How do humans conceptualize time? One clear pattern is that cultures around the world base their temporal concepts on spatial concepts. For instance, in English it is common to say things like "The week ahead" or "Way back in 1942." In these examples‒ like others in many other languages around the world‒ time is construed relative to a canonical observer: future events are construed as being in front of ego, and past events are construed as being behind. This particular pattern, however, is not universal, and therefore it is not innately determined in the human brain. Previous work by Professor Rafael Núñez, for example, has demonstrated with converging linguistic and gestural data that the Aymara people of the Andes operate with the reverse pattern, with the future construed as behind ego, and the past as in front of ego. This, however, is not simply the result of a "180 degree turn", but the outcome of a complex construal that recruits various asymmetrical properties of the front‒back bodily experience. It may turn out that there is considerable cross‒cultural variation in spatial construals of time. After all, there is well‒known cross‒cultural variation in how cultures conceptualize space to begin with. Some cultures favor geocentric ways of talking about space (e.g. "The tree is downhill from the house") over our more familiar egocentric ways (e.g. "The tree is on the left side of the house"). Would a culture that conceptualizes space geocentrically conceptualize time accordingly?
On a recent field trip to Papua New Guinea with anthropologist Jürg Wassmann from the University of Heidelberg, Professor Núñez and graduate student Kensy Cooperrider investigated this question. The team analyzed spatial construals of time among the Yupno, an indigenous group in a remote mountain area, focusing in particular on the spontaneous gestures Yupno participants produced when talking about temporal concepts. Spontanous gestures provide a naturalistic and largely unconscious source of data about how it is these temporal concepts are spatialized. Beyond providing mere exotic examples, such studies provide crucial insight into the roles of cultural dynamics, environment, and embodiment in shaping human conceptual systems and their biological realization.