Proceedings of the Annual Meeting of the Cognitive Science Society

Spatial-numerical associations (SNAs) reflect systematic mappings between numerical magnitude and spatial directionality and are shaped by both biological predispositions and cultural experiences. The present study examined the developmental emergence of horizontal and vertical SNAs in Japanese-speaking children exposed to both left-to-right and top-to-bottom writing conventions. In Study 1, children aged 2–7 years and adults completed card-ordering, counting, and sticker-placing tasks in which stimuli were arranged horizontally or vertically. Horizontal SNAs showed a left-to-right bias in children aged 5 and older. In contrast, vertical SNAs changed with age, shifting from a bottom-to-top bias in early childhood to a top-to-bottom bias by around age 7. In Study 2, we examined whether this developmental shift was related to literacy-related experience. Logistic regression analyses showed that hiragana character-sound knowledge significantly predicted top-to-bottom vertical SNAs in 5- to 7-year-olds, controlling for age and nonverbal intelligence. These results demonstrate that SNAs are not fixed mappings but rather flexible representations partially shaped by literacy-related experiences.