Whole Brain Size and General Mental Ability: A Review

Figures & data

Figure 1 Mean brain weight for 4-year age periods in various subgroups. Brain weight is plotted at midpoint of each age period (e.g., the point at age 6 years represents the average for subjects between 4 and 8 years; White men, open triangles; Black men, solid triangles; White women, open squares; Black women, solid squares). Differences in brain weights among various groups become apparent at age 6 years. (From Ho et al., 1980, p. 636, Figure 2.)

Figure 2 The relation between the ratio of brain mass/body surface area and body surface area in White men and women. Ankney (1992) calculated the ratios by estimating brain mass at a given body surface area using the equations in Ho et al. (1980, Table 3): men, brain mass = 1,077 g (±56) +173 (±31) × body surface area (r = +0.27, p < 0.01); women, brain mass = 949 g (±52) +188 (±32) × body surface area (r = +0.24, p < 0.01). (From Ankney, 1992, p. 331, Figure 1. Copyright 1992 by Ablex Publishing Corp. Reprinted with permission.).

Figure 3 The relation between brain mass and body height in White men and women. Lines drawn from equations in Ho et al. (1980, Table 1): men, brain mass = 920 g (±113) + 2.70 (±0.65) × body height (r = 0.20, p < 0.01); women, brain mass = 748 g (±104) + 3.10 (±0.64) × body height (r = +0.24, p < 0.01). (From Ankney, 1992, p. 333, Figure 4. Copyright 1992 by Ablex Publishing Corp. Reprinted with permission.).

Figure 4 Cranial capacity for a stratified random sample of 6,325 U.S. Army personnel. The data, grouped into six sex-by-race categories, are collapsed across military rank. (East Asian men, closed circles; White men, closed squares; Black men, closed triangles; East Asian women, open circles; White women, open squares; Black women, open triangles). They show that, across the 19 different analyses controlling for body size, men averaged larger cranial capacities than did women, and East Asians averaged larger than did Whites or Blacks. Analysis 1 presents the data unadjusted for body size showing no difference for East Asian and White men. (From Rushton, 1992a, p. 408, Figure 1. Copyright 1992 by Ablex Publishing Corp. Reprinted with permission.).

Figure 5 Mean cranial capacity (cm³) for African Americans, European Americans, and East Asian Americans from birth through adulthood. Data for birth through age 7 years from the U.S. Perinatal Project; data for adults from the U.S. Army data in Figure 4. (From Rushton, 1997, p. 15, Figure 2. Copyright 1997 by Ablex Publishing Corp. Reprinted with permission.).

Figure 6 Average encephalization quotient (EQ; natural log), a measure of neural tissue corrected by body size, plotted against elapsed geologic time in millions of years. (After Russell, 1983).

