 221	1,2873236
Italy	102	20 585	17 221	1,1953429
Netherlands	102	22 176	17 221	1,2877301
Sweden	101	20 659	16 702	1,2369177
Switzerland	101	25 512	16 702	1,5274817
Belgium	100	23 223	16 183	1,4350244
China	100	3 105	16 183	0,191868
NewZealand	100	17 288	16 183	1,0682815
U. Kingdom	100	20 336	16 183	1,2566273
Hungary	99	10 232	15 664	0,6532176
Poland	99	7 619	15 664	0,4864019
Australia	98	22 452	15 145	1,4824695
Denmark	98	24 218	15 145	1,5990756
France	98	21 175	15 145	1,3981512
Norway	98	26 342	15 145	1,7393199
United States	98	29 605	15 145	1,9547706
Canada	97	23 582	14 626	1,6123342
Czech Republic	97	12 362	14 626	0,8452072
Finland	97	20 847	14 626	1,4253384
Spain	97	16 212	14 626	1,108437
Argentina	96	12 013	14 107	0,8515631
Russia	96	6 460	14 107	0,4579287
Slovakia	96	9 699	14 107	0,687531
Uruguay	96	8 623	14 107	0,6112568
Portugal	95	14 701	13 589	1,0818309
Slovenia	95	14 293	13 588	1,051884
Israel	94	17 301	13 069	1,3238197
Romania	94	5 648	13 069	0,4321677
Bulgaria	93	4 809	12 550	0,3831873
Ireland	93	21 482	12 550	1,7117131
Greece	92	13 943	12 031	1,1589228
Malaysia	92	8 137	12 031	0,6763361
Thailand	91	5 456	11 512	0,4739402
Croatia	90	6 749	10 993	0,6139361
Peru	90	4 282	10 993	0,3895206
Turkey	90	6 422	10 993	0,5841899
Colombia	89	6 006	10 474	0,5734199
Indonesia	89	2 651	10 474	0,2531029
Suri name	89	5 161	10 474	0,4927439
Brazil	87	6 625	9 436	0,7020983
Iraq	87	3 197	9 436	0,3388088
Mexico	87	7 704	9 436	0,8164476
Samoa (Western)	87	3 832	9 436	0,4061043
Tonga	87	3 000	9 436	0,3179313
Lebanon	86	4 326	8 917	0,4851407
Philippines	86	3 555	8 917	0,3986767
Cuba	85	3 967	8 398	0,4723744
Morocco	85	3 305	8 398	0,3935461
Fiji	84	4 231	7 879	0,5369971
Iran	84	5 121	7 879	0,6499556
Marshall Islands	84	3 000	7 879	0,380759
Puerto Rico	84	8 000	7 879	1,0153573
Egypt	83	3 041	7 360	0,4131793
India	81	2 077	6 322	0,3285353
Ecuador	80	3 003	5 803	0,517491
Guatemala	79	3 505	5 284	0,6633232
Barbados	78	12 001	4 765	2,5185729
Nepal	78	1 157	4 765	0,2428122
Qatar	78	20 987	4 765	4,4044071
Zambia	77	719	4 246	0,1693358
Congo (Brazz)	73	995	2 170	0,4585253
Uganda	73	1 074	2 170	0,4949309
Jamaica	72	3 389	1 651	2,0526953
Kenya	72	980	1 651	0,5935796
South Africa	72	8 488	1 651	5,1411266
Sudan	72	1 394	1 651	0,8443368
Tanzania	72	480	1 651	0,2907329
Ghana	71	1 735	1 132	1,5326855
Nigeria	67	795	– 944	-0,842161
Guinea	66	1 782	– 1 463	-1,218045
Zimbabwe	66	2 669	– 1 463	-1,824334
Congo (Zaire)	65	822	– 1 982	-0,414733
Sierra Leone	64	458	– 2 501	-0,183127
Ethiopia	63	574	– 3 020	-190,0662
Equatorial Guinea	59	1 817	– 5 096	-0,356554

10. I.Q and diseases

11. I.Q and BMI

12. I.Q and Life Expectancy 

There is a strong positive correlation between intelligence and longevity, the higher Q.I tend to live longer.

This correlation is mainly genetic. In fact, the genes involved in higher intelligence are also responsible for increasing longevity.

“The finding of common genetic effects between lifespan and intelligence has important implications for public health, and for those interested in the genetics of intelligence, lifespan or inequalities in health outcomes including lifespan”

“The association between intelligence and lifespan is mostly genetic” Int. J. Epidemiol. Advance Access published July 26, 2015.

