Faculty Research Interests

DEVELOPMENTAL PSYCHOLOGY

Carey, Susan — An understanding of concep­tual development rests on two related but distinct enterprises. First, one must charac­terize the evolutionarily given representational primitives out of which human conceptual understanding is built. Second, one must characterize the processes through which conceptual understanding that transcends those initial primitives is built. Research in my laboratory contributes to both enterprises.

With respect to evolutionarily given conceptual primitives, recent work has concen­trated on infant representation of objects, object kinds, criteria of individuation and numerical identity, number, and attentional states of human and nonhuman agents. In collaboration with Marc Hauser, I have also explored some of these same representational systems in nonhuman primates.

With respect to human conceptual devel­opment, recent work has described several respects in which conceptual development is discontinuous—that is, several respects in which conceptual understanding at a later point in development transcends the innate starting points. Later conceptual systems that go beyond what was previously avail­able include: 1) Explicit representational devices with more representational power than the nonverbal representational systems from which they are built. An example is the integer list representational system for natural numbers; and 2) Intuitive theories formulated over conceptual primitives incommensurable with those that articulate earlier theories.
Examples include a vitalistic theory of living things constructed by children between ages 5 and 10, a continuous theory of matter in which weight and density are differentiated constructed by children between ages 8 and 12, as well as cases from the history of science.

My most recent theoretical work concerns the bootstrapping mechanisms that underlie conceptual change and the construction of new representational resources.

Recent papers include:

Saxe, R., Tenenbaum, J., and Carey, S. (in press) “Secret agents: 10 and 12-month­olds infer an unseen cause of the motion of an inanimate object.” Psychological Science.

Astuti, R., Solomon, G., and Carey, S. (2004). Constraints on Conceptual Develop­ment: A Case Study of the Acquisition of Folk-biological and Folksociological Knowledge in Madagascar. Monographs of the Society for Research in Child Development.

Carey, S. (2004). “Bootstrapping and the origin of concepts.” Daedalus. Winter, 59-68.

Preissler, M.A. & Carey, S. (2004). “Do pictures and words function as symbols for 18- and 24-month-old children?” Journal of Cognition and Development.

Pinker, Steven — see listing above under Cogni­tion, Brain, and Behavior.

Snedeker, Jesse — My laboratory explores many facets of language development, comprehension, production and representa­tion. We study typically-developing children (from infancy into middle childhood), adults and a variety of special populations (e.g., children with cochlear implants, international adoptees, high-functioning autistics). Our methods are diverse. We track eye-movements during spoken language comprehension, analyze corpora, study parent-child interac­tions, conduct training studies to explore the process learning words and grammars, and probe the linguistic intuitions of naïve speakers. Our primary interest is how language conveys meaning. We aim for methodological simplicity and theoretical clarity.

Projects underway include:

1) Syntactic priming in children. Do young children, like adults, represent the gram­matical structure of a sentence? Or do they have more concrete representations based on individual words rather than syntactic catego­ries? Recently we found that young 3-year olds show abstract structural priming during comprehension. Now we are exploring this in younger children and attempting to charac­terize the nature of these abstractions.

2) Language development in internationally-adopted children. Adoptees learn a second language under similar circumstances to infant first language learners. Yet they are older and more cognitively mature. By comparing these groups we can learn which aspects of language acquisition are influenced by cognitive devel­opment and maturation and which are not.

3) The interface between language and communication: Understanding an utterance involves both linguistic decoding (semantics) and inferences about the speaker’s intended meaning (pragmatics). Our studies examine how these processes interact during language comprehension and how they develop during childhood. We focus on the use of scalar implicatures in the interpretation of quanti­fiers and numerals and the role of contrast in interpreting adjectives.

Other projects explore: word learning in children with autism spectrum disorders, the semantics of adjectives, the role of prosody in syntactic ambiguity resolution, how children learn the meanings of verbs, and the nature of polysemy.

Snedeker, J., Geren, J., and Shafto, C. (2007). “Starting over: International adoption as a natural experiment in language develop­ment.” Psychological Science (forthcoming).

Snedeker, J. & Yuan, S. (in press). “The development of parsing: Children use lexical and prosodic cues in online sentence compre­hension.” Journal of Memory and Language (forthcoming).

Barner, D. & Snedeker, J. (2005). “Quan­tity judgments and individuation: Evidence that mass nouns count.” Cognition, 97, 41-66.

Snedeker, J. & Trueswell, J. (2004). “The developing constraints on parsing decisions: The role of lexical-biases and referential scenes in child and adult sentence processing.” Cogni­tive Psychology, 49(3), 238-299.

Spelke, Elizabeth — Perceptual and Cogni­tive Development. My laboratory focuses on the sources of uniquely human cognitive capacities, including the capacity for formal mathematics, the capacity for constructing and using symbolic representations such as maps, the capacity for developing comprehen­sive taxonomies of objects, and the capacity for reasoning about human agents and their mental states. I study these sources by looking at their origins and growth in human infants and children and, increasingly, by considering human cognition in relation to the capacities of nonhuman primates.

Current studies are asking: 1) how infants recognize objects, extrapolate object motions, and represent object persistence over occlu­sion; and 2) how infants recognize human agents and reason about their goal-directed actions. The lab is also studying infants’ formation of global categories of objects (e.g., animals, artifacts, food) and people (e.g., gender categories, ethnic categories). Through collaborative research with Marc Hauser, the lab compares human infants’ representations of objects and agents to those of both labora­tory-reared and semi-free-ranging monkeys.

Other projects are probing the spatial representations that underlie navigation and the sense of orientation, both in young children and in adults. Our research provides evidence for a change in children’s representations of their surroundings coincident with the acquisi­tion of aspects of spatial language; we are trying to understand this relationship through a series of studies of adults and children.

In addition, my lab is studying human infants’ abilities to represent both small exact numerosities and large approximate numerosi­ties. Further studies investigate how children learn the meanings of number words and the counting routine, focusing on points in devel­opment when words like “three” seem to mean something very different to a child than to an adult. Finally, studies are probing exact and approximate number representations in adults with behavioral and neuroimaging methods.

Selected recent publications:

Lipton, J. S. & Spelke, E. S. (2003). “Origins of number sense: Large number discrimination in human infants.” Psycho­logical Science, 14, 396-401.

Hauser, M. D., Tsao, F., Carcia, P., & Spelke, E. S. (2003). “Evolutionary founda­tions of number: Spontaneous representa­tion of numerical magnitudes by cotton-top tamarins.” Proceedings of the Royal Society (London).

Smith, W. C., Johnson, S. C. & Spelke, E. S. (2003). “Motion and edge in perception of object unity.” Cognitive Psychology, 46, 31-64.

Barth, H., Kanwisher, N., & Spelke, E. (2003). “The construction of large number representations in adults.” Cognition, 86, 201-221.