Appendix 1 Brain volume relation to GMA using neurologically normal subjects

Source	Sample	GMA measure	Correlation
Willerman, Schultz, Rutledge and Bigler (1991)	20 European-American male university students with mean age = 18 years	WAIS-R	0.51
Willerman et al. (1991)	20 European-American female university students with mean age = 18 years	WAIS-R	0.33
Andreasen et al. (1993)	37 European-American males aged 18–75 years	WAIS-R	0.40
Andreasen et al. (1993)	30 European-American females aged 18–75 years	WAIS-R	0.44
Raz et al. (1993)	29 European-Americans (17 men, 12 women) with mean age = 43.8 years (SD = 21.5)	CFIT	0.43
Egan et al. (1994; corrected by Egan, Wickett, & Vernon, 1995)	40 British military (unreported sex and race breakdown) with mean age = 23 (SD = 5), corrected for height, weight, and restricted range	WAIS-R	0.48
Castellanos et al. (1994)	46 children aged 5–19 years of unknown background	WISC-R subscales	0.33
Harvey, Persaud, Ron, Baker, and Murray (1994)	34 healthy male and female British hospital staff and locals (62% Caucasian; 38% Afro-Caribbean) used as control group	NART	0.69
Jones et al. (1994)	67 healthy male and female British, aged 16–60 years, some Afro-Caribbean, used as a community control group	NAT or verbal subtest of the WAIS	0.30
Wickett et al. (1994)	40 White Canadian women aged 20–30 years; height and weight partialed out and corrected for restriction of range	MAB	0.40
Kareken et al. (1995)	68 Caucasian and non-Caucasian adults of both sexes aged 18–45 years	Average of various subtests	0.25
Reiss, Abrams, Singer, Ross, and Denckla (1996)	12 boys, mainly White, aged 5–17 years	WISC-R	0.52
Reiss et al. (1996)	57 girls, mainly White, aged 5–17 years	WISC-R	0.37
Flashman, Andreasen, Flaum, and Swayze (1998)	90 healthy normal volunteer controls (47% female) with mean age = 27 years (SD = 10)	WAIS-R	0.25
Tramo et al. (1998)	20 individuals (10 pairs of identical twins) aged 24–43 years; we use their total cortical surface area as the estimate of brain size	WAIS-R	0.20
Gur et al. (1999)	40 men with a mean age = 26 years (SD = 5.5)	Various	0.40
Gur et al. (1999)	40 women with a mean age = 26 years (SD = 5.5)	Various	0.39
Tan et al. (1999)	54 female university students in Turkey, aged 18–26 years	CFIT	0.62
Tan et al. (1999)	49 male university students in Turkey, aged 18–26 years	CFIT	0.28
Wickett et al. (2000)	68 individuals (34 pairs of brothers) aged 20–35 years	g, from MAB and other tests	0.38
Pennington et al. (2000)	96 individuals (48 pairs of MZ and DZ twins), mean age = 17 years (SD = 4.1)	WISC-R and WAIS-R	0.42
Pennington et al. (2000)	36 individuals (18 pairs of MZ and DZ twins), mean age = 19 years (SD = 3.7)	WISC-R and WAIS-R	0.31
Schoenemann, Budinger, Sarich, and Wang (2000)	72 individuals (36 pairs of sisters) aged 18–43 years	g, from 11 diverse cognitive tasks including Raven's Matrices with corrections for age	0.45
Aylward et al. (2002)	83 White men and women aged 8–46 years used as healthy controls	Unspecified IQ test	0.04
MacLullich et al. (2002)	97 healthy men aged 68 years (SD = 1.3)	g, from various tests including NART and Raven's Matrices	0.42
Ivanovic et al. (2004)	47 male 18-year-old high school students in Chile selected from the richest and poorest counties	WAIS-R	0.55
Ivanovic et al. (2004)	49 female 18-year-old high school students in Chile selected from the richest and poorest counties	WAIS-R	0.37
Deary et al. (2007)	48 male 71- to 76-year-olds resident in Scotland	NART	0.56
Number of samples: 28
Total N: 1,389
Unweighted mean r = 0.40
N-weighted mean r = 0.38

Note. CFIT, Culture-Free Intelligence Test; MAB, Multidimensional Aptitude Battery; MRI, Magnetic Resonance Imaging; NART, New Adult Reading Test; PMAT, Primary Mental Abilities Test; WAIS-R, Wechsler Adult Intelligence Scale-Revised; WISC, Wechsler Intelligence Scale for Children.

