Mathematical abilities and the advantage of organizing information on a working memory line

Abstract Working memory (WM) plays a crucial role in mathematical problem-solving. Previous research has linked math abilities to both item and order WM. Recently, it has been suggested that organizing serial order in verbal WM along a horizontally oriented working memory line (WML) may also support mathematical performance. For instance, psychology students who consistently spatialized their WML from left to right obtained higher math scores. While this categorical approach offers a useful starting point, confirming the relationship through continuous analyses is essential to reduce the risk of false positives. To understand its developmental trajectory, it is also important to assess whether the relationship is already present at younger ages. Moreover, it remains to be clarified whether the effect is due to spatialization in general, or to alignment with the reading direction of the instruction language. Studying 738 pupils aged 13 and 15, we found that the WML–math relationship is already present by age 13. This benefit lies in spatializing the WML from left to right, not in spatialization per se, and remains significant after controlling for item WM, order WM and general task performance. These findings indicate a unique relationship between the WML and mathematics performance.