Do iq scores change
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Do IQ Scores Change Over Time?
Stability and Variability of IQ Scores
IQ scores are generally considered stable across the lifespan, but research indicates that this stability is not absolute. Studies have shown that while many individuals exhibit negligible changes in IQ, a significant minority experience marked and real changes. These changes can be variable in timing, idiosyncratic in source, and often transient. For instance, a study on children aged 7 to 13 found that most IQ changes were either negligible or unreliably measured, but a nontrivial minority showed significant naturalistic changes.
Factors Influencing IQ Changes
Literacy and Education
One of the primary factors influencing changes in IQ scores is literacy. Variations in literacy levels across different times, places, and races have been highly associated with changes in IQ scores. This suggests that as universal literacy improves, differences in IQ scores between populations and racial groups are likely to diminish. Additionally, cross-national studies have found that IQ scores are positively correlated with education levels and negatively correlated with agricultural lifestyles, indicating that cognitive demands in developed countries promote an increase in cognitive ability.
Societal and Environmental Influences
Societal and educational changes also play a significant role in the comparability of IQ scores over time. For example, a study comparing Estonian students over several decades found a secular rise in IQ scores, known as the Flynn Effect. However, the meaning of subtests and the g score has changed over time, making direct comparisons between different cohorts challenging. Environmental factors such as socioeconomic status and parental attitudes towards intellectual development have also been shown to influence IQ scores.
Neurodevelopmental Changes
Neuroimaging studies have provided insights into how brain development correlates with changes in IQ. Research has shown that both verbal and non-verbal IQ can rise or fall during the teenage years, with these changes closely linked to alterations in local brain structure. This suggests that an individual's intellectual capacity relative to their peers can fluctuate during adolescence, emphasizing the dynamic nature of cognitive development.
Special Populations
In children with developmental delays, significant IQ changes have been observed over short periods. For instance, a study on preschoolers with developmental delays found a significant increase in mean IQ scores over two years, with 26% of the subjects showing an increase of 16 points or more. Factors such as initial clinical diagnosis and intervention played a role in these changes.
Conclusion
In summary, while IQ scores are generally stable, they can and do change over time due to a variety of factors including literacy, education, societal changes, and neurodevelopmental processes. These changes are often complex and influenced by both genetic and environmental variables. Understanding these dynamics is crucial for developing effective interventions aimed at improving cognitive abilities.
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