Appendix 2 Head size relation to GMA using neurologically normal subjects

Study	Sample	Head size measure	GMA measure	Correlation
Pearl (1906)	935 German male soldiers	Perimeter	Officers’ rating	0.14
Pearson (1906)	2,398 British boys aged 3–20 years, standardized to age 12	Length	Teachers’ estimate	0.14
Pearson (1906)	2,188 British girls aged 3–20 years, standardized to age 12	Length	Teachers’ estimate	0.08
Pearson (1906)	1,011 British male university students	Length	Grades	0.11
Murdock & Sullivan (1923)	291 American boys aged 6–17 years, standardized by age	Perimeter	Various IQ tests	0.20
Murdock & Sullivan (1923)	395 American girls aged 6 to 17 years, standardized by age	Perimeter	Various IQ tests	0.27
Reid & Mulligan (1923)	449 Scottish male medical students	Capacity	Grades	0.08
Sommerville (1924)	105 White male university students	Capacity	Thorndike	0.08
Estabrooks (1928)	172 White boys aged 7 years	Capacity	Binet IQ test	0.23
Estabrooks (1928)	207 White girls aged 7 years	Capacity	Binet IQ test	0.16
Porteus (1937)	200 White Australian children	Perimeter	Porteus Maze	0.20
Schreider (1968)	80 adult Otomi Amerindians from Mexico	Perimeter	Form board	0.39
Schreider (1968)	158 French farmers of unreported sex	Perimeter	Raven's Matrices	0.23
Klein, Freeman, Kagan, Yarborough, and Habicht (1972)	172 Guatemalan Amerindian boys aged 3–6 years	Perimeter	Knowledge tests, with age standardized	0.23
Klein et al. (1972)	170 Guatemalan Amerindian girls aged 3–6 years	Perimeter	Knowledge tests, with age standardized	0.29
Susanne & Sporcq (1973)	2,071 Belgian male conscripts	Perimeter	Raven's Matrices	0.19
Weinberg, Dietz, Penick, and McAlister (1974)	334 White boys aged 8–10 years	Perimeter	WISC	0.35
Passingham (1979)	415 English villagers (212 men, 203 women) aged 18–75 years	Capacity	WAIS	0.13
Susanne (1979)	2,071 Belgian male conscripts	Perimeter	Matrices	0.19
Pollitt, Mueller, and Liebel (1982)	91 boys and girls aged 3–6 years	Perimeter	Stanford-Binet	0.23
Majluf (1983)	120 boys and girls aged 8–20 months	Perimeter	Bayley motor development test	0.35
Ounsted, Moar, and Scott (1984)	214 boys aged 4 years	Perimeter	Language test	0.06
Ounsted et al. (1984)	167 girls aged 4 years	Perimeter	Language test	0.07
Henneberg, Budnik, Pezacka, and Puch (1985)	151 Polish male medical students aged 18–30 years	Capacity	Baley's Polish language IQ test	0.09
Henneberg et al. (1985)	151 Polish female medical students aged 18–30 years	Capacity	Baley's Polish language IQ test	0.19
Sen et al. (1986)	150 16- to 18-year-old males in India	Perimeter	Raven's Matrices	0.02
Sen et al. (1986)	150 16- to 18-year-old females in India	Perimeter	Raven's Matrices	0.54
Broman et al. (1987)	18,907 Black boys and girls aged 7 years	Perimeter	WISC	0.19
Broman et al. (1987)	17,241 White boys and girls aged 7 years	Perimeter	WISC	0.24
Ernhart, Marler, and Morrow-Tlucak (1987)	257 3-year-old boys and girls	Perimeter	Stanford-Binet	0.12
Bogaert & Rushton (1989)	216 White Canadian male and female university students, adjusted for sex	Perimeter	MAB	0.14
Lynn (1989)	161 Irish boys aged 9–10 years	Perimeter	PMAT	0.15
Lynn (1989)	149 Irish girls aged 9–10 years	Perimeter	PMAT	0.23
Lynn (1990)	205 Irish children aged 9 years	Perimeter	Raven's Matrices	0.26
Lynn (1990)	91 English children aged 9 years	Perimeter	Raven's Matrices	0.26
Osborne (1992)	106 European-American boys aged 13–17 years; controls for height and weight	Capacity	Basic	0.16
Osborne (1992)	84 African-American boys aged 13–17 years; controls for height and weight	Capacity	Basic	0.34
Osborne (1992)	118 European-American girls aged 13–17 years; controls for height and weight	Capacity	Basic	0.23
Osborne (1992)	168 African-American girls aged 13–17 years; controls for height and weight	Capacity	Basic	0.13
Rushton (1992b)	73 East Asian-Canadian male and female university students	Perimeter	MAB	0.14
Rushton (1992b)	211 White Canadian male and female university students	Perimeter	MAB	0.21
Lynn & Jindal (1993)	100 9-year-old boys from northern India	Perimeter	Matrices	0.14
Lynn & Jindal (1993)	100 9-year-old girls from northern India	Perimeter	Matrices	0.25
Reed & Jensen (1993)	211 European-American male college students	Capacity	Raven's Matrices	0.02
Wickett et al. (1994)	40 White Canadian female university students	Perimeter	MAB	0.11
Furlow, Armijo-Prewitt, Gangestad, and Thornhill, (1997)	128 undergraduates, (60% female; 52% Caucasian, 38% Hispanic)	Perimeter	CFIT	0.19
Rushton (1997)	100 East Asian-American 7-year-olds, 54% female	Perimeter	WISC	0.21
Tramo et al. (1998)	20 individuals (10 pairs of identical twins) aged 24–43 years	Perimeter	WAIS-R	0.14
Tan et al. (1999)	54 female university students in Turkey	Capacity	CFIT	0.55
Tan et al. (1999)	49 male university students in Turkey	Capacity	CFIT	0.29
Ivanovic, Olivares, Castro, and Ivanovic (1996).	4,124 school children of both sexes aged 6–17 years in Chile	Perimeter-for-age	School grades	0.24
Ivanovic, Forno, Castro, and Ivanovic (2000)	4,509 5- to 22-year-old male and female students in Chile	Perimeter-for-age	Raven's Matrices	0.22
Wickett et al. (2000)	68 individuals (34 pairs of brothers) aged 20–35 years	Perimeter	g, from MAB and other tests	0.19
Ivanovic et al. (2004)	47 male 18-year-old high school students in Chile selected from the richest and poorest counties	Perimeter-for-age	WAIS-R	0.50
Ivanovic et al. (2004)	49 female 18-year-old high school students in Chile selected from the richest and poorest counties	Perimeter-for-age	WAIS-R	0.40
Beckett et al. (2006)	77 Romanian children (66% male) adopted into UK families with head size measured before age 43 months and GMA scores measured at 11 years	Perimeter	4 scales from WISC-III (UK)	0.27
Bates (2007)	164 university students aged 21 years (124 female, 40 male)	Perimeter	Raven's Matrices	0.21
Rushton, Cvorovic, et al. (2007)	323 16- to 66-year-old Serbian Roma Gypsies (111 males, 212 females)	Capacity	Raven's Matrices	0.13
Rushton, Vernon, et al. (2007)	239 18- to 25-year-old Canadians (108 males, 131 females; 77% White)	Perimeter	g, from MAB and Wonderlic	0.19
Number of samples: 59
Total N: 63,405
Unweighted mean r: 0.21
N-weighted mean r: 0.20

