When we say “I knew him way back when,” or “the best years are still ahead of you,” we’re using space to set up a timeline, with the past trailing behind us and the future stretching forward. Scientists long assumed that all people envisioned time that same way. But more recent studies have shown that’s not the case: Mandarin Chinese speakers may refer to the past as above them and the future as below. When the Pormpuraawans, a tribe in the Australian outback, think of time’s physical progress, they leave their own location out of it: time flows from east to west, regardless of which way they themselves are facing.
Now, researchers have worked with a group of people who seem think of time’s movement through space in yet another way: by referencing not relative locations or cardinal directions, but topographical features. For the Yupno people in Papua New Guinea, rather than marching ever onward, time wends its way uphill.