Question
Can a child's IQ change?
Short answer
Yes, a child’s IQ score can shift, especially when they are young. In children retested on the WISC-V after about 2.6 years, only the overall IQ and two index scores were highly stable. Schooling also matters: each extra year of education adds about 1 to 5 IQ points on average. Rank is fairly stable over decades.
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Short-term: some scores move more than others
A child's overall IQ is more stable than the parts that make it up. In 225 clinic children retested on the WISC-V after an average of 2.6 years, only the Full Scale IQ, Verbal Comprehension and Visual Spatial scores had stability coefficients above 0.80 (Watkins et al., 2022). Other index scores moved more. So a child who scored 108 at 7 might well score a few points differently at 10, and single index scores deserve extra caution.
Long-term: rank is fairly stable
Over a lifetime, the order of people stays recognizable. In the Lothian Birth Cohort 1921, scores on the same test at age 11 and age 90 correlated .54, or .67 after correction for range restriction (Deary et al., 2013). That is strong stability across almost 80 years, but far from fixed: many people moved up or down a good distance.
Try one · Spatial Reasoning
Which option is the same shape, only rotated?
Tap the option you think is right, or show the answer.
Show the answer
Option 2 is the original figure turned a quarter turn counterclockwise.
How to solve it
- Pick a landmark: the marked cell or the end of the longest arm.
- Turn the figure in your head and watch where that landmark goes, and which side the other cells end up on.
- Turning the figure a quarter turn counterclockwise gives option 2.
- Each of the other options is a mirror image: flipping it over would match, but no turn does.
That was 1 puzzle. The full test has 25.
Why children's scores are still settling
In a sample of about 11,000 twin pairs, the heritability of general cognitive ability rose from 41% at age 9 to 55% at 12 and 66% at 17 (Haworth et al., 2010). The researchers suggest that as children grow up, they increasingly select and shape their own experiences. Either way, a childhood score is an early reading, not a final verdict.
What moves it
- Schooling: about 1 to 5 IQ points per additional year of education, across many study designs (Ritchie & Tucker-Drob, 2018).
- Reading: among identical twins, the twin who read better earlier tended to score higher later (Ritchie, Bates & Plomin, 2015).
- Not much else that is sold for it: music training showed about zero effect on general cognitive skills once study quality was accounted for (Sala & Gobet, 2020).
See at what age a child can take an IQ test, does education increase IQ and intelligence across the lifespan.
Sources
- Watkins, M. W., Canivez, G. L., Dombrowski, S. C., et al. (2022). Long-term stability of Wechsler Intelligence Scale for Children, Fifth Edition scores in a clinical sample. Applied Neuropsychology: Child, 11(3), 422-428. doi:10.1080/21622965.2021.1875827 pubmed.ncbi.nlm.nih.gov/33556254/
- Deary, I. J., Pattie, A., & Starr, J. M. (2013). The stability of intelligence from age 11 to age 90 years: The Lothian Birth Cohort of 1921. Psychological Science, 24(12), 2361-2368. doi.org/10.1177/0956797613486487
- Haworth, C. M. A., et al. (2010). The heritability of general cognitive ability increases linearly from childhood to young adulthood. Molecular Psychiatry, 15(11), 1112-1120. doi.org/10.1038/mp.2009.55
- Ritchie, S. J., & Tucker-Drob, E. M. (2018). How much does education improve intelligence? A meta-analysis. Psychological Science, 29(8), 1358-1369. doi.org/10.1177/0956797618774253
- Ritchie, S. J., Bates, T. C., & Plomin, R. (2015). Does learning to read improve intelligence? Child Development, 86(1), 23-36. doi.org/10.1111/cdev.12272
- Sala, G., & Gobet, F. (2020). Cognitive and academic benefits of music training with children: A multilevel meta-analysis. Memory & Cognition, 48, 1429-1441. doi.org/10.3758/s13421-020-01060-2