The Aymara subjects, particularly the elderly who didn't have mastery of Spanish, thumbed or waved over their shoulders when speaking about the future. And they swept their hands or arms in front of them while speaking of the past – closer to their bodies for events in the recent past and wider gestures for events in the distant past.
“It was quite striking when people were starting to point . . . in directions that seemed totally unnatural to us,” Núñez said. “We're talking about non-technical, everyday notions of chronology here.”
This is so unnatural, that if this appeared as a characteristic of an alien race in an SF story, I'd think it was phony-baloney.