Faktorenanalytische Untersuchungen zur Differenzierungshypothese der Intelligenz: Die Leistungsdifferenzierungshypothese

Intellectual functioning in old and very old age: Cross-sectional results from the Berlin Aging Study.

“…findings indicate that very old, low-ability participants have the most dedifferentiated pattern of intellectual performance because they are most likely to perform at a level that is uniformly low across all tests of the battery. Historically, this dedifferentiation of task profiles in very old, low-ability individuals is consistent with the so-called ability differentiation hypothesis put forward in the 1960s (Reinert, Baltes, & Schmidt, 1965, 1966Wewetzer, 1968). In light of our methodological precautions in computing the intraindividual task dispersion score, we hold it unlikely that this late-life flattening of the ability profile in lowability individuals primarily reflects a floor effect in the technical sense of a measurement artifact.…”

Ability structure in 10-11-year-old children and the theory of fluid and crystalized intelligence.

“…Depending on the age level and school situation as well as on the sampling of variables, a comparison among samples varying in age may present results that appear to be contradictory. The present findings suggest that the degree of differentiation not only depends on age-or on the absolute level of intellectual performance, the latter hypothesized by Reinert, Baltes, and Smidt (1965)-but also on the covariation of motivational and rewarding experiences over domains of in-tellectual functioning, quite possibly somewhat independent of age or the level of performance per se. Intellectual tasks most related to formal teaching of complex skills formed a rather tight unit at the age of 10-11 years and in a school system with little specialization at that level.…”

Spearman's “Law of Diminishing Returns” tested with two methods

“…When consulting the literature the majority of studies support SLODR (ability) (e.g., Abad, Colom, Juan-Espinosa, & Garcia, 2003;Baumeister & Bartlett, 1962;Birren, 1952;Carlstedt, 2001;Coyle, 2002;Deary et al, 1996;Der & Deary, 2002;Detterman & Daniels, 1989;Detterman et al, 1992;Evans, 1999;Filella, 1960;Jäger, 1964;Jäger & Todt, 1964;Jensen, 2003;Kane, 2000;Legree, Pifer, & Grafton, 1996;Lienert, 1961Lienert, , 1964Lienert & Faber, 1963;Lynn, 1992;Lynn & Cooper, 1993, 1994Mitchell, 1956;Maxwell, 1972;Nesselroade & Thompson, 1995;Reinert, Baltes, & Schmidt, 1965;Segel, 1948;Spearman, 1927;Wewetzer, 1958) but some studies either find no difference in g saturation or find the opposite pattern (Amelang & Langer, 1968;Bloom et al, 1988;DeVoss, 1926;Eyferth, 1963;Facon, 2004;Fogarty & Stankov, 1995;Hartmann & Teasdale, 2004, accepted for publication; Roesslein, 1953). However, not all studies are equally valid and it is therefore necessary to look at the individual studies in order to investigate whether the specific study controls for potential confounders.…”