Investigating changes in IQ scores over a decade in Brazil: factors at play.

ABSTRACT

PURPOSE: This study aimed to determine whether the factors underlying potential differences between two birth cohorts, born in 1982 and 1993, influence the changes in IQ over time. METHODS: Data from two Brazilian birth cohorts were used (1993 and 1982 Pelotas Birth Cohorts). The IQ scores were assessed using the WAIS-III test. RESULTS: Results showed that women born in 1993 had a higher average IQ score than those born in 1982, but no difference was found among men. The increase in IQ scores was only limited to participants from families with an income ranging from 1.1 to 3 times the minimum wage at the time of birth. The mean IQ score of participants born to mothers below the age of 20 remained stable over time, but increase for participants whose mothers were 20 years of age or older at the time of birth. CONCLUSIONS: This study emphasizes the importance of considering socio-economic and demographic factors when examining differences in IQ scores over time. Further research is needed to understand the underlying mechanisms of these findings.