Research Interests

My research focuses on early conceptual and category development, and on early word learning. In particular, I am interested in how language affects and interacts with category development, and how children’s incipient categories can provide a window onto their early theories about the world. I have approached these issues from complementary angles, considering the sources of information children exploit in learning new words, the strength of different types of word learning, and the power of language to convey category information even to children just beginning to produce their first words.

Effects of language on early thought

How do children learn about non-obvious categories? How do they learn about atypical or misleading exemplars of a particular category? One way is through experience, by noting causal or functional similarities between category members. However, forming a non-obvious category on one’s own can be time-consuming and may involve experience that is difficult to obtain. Moreover, it requires that every individual in every generation has the experience for him or herself. Another, arguably more reliable and efficient way to determine category membership is through language: When a trusted source informs us of a counter-intuitive category to which something belongs, it reflects a non-obvious way that others have found useful to think and reason about that object in the past, and it can cause us to revise a classification immediately. For language to have this effect, however, listeners must forgo their own compelling, perceptually based classifications in favor of classifications they may not understand.

In a series of studies with infants, toddlers, and preschoolers, we have been investigating children’s willingness to accept a category label for an object when that label conflicts with their own, spontaneously generated perceptual expectations about that object. Results to date suggest that certainly by 24 months, and possibly at 18 months, children are willing to accept and use a counter-intuitive category label for an object in order to make an inference that is the opposite of the one they would make without the label. For example, when shown a digitally created animal that looks like a cat, those who hear it referred to as a "dog" are more likely to have it play with a stick than those who hear it referred to without a label (who are more likely to have it play with a ball of yarn).

Interestingly, there seem to be limits on how willing children are to accept "on faith" the accuracy of a counter-intuitive label. In particular, preschoolers sometimes reject the counter-intuitive labels, insisting that a cat-like animal plays with a ball of yarn, even when the researcher explicitly refers to it as a "dog." Another line of research is considering whether these labels can be made more acceptable by situating them in a potentially explanatory context. For example, preschoolers who reject the label "dog" for the cat-like animal are significantly less likely to do so when the same object is referred to as a "baby dog" suggesting that they may be able to exploit knowledge-based reasoning, possibly essentialist notions about innate potential and growth, in order to explain the disparity between what the animal looks like and what it is being called.

Outstanding questions:

How does the evaluation of the source of category information develop? Are children as likely to accept non-obvious category information from all speakers? Or only adults? How do they calibrate what another individual is likely to know?

What circumstances lead to rejections of category labels? When rejections occur, do children try to explain the rationale? Do they seek clarification?

How do "global" categories become differentiated? How do differences in non-obvious properties between members of the category of living things, for example, become established?

Relevant publications:

Jaswal, V. K., & Malone, L. S. (in press). Turning believers into skeptics: 3-year-olds' sensitivity to cues to speaker credibility. Journal of Cognition and Development.

Jaswal, V. K. (in press). The effect of vocabulary size on toddlers' receptiveness to unexpected testimony about category membership. Infancy.

Jaswal, V. K. (in press). Division of linguistic labor. To appear in P. Hogan (Ed.), The Cambridge encyclopedia of the language sciences. Cambridge, England: Cambridge University Press.

DeLoache, J. S., Ganea, P. A., & Jaswal, V. K. (in press). Early learning through language. Chapter to appear in J. Colombo, P. McCardle, & L. Freund (Eds.), Measuring language in infancy. Hillsdale, NJ: Erlbaum.

Jaswal, V. K., & Markman, E. M. (2007). Looks aren't everything: 24-month-olds' willingness to accept unexpected labels. Journal of Cognition and Development, 8, 93-111.

Jaswal, V. K. (2006). Preschoolers favor the creator's label when reasoning about an artifact's function. Cognition, 99, B83-B92.

Jaswal, V. K. (2004). Don't believe everything you hear: Preschoolers' sensitivity to speaker intent in category induction. Child Development, 75, 1871-1885.

Markman, E. M., & Jaswal, V. K. (2003). Abilities and assumptions underlying conceptual development. In D. H. Rakison & L. M. Oakes (Eds.), Early category and concept development: Making sense of the blooming, buzzing confusion (pp. 384-402). Oxford: Oxford University Press.

Jaswal, V. K., & Markman, E. M. (2002). Children’s acceptance and use of unexpected category labels to draw non-obvious inferences. In W. Gray & C. Schunn (Eds.), Proceedings of the twenty-fourth annual conference of the Cognitive Science Society (pp. 500-505). Hillsdale, NJ: Erlbaum.

Early word learning

How do children learn words so quickly, apparently effortlessly, and often accurately? Direct, ostensive labeling, which involves overt cues to reference like eye gaze, pointing, joint focus of attention, and voice direction, has sometimes been taken as the prototypical word learning situation--at least in experimental studies. However, only a fraction of an individual’s vocabulary can be learned through direct instruction. Indeed, most words must be learned indirectly, through overhearing or inference. In this line of research, we have been comparing how well 2- and 3-year-olds learn words when they are explicitly taught those words versus when they are indirectly exposed to them. Results to date suggest--somewhat surprisingly--that the learning from these two contexts is largely equivalent, in terms of the strength of the word-referent mapping, its robustness over a delay, and even its openness to revision on the basis of new information.

Outstanding questions:

Are different inferences licensed by different word learning contexts?

How does grammatical form class influence children’s memory for new words? What role does the context in which the word was first encountered play on memory?

Relevant publications:

Markman, E. M., & Jaswal, V. K. (2004). Acquiring and using a grammatical form class: Lessons from the proper-count distinction. In D. G. Hall & S. Waxman (Eds.), Weaving a lexicon (pp. 371-409). Cambridge, MA: MIT Press.

Jaswal, V. K., & Markman, E. M. (2003). The relative strengths of indirect and direct word learning. Developmental Psychology, 39, 745-760.

Jaswal, V. K., & Markman, E. M. (2001). Learning proper and common names in inferential versus ostensive contexts. Child Development, 72, 768-786.

Constraints on learning

Are lexically-specific assumptions about words necessary to explain early word learning? A recent thread in the literature has suggested that domain-general learning processes and pragmatic abilities can explain children’s “word-learning wizardry,” and that there is therefore no need to invoke lexically-specific assumptions or constraints. With Mikkel Hansen (Roskilde University) and Ellen Markman (Stanford), we suggest that pragmatic abilities clearly play an important role in early word learning, but they do not seem sufficient to explain some of the key phenomena. In particular, there are some important differences between how children learn words for objects and how they learn other kinds of information about those objects.

Relevant publications:

Jaswal, V. K., & Hansen, M. B. (2006). Learning words: Children disregard some pragmatic information that conflicts with mutual exclusivity. Developmental Science, 9, 158-165.