Intensive schooling and cognitive ability: A case of Polish educational reform

Abstract

Intelligence is the most critical predictor of school successes, yet the length and quality of education influence cognitive development as well. Using data collected during the recent educational reform introduced in Poland, this study examined whether schooling's intensity relates to changes in cognitive abilities. Due to the reformed structure and curricula, students who attended the last two grades of the reformed primary school (i.e., new grades 7–8) had to master in two years the curricula that were earlier realized in three years of middle schools. We examined changes in cognitive abilities in two cohorts: pre-reform middle schoolers (2nd grade, average age 14) and post-reform primary schoolers (7th grade, average age 13), measured at the beginning of 2nd/7th grade and the end of the school year. At the beginning of the school year, there was a slight yet significant difference in cognitive ability between cohorts (d = 0.22, or an equivalent of 3 IQ points) – the combined effect of age and prior school influences. We also observed a statistically significant increase in intelligence in both groups (average change in latent means d = 0.14/2 IQ points), with a slightly stronger effect among more intensively educated primary schoolers (d = 0.20/3 IQ points) than middle-school students (d = 0.09/1 IQ point). However, after separate analyses for verbal and nonverbal intelligence, together with additional robustness checks, we conclude that the effect of more intensive schooling on cognitive growth was not systematic and quite unstable. We discuss the consequences of these findings and future research directions.