How to cook a SNARC: Number placement in text rapidly changes spatial–numerical associations

Most theoreticians believe that reading habits explain why Western adults associate small numbers with left space and large numbers with right space (the SNARC effect). We challenge this belief by documenting, in both English and Hebrew, that SNARC changes during reading: small and large numbers in our texts appeared near the left or right ends of the lines, positioned either spatially congruent or incongruent with reading habits. In English, the congruent group showed reliable SNARC before and after reading and the incongruent group’s SNARC was significantly reduced. In Hebrew the incongruent reading condition even induced a reverse SNARC. These results show that SNARC is a fleeting aspect of number representation that captures multiple spatial associations.     

不同加工深度非符号数量信息的SNARC效应：眼动证据

通过两项眼动实验考察了个体在水平和垂直方向上对点阵数量进行较浅(浏览)和较深(数字比较)程度加工时的数量空间表征联系。结果显示：点阵在水平方向上出现了SNARC效应, 且SNARC效应的大小不受加工深浅的影响, 而在垂直方向上没有出现SNARC效应。表明(1)点阵数量SNARC效应的稳定性不如阿拉伯数字; (2)方向对点阵SNARC效应的影响更大, 加工程度的影响则不明显。结合加工程度、空间方向和点阵数量的自身特征等对研究发现进行了讨论, 认为数字的空间表征在多个因素的共同影响下可能呈现出多样性。     

书写习惯对数字空间表征SNARC效应的影响

本文设计两个实验,采用大小判断任务,选取读写习惯相反的维、汉大学生为研究对象,探讨两类被试对阿拉伯数字和母语数字空间表征的一致性与差异性。结果发现：（1）维、汉被试均表现出对阿拉伯小数反应左手快于右手,对大数反应右手快于左手,即出现正向SNARC效应;（2）维吾尔族被试表现出对母语小数反应右手快于左手,对大数反应左手快于右手,即对母语数字出现反向SNARC效应;汉族被试表现出对母语小数反应左手快于右手,对大数反应右手快于左手,即对母语数字出现正向SNARC效应。结论：（1）维、汉被试对于阿拉伯数字的SNARC效应存在一致性;（2）维、汉被试母语数字的SNARC效应存在差异性;（3）数字空间对应性与书写习惯是导致结果的重要因素。     

Reading habits for both words and numbers contribute to the SNARC effect

This study compared the spatial representation of numbers in three groups of adults: Canadians, who read both English words and Arabic numbers from left to right; Palestinians, who read Arabic words and Arabic-Indic numbers from right to left; and Israelis, who read Hebrew words from right to left but Arabic numbers from left to right. Canadians associated small numbers with left and large numbers with right space (the SNARC effect), Palestinians showed the reverse association, and Israelis had no reliable spatial association for numbers. These results suggest that reading habits for both words and numbers contribute to the spatial representation of numbers.     

SNARC效应: 现状、理论与建议

SNARC效应是当对数字进行奇偶判断时,即使数的奇偶性与数的大小无关,但右手（左手）对相对大（小）的数的反应快。首先介绍SNARC效应的起源和理论解释,然后总结SNARC效应的特性,论述SNARC效应和Simon效应以及MARC 效应的关系,并对SNARC效应的脑机制进行了概述,最后提出3个有待深入研究的问题：（1）SNARC效应的加工处理机制;（2）SANRC效应的理论探索;（3）SNARC效应的本质。     

数字空间联结的灵活性及其内在机制

数字空间联结一直是认知心理学领域研究的热点之一。探索数字空间联结的一个重要指标为空间-数字反应联合编码(spatial-numerical association of response codes, SNARC)效应(左/右手对小/大数反应更快更准确)。以往研究已验证SNARC效应的普遍性及其在方向上的灵活性, 并提出多种理论解释。此外, SNARC效应在加工阶段上也具有灵活性, 其原因可能有：(1)加因素法则的理解偏差; (2)观察的角度单一; (3)观察效标的差异; (4)使用任务的差异。结合以上因素, 提出双阶段(数量信息的空间表征、空间表征到反应选择)加工模型, 不同的操控因素分别作用于两个阶段可能是引起SNARC效应灵活变化的核心原因。未来研究可从对比任务差异、引入不同干扰因素等方面进一步验证双阶段加工模型, 并结合认知神经科学技术揭示数字空间联结灵活性的内在神经机制。     

