Automaticity in processing spatial-numerical associations: Evidence from a perceptual orientation judgment task of Arabic digits in frames

Human adults are faster to respond to small/large numerals with their left/right hand when they judge the parity of numerals, which is known as the SNARC (spatial-numerical association of response codes) effect. It has been proposed that the size of the SNARC effect depends on response latencies. The current study introduced a perceptual orientation task, where participants were asked to judge the orientation of a digit or a frame surrounding the digit. The present study first confirmed the SNARC effect with native Chinese speakers (Experiment 1) using a parity task, and then examined whether the emergence and size of the SNARC effect depended on the response latencies (Experiments 2, 3, and 4) using a perceptual orientation judgment task. Our results suggested that (a) the automatic processing of response-related numerical-spatial information occurred with Chinese-speaking participants in the parity task; (b) the SNARC effect was also found when the task did not require semantic access; and (c) the size of the effect depended on the processing speed of the task-relevant dimension. Finally, we proposed an underlying mechanism to explain the SNARC effect in the perceptual orientation judgment task.当成年人类判断数字的奇偶性时，对小/大数字会分别用左手/右手做出更快反应，这一现象被称为SNARC效应（spatial-numerical association of response codes）。已有研究提出，SNARC效应的强度取决于反应时。本研究引入了一项知觉方位判断任务，要求被试判断数字本身或数字周围边框的方位。本研究首先通过奇偶判断任务，在母语为汉语的被试中验证了SNARC效应（实验1）；随后采用知觉方位判断任务，考察了SNARC效应的产生及其强度是否依赖于反应时（实验2、3、4）。本研究结果显示：（1）在奇偶判断任务中，母语为汉语的被试会自动化加工与反应相关的数字-空间信息；（2）当任务无需进行语义通适时，同样可观测到SNARC效应；（3）该效应的强度取决于任务相关维度的加工速度。最后，本研究提出了一种可解释知觉方位判断任务中SNARC效应的潜在机制。