Department of Psychology, University of Potsdam, Germany.
Department of Neuroscience, University of Padua, Italy.
Cognition. 2022 Apr;221:104991. doi: 10.1016/j.cognition.2021.104991. Epub 2021 Dec 27.
Previous studies suggest that associations between numbers and space are mediated by shifts of visuospatial attention along the horizontal axis. In this study, we investigated the effect of vertical shifts of overt attention, induced by optokinetic stimulation (OKS) and monitored through eye-tracking, in two tasks requiring explicit (number comparison) or implicit (parity judgment) processing of number magnitude. Participants were exposed to black-and-white stripes (OKS) that moved vertically (upward or downward) or remained static (control condition). During the OKS, participants were asked to verbally classify auditory one-digit numbers as larger/smaller than 5 (comparison task; Exp. 1) or as odd/even (parity task; Exp. 2). OKS modulated response times in both experiments. In Exp.1, upward attentional displacement decreased the Magnitude effect (slower responses for large numbers) and increased the Distance effect (slower responses for numbers close to the reference). In Exp.2, we observed a complex interaction between parity, magnitude, and OKS, indicating that downward attentional displacement slowed down responses for large odd numbers. Moreover, eye tracking analyses revealed an influence of number processing on eye movements both in Exp. 1, with eye gaze shifting downwards during the processing of small numbers as compared to large ones; and in Exp. 2, with leftward shifts after large even numbers (6,8) and rightward shifts after large odd numbers (7,9). These results provide evidence of bidirectional links between number and space and extend them to the vertical dimension. Moreover, they document the influence of visuo-spatial attention on processing of numerical magnitude, numerical distance, and parity. Together, our findings are in line with grounded and embodied accounts of numerical cognition.
先前的研究表明，数字和空间之间的联系是通过沿水平轴的视空间注意的转移来介导的。在这项研究中，我们通过眼动追踪来研究外显（数字比较）或内隐（奇偶判断）加工数量大小的两个任务中，由光刺激（OKS）引起的注意力垂直转移的影响。参与者暴露在黑白条纹（OKS）中，这些条纹垂直（向上或向下）移动或保持静止（对照条件）。在 OKS 期间，参与者被要求口头分类听觉一位数作为大于 5（比较任务；实验 1）或作为奇数/偶数（奇偶任务；实验 2）。OKS 调节了两个实验中的反应时间。在实验 1 中，向上的注意力转移减少了大小效应（对大数字的反应较慢）并增加了距离效应（对接近参考的数字的反应较慢）。在实验 2 中，我们观察到奇偶、大小和 OKS 之间的复杂相互作用，表明向下的注意力转移会使大奇数的反应变慢。此外，眼动跟踪分析显示，数字处理对眼动的影响在实验 1 中，与大数字相比，小数字的处理过程中眼动向下转移；在实验 2 中，大偶数（6,8）之后出现左眼动转移，大奇数（7,9）之后出现右眼动转移。这些结果为数字和空间之间的双向联系提供了证据，并将其扩展到垂直维度。此外，它们记录了视空间注意对数字大小、数字距离和奇偶处理的影响。总的来说，我们的发现符合数字认知的基础和具身理论。
