Intelligence Differentiation in Early Childhood
According to the age differentiation hypothesis, cognitive abilities become more differentiated with increasing age during childhood. Using data from the German standardization of the SON-R 2½–7 intelligence test, we examined age-related differentiation of cognitive abilities from age 2½ to age 7. The SON-R 2½–7 is a nonverbal intelligence test for children and consists of six subtests. SON-R 2½–7 supposedly has a two-factorial structure, with a reasoning and a performance factor. We used age-weighted measurement models to describe the age gradients of model parameter estimates. In line with the differentiation hypothesis, we observed a decrease in the correlation between both factors with increasing age. We tested the significance of this observed decrease using a permutation test. Participants were allocated age randomly in 1,000 datasets. Age-weighted measurement models were estimated to observe the age gradients of the correlation between the two factors in these datasets. The results of the permutation test show that the decrease in the correlation observed in the real dataset is significant but of small magnitude. The findings provide some support for intelligence differentiation with increasing childhood age.
1941). An analysis of the mental factors of various age groups from nine to sixty. Genetic Psychology Monographs, 23, 191–234.(
1980). Integration vs. differentiation of fluid-crystallized intelligence in old age. Developmental Psychology, 16, 625–635.(
1955). On the growth of intelligence. American Psychologist, 10, 805–818.(
1990). Comparative fit indexes in structural models. Psychological Bulletin, 107, 238–246.(
1995). The three-stratum theory of cognitive abilities: Test of the structure of intelligence across the lifespan. Intelligence, 20, 309–328.(
1954). The differentiation of intellectual ability. British Journal of Educational Psychology, 24, 76–90.(
1993). Human cognitive abilities: A survey of factor-analytic studies. New York: Cambridge University Press.(
1971). Abilities: Their structure, growth and action. Boston, MD: Houghton Mifflin.(
1987). Intelligence: Its structure, growth, and action. Amsterdam: North-Holland.(
1996). Intelligence and the differentiation hypothesis. Intelligence, 23, 105–132.(
2007). Sensitivity of fit indexes to misspecified structural or measurement model components: Rationale of two-index strategy revisited. Structural Equation Modeling, 12, 343–367.(
1960). Educational and sex differences in the organization of abilities in technical and academic students in Colombia, South America. Genetic Psychology Monographs, 61, 115–163.(
1946). A developmental theory of intelligence. American Psychologist, 1, 372–378.(
2004). Kernel estimation, shape-invariant modeling and structural analysis. In R. Hauspie N. Cameron L. Molinari, Eds., Methods in human growth research (pp. 179–204). Cambridge: Cambridge University Press.(
2009). Intelligence and Development Scales (IDS). Bern: Huber.(
2009). Complementary and competing factor analytic approaches for the investigation of measurement invariance. Review of Psychology, 16, 87–102.(
1966). Refinement and test of the theory of fluid and crystallized general intelligences. Journal of Educational Psychology, 57, 253–270.(
1982). Mehrmodale Klassifikation von Intelligenzleistungen: Experimentell kontrollierte Weiterentwicklung eines deskriptiven Intelligenzstrukturmodells [(
Multimodal classification of intelligence tests: Experimentally controlled development of a descriptive model of intelligence structure]. Diagnostica, 28, 195–225.
1984). Intelligenzstrukturforschung: Konkurrierende Modelle, neue Entwicklungen, Perspektiven [Intelligence structure research: Competing models, new developments, perspectives]. Psychologische Rundschau, 35, 21–35.(
2000). Testing the age-related differentiation hypothesis through the Wechsler’s scales. Personality and Individual Differences, 29, 1069–1075.(
2004). Lifespan transformations in the couplings of mental abilities and underlying cognitive processes. Psychological Science, 15, 155–163.(
1963). Über die Faktorenstruktur des HAWIK auf verschiedenen Alters- und Intelligenzniveaus [(
On the factor structure of the HAWIK at various levels of age and intelligence]. Diagnostica, 9, 3–11.
2006). A nonarbitrary method of identifying and scaling latent variables in SEM and MACS models. Structural Equation Modeling, 13, 59–72.(
1999). Test theory: A unified treatment. Mahwah, NJ: Erlbaum.(
2009). CHC theory and the human cognitive abilities project: Standing on the shoulders of the giants of psychometric intelligence research. Intelligence, 37, 1–10.(
1998). The Intelligence Test Desk Reference: Gf-Gc cross-battery assessment. Boston: Allyn & Bacon.(
1998–2007). Mplus user’s guide (5th ed.). Los Angeles, CA: Muthén and Muthén.(
1995). Selection and related threats to group comparisons: An example comparing factorial structures of higher and lower ability groups of adult twins. Psychological Bulletin, 117, 271–284.(
1970). Comparative factor analytic studies of intelligence through the human life-span. In L. R. Goulet P. B. Baltes, Eds., Life-span developmental psychology: Research and theory (pp. 468–485). New York: Academic Press.(
2010). Memory maintenance and inhibitory control differentiate from early childhood to adolescence. Developmental Neuropsychology, 35, 679–697.(
1997). Snijders-Oomen Nonverbaler Intelligenztest SON-R 5.5–17 [(
Snijders-Oomen nonverbal intelligence test SON-R 5.5–17]. Göttingen: Hogrefe.
1943). Intelligentieonderzoek van doofstomme kinderen: een nieuwe testschaal. Proefschrift [(
Intelligence assessment for children with hearing and speaking impairments: A new test scale]. Nijmegen: Berkhout.
1927). The abilities of man. London: Macmillan.(
1990). Structural model evaluation and modification: An interval estimation approach. Multivariate Behavioral Research, 25, 173–180.(
2007). Snijders-Oomen Nonverbaler Intelligenztest von 2½ bis 7 Jahren (SON-R 2½– 7). Handanweisung und deutsche Normen (2. veränd. Aufl.) [(
Snijders-Oomen nonverbal intelligence test for 2½- to 7-year-olds. Manual and German standardization (2nd ed.)]. Göttingen: Hogrefe.
2004). Age-related differentiation of cognitive abilities in ages 3–7. Personality and Individual Differences, 36, 1965–1974.(
2009). Differentiation of cognitive abilities across the lifespan. Developmental Psychology, 45, 1097–1118.(
2008). Adult age trends in the relations among cognitive abilities. Psychology and Aging, 23, 453–460.(