Note. CFIT, Culture-Free Intelligence Test; MAB, Multidimensional Aptitude Battery; NART, New Adult Reading Test; PMAT, Primary Mental Abilities Test; WAIS-R, Wechsler Adult Intelligence Scale-Revised; WISC, Wechsler Intelligence Scale for Children; WISC-III (UK), Wechsler Intelligence Scale for Children, 3rd Edition, UK standardization; Wonderlic, Wonderlic Personnel Test.

Ho K. C., Roessmann U., Straumfjord J. V., Monroe G. Analysis of brain weight: I & II. Archives of Pathology and Laboratory Medicine 1980; 104: 635–645

 PubMed Web of Science ®Google Scholar

Ankney C. D. Sex differences in relative brain size: The mismeasure of woman, too?. Intelligence 1992; 16: 329–336

 Web of Science ®Google Scholar

Rushton J. P. Cranial capacity related to sex, rank, and race in a stratified random sample of 6,325 U.S. military personnel. Intelligence 1992a; 16: 401–413

 Web of Science ®Google Scholar

Rushton J. P. Cranial size and IQ in Asian Americans from birth to age seven. Intelligence 1997; 25: 7–20

 Web of Science ®Google Scholar

Russell D. A. Exponential evolution: Implications for intelligent extraterrestrial life. Advances in Space Research 1983; 3: 95–103

 PubMedGoogle Scholar

Willerman L., Schultz R., Rutledge J. N., Bigler E. D. In vivo brain size and intelligence. Intelligence 1991; 15: 223–228

