The relationship between intelligence and academic performance has been the subject of ongoing research in psychology and education. In a study conducted by Kpolovie (2016), published in the International Journal of Recent Scientific Research, this relationship was systematically examined over four years with a sample of 637 Nigerian students followed from the ages of 14 to 17. The methodological design adopted was longitudinal research, using the Culture Fair Intelligence Test (CFIT) to measure intelligence, and the JSCE and SSCE exams as indicators of academic performance in Mathematics and English. The statistical analysis applied partial correlation to isolate the effects of the variables.
The study reveals a strong relationship between intelligence quotient (IQ) and academic performance, particularly in Mathematics. When controlling for the effect of English Language, the correlation between IQ and mathematical performance was 0.499 in junior high and 0.495 in senior high. This means that intelligence explains about 24.9% and 24.5% of the variance in mathematical performance, respectively. For English Language, when controlling for the effect of Mathematics, the correlations were 0.411 and 0.346, indicating that IQ accounted for 16.89% and 11.97% of the variance in English performance, respectively, in the two levels of education analyzed (Kpolovie, 2016, p. 11429-11433).
A particularly notable point of the study was the evidence of stability of intelligence over the four years: the correlation between IQ scores at the two time points was 0.702, reinforcing the theoretical robustness of the differentiation between fluid (ff) and crystallized (cg) intelligence, as proposed by Cattell. According to this theory, fluid intelligence stabilizes after the age of 14 — exactly the initial age of the sample investigated — while crystallized intelligence continues to develop based on school and cultural experiences (Kpolovie, 2016, p. 11433-11434).
The study also presents a conceptually relevant finding: when the effect of intelligence was controlled, the correlation between performance in Mathematics and English dropped dramatically and was no longer statistically significant. This suggests that the apparent relationship between these subjects derives largely from a common latent factor—general intelligence—and not from a direct impact between one subject and another. This observation shows that intelligence acts as an integrative construct that influences multiple spheres of school performance, reinforcing its centrality in cognitive theories (Kpolovie, 2016, p. 11431-11433).
Additionally, the author points out that, although factors such as school environment, pedagogical methods and motivation also affect academic performance, it is intelligence — understood as the general mental capacity to learn quickly, solve problems, think rationally and adapt efficiently — that plays a preponderant and often neglected role in the educational policies of developing countries such as Nigeria (Kpolovie, 2016, p. 11427-11428).
The study concludes that it presents robust empirical evidence that intelligence, especially in its fluid dimension, is strongly associated with academic performance in formal educational contexts. Public policies and pedagogical practices that disregard this variable run the risk of obscuring one of the main determinants of academic success. As the author himself argues, it is urgent to incorporate intelligence assessments as a diagnostic and predictive tool in the educational system, not with the aim of labeling, but of personalizing interventions and maximizing students’ cognitive development.
Reference:
KPOLOVIE, PJ Intelligence and academic achievement: a longitudinal survey. International Journal of Recent Scientific Research, vol. 7, no. 5, p. 11423–11439, 2016.
