Teaching mathematics....late...

Very interesting article from Psychology Today regarding an experiment by L. P. Benezet in 1929 where we deliberately stopped the teaching of mathematics (specifically arithmetic) to very young school children with the result that they became much stronger at mathematics when it was introduced much later on in the curriculum:

When Less is More: The Case for Teaching Less Math in Schools
In an experiment, children who were taught less learned more.
Published on March 18, 2010 by Peter Gray

In 1929, the superintendent of schools in Ithaca, New York, sent out a challenge to his colleagues in other cities. "What," he asked, "can we drop from the elementary school curriculum?" He complained that over the years new subjects were continuously being added and nothing was being subtracted, with the result that the school day was packed with too many subjects and there was little time to reflect seriously on anything. This was back in the days when people believed that children shouldn't have to spend all of their time at school work--that they needed some time to play, to do chores at home, and to be with their families--so there was reason back then to believe that whenever something new is added to the curriculum something else should be dropped.

A further link to more information about Benezet and references to the original papers on the subject:

L. P. Benezet, "The Teaching of Arithmetic I, II, III: The Story of an Experiment," Journal of the National Education Association

1. Volume 24(8): 241-244 (November 1935)
2. Volume 24(9): 301-303 (December 1935)
3. Volume 25(1): 7-8 (January 1936) 

The articles were reprinted in the Humanistic Mathematics Newsletter #6: 2-14 (May 1991).

And a link to a PDF of all three parts.