 Web of Science ®Google Scholar

Andreasen N. C., Flaum M., Swayze V., O'Leary D. S., Alliger R., Cohen G., et al. Intelligence and brain structure in normal individuals. American Journal of Psychiatry 1993; 150: 130–134

 PubMed Web of Science ®Google Scholar

Raz N., Torres I. J., Spencer W. D., Millman D., Baertschi J. C., Sarpel G. Neuroanatomical correlates of age-sensitive and age-invariant cognitive abilities: An in vivo MRI investigation. Intelligence 1993; 17: 407–422

 Web of Science ®Google Scholar

Egan V., Chiswick A., Santosh C., Naidu K., Rimmington J. E., Best J. J. K. Size isn't everything: A study of brain volume, intelligence and auditory evoked potentials. Personality and Individual Differences 1994; 17: 357–367

 Web of Science ®Google Scholar

Egan V., Wickett J. C., Vernon P. A. Brain size and intelligence: Erratum, addendum, and correction. Personality and Individual Differences 1995; 19: 113–115

 Web of Science ®Google Scholar

Castellanos F. X., Giedd J. N., Eckburg P., Marsh W. L., Vaituzis A. C., Kaysen D., et al. Quantitative morphology of the caudate nucleus in attention deficit hyperactivity disorder. American Journal of Psychiatry 1994; 151: 1791–1796

 PubMed Web of Science ®Google Scholar

Harvey I., Persaud R., Ron M. A., Baker G., Murray R. M. Volumetric MRI measurements in bipolars compared with schizophrenics and healthy controls. Psychological Medicine 1994; 24: 689–699

 PubMed Web of Science ®Google Scholar

Jones P. B., Harvey I., Lewis S. W., Toone B. K., Van Os J., Williams M., et al. Cerebral ventricle dimensions as risk factors for schizophrenia and affective psychosis: An epidemiological approach to analysis. Psychological Medicine 1994; 24: 995–1011

 PubMed Web of Science ®Google Scholar

Wickett J. C., Vernon P. A., Lee D. H. In vivo brain size, head perimeter, and intelligence in a sample of healthy adult females. Personality and Individual Differences 1994; 16: 831–838

 Web of Science ®Google Scholar

Kareken D. A., Gur R. C., Mozley P. D., Mozley L. H., Saykin A. J., Shtasel D. L., et al. Cognitive functioning and neuroanatomic volume measures in schizophrenia. Neuropsychology 1995; 9: 211–219

 Web of Science ®Google Scholar

Reiss A. R., Abrams M. T., Singer H. S., Ross J. R., Denckla M. B. Brain development, gender and IQ in children: A volumetric study. Brain 1996; 119: 1763–1774

 PubMed Web of Science ®Google Scholar

Flashman L. A., Andreasen N. C., Flaum M., Swayze V. W., II. Intelligence and regional brain volumes in normal controls. Intelligence 1998; 25: 149–160

 Web of Science ®Google Scholar

Tramo M. J., Loftus W. C., Stukel T. A., Green R. L., Weaver J. B., Gazzaniga M. S. Brain size, head size, and intelligence quotient in monozygotic twins. Neurology 1998; 50: 1246–1252

 PubMed Web of Science ®Google Scholar

Gur R. C., Turetsky B. I., Matsui M., Yan M., Bilkur W., Hughett P., et al. Sex differences in brain gray and white matter in healthy young adults: Correlations with cognitive performance. Journal of Neuroscience 1999; 19: 4065–4072

 PubMed Web of Science ®Google Scholar

Tan U., Tan M., Polat P., Ceylan Y., Suma S., Okur A. Magnetic resonance imaging brain size/IQ relations in Turkish university students. Intelligence 1999; 27: 83–92

 Web of Science ®Google Scholar

Wickett J. C., Vernon P. A., Lee D. H. Relationships between factors of intelligence and brain volume. Personality and Individual Differences 2000; 29: 1095–1122

