数字SNARC效应的发生阶段

Occurrence stage of SNARC effect

目前关于数字SNARC效应发生在早期的刺激表征阶段还是晚期的反应选择阶段的结果不一。本研究通过3个实验探究了其发生阶段。采用整体−局部范式,构建了一种复合实验刺激——由数字构成的箭头,并以此为实验材料,分别要求被试比较数字大小(箭头方向的整体优先表征干扰数字的空间表征)和判断箭头方向(箭头方向判断任务在反应选择阶段与数字加工产生反应竞争)。结果发现,水平方向干扰数字的空间表征阻碍了数字SNARC效应产生(实验1a);垂直方向干扰数字的空间表征对数字SNARC效应没有影响(实验1b);干扰反应选择阶段阻碍了数字SNARC效应产生(实验2)。实验结果表明干扰数字加工的刺激表征阶段和反应选择阶段都会影响数字SNARC效应的产生,支持数字SNARC效应的双阶段加工模型。

The spatial−numerical association of response codes(SNARC)effect demonstrates that responding to small numbers with the left key is faster than with the right key,and the reverse is true for large numbers.A long-standing debate concerns whether the SNARC effect occurs only in the early stimulus-representation stage,only in the late response-selection stage or in both stages simultaneously.This study aims to manipulate these two processing stages to investigate the effects of interference on the SNARC effect.Using the global and local paradigm,a compound stimulus—arrows made up of numbers—was designed as the experimental material.In Experiment 1a,a within-subject experimental design with 2(Number magnitude:small,large)×3(Arrow direction:left,right,left-right bidirectional)×2(Response hand:left hand,right hand)was conducted.Forty subjects were asked to judge whether a number is larger or smaller than 5.In Experiment 1b,a within-subject experimental design with 2(Number magnitude:small,large)×3(Arrow direction:up,down,up-down bidirectional)×2(Response hand:left hand,right hand)was employed.Forty subjects were asked to judge whether a number is larger or smaller than 5.Experiment 2 followed the design of Experiment 1a,but forty subjects were asked to judge whether the arrow pointed left or right.Results showed that horizontal interference with the spatial representation of numbers hindered the SNARC effect(Experiment 1a),but vertical interference with the had no influence(Experiment 1b).Interference at the response-selection stage also impeded the SNARC effect(Experiment 2).According to global precedence theory,the global representation of horizontal arrow directions interferes with the spatial representation of local numbers,causing the SNARC effect to disappear in Experiment 1a.According to mental number line theory,individuals mentally represent numbers along a left-to-right axis.Thus,interference from the global representation of vertical arrow directions does not influence the SNARC effect in Experiment 1b.In Experiment 2,when arrows made up of numbers were used,participants judged arrow directions,and the numbers were automatically processed and spatially represented unconsciously.However,the cognitive resources required for the arrow direction judgment or the occupation of corresponding reaction positions during the response-selection stage diminished the SNARC effect.In summary,the early stimulus-representation stage and late response-selection stage are crucial for the occurrence of the SNARC effect,supporting the two-stage processing model of SNARC effect.