Eccher Elena, Josserand Mathilde, Caparos Serge, Boissin Esther, Buiatti Marco, Piazza Manuela, Vallortigara Giorgio
Center for Mind/Brain Science, University of Trento, Rovereto, (TN), Italy.
Laboratoire d'Eco-Anthropologie, CNRS UMR 7206 / Muséum National d'Histoire Naturelle, Paris, France.
Nat Commun. 2025 Jan 10;16(1):495. doi: 10.1038/s41467-024-55685-x.
Number and space are inherently related. Previous research has provided evidence that numbers are aligned to a so-called "mental number line", which is malleable and affected by cultural factors mostly linked to literacy-related habits. However, preverbal humans and non-human animals also map numerosities into space, in a consistent left-to-right direction. These contrasting findings raise the question of whether Spatial Numerical Associations (SNA) are culturally or biologically determined. Here, we investigated Italian adults, Italian preschoolers, and Himba adults (an indigenous population with an oral cultural system) to examine whether cultural influences are necessary for SNA to emerge. We found that, when explicitly asked to order numerosities, only Italian adults showed a consistent left-to-right preference, while preschoolers and Himba adults did not have a consistent preference for one direction or the other. On the other hand, in a numerosity comparison task, all groups performed better when small numerosities were presented in the left hemispace. These results suggest that humans may display two forms of SNAs, one that emerges mostly in implicit tasks and is biologically determined, and one that emerges in explicit ordering tasks and is determined by cultural habits.
数字与空间内在相关。先前的研究已提供证据表明，数字与一条所谓的“心理数字线”对齐，这条线具有可塑性，并受主要与读写习惯相关的文化因素影响。然而，尚未掌握语言能力的人类和非人类动物也会以从左到右的一致方向将数量映射到空间中。这些相互矛盾的发现引发了一个问题，即空间数字关联（SNA）是由文化还是生物学决定的。在这里，我们对意大利成年人、意大利学龄前儿童和辛巴成年人（一个拥有口头文化系统的原住民群体）进行了调查，以检验文化影响对于SNA的出现是否必要。我们发现，当被明确要求对数量进行排序时，只有意大利成年人表现出从左到右的一致偏好，而学龄前儿童和辛巴成年人对一个方向或另一个方向没有一致的偏好。另一方面，在数量比较任务中，当小数量出现在左半空间时，所有组的表现都更好。这些结果表明，人类可能表现出两种形式的SNA，一种主要出现在隐性任务中且由生物学决定，另一种出现在明确的排序任务中且由文化习惯决定。
