The fact that Chinese speakers may be more likely to think about time on a vertical or a horizontal plane is an example of what

Linguistic Determinism

Explanation:

Edward Sapir and later Benjamin Lee Worf espoused that the language a human speaks can have an effect on the way their mind processes mental functions such as memory, thought and perception.

This called the Sapir–Whorf hypothesis and Linguistic Determinism is the form of it that explains why Chinese speakers may be more likely to think about time on a vertical or a horizontal plane.