Developing number–space associations: SNARC effects using a color discrimination task in 5-year-olds

Human adults’ numerical representation is spatially oriented; consequently, participants are faster to respond to small/large numerals with their left/right hand, respectively, when doing a binary classification judgment on numbers, known as the SNARC (spatial–numerical association of response codes) effect. Studies on the emergence and development of the SNARC effect remain scarce. The current study introduces an innovative new paradigm based on a simple color judgment of Arabic digits. Using this task, we found a SNARC effect in children as young as 5.5 years. In contrast, when preschool children needed to perform a magnitude judgment task necessitating exact number knowledge, the SNARC effect started to emerge only at 5.8 years. Moreover, the emergence of a magnitude SNARC but not a color SNARC was linked to proficiency with Arabic digits. Our results suggest that access to a spatially oriented approximate magnitude representation from symbolic digits emerges early in ontogenetic development. Exact magnitude judgments, on the other hand, rely on experience with Arabic digits and, thus, necessitate formal or informal schooling to give access to a spatially oriented numerical representation.     

身体形式和社会环境对SNARC效应的影响:基于具身认知观的理解

目前SNARC效应在认知心理学领域得到了广泛研究,然而较少有研究考察身体形式和社会环境对SNARC效应的影响.研究以127名在校大学生为被试,使用奇偶判断任务、Go/No-go任务以及合作情境下的Go/No-go任务依次展开了三个研究,拟揭示身体形式和社会环境对SNARC效应的影响.实验一要求被试双手完成奇偶判断任务,结果出现了经典的SNARC效应.实验二要求被试完成Go/No-go任务,并让被试单手(左手或右手)对奇数或偶数进行反应,结果SNARC效应没有出现,这表明认知主体的身体形式对SNARC效应产生了影响.实验三要求被试合作完成Go/No-go任务,该实验按照被试所坐的位置(左边和右边)和反应手(左手和右手),设计了四个条件,结果只有身体位置和反应手完全一致时出现了 SNARC 效应.以上结果一方面表明了具身认知观的合理性,另外一方面扩展了以往对SNARC效应本质的理解.     

The SNARC effect: an instance of the Simon effect?

Our aim was to investigate the relations between the Spatial-Numerical Association of Response Codes (SNARC) effect and the Simon effect. In Experiment 1 participants were required to make a parity judgment to numbers from 1 to 9 (without 5), by pressing a left or a right key. The numbers were presented to either the left or right side of fixation. Results showed the Simon effect (left-side stimuli were responded to faster with the left hand than with the right hand whereas right-side stimuli were responded to faster with the right hand), and the SNARC effect (smaller numbers were responded to faster with the left hand than with the right hand, whereas larger numbers were responded to faster with the right hand). No interaction was found between the Simon and SNARC effects, suggesting that they combine additively. In Experiment 2 the temporal distance between formation of the task-relevant non-spatial stimulus code and the task-irrelevant stimulus spatial code was increased. As in Experiment 1, results showed the presence of the Simon and SNARC effects but no interaction between them. Moreover, we found a regular Simon effect for faster RTs, and a reversed Simon effect for longer RTs. In contrast, the SNARC effect did not vary as a function of RT. Taken together, the results of the two experiments show that the SNARC effect does not simply constitute a variant of the Simon effect. This is considered to be evidence that number representation and space representation rest on different neural (likely parietal) circuits.     