Survival curve in men and women. The lowest quartile is Q.I less than 90. The highest quartile is individuals with a Q.I greater than 110.

Among the most talented individuals, Q.I remains correlated with longevity.

Sources and References

Ref	SOURCES
0	Calculation for an average of 100 Only valid if the IQ distribution in the population considered follows a bell curve (this is true for the general population but not necessarily for a particular population)
1	Jaques Bénesteau (sur ce site)
2	Devlin, Daniels and Roeder – Nature 31-07-97 – Meta-analyse of 212 studies
3	Herrnstein & Murray – The Bell Curve (1994)
4	Estimation from Arthur HU
5	Per définition
6	TBC pp 246-247
7	JP. Rushton – 2000
8	Wiegmann and al. 1992 (Quoted by Brand 1996 pp 154 et 207 ) WIEGMAN, O., KUTTSCHREUTER, M. & BAARDA, B. (1992). ‘A longitudinal study of the effects of television viewing on aggressive and prosocial behaviours.‘ British Journal of Social Psychology 31, 147-164.
9	Egan 1989
10	John Crawford 1992
11	White, K.R. 1982 (quoted by Brand 1996) The relation between socioeconomic status and academic achievement Psychological Bulletin 91, 3, 461-8
12	Yoshikawa
13	Jensen A.R. 1978 (Quoted in TBC pp 110 et 687) : Genetic and behavioral effects of nonrandom mating. In Human Variation : Bpopsycholgy of Age, Race and Sex.R.T. Osborne, C.E. Noble, and N. Weyl (eds.). New York : Academic Press, pp. 5-105 Voir aussi : Jensen 1998 p 183
14	Chris Brand
15	Hunter J. E. & Hunter R.F. 1984 (Quoted in TBC pp 81 and 575) : Validity and utility of alternative predictors of job performance. Psychological Bull. 96:72-98
16	Jensen 1998 – p 149
17	Phil Rushton in ‘Race, Evolution and Behaviour‘ (1995), p70 (Diagram)
18	Tom Bouchard and Matt McGue in Familial studies of intelligence (1981, Science 212, 4498, 1055-1059)
19	Jensen 1998 – pp 169 et 178 + page 179 from Mac Gue 1993
20	Jensen 1998 p 178 Mc Gue et al., 1993, pp. 60-67 (Behavioral genetics of cognitive ability : a life time perspective in R. Plomin & G.E. McClearn (Eds.), Nature, Nurture, and psychology (pp 59-76). Washington, DC: American Psychological Association) Scarr, 1989 pp 103-105 (Protecting general intelligence : constructs and consequences for interventions. In R.L. Linn (Ed.), Intelligence : Measurement, theory, and public policy (pp 74-118) Chicago : University of Illinois Press) Segal 1997 ( Same age unrelated siblilngs : a unique test of within-family environmental influences on IQ similarity Journal of Educational Psychology, 89, 381-390)
21	RECORD, R. G., McKEOWN, T & EDWARDS, J. H. (1970). An investigation of the differences in measured intelligence between twin and single births. Annals of Human Genetics 34, 11-20.
22	INED (France) 1973
23	Lynn et Vanhanen 2002 : “IQ and the Wealth of Nation” – Praeger (USA) 2002
24	Douglas S. Berkman et al.: “Effects of stunting, diarrhoeal disease, and parasitic infection during infancy on cognition in late childhood: a follow up study” in The Lancet 16-02-2002
25	Calculation of Razib (Gene Expression) from the data of # 23 and Pew.
26	Significant correlation found by VORACEK, Martin (2003), using the same data as Lynn & Vanhanen 2002 [24]. “Personality and Individual Differences (in Press)
27	Thomas D Matte, Michaeline Bresnahan, Melissa D Begg, and Ezra Susser “Influence of variation in birth weight within normal range and within sibships on IQ at age 7 years: cohort study” BMJ, Aug 2001; 323: 310 – 314.
28	Rao MR, Brenner RA, Schisterman EF, Vik T, Mills JL. (2004): “Long term cognitive development in children with prolonged crying.” Arch Dis Child. 2004 Nov;89(11):989-92.
29	Hagan (2005): “The cognitive cost of being a twin: evidence from comparisons within families in the Aberdeen children of the 1950s cohort study” BMJ Online First (Public release date: 18-Nov-2005)
30	Flensborg-Madsen T., Mortensen E.L. (2017) “Associations of Early Developmental Milestones With Adult Intelligence”, Child Development.