Tuesday, April 12, 2011
Last week, we learned that the N1 component in normal reading adults differentiated between words and symbols, while the N1 component in pre-reading kindergartners did not. The question now is, at what point in development does N1 component start resembling that of adults? Maurer and colleagues tested the same kindergartners from their 2005 paper when the kids were in second grade to see how their brain activity changed after two years of reading instruction.
These were their findings:
1. The N1 component differentiates between words and simple strings in the second graders.
2. Second graders actually had a greater words/symbols N1 difference than adults.*
3. There is a correlation between N1 specialization and reading fluency. In other words, the difference in N1 amplitude between words and symbols was correlated with faster reading in the second graders.
4. The N1 negativity was more left lateralized in adults than in children. The N1 topography was bilateral for 2nd graders, and right lateralized in kindergareners.
Conclusions: Two years of reading instruction is enough for the brain to start differentiating between words and meaningless symbols. In terms of the development of N1 specialization, there are hints of a U shaped curve, with 2nd graders displaying even greater word/symbol differences than adults.
* Amplitudes in general were bigger in the second graders, but the difference held when amplitudes were normalized between children and adults
Maurer U, Brem S, Kranz F, Bucher K, Benz R, Halder P, Steinhausen HC, & Brandeis D (2006). Coarse neural tuning for print peaks when children learn to read. NeuroImage, 33 (2), 749-58 PMID: 16920367