There is an interesting article in the New York Times on cognitive neuroscience is showing that pre-schoolers are capable of learning mathematical concepts. How novel. The third paragraph:
For much of the last century, educators and many scientists believed that children could not learn math at all before the age of five, that their brains simply were not ready.
This timescale coincides with Angeline Lillard’s observations in Montessori: The Science behind the Genius (Lillard, 2005) about how constructivist approaches to teaching, like Montessori’s, were devalued and derogated because the more factory-like approaches were seen as more efficient during a time when the marvels of the industrial revolution were continuously impressing. This general theory, of course, may or may not be related to the theory of teaching specific concepts like math. It is disappointing that the references to such a broad statement are not provided in the article.