Department of Psychology, University of Potsdam, Potsdam, Germany.
Department of Psychology, Brandenburg Medical School Theodor Fontane, Neuruppin, Germany.
Ann N Y Acad Sci. 2020 Oct;1477(1):44-53. doi: 10.1111/nyas.14418. Epub 2020 Jul 9.
"Left" and "right" coordinates control our spatial behavior and even influence abstract thoughts. For number concepts, horizontal spatial-numerical associations (SNAs) have been widely documented: we associate few with left and many with right. Importantly, increments are universally coded on the right side even in preverbal humans and nonhuman animals, thus questioning the fundamental role of directional cultural habits, such as reading or finger counting. Here, we propose a biological, nonnumerical mechanism for the origin of SNAs on the basis of asymmetric tuning of animal brains for different spatial frequencies (SFs). The resulting selective visual processing predicts both universal SNAs and their context-dependence. We support our proposal by analyzing the stimuli used to document SNAs in newborns for their SF content. As predicted, the SFs contained in visual patterns with few versus many elements preferentially engage right versus left brain hemispheres, respectively, thus predicting left-versus rightward behavioral biases. Our "brain's asymmetric frequency tuning" hypothesis explains the perceptual origin of horizontal SNAs for nonsymbolic visual numerosities and might be extensible to the auditory domain.
"左"和"右"坐标控制着我们的空间行为，甚至影响着抽象思维。对于数字概念，水平空间-数字关联（SNA）已经得到了广泛的记录：我们将小数量与左关联，将大量与右关联。重要的是，即使在没有语言的人类和非人类动物中，增量也普遍被编码在右侧，从而质疑了方向性文化习惯（如阅读或手指计数）的基本作用。在这里，我们基于动物大脑对不同空间频率（SF）的不对称调谐，提出了 SNA 起源的生物非数值机制。由此产生的选择性视觉处理预测了普遍的 SNA 及其对上下文的依赖性。我们通过分析用于记录新生儿 SNA 的刺激物的 SF 内容来支持我们的提议。正如预测的那样，具有少量与大量元素的视觉模式中包含的 SF 分别优先激活右半球和左半球，从而预测出向左和向右的行为偏向。我们的“大脑不对称频率调谐”假说解释了非符号视觉数量的水平 SNA 的感知起源，并且可能扩展到听觉领域。