 Web of Science ®Google Scholar

Pennington B. F., Filipek P. A., Lefly D., Chhabildas N., Kennedy D. N., Simon J. H., et al. A twin MRI study of size variations in the human brain. Journal of Cognitive Neuroscience 2000; 12: 223–232

 PubMed Web of Science ®Google Scholar

Schoenemann P. T., Budinger T. F., Sarich V. M., Wang W. Brain size does not predict general cognitive ability within families. Proceedings of the National Academy of Sciences 2000; 97: 4932–4937

 PubMed Web of Science ®Google Scholar

Aylward E. H., Minshew N. J., Field K., Sparks B. F., Singh N. Effects of age on brain volume and head circumference in autism. Neurology 2002; 59: 175–183

 PubMed Web of Science ®Google Scholar

MacLullich A. M. J., Ferguson K. J., Deary I. J., Seckl J. R., Starr J. M., Wardlaw J. M. Intracranial capacity and brain volumes are associated with cognition in healthy elderly men. Neurology 2002; 59: 169–174

 PubMed Web of Science ®Google Scholar

Ivanovic D. M., Leiva B. P., Castro C. G., Olivares M. G., Jansana J. M. M., Castro V. G., et al. Brain development parameters and intelligence in Chilean high school graduates. Intelligence 2004; 32: 461–479

 Web of Science ®Google Scholar

Deary I. J., Ferguson K. J., Bastin M. E., Barrow W. S., Reid L. M., Seckl J. R., et al. Skull size and intelligence, and King Robert Bruce's IQ. Intelligence 2007; 35: 519–525

 Web of Science ®Google Scholar

Pearl R. On the correlation between intelligence and the size of the head. Journal of Comparative Neurology and Psychology 1906; 16: 189–199

 Google Scholar

Pearson K. On the relationship of intelligence to size and shape of head, and to other physical and mental characters. Biometrika 1906; 5: 105–146

 Google Scholar

Murdock J., Sullivan L. R. A contribution to the study of mental and physical measurements in normal school children. American Physical Education Review 1923; 28: 209–330

 Google Scholar

Reid R. W., Mulligan J. H. Relation of cranial capacity to intelligence. Journal of the Royal Anthropological Institute 1923; 53: 322–331

 Google Scholar

Sommerville R. C. Physical, motor and sensory traits. Archives of Psychology 1924; 12: 1–108

 Google Scholar

Estabrooks G. H. The relation between cranial capacity, relative cranial capacity and intelligence in school children. Journal of Applied Psychology 1928; 12: 524–529

 Google Scholar

Porteus S. D. Primitive Intelligence and Environment, et al. Macmillan, New York 1937

 Google Scholar

Schreider E. Quelques corrélations somatiques des tests mentaux. Homo 1968; 19: 38–43

 Google Scholar

Klein R. E., Freeman H. E., Kagan J., Yarborough C., Habicht J. P. Is big smart? The relation of growth to cognition. Journal of Health and Social Behavior 1972; 13: 219–250

 PubMed Web of Science ®Google Scholar

Susanne C., Sporcq J. Etude des correlations existent entre des tests psycho-techniques et des mensurations cephaliques. Bulletin de la Société Royale Belge d'Anthropologie et de Préhistoire 1973; 84: 59–69

 Google Scholar

Weinberg W. A., Dietz S. G., Penick E. C., McAlister W. H. Intelligence, reading achievement, physical size and social class. Journal of Pediatrics 1974; 85: 482–489

 PubMed Web of Science ®Google Scholar

Passingham R. E. Brain size and intelligence in man. Brain, Behavior and Evolution 1979; 16: 253–270

 PubMed Web of Science ®Google Scholar

Susanne C. On the relationship between psychometric and anthropometric traits. American Journal of Physical Anthropology 1979; 51: 421–423

 Web of Science ®Google Scholar

Pollitt E., Mueller W., Liebel R. L. The relation of growth to cognition in a well-nourished preschool population. Child Development 1982; 53: 1157–1163

