Abstract
Efforts to integrate accounts of scaffolding with KarmiloffโSmith's (1992) RR model have produced renewed interest in the language that tutors use to guide activity, since this provides a mechanism by which redescription of learners' representations might be achieved. The present research examined the impact of two forms of parental input, explicit operationalizations of strategies and explanations of principles, on changes in children's performance and understanding across a series of Balance Scale problems. Children aged 6โ8 years worked on these at three timeโpoints, receiving assistance at the first. Relative to controls who received no assistance on these problems, these children showed more rapid gains in the accuracy of attempted solutions, and were unique in exhibiting improvement in explicit understanding. Gains of both types were most pronounced amongst children whose parents focused on verbalizing the weight ร distance computations necessary to solve the problems, and on providing explanations of the underlying principle at work. These children showed earlier integration between performance and understanding, and made earlier use of such explanations themselves, the frequency with which they did so being directly related to parental use. The study provides clear evidence that appropriation of tutors' language may be a significant mechanism in representational change, but it also indicates that initial representational level may constrain children's capacity to benefit from this. Copyright ยฉ 2007 John Wiley & Sons, Ltd.