University of Saskatchewan, Canada.
University of Saskatchewan, Canada.
Neuropsychologia. 2019 Feb 18;124:311-321. doi: 10.1016/j.neuropsychologia.2018.11.009. Epub 2018 Nov 22.
Recent studies have proposed that the sum-counting strategy for simple addition (i.e., count up of the summed value of the two operands one by one) used at early age becomes automatized in adults, challenging the long held view that skilled adults solve simple addition problems by fact retrieval. As arithmetic skill develops, however, the sum-counting strategy usually is replaced by a more advanced and efficient min-counting strategy (i.e., start counting at the value of the larger addend and count up by ones equal to the smaller or "min" addend). Thus, one would expect the min strategy, rather than the sum strategy, to become automatized if we assume automatic counting procedures exist. The present study sought evidence of the min-strategy in adults by investigating the size congruency effect (SCE) through behavioural and event related brain potential (ERP) experiments. The SCE is observed in number comparison tasks (e.g., identify the larger of two numbers), where RT is slower when the physical and numerical size of the numbers are incongruent compared to when they are congruent. The min-counting strategy inherently requires a number comparison stage, because the min and max number must be determined before the counting begins. Experiment 1 tested 72 participants on addition and number comparison tasks. The results showed a robust behavioural SCE for number comparison but not for simple addition. Experiment 2 tested 20 participants with a large number of addition and number comparison problems and recorded ERP. The behavioural results replicated the findings of Experiment 1. The ERP results revealed brain signatures in line with previous studies and the current behavioural findings. No SCE indicated the absence of a number comparison stage for addition; thus, the present findings ruled out the possibility of a fast min-counting strategy, or more generally a min strategy, for adults' simple addition.
最近的研究提出，儿童早期使用的简单加法的逐位累加策略（即，逐个累加两个操作数的和值）在成人中变得自动化，这挑战了长期以来认为熟练的成年人通过事实检索来解决简单加法问题的观点。然而，随着算术技能的发展，逐位累加策略通常会被一种更高级和有效的最小累加策略（即，从较大的加数开始，每次累加等于较小的加数或“min”加数的 1）所取代。因此，如果我们假设自动计数过程存在，那么人们会期望最小策略而不是逐位累加策略变得自动化。本研究通过行为和事件相关脑电位（ERP）实验，通过考察大小一致性效应（SCE），来寻找成人中最小策略的证据。大小一致性效应在数字比较任务中观察到（例如，识别两个数字中的较大数），与物理和数字大小一致相比，当它们不一致时，反应时间（RT）会变慢。最小累加策略本质上需要一个数字比较阶段，因为在计数开始之前，必须确定最小和最大数。实验 1 在加法和数字比较任务中测试了 72 名参与者。结果表明，数字比较存在强大的行为 SCE，但简单加法没有。实验 2 测试了 20 名参与者，他们进行了大量的加法和数字比较问题，并记录了 ERP。行为结果复制了实验 1 的发现。ERP 结果显示出与之前的研究和当前行为发现一致的大脑特征。加法没有 SCE 表明没有数字比较阶段；因此，目前的发现排除了成人简单加法的快速最小累加策略或更一般的最小策略的可能性。
