Mandarin speakers have different space-time mappings than English speakers, but how Mandarin-speaking children spatialize time is unknown. We explored the development of 3D time-space representations in Chinese children aged 3 to 5. 145 Mandarin-speaking children, divided into three conditions (Exp1: horizontal, vertical, and Exp2: sagittal axes), undertook an MTL task for ten picture stories. We analysed their choices in 3-step temporal events, intending to test their sequential and directional preference of time (e.g., order vs. disorder; left-to- right vs. right-to-left). The results showed that Chinese children acquired sequential temporal representations on the horizontal and vertical axes at age 4, similar to English-speaking children. However, their directional preferences appeared earlier than English children (Exp1). Furthermore, the sagittal axis had different patterns: sequentiality emerged only at age 5, but directional preference still has not emerged in the whole 3- 5age group.These findings emphasize that language and culture impact children's conceptualization of time.

Although space helps children to grasp time, comprehending temporal metaphors remains challenging. Particularly, Mandarin has different degree of ambiguity in sagittal time-space metaphors, where ‘qian' (front/past) expresses both future-in-front and past-in-front mappings but ‘hou' (back/future) predominately expresses future-at-back mappings. Temporal metaphors with a longer duration unit (e.g., year vs. hour) also increase this challenge. We investigated: 1) when children understand sagittal time-space metaphors; 2) whether different degree of ambiguity leads children to having an asymmetric understanding of the past and future; 3) how the unit of temporal duration affects time understanding. 138 Mandarin-speaking children (3-5 years) undertook an 8-item sagittal time-space metaphors test. The results showed that age 5 is a milestone to understand sagittal time-space metaphors, and a longer unit of time duration and more ambiguous space-time metaphors hinder children's time comprehension. This study reveals the development of time cognition in non-western children and demonstrates how language impacts cognition.