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

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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.

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Author information

Authors and Affiliations

  1. Universidade Federal de Pelotas, Pelotas, Brazil

    Pedro San Martin Soares, Fernando César Wehrmeister, Ana Maria Menezes, Helen Gonçalves, Bernardo Horta, Janaina Motta & Fernando Hartwig

Authors
  1. Pedro San Martin Soares
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  2. Fernando César Wehrmeister
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  3. Ana Maria Menezes
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  4. Helen Gonçalves
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  5. Bernardo Horta
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  6. Janaina Motta
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  7. Fernando Hartwig
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Contributions

All authors contributed to study design, data analysis, data interpretation, and drafting and revision of the manuscript, and gave final approval of the version to be submitted for publication. The corresponding author had full access to all the data in the study and had final responsibility for the decision to submit for publication. The authors declare no conflicts of interest.

Corresponding author

Correspondence to Pedro San Martin Soares.

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Conflict of interests

The authors declare no competing interests.

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Supplementary file1 (DOCX 99 KB)

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Soares, P.S.M., Wehrmeister, F.C., Menezes, A.M. et al. Investigating changes in IQ scores over a decade in Brazil: factors at play. Soc Psychiatry Psychiatr Epidemiol (2024). https://doi.org/10.1007/s00127-024-02623-3

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  • DOI: https://doi.org/10.1007/s00127-024-02623-3

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