 PubMed Web of Science ®Google Scholar

Majluf A. Desarrollo mental, postural y somatico de infants de 8, 14y 20 meses de edad, de clase socioeconomica media y baja de Lima. Revista Latinoamericana de Psicologia 1983; 15: 369–386

 Google Scholar

Ounsted M., Moar V. A., Scott A. Associations between size and development at four years among children who were small-for-dates and large-for-dates at birth. Early Human Development 1984; 9: 259–268

 PubMed Web of Science ®Google Scholar

Henneberg M., Budnik A., Pezacka M., Puch A. E. Head size, body size and intelligence: Intraspecific correlations in Homo sapiens sapiens. Homo 1985; 36: 207–218

 Google Scholar

Sen A. K., Phulia S. S., Wasnik B. K. Physical growth and intellectual level: A comparative study between scheduled caste and general caste students. Indian Journal of Current Psychological Research 1986; 1: 101–106

 Google Scholar

Broman S. H., Nichols P. L., Shaughnessy P., Kennedy W. Retardation in Young Children, et al. Erlbaum, Hillsdale, NJ 1987

 Google Scholar

Ernhart C. B., Marler M. R., Morrow-Tlucak M. Size and cognitive development in the early preschool years. Psychological Reports 1987; 61: 103–106

 PubMed Web of Science ®Google Scholar

Bogaert A. F., Rushton J. P. Sexuality, delinquency and r/K reproductive strategies: Data from a Canadian university sample. Personality and Individual Differences 1989; 10: 1071–1077

 Web of Science ®Google Scholar

Lynn R. A nutrition theory of the secular increases in intelligence. Positive correlations between height, head size and IQ. British Journal of Educational Psychology 1989; 59: 372–377

 Web of Science ®Google Scholar

Lynn R. New evidence on brain size and intelligence: A comment on Rushton and Cain and Vanderwolf. Personality and Individual Differences 1990; 11: 795–797

 Web of Science ®Google Scholar

Osborne R. T. Cranial capacity and IQ. Mankind Quarterly 1992; 32: 275–280

 Google Scholar

Rushton J. P. Life history comparisons between Orientals and Whites at a Canadian university. Personality and Individual Differences 1992b; 13: 439–442

 Web of Science ®Google Scholar

Lynn R. Further evidence for the existence of race and sex differences in cranial capacity. Social Behavior and Personality 1993; 21: 89–92

 Web of Science ®Google Scholar

Reed T. E., Jensen A. R. Cranial capacity: New Caucasian data and comments on Rushton's claimed Mongoloid-Caucasoid brain size differences. Intelligence 1993; 17: 423–431

 Web of Science ®Google Scholar

Furlow F. B., Armijo-Prewitt T., Gangestad S. W., Thornhill R. Fluctuating asymmetry and psychometric intelligence. Proceedings of the Royal Society of London, B 1997; 264: 823–829

 Web of Science ®Google Scholar

Ivanovic D. M., Olivares M. G., Castro C. G., Ivanovic R. M. Nutrition and learning in Chilean school age children: Chile's Metropolitan Region Survey 1986–1987. Nutrition 1996; 12: 321–328

 PubMed Web of Science ®Google Scholar

Ivanovic R. M., Forno H. S., Castro C. G., Ivanovic D. M. Intellectual ability and nutritional status assessed through anthropometric measurements of Chilean school-age children from different socioeconomic status. Ecology of Food and Nutrition 2000; 39: 35–59

 Web of Science ®Google Scholar

Beckett C., Maughan B., Rutter M., Castle J., Colvert E., Groothues C., et al. Do the effects of early severe deprivation on cognition persist into early adolescence? Findings from the English and Romanian adoptees study. Child Development 2006; 77: 696–711

 PubMed Web of Science ®Google Scholar

Bates T. C. Fluctuating asymmetry and intelligence. Intelligence 2007; 35: 41–46

 Web of Science ®Google Scholar

Rushton J. P., Ankney C. D. The evolution of brain size and intelligence. Evolutionary Cognitive Neuroscience, S. M. Platek, J. P. Keenan, T. K. Shackelford. MIT Press, Cambridge, MA 2007; 121–161

 Google Scholar