Research in the Cognition and Development Laboratory is organized around several themes that are broadly united under the question of how humans carve up entities in the world into meaningful categories and how they think about these categories. This general orientation leads to the following research themes:

• The Emergence of Intuitive Theories
• Conceptual Change
• Words and Concepts
• Mature Understandings of the Division of Cognitive Labor
• Developing Notions of Expertise and the Division of Cognitive Labor
• The Shallowness of Intuitive Theories
• Constraints on Theory and Concept Structure
• Modes of Construal

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The Emergence of Intuitive Theories

It is now common place to view the young child as holding intuitive theories that enable them to reason about the world and which heavily influence the structure of their concepts and their categorization. Children are said to be endowed with theories of biology, folk psychology, physical mechanics, as well as of much more specific phenomena such as disease contagion or the day/night cycle. In all these cases, however, there have been few details revealed concerning how these theories are mentally represented, with most research to date tending to demonstrate that some aspect of early thought seems to go beyond mere associative principles. In the C&D lab we have conducted a wide variety of studies more systematically exploring what early intuitive theories look like. [Back to top]

Concepts seem to change over time, some times in terms of their referents, other times in terms of their internal meanings even as referents stay relatively constant. There are many different representational models that might correspond to apparent patterns of conceptual change, ranging from radical organizations of the theories in which concepts are embedded to shifting default biases in terms of which intuitive theories are used in which situations. Several studies in the C&D lab examine patterns of change in more detail with a goal of better understanding the conditions that most often lead to particular patterns of conceptual change. In general the studies tend to discount the idea of wholesale theoretical revolutions in favor of other mechanisms of more gradual change. [Back to top]

There has been a long standing interest in the C&D lab on interactions between word meanings and conceptual structure. Studies in this area have ranged from investigations of Japanese numerical classifiers in children and their relations to broad conceptual categories, to shifts in what instances are thought to be denoted by word meanings, to studies of how changing patterns of metaphor comprehension relate to changing conceptual structures. With adults, there have been studies on conceptual change, metaphor, and categorization. There is an increasing interest in exploring different models of category specific impairments in special populations as well. [Back to top]

All social groups quickly evolve into ones where there is a distribution of cognitive labor with their members having different areas of expertise. As members of those groups, people frequently make judgements about how knowledge is clustered in the minds of others. A series of studies is investigating how people make such judgements, with the surprising finding of strong group differences among adults in how to approach this problem. During adolescence there also appears to be a major shift in how such ways of organizing knowledge are envisioned. There are several alternative ways of viewing clusters of knowledge in the minds of others and the tradeoffs associated with each of these alternatives are an active area of interest. [Back to top]

Unlike adults, young children are not able to survey all of knowledge and do not have a mental map of the overall division of cognitive labor. They are, however, able to understand clusters of knowledge in more local comparisons. A series of ongoing studies has demonstrated that young children do cluster bits of knowledge and understanding in the minds of others in ways that reveal their intuitive notions of coherent domains of real world phenomena. For example, children as young as five know that an expert in one area of physical mechanics is more likely to understand another area of physical mechanics than one of biology. They seem to solve these tasks by referring to notions of how various phenomena in the world are unified by common underlying principles. Other studies have examined the more fragile emergence of these abilities in preschoolers. [Back to top]

Adults often fall sway to a powerful illusion concerning their understanding of how much of the world around them actually works. A series of studies have documented an illusion of explanatory depth (IOED) in which adults are often surprisingly overconfident in their estimates of how well they understand various aspects of the world. They tend to especially overestimate their knowledge with respect to explanatory knowledge as opposed to knowledge of procedures, or memorized facts. Ongoing studies are asking why the illusion of knowing is so much more pronounced in some areas than others. A key related question here concerns how the illusion emerges in development. Another line of work is interested in showing how people prematurely terminate inspections of diagrams and other materials at a point where they think they fully understand the materials but in fact still have substantial holes of ignorance. [Back to top]

Not all explanations seem equally plausible to young children. Several studies are examining how children decide among competing explanations. Some aspects of their choices are governed by factors described earlier, such as the structure of already existing intuitive theories or notions about the division of cognitive labor. We are also exploring how children chose among explanations in terms of using structural properties such as circularity or causal informativeness. Other constraints arise from much broader sorts of categorical and causal knowledge. One line of work examines how knowledge of "causal potency" influences understanding of high level categories. Adults and children have implicit notions of what sorts of properties are most causally central to broad domains such as artifacts and natural kinds, notions that can be largely independent of intuitions about what properties are most typical of lower level categories. For example although video cassettes and crows might be rated as equally likely to be black by many adults, blackness if judged as being more causally central to crows. Large sets of such intuitions across many categories reveal causal potency "profiles" that are highly similar across all members of broad categories such as animals, and hand tools. Other studies are examining whether even the perceptual similarity of entities are influenced by underlying notions of what is causally central to a category. Developmental studies reveal that similar profiles may be guiding the young child's emerging understanding of what sorts of properties are central to categories and domains. These developmental studies also show that abstract notions of what sorts of properties are causally potent normally precede more concrete notions about how the properties are causally efficacious. [Back to top]

Various modes or construal or cognitive stances are common in every day discourse. For example, an intentional stance involves descriptions of events in which mental states and activities are considered critical to explaining underlying causal patterns. Although this area is often known as "theory of mind", that label has come to be associated with the dominant task in the area, "the false belief task". There are, however, many other aspects of our understanding of the mind that are critical to how the intentional stance guides our interpretations of events. Several studies look at adult and children's notions of intentional agents. These studies range from investigations into naïve intuitions of how implicit and explicit thought, or unconscious and conscious processes, influence behavior to questions about how cognitive operations are normally understood. Other studies contrast the intentional stance with otherreasoning heuristics, what we call teleological and mechanical stances, and ask how each of these "modes of construal" influence how we understand and remember various phenomena. One topic of considerable interest is how the different modes of construal emerge in childhood and come to be associated with different patterns of regularities in the world. [Back to top]