Domain-specificity of Flynn effects in the CHC-model: Stratum II test score changes in Germanophone samples (1996–2018)

Generational IQ test score changes and the positive manifold of intelligence: evidence from Austrian Air Force pilots and air traffic controllers (1992-2016)

Increasingly inconsistent generational IQ test score change patterns across recent decades have been suggested to be due to increased ability differentiation as a consequence of cross-temporally decreasing strengths of the positive manifold of intelligence. Here, we investigate the Flynn effect and directly test the idea of a changing positive manifold, based on the performance of N = 204 Austrian Air Force pilots and air traffic controllers across twelve IQ subtests. Subscale change scores indicated consistent gains in measures related to the CHC (Cattell-Horn-Carroll) stratum II domains of fluid reasoning, quantitative knowledge, and retrieval. However, change patterns in the stratum II domains working memory and comprehension knowledge were ambiguous and suggest stratum I-based differentiation of the Flynn effect. In all, our results indicate positive and substantial Flynn effects in the majority of examined subscales, but no evidence for any meaningful changes in the positive manifold strength.

Generalizability of the Swedish WISC-V to the Finland-Swedish minority - the FinSwed study

International guidelines highlight the importance of using appropriate and culturally fair test materials when conducting clinical psychological assessments. In the present study, the generalizability of the Swedish WISC-V with Scandinavian normative data was explored in 6-16-year-old Swedish-speaking children in Finland (N = 134), as no local test versions or norms are available for this minority. First, metric measurement invariance was established, i.e., the constructs measured were equivalent between the standardization data and the present sample. Second, the performance of this minority group on the Swedish WISC-V was compared to the Scandinavian normative mean. The findings showed that the Finland-Swedish children performed overall higher than the normative mean on the Swedish WISC-V, with an FSIQ of 103. The performance was significantly higher also in the indexes VSI, FRI, and WMI as well as in several subtests. However, in the subtest Vocabulary, the Finland-Swedish children achieved significantly lower scores than the Scandinavian mean. Further analyses showed significant associations between cognitive performance and age as well as parental education. For the VCI and the FSIQ, performance increased significantly with age, despite the use of age-standardized scaled scores. The general high performance was suggested to relate to the overall high educational level of the Finland-Swedes as well as to other cultural and test-related factors. The results have implications for clinicians conducting assessments with this minority, but also highlight the importance of establishing test fairness by validating tests when used in different cultural groups.

Increasing IQ Test Scores and Decreasing g: The Flynn Effect and Decreasing Positive Manifold Strengths in Austria (2005-2018)

After almost a century of global generational IQ test score gains, the Flynn effect has, in the past decades, been observed to show stagnation and reversals in several countries. Tentative evidence from academic achievement data has suggested that these trajectory changes may be rooted in a decreasing strength of the positive manifold of intelligence due to increasing ability differentiation and specialization in the general population. Here, we provide direct evidence for generational IQ test score and positive manifold strength changes based on IQ test standardization data from 1392 Austrian residents between 2005 and 2018. Our analyses revealed positive Flynn effects across all domains of the IQ test (Cohen's d from 0.21 to 0.91) but a trend toward decreasing strength in the positive manifold of intelligence (R2 from .908 to .892), though these changes were not statistically significant. Our results are consistent with the idea that increasingly inconsistent Flynn effect trajectories may be attributed to increasing ability differentiation and specialization in the general population over time.

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.