The development of enumeration skills over childhood is thought to reflect improvements in both subitizing (for small sets) and serial counting (for larger sets). However, investigations into the contribution of subitizing to advancing mathematics ability are limited by challenges in measuring subitizing capacity across developmental populations. Subitizing capacity in adults is traditionally assessed by calculating the bilinear inflection point for reaction times or accuracy across set sizes, but in children greater variability and dramatic improvements in counting ability introduce problems with this approach. This study demonstrates this limitation in a sample of elementary school children and proposes a novel probabilistic approach to measuring subitizing capacity. This metric captures well-established trends in the development of children’s subitizing. Furthermore, the proposed metric predicts unique variance in symbolic arithmetic ability, corroborating previous research that suggests a foundational role for subitizing in the development of numerical cognition. Findings demonstrate the advantages of a probabilistic approach to determining subitizing capacity in young children and suggest that it may be practically and theoretically well-suited for investigating subitizing and its role in mathematics development.

童年时期计数技能的发展被认为反映了子化（对于小集合）和连续计数（对于大集合）的改进。然而，在衡量不同发育人群的辅助能力方面存在挑战，因此对辅助化对提高数学能力的贡献的调查受到限制。成人的适应能力传统上是通过计算双线性拐点的反应时间或跨集合大小的准确性来评估的，但在儿童中，更大的可变性和计数能力的显着提高会给这种方法带来问题。这项研究在小学生样本中证明了这种局限性，并提出了一种新的概率方法来衡量辅助能力。该指标反映了儿童适应发展的成熟趋势。此外，所提出的度量标准预测了符号算术能力的独特差异，证实了先前的研究，该研究表明 subitizing 在数值认知的发展中具有基础性作用。研究结果证明了概率方法在确定幼儿辅助能力方面的优势，并表明它可能在实践和理论上非常适合研究辅助能力及其在数学发展中的作用。