Children have not yet been converted from naturally curious language explorers into teacher-dependent grammar learners.
I took Spanish for three years in high school (Hola, Srta. Chambless!), and I was very fortunate that my teacher taught the class in Spanish, and required us to participate by speaking Spanish. After the first six weeks of the first year, no English was allowed, and precious little during that time. It was brilliant. It forced us to learn Spanish the way kids in Spanish-speaking families learn it - by experiencing it and figuring things out, not by sitting at a desk with a vocab list and a dictionary.
I've often wondered why no one has developed a computer language training curriculum modelled after some of the more effective human language training methods. But that's beside the point of Kauffman's thesis above. Ultimately, we learn what we love. And we love what we find out for ourselves as the result of exploring the things we find interesting, not what is hammered into us by some random instructor.