Full Idea
Very young children have been shown (Brown and Halon 1970) to be 'reinforced' not for their grammar but for the informational content of what they say.
Gist of Idea
We train children in truth, not in grammar
Source
Georges Rey (Contemporary Philosophy of Mind [1997], 4.2.1)
Book Reference
Rey,Georges: 'Contemporary Philosophy of Mind' [Blackwell 1997], p.113
A Reaction
This is what you would expect. It doesn't follow that the grammar comes from innate mechanisms, because the pressure to get the information right could impose increasing accuracy in grammar.