Department of Psychology.
Department of Cognitive Sciences, University of California-Irvine.
Dev Psychol. 2014 Jun;50(6):1640-52. doi: 10.1037/a0035901. Epub 2014 Feb 10.
Children's understanding of numbers is often assessed using a number-line task, where the child is shown a line labeled with 0 at one end and a higher number (e.g., 100) at the other end. The child is then asked where on the line some intermediate number (e.g., 70) should go. Performance on this task changes predictably during childhood, and this has often been interpreted as evidence of a change in the child's psychological representation of integer quantities. The present article presents theoretical and empirical evidence that the change in number-line performance actually reflects the development of measurement skills used in the task. We compare 2 versions of the number-line task: the bounded version used in the literature and a new, unbounded version. Results indicate that it is only children's performance on the bounded task (which requires subtraction or division) that changes markedly with age. In contrast, children's performance on the unbounded task (which requires only addition) remains fairly constant as they get older. Thus, developmental changes in performance on the traditional bounded number-line task likely reflect the growth of task-specific measurement skills rather than changes in the child's understanding of numerical quantities.
儿童对数字的理解通常通过数轴任务来评估，在该任务中，向儿童展示一条标有 0 的线，一端为 0，另一端为更高的数字（例如 100）。然后，要求儿童在这条线上的某个中间数字（例如 70）应该在哪里。在儿童时期，这项任务的表现会发生可预测的变化，这通常被解释为儿童对整数数量的心理表示发生变化的证据。本文提出了理论和经验证据，表明数轴表现的变化实际上反映了任务中使用的测量技能的发展。我们比较了两种版本的数轴任务：文献中使用的有界版本和新的无界版本。结果表明，只有儿童在有界任务（需要减法或除法）上的表现随着年龄的增长而显著变化。相比之下，随着年龄的增长，儿童在无界任务（仅需要加法）上的表现相当稳定。因此，传统有界数轴任务表现的发展变化可能反映了特定于任务的测量技能的增长，而不是儿童对数字数量的理解的变化。
