People with spatial sequence synesthesia have clear and stable mental images of spatial arrays of numbers, days of the week, and months. The shapes of the arrays vary by individual. We conducted an experiment to estimate the shapes of spatial arrays in people without synesthesia. We presented a pair of Japanese characters that represent the days of the week on a display, and asked participants without synesthesia to state which day they thought came later by pressing a key that was congruent with the spatial position of the day shown. We then estimated the shape of the spatial array in the participants' mental space (mental weekday lines) from the distribution of the reaction times. We found that these ‘estimated mental weekday lines’ differed by individual, and that the shapes (straight or bent lines, U-shapes, zigzags, or triangles) were similar to the spatial arrays found in individuals with synesthesia. We then conducted simulations using a self-organizing map and found that differences in the shapes of the spatial arrays compared with those in individuals with synesthesia could be explained by the inputs to the network. These results support the hypothesis that interactions between spatial and ordinal/cardinal representations in both synesthetes and non-synesthetes develop under the influence of self-organizing learning.

具有空间序列联觉的人具有清晰，稳定的心理图像，这些图像由数字，一周中的某几天和几个月的空间组成。阵列的形状因人而异。我们进行了一项实验，以估计没有联觉的人的空间阵列的形状。我们在显示屏上呈现了一对代表星期几的日语字符，并要求没有联觉的参与者通过按下与所显示的一天的空间位置一致的键来说明他们认为以后的哪一天。然后，我们根据反应时间的分布来估算参与者心理空间（心理工作日线）中空间阵列的形状。我们发现，这些“预计的工作日心理线”因人而异，并且形状（直线或弯曲线，U形，锯齿形，或三角形）类似于具有联觉的个体的空间阵列。然后，我们使用自组织图进行了仿真，发现与联觉个体相比，空间阵列的形状差异可以通过网络输入来解释。这些结果支持这样的假说：在自组织学习的影响下，合成和非合成的空间和序数/基数表示之间的相互作用都得到发展。