Time
Humans, like creatures ranging from amoebas to elephants, come with built-in equipment for perceiving some aspects of time, such as the rhythms of night and day, and the turning of the seasons. What separates humans from other animals is that we dice it into units, even ones that go beyond what is perceivable, such as milliseconds, or that transcend our life span, such as millennia. In short, humans everywhere create and rely on time concepts – ideas about the nature of time.
But what are these time concepts? What is going on in the mind of, e.g., a speaker of Yupno, high in the mountains of Papua New Guinea, or English for that matter, when answering questions about the difference between yesterday and tomorrow? Recent research in cognitive science is uncovering a surprising answer. Across cultures, human time depends, in large part, on metaphor (a type of analogy or figure of speech) – in particular, on so-called conceptual metaphor, in which we think of something, in this case time, in terms of something else, in this case space. Thus, we build our understanding of duration, of time’s passage and of sequences of events out of familiar spatial ideas such as size, movement and location. This basic “time is like space” metaphor appears to be universal – yet it also takes strikingly different forms from one culture to the next.
The puzzle of how humans are able to understand time is an ancient one. But only in the past century have researchers started to study time concepts with an empirical eye, by looking closely at the language people use to talk about time. Benjamin Lee Whorf, famous for his idea that the language you speak guides the way you think, keenly observed in the early 20th century that speakers of English and many other European languages talk of time as “motion on a space” and imagine time units as standing “in a row.”
Whorf also claimed that the Hopi, a Native American tribe, conceived of time in their language without spatial metaphors. Later researchers showed that such metaphors are actually rampant in Hopi, just as they are in English. More remarkably, it turns out that all human cultures seem to treat time through spatial metaphors. Durations are talked about using words for size (“a short weekend”). Time’s passage is treated as movement (“the week flew by”). Events are imagined as located at different positions on a path.
However, even as people of all cultures lean on spatial concepts for understanding time, exactly which spatial metaphors they use can vary. Take the future-in-front metaphor, found in English and many other languages (as in “the week ahead of us”). This metaphor was long thought to be universal, but in 2006 a striking counterexample was encountered in South America. In Aymara, a language spoken in the Andes, many phrases actually suggest the opposite metaphor. For example, the expression “a long time ago” could be loosely rendered in Aymara as “a lot of time in front.”
For the Aymara, knowledge acquired through visual perception is taken to be certain and reliable. It is of utmost importance to communicate facts and stories by grammatically marking whether what is being said has been seen directly or learned from another source. For example, they can tell whether last year was dry or wet – they saw it with their own eyes. But how next year is going to be is anybody’s guess – nobody has seen it. The known past is therefore conceived as being visually in front of them and the unknown future out of view behind them.
Elsewhere, divisions between past, present and future are made in other ways. In Pormpuraaw, an Aboriginal Australian community, past and future are determined by cardinal directions, with past times to the east and future times to the west. In Yupno, the future is uphill and the past downhill. These different spatial metaphors reflect different cultural preoccupations, such as the mountainous landscape Yupno speakers call home.
Although all cultures make use of time-as-space metaphors, a skeptic could counter that spatial metaphors might merely be used for communicating about time; maybe in the privacy of our own minds, metaphors fall away. In fact, people draw on space when reasoning about time in all kinds of situations and even when all by themselves.
The human reliance on spatial metaphors for abstract thinking may have deep evolutionary roots and is not likely to change anytime soon. The particular metaphors we lean on, however, are a product of culture and are much more malleable. Consequently, new spatial metaphors for our dearest abstract concepts will almost certainly enter the picture as our culture evolves.
KENSY COOPERRIDE & RAFAEL NÚÑEZ, SCIENTIFIC AMERICAN MIND