Why do humans use language, and what is it good for? Without the symbolic systems of natural language, our cousins in the animal kingdom perceive the building blocks of experience - like time, space, color, and number - through the lens of their blurry perceptual systems. Without symbols, it's really hard to tell apart 24 things from 25, or to figure out where green ends and blue begins, or to keep track of how long we've been running on a treadmill (it always seems longer than we think!). Although a hugely important function of language is communication - sharing our experiences and observations about the world with others for mutual benefit - my research also emphasizes the role that language plays in our organization of experience, and how the symbolic systems that get expressed through language allow us to transcend the limits of perception.
Driven by needs to coordinate our behaviors, humans created artifacts like clocks, currencies, and written symbols, each of which were accompanied by changes to our language, and to how we reason about these abstract dimensions of experience. Our human ancestors began carving symbols for number into clay about 11,000 years ago in present-day Iraq. These same cultures produced body counting systems that counted in multiples of 12, which are the basis for our 24 hour day, and our 60 minute clock. And over time, many different groups began to develop systems for counting and computing, and for talking about large precise numbers. My research investigates the origin of such abilities in both children and adult learners. Across different cultures, many different systems for representing number, time, space, color, and even other people's minds and moral beliefs exist. We study children who learn these different systems in cultures spanning the globe, including India, Korea, the US, Mexico, Canada, Japan, Iran, China, and Europe. Also, in the case of number, our lab is co-leading an NSF-funded consortium of over 130 labs called ManyNumbers, a worldwide study of early numeracy.
Our work has found that children learn about the perceptual world by first learning the structure of the linguistic systems that humans use to represent it. They learn conceptual knowledge of time - like how to estimate duration, or to organize events - by first learning words like second, minute, hour, and day, and how these words are structurally related to each other. Children don't learn simply by mapping words onto the world like some theories argue: instead they use the relations between words (like that a minute is 60 seconds) to figure out what the world is like. We have found similar patterns in our studies of time, number, and color, where in each case children start by learning rote sequences of words and how they relate to one another, and only very late figure out how these words relate to perception.
In addition to studying how children acquire abstract concepts like time, number, and color, our lab also studies how linguistic structures - and children's ability to represent them - impact logical reasoning, pragmatic reasoning, and our ability to reason about other people's minds. We also study how symbolic systems impact our reasoning about fairness (e.g., how fairness concerns change when people are paid with money, rather than simply sharing resources). And in adult learners, we study the evolution of symbolic systems using language games, where people are required to make up new written symbols to express abstract ideas. Finally, we study social cognition from a cross-cultural perspective. We have studied social reasoning in children from Iran, Korea, India, the US, and Canada, focusing on how children different universal moral norms from conventions that differ cross-culturally, and also on how children in different cultures reason about group membership, political conflict, and a belief in a "just world".
A unique aspect of our research is its tight connection with adjacent fields like philosophy of mind, anthropology, and especially linguistics where we publish many papers on logical reasoning, pragmatics, and how language interfaces with theory of mind.
Research (click HERE for publications)
Language, thought, and object perception
Mass / count distinction and acquisition
Quantifier acquisition & counting
Gradable adjectives and measurement
Singular / plural morphology
Numerical estimation and non-linguistic representation
Non-linguistic mathematical computation and the "mental abacus"
Classifier languages and individuation