Free versus anchored numerical estimation: A unified approach.

  title={Free versus anchored numerical estimation: A unified approach.},
  author={John Opfer and Clarissa Thompson and Dan Kim},
Children's number-line estimation has produced a lively debate about representational change, supported by apparently incompatible data regarding descriptive adequacy of logarithmic (Opfer, Siegler, & Young, 2011) and cyclic power models (Slusser, Santiago, & Barth, 2013). To test whether methodological differences might explain discrepant findings, we created a fully crossed 2×2 design and assigned 96 children to one of four cells. In the design, we crossed anchoring (free, anchored) and… CONTINUE READING