Abstract: Spatial-numerical associations is a phenomenon in which numbers are closely related to space. A large number of studies have confirmed that this associations is a widespread phenomenon, but there is still controversy over the intrinsic mechanism of this connection. It has two dominant explanations for the spatial-numerical associations: 1. Mental Number Line: people use the Mental Number Line stored in long-term memory to process the numbers, which is according to reading habits from left to right, arrange the numbers in ascending order on a similar physical line, the small number is on the left and the big number is on the right, and this line is placed on a specific spatial frame; 2. Working Memory Account: when people are dealing with verbal information such as numbers and letters, an empirically based mental "workspace" is created to process and manipulate these verbal information. The "workspace" consists of the association between relevant verbal information and specific spatial templates selected from long-term memory based on experience, and is populated based on the most common experience of these content, for example, numbers are in ascending order from left to right. When the brain matches the presented number with a specific spatial template in the "workspace," the spatial coding begins to form, creating a spatial-numerical connection. Based on the previous researches, the researchers found that the Mental Number Line does not explain the flexibility of the spatial-numerical associations, for example, 1. the SNARC effect depends on the range of numbers in which the numbers are located in the experimental task; 2. the SNARC effect is affected by the visual object; 3. changing the instruction will affect the SNARC effect. Therefore, this paper discusses the applicability of working memory accounts by analyzing the digital-spatial associations phenomenon that can not be explained by the Mental Number Line, and explains this phenomenon through the five core viewpoints of working memory: 1. whenever a particular set of items (such as number sets 1 through 9) is used as the experimental material, all items within the item set are active during task execution; 2. based on people's experience in digital item, the digital “spatialization” of working memory is presented in a horizontal direction from left to right; 3. the direction of verbal item representation is not only related to the direction of storing a specific spatial template in working memory, but also affected by long-term memory; 4. when the presented verbal item matches the set of items stored in the "workspace" that is active, spatial encoding of the verbal item is formed; 5. working memory can activate multiple item sets simultaneously. In this way, we can better understand the intrinsic mechanism and cause of the digital-spatial associations. However, there are still some problems that need to be solved: 1. is the spatial-numerical associations innate or acquired? 2. is the spatial-numerical associations mutual affected by Mental Number Line and Working Memory Account? 3. what is the spatial representation of negative numbers?. These need a lot of research to explore it.

Key words: numerical cognition, spatial-numerical associations, SNARC effect, working memory

摘要： 已有研究证实数字-空间联结是普遍存在的现象，但关于这种联结的解释仍存在争论。当前对数字-空间联结主要有两种解释。其中，心理数字线假设数字的心理表征是一条从左到右方向的水平线，而工作记忆假设认为数字-空间联结是任务执行期间暂时的工作记忆表征。本文通过分析心理数字线不能解释的数字-空间联结现象及局限性，来探讨工作记忆解释的适用性，并通过工作记忆的核心观点来解释数字-空间联结现象，以期更好地揭示数字-空间联结的内在机制。但关于工作记忆解释仍有亟待解决的问题，还需实证研究探讨。

关键词: 数字认知, 数字-空间联结, SNARC效应, 工作记忆