Current Research
EARLY WORD LEARNING
Many of our projects focus on word learning in infants, toddlers, and preschoolers.
In one ongoing series of investigations, we are exploring the role that causal information plays in supporting early word learning. The foundational study in the series demonstrated that children learn words more easily when they are told about the causal properties of the objects that those words refer to. For example, children are more likely to learn that a funny-looking alien creature is called a ‘blicket’ if they are told that this type of alien uses its teeth to grind rocks into little pieces to eat (i.e., a causal property) than if they are told that this type of alien has teeth that look like little rocks (i.e., a non-causal property). Causal Supports for Early Word Learning [pdf]
We are now asking a number of additional questions about this effect.
- What mechanisms are responsible? Does causal information enhance children’s attention while they are being taught new words and/or does it make memories for those words last longer?
- How does the influence of causal information develop? Are infants and older children equally likely to benefit from causal information?
- Can we effectively integrate causal information into natural word-learning contexts? Can parents and teachers improve children’s word learning by reading them books that are rich in causal information improve word learning? Or by engaging them in hands-on projects that highlight related causal information?
In a second series of studies, we are exploring the role that gestural cues (like pointing) play in facilitating word learning. The foundational study in this series demonstrated that young children are able to use eye gaze and pointing to figure out what object a new word refers to. Moreover, these cues support word learning, not only by directing attention to the intended referent at the time of labeling, but by highlighting the communicative nature of the exchange. Socio-Pragmatics and Attention: Contributions to Gesturally Guided Word Learning in Toddlers [pdf]
In subsequent work, we have been testing children who have difficulty learning language (e.g., late talkers, children on the autism spectrum) to see if their use of gestural cues differs in important ways. Preliminary results from our study of children with autism suggests that they are able to capitalize on pointing, but not eye gaze alone, in learning new words.
In a third series of studies, we have begun to explore the influence of environmental factors on early word learning. Unfortunately, children from lower socio-economic strata tend to enter preschool with a substantially lower vocabulary than do their higher SES counterparts (Hart & Risley, 1995). We are interested in developing new ways to eliminate this disparity. We are beginning our efforts by attempting to clarify the nature of the differences. By specifying the full range of strengths and weaknesses of children in vocabulary knowledge and word learning skills, we believe we will be in a better position to develop more efficient and effective interventions.
MOTIVATION IN WORD-LEARNING
Our lab is deeply interested in learning about the process by which children learn new words. However, you cannot possibly have a full understanding of how children learn without also asking the question of why children learn. What motivates them to care enough to seek out and store information about new things they come across in a day?
The Early Learning Lab’s PhD student, Aubry Alvarez, has made questions about motivation the primary focus of her thesis project. Aubry has worked with 3- and 4-year-olds to see what kind of information motivates them to learn more about new creatures or objects. She has also considered the effects of providing additional incentives (such as stickers) in addition to simple descriptions for these new items.
As part of this project, we allowed 3-year-olds to choose what type of information they learned about unfamiliar animals and objects. We found that children are more likely to prefer information about an item’s function. In the next study, we asked 3- and 4-year olds to complete a boring task in order to learn about an unfamiliar animal or object and allowed children to continue learning for as long as they wanted. Half of the children were given information about items’ functions and half were given information about some other property of the items. Additionally, half of the children in each of these groups were given stickers every time they learned about a new item. Initial findings from this study indicate that kids are far more willing to persist with a somewhat tedious task when they are “rewarded” with information that tells what a new object or creature does in the world.
Past Research
Constraints on Infant Categorization
One of the most important accomplishments of infancy involves partitioning the world into meaningful categories (e.g., Mandler & McDonough, 1993; Quinn & Eimas, 1997). Infants' success at this task is particularly remarkable given the vast quantities of information that they must process in doing so. Like adults, infants are faced with an infinite array of objects, each characterized by an infinite number of attributes (e.g., size, shape, color). One of the principal goals of our research is to identify constraints that help to limit the information that enters into the categorization process, and to specify the mechanisms by which they do so. Thus far, our research has identified object functions and names as strong candidates.
Object functions
Our work demonstrates that 14- and 18-month-old infants are more likely to organize novel objects into categories after observing their functions (Booth, 2001; Booth & Waxman, 2002). Importantly, because the functions in these studies were not available at test, infants' categorical responses were necessarily based on other object properties. This suggests not only that object functions are salient to infants, but also that these cues draw infants' attention to other similarities among novel objects.
In subsequent work, we more precisely demonstrated that object functions increase the efficiency with which new categories are formed (Booth, Schuler & Zajicek, 2010). Indeed, infants were more likely to categorize after a single training trial if object functions were demonstrated than if they were not. We also demonstrated that there are two mechanisms by which function facilitates early categorization: 1) drawing attention to global perceptual commonalities among objects and 2) drawing attention specifically to functionally relevant object properties (Booth, 2008a). These effects do not appear to be the result of the dynamic nature of functions alone (Booth, Schuler & Zajicek, 2010), but instead seem to hinge on the causal relations that they embody (Booth, 2008b). In continuing work, we are attempting to further specify what is it about object function that supports its facilitative effect on categorization. Specifically, we are exploring the role that human agency and intentionality play.
Object names
Our research (in collaboration with Dr. Sandra Waxman and the Project on Child Development) also demonstrates that words help infants as young as 11-months of age to isolate commonalities among objects (Waxman & Booth, 2