Institute of Pharmacology & Toxicology, University of Zurich, Zurich, Switzerland.
Brain Cogn. 2010 Dec;74(3):306-11. doi: 10.1016/j.bandc.2010.08.011. Epub 2010 Sep 22.
Little is known about the neuropsychological factors that contribute to individual differences in the asymmetric orientation along the mental number line. The present study documents healthy subjects' preference for small numbers over large numbers in a random number generation task. This preference, referred to as "small-number bias" (SNB), varied with prefrontal functional lateralization: it was larger in participants with over-proportionately better performance in design fluency compared to letter fluency than in participants with over-proportionately better performance in letter fluency when compared to design fluency. Asymmetries in learning and memory tasks (verbal vs. non-verbal) were not related to direction or size of the SNB. We conclude that hemispheric asymmetries of specifically prefrontal executive functions are predictive of an individual's lateral orientation bias along the mental number line. Therefore, the focus on parietal contributions to spatial-numerical associations may not be justified. Random number generation may be a helpful method to further explore these associations uncontaminated by the asymmetric involvement of response effectors.
关于导致心理数字线不对称定向个体差异的神经心理学因素，我们知之甚少。本研究记录了健康受试者在随机数字生成任务中对小数字的偏好超过大数字的情况。这种偏好被称为“小数字偏倚”（SNB），与前额叶功能的侧化有关：与字母流畅性相比，在设计流畅性方面表现出不成比例优势的参与者的 SNB 大于在字母流畅性方面表现出不成比例优势的参与者。学习和记忆任务（言语与非言语）的不对称性与 SNB 的方向或大小无关。我们得出结论，特定于前额叶执行功能的半球不对称性可预测个体沿心理数字线的横向定向偏差。因此，关注顶叶对空间-数字关联的贡献可能没有道理。随机数字生成可能是一种有用的方法，可以进一步探索这些关联，而不受反应效应器的不对称参与的干扰。
