The Flynn effect in Germanophone preschoolers (1996–2018): Small effects, erratic directions, and questionable interpretations

Measurement-Invariant Fluid Anti-Flynn Effects in Population-Representative German Student Samples (2012-2022)

Generational IQ test scores in the general population were observed to increase over time (i.e., the Flynn effect) across most of the 1900s. However, according to more recent reports, Flynn effect patterns have seemingly become less consistent. So far, most available evidence on this phenomenon has been categorized by drawing on the classic fluid vs. crystallized intelligence taxonomy. However, recent evidence suggests that subdomain-specific trajectories of IQ change may well be more complex. Here, we present evidence for cross-temporal changes in measurement-invariant figural reasoning tasks in three large-scale, population-representative samples of German secondary school students (total N = 19,474). Analyses revealed a consistent pattern of significant and meaningful declines in performance from 2012 to 2022. Results indicate a decrease in figural reasoning of 4.68 to 5.17 IQ points per decade (corresponding to small-to-medium effects, Cohen ds from 0.34 to 0.38). These findings may be interpreted as tentative evidence for a decreasing strength of the positive manifold of intelligence as a potential cause of the increasing number of recent reports about inconsistent IQ change trajectories.

Factorial Validity of the German KABC-II at Ages 7 to 12 in a Clinical Sample: Four Factors Fit Better than Five

Multidimensional intelligence test batteries such as the KABC-II are widely used in clinical practice. Although validity evidence should be provided for all intended uses of a test, data on the factorial validity of the KABC-II mostly relies on the standardization samples and raises some concerns about the adequacy of the factor structure. Confirmatory factor analyses of the KABC-II core subtests were conducted in a sample of 627 children who had been assessed in German Centers for Social Pediatrics. The standard structure of the KABC-II was superior to unidimensional models but, as in previous research, evidenced cross-loadings and a high correlation between Planning/Gf and Simultaneous/Gv. Pattern Reasoning was more closely related to Simultaneous/Gv than to Planning/Gf. A four-factorial structure combining subtests from Planning/Gf and Simultaneous/Gv to form a common factor emerged as a better representation of the data. Story Completion showed a secondary loading on Knowledge/Gc. On average, most subtest variance was accounted for by the general factor. Models with bonus points for fast responses generally fitted worse than those without. Clinicians should be aware that Planning/Gf and Simultaneous/Gv measure both visual and fluid abilities. Scales of the KABC-II should not be interpreted as dimensions independent of the general factor.