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Remember how the early childhood field responded to the children’s brain development research at the end of the 20^th century? Now, almost 10 years later, new findings provide exciting information about how children’s brains vary according to IQ levels and physical development. No doubt, these findings will prompt more research on human intellectual growth.

The National Institute of Mental Health (NIMH) reported findings in the journal Nature on March 30, 2006, on data collected from a 17-year study of 307 children, ages 5-19 years. The results indicate that “the brains of highly intelligent children develop in a different pattern from those with more average abilities.” NIMH researchers and faculty from McGill University in Montreal compared children’s multiple magnetic resonance imaging (MRI) scans to their IQ scores. The children were divided into three groups: highly intelligent children had IQ scores of 121-149; moderately intelligent children had scores of 109-120; and average children had scores of 83-108.

The study “suggests that performance in IQ tests is associated with changes in the brain in adolescence.” NIMH lead researcher Philip Shaw states: “It’s not that brainy children have more gray matter. The story of intelligence is in the trajectory of brain development.” The most unusual changes were in the thickness of the cerebral cortex, the thin sheet of neurons that covers the outer surface of the brain and the location of many higher mental processes, including planning and abstract reasoning.

“Youth with superior IQs are distinguished by how fast the thinking part of their brains thickens and thins as they grow up.” The scans “showed that their brain’s outer mantle, or cortex, thickens more rapidly during childhood, reaching its peak later than in [children in the lower IQ groups].” The finding suggests that the smarter children have “a longer developmental window for high-level thinking circuitry.” Wade writes in The New York Times: “ . . . Basically the brain seems to be rewiring itself as it matures, with the thinning of the cortex reflecting a pruning of redundant connections.”

For example, “the smartest 7-year-olds tended to start out with a relatively thinner cortex that thickened rapidly, peaking by age 11 or 12 before thinning. In their peers with average IQ, an initially thicker cortex peaked at age 8, with gradual thinning thereafter.” In summary, “IQ is related to the dynamics of cortex maturation.” A final statement from NIMH points to a future “search for gene variants that might be linked to the newly discovered trajectories.” Shaw points out that “mounting evidence suggest[s] that the effects of genes often depends on interactions with environmental events, so the determinants of intelligence will likely prove to be a very complex mix of nature and nurture.”

Yes, early childhood educators, children need both nature and nurture!

Sources

(i)Giles, J. "Scans suggest IQ scores reflect brain structure: Research results reignite intelligence controversy." Nature, vol. 440, no. 7084, 30 March 2006, pp. 588-589. Published online: 29 March 2006: www.nature.com

(ii) "NIMH: Cortex Matures Faster in Youth with Highest IQ," March 29, 2006.
http://www.nimh.nih.gov/press/youthcortexiq.cfm. This press release features a color graphic of the variations among the three groups of IQ measures.

(iii) Shaw, P., D. Greenstein, J. Lerch, L. Clasen, R. Lenroot, N. Gogtay, A. Evans, J. Rappaport, & J. Giedd. (30 March 2006). "Intellectual ability and cortical development in children and adolescents." Nature, vol. 440, 30 March 2006, pp. 676-679. [Note: Lerch & Evans are with the Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada; the remaining authors are with the Child Psychiatry Branch, National Institute of Mental Health, Bethesda, Maryland, USA.]

(iv) Wade, N. (March 30, 2006). "Scans show different growth for intelligent brains." The New York Times. www.nytimes.com.

Contributed by Edna Ranck

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