> Extending the first three studies to non-students, we found that residents of mountainous U.S. states were more introverted than residents of flat states (Study 4).

> The terrain did not make people more introverted, but introverts were happier in the secluded area than in the flat/open area, which is consistent with the person–environment fit hypothesis.

https://www.sciencedirect.com/science/article/abs/pii/S00926...