Does Mandarin spatial metaphor for time influence Chinese deaf signers’ spatio-temporal reasoning?

In Mandarin Chinese, the space-time word “前/qian” is used to express both the spatial concept of front/forward and the temporal concept of early/before (e.g., “前天/qian-tian”, literally front day, meaning the day before yesterday). This is consistent with the fact that Mandarin speakers can gesture to the front of the body to refer to a past event, and more generally can have past-in-front space-time mappings. In Chinese Sign Languages, however, the spatial front/forward and the temporal early/before are signed differently as the sign for spatial front is only used for the spatial concept of forward, and the sign for before/past is directed to the back. In this study we investigate whether the Mandarin sagittal spatial metaphors for time influence Chinese deaf signers’ spatio-temporal reasoning. In two experiments, we found that Chinese deaf signers with higher Mandarin proficiency were more likely to interpret the Mandarin word “前/qian” as the temporal conception of past (Study 1), and to perform past-in-front space-time mappings (Study 2) as opposed to signers with lower Mandarin proficiency. The findings of the study not only provide within-culture evidence for the influence of language on thought, but also demonstrate that even cross-modal space-time metaphors can have an impact on deaf-signers’ spatio-temporal reasoning.