Average iq by age
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Average IQ Scores by Age: Key Findings
Average IQ in Adolescents (Ages 14–17)
Research on students aged 14 to 17 in Vietnam found that the average IQ in this group was 102.28, with a small annual increase of about 2 points per year as age increased within this range. The study also noted that IQ scores followed a normal distribution, with nearly half of the students falling into the average IQ category. Differences were observed between ethnic groups, but the overall trend showed a gradual increase in IQ with age during adolescence .
IQ in Childhood (Around Age 8)
A large study from the UK assessed IQ at age 8 and found that maternal diet during pregnancy was linked to children's IQ scores. Children whose mothers had healthier diets (rich in fruits and vegetables) tended to have higher average IQs at age 8 compared to those whose mothers had less healthy diets. However, the study did not provide a specific average IQ value for this age group .
IQ Trends Across the Lifespan
Meta-analyses and cross-national studies have shown that average IQ scores can change over time and across age groups. The "Flynn effect" describes a general increase in average IQ scores over decades, with gains of about 0.22 points per year. These gains are often stronger in younger generations and in middle-income countries, suggesting that environmental factors and societal changes play a role in shaping average IQ by age .
Heritability and Environmental Influence on IQ by Age
The heritability of IQ increases with age, reaching its highest point (about 80%) in late adolescence and early adulthood (ages 18–20). At the same time, the influence of shared environment decreases as people get older. This means that genetic factors become more important in determining IQ as individuals age, while the impact of family and shared environment lessens .
IQ in Young Adults
A study examining IQ and early life mortality found that the average IQ of living young adults was about 100, while those who died young had a lower average IQ of about 95. This suggests that average IQ in young adulthood is around 100, consistent with the general population mean .
Age-Related IQ Patterns in Specific Populations
In Saudi Arabia, research found that children in the public school system showed an age-related decline in IQ when compared to British and American norms. However, younger age groups in Saudi Arabia have shown IQ gains over time, reflecting the Flynn effect. The study also highlighted the influence of education and maternal factors on children's IQ scores .
Considerations in Measuring IQ by Age
Studies have shown that different intelligence tests and scoring methods (such as ratio IQs versus standard IQs) can yield different results, especially at the extremes of the IQ distribution and for different age groups. This means that exact IQ scores may not always be directly comparable across ages or tests, and caution is needed when interpreting individual scores 78.
Conclusion
Average IQ scores tend to increase slightly during adolescence, with a typical mean around 100 in young adults. The heritability of IQ grows with age, while environmental influences decrease. Over decades, average IQ scores have risen globally, especially among younger generations. However, differences in testing methods, population groups, and environmental factors can affect average IQ by age, so results should be interpreted with care.
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