正负数混合呈现对负数SNARC效应的影响

采用数字大小判断任务,探讨正负数混合呈现对负数SNARC效应的影响。结果发现,负数单独呈现条件下,负数出现反转的SNARC效应;负数和无加号正数混合呈现,且只对负数作反应条件下,负数有反转SNARC效应;负数和有加号正数混合呈现,且只对负数作反应条件下,负数出现反转SNARC效应;负数和无加号正数混合呈现,并对正负数分别作反应的条件下,负数有反转SNARC效应出现,而正数出现SNARC效应。说明负数空间表征受其绝对值大小的影响,绝对值较小的负数(-1、-2)表征在心理数字线的左侧,绝对值较大的负数(-8、-9)表征在数字线的右侧,且不能延伸至心理数字线左侧。     

正负数混合呈现对负数SNARC效应的影响

采用数字大小判断任务,探讨正负数混合呈现对负数SNARC效应的影响。结果发现,负数单独呈现条件下,负数出现反转的SNARC效应;负数和无加号正数混合呈现,且只对负数作反应条件下,负数有反转SNARC效应;负数和有加号正数混合呈现,且只对负数作反应条件下,负数出现反转SNARC效应;负数和无加号正数混合呈现,并对正负数分别作反应的条件下,负数有反转SNARC效应出现,而正数出现SNARC效应。说明负数空间表征受其绝对值大小的影响,绝对值较小的负数(-1、-2)表征在心理数字线的左侧,绝对值较大的负数(-8、-9)表征在数字线的右侧,且不能延伸至心理数字线左侧。     

Negative numbers eliminate,but do not reverse,the attentional SNARC effect

Three experiments are reported examining whether the presentation of irrelevant negative numbers at central fixation interacts with attentional orienting beyond fixation. It has been previously shown that number perception influences spatial attention, with the presentation of spatially nonpredictive numbers resulting in the allocation of attention to the left when the number is low (e.g., 1 or 2) and to the right when the number is high (e.g., 8 or 9). In the present experiment, it is examined whether this attentional spatial numerical association of response codes (SNARC) effect is influenced by the presentation of negative numbers, which should have spatial properties that are in direct opposition to their positive counterparts (e.g., −1 or −2 would be considered high numbers relative to −8 or −9, which would be considered low numbers). Though the presentation of negative numbers does not lead to a reversal of the attentional SNARC effect, it does lead to an elimination of the effect, providing insight into how the attentional SNARC effect develops.     

听觉通道下负数的低水平加工引起注意的SNARC效应

采用刺激探测任务,探讨了听觉通道下负数的低水平加工能否引起注意的SNARC效应。结果表明:(1)负数的低水平加工能够产生注意的SNARC效应,即线索为绝对值小的负数时,被试对左耳目标反应更快;线索为绝对值大的负数时,被试对右耳目标反应更快。(2)负数的加工所引起听觉空间注意的转移并不依赖于负数所在的情境,而仅通过其绝对值大小与空间表征发生关联。这一结论与视觉条件下所得到的结论不一致,并支持了系统发生论假说。     

Spatial structure of quantitative representation of numbers: Evidence from the SNARC effect

Dehaene, Bossini, and Giraux (1993) revealed that subjects responded to large numbers faster with the choice on the right than with the choice on the left, whereas the reverse held true for small numbers (SNARC effect). According to Dehaene et al. (1993), the SNARC effect depends on the quantitative representation of number, such as a left-to-right-oriented analog number line. The main goal of the present study was twofold: first, to investigate whether the vertical SNARC effect could be observed, and, second, to verify whether Dehaene et al.'s (1993) explanation of the SNARC effect is correct. Experiments 2A and 2B showed the vertical SNARC effect in a parity judgment task. Subjects responded to large numbers faster with the top choice than with the bottom choice, whereas the reverse held true for small numbers. However, Experiment 3 failed to show the SNARC effect in a number magnitude judgment task, suggesting that the quantitative representation could be dissociated from the spatial code that produces the SNARC effect.     

Spatial representation of magnitude in humans (<Emphasis Type="Italic">Homo sapiens</Emphasis>), Western lowland gorillas (<Emphasis Type="Italic">Gorilla gorilla gorilla</Emphasis>), and American black bears (<Emphasis Type="Italic">Ursus americanus</Emphasis>)

The spatial-numerical association of response codes (SNARC) effect is the tendency for humans to respond faster to relatively larger numbers on the left or right (or with the left or right hand) and faster to relatively smaller numbers on the other side. This effect seems to occur due to a spatial representation of magnitude either in occurrence with a number line (wherein participants respond to relatively larger numbers faster on the right), other representations such as clock faces (responses are reversed from number lines), or culturally specific reading directions, begging the question as to whether the effect may be limited to humans. Given that a SNARC effect has emerged via a quantity judgement task in Western lowland gorillas and orangutans (Gazes et al., Cog 168:312–319, 2017), we examined patterns of response on a quantity discrimination task in American black bears, Western lowland gorillas, and humans for evidence of a SNARC effect. We found limited evidence for SNARC effect in American black bears and Western lowland gorillas. Furthermore, humans were inconsistent in direction and strength of effects, emphasizing the importance of standardizing methodology and analyses when comparing SNARC effects between species. These data reveal the importance of collecting data with humans in analogous procedures when testing nonhumans for effects assumed to bepresent in humans.     

符号数量和非符号数量的空间表征:5岁儿童的SNARC效应和距离效应

对物理刺激的数量信息表征是符号数字表征的前提和基础,据此假设在儿童的SNARC效应发生的时序问题上,非符号数量(如面积)的空间表征早于符号数量(如阿拉伯数字)的空间表征。本研究邀请5岁幼儿完成数字比较和面积比较两类任务,结果发现在数字比较任务中没有出现SNARC效应,但却存在距离效应;在面积比较任务中出现了SNARC效应和距离效应。可以推断,在阿拉伯数字的空间表征出现之前,儿童已经能够对非符号数量信息进行空间表征。     

数字空间联结的工作记忆机制

大量研究证实数字空间联结是一种稳定存在的表征形式。而关于数字空间联结的机制目前仍存在较大争论,本文在系统整理了大量有关长时记忆"心理数字线"难以解释的研究后,分析总结了工作记忆在数字空间联结中的重要作用。基于多个研究任务分析了工作记忆不同成分,即中央执行、语音环路和视空模板等,在数字空间联结中的重要作用,并系统介绍了对数字空间联结的工作记忆序列位置的解释。总之,数字空间联结的工作记忆机制仍有较多需要解决的问题,具有进一步探索的广泛空间。     

Searching for the functional locus of the SNARC effect: Evidence for a response-related origin

Dehaene, Bossini, and Giraux (1993) showed that when participants make parity judgments, responses to numerically small numbers are made faster with the left hand, whereas responses to large numbers are made faster with the right hand (the SNARC [spatial-numerical association of response codes] effect). According to one view, the SNARC effect arises at an early processing stage due to (in)congruencies between the digit's side of presentation and its representation on the mental number line, independently of response effector(s). Alternatively, the SNARC effect might arise at a later response-related stage due to (in)congruencies between the digit's representation on the mental number line and the side of response, independently of the side of presentation. The results of three experiments, using central and lateralized stimuli, and vocal and manual responses, clearly support the view that the SNARC effect arises at a relatively late response-related stage, without substantive contributions from earlier processing stages.     

The SNARC effect in the processing of second-language number words: Further evidence for strong lexico-semantic connections

We present new evidence that word translation involves semantic mediation. It has been shown that participants react faster to small numbers with their left hand and to large numbers with their right hand. This SNARC (spatial-numerical association of response codes) effect is due to the fact that in Western cultures the semantic number line is oriented from left (small) to right (large). We obtained a SNARC effect when participants had to indicate the parity of second-language (L2) number words, but not when they had to indicate whether L2 number words contained a particular sound. Crucially, the SNARC effect was also obtained in a translation verification task, indicating that this task involved the activation of number magnitude.