I have been reading an excellent little book titled Scripture by Heart by Joshua Choonmin Kang. More than techniques for memorizing, it provides an overall strategy or philosophy for memorizing the Bible. Chapter 3 of the 30-chapter book is based on Proverbs 22:6. In his discussion of "Forming a Biblical Value System," Kang writes, "When it comes to value formation in children, educational psychologists tell us, the earlier, the better. The first five years are critical."
Unfortunately, Kang does not give any sources for the statement about value formation in children. One could Google it or check out a book on child or educational psychology. The main thing I wonder about is the specific "first five years" aspect. I know children are impressionable, and the younger they are the more impressionable they are. And having a 19-month-old son as well as another baby due this year, I am highly interested in value formation in children.
I also wonder, being interested not only in this Bible verse and child training but also language, whether the verse applies not only to value formation in children but also to psycholinguistics and how/whether/when we raise children bi- or multilingual?