Interesting! I agree but the author didn’t mention what kind of rural areas. The author did also mention round houses or scrubland so it could be either.
Rural inhabitants have more exposure to distance and living on plains than people living in highly developed, commercialized cultures. — En.wikipedia.org. (2017). Vertical–horizontal illusion. [online] Available at:https://en.wikipedia.org/wiki/Vertical%E2%80%93horizontal_illusion[Accessed 24 Nov. 2017].
This publication could help shed more light on this issue. Thanks for translating Nancy!