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

Generational intelligence test score changes were predominantly positive over most of the past century. However, so far, only little is known about this so-called Flynn effect in children that have not yet been exposed to formal schooling. So far, the cross-temporal trajectory of performance changes on developmental tests is unclear. Here, we investigated test score changes in Germanophone preschoolers on six areas of the Viennese Developmental Test (VDT/WET). First, we used data of standardization samples (N = 1630) in Austria and Germany to calculate changes between 1996 and 2008.5. Subsequently, we used a cross-temporal meta-analytic approach to investigate another 22 independent samples (k = 1251) from 2001 to 2018. Examination of both raw score and latent mean changes yielded mostly non-significant and trivial changes in cognitive development between three standardizations. Only change scores of the most fluid developmental domain showed positive signs, thus conforming to prior observations of larger Flynn effect for fluid than for crystallized intelligence (maximum overall changes ranged from −1.44 to 0.78 IQ points per decade). Results of our cross-temporal analyses were largely consistent in signs with overall changes, but failed to reach nominal significance in all instances. Our findings indicate that there is no convincing evidence for a Flynn effect in cognitive development in three-to-six year-olds. These findings support the role of education as an important driver of test score gains. Future research needs to determine if such a pattern may be a precursor of a Flynn effect stagnation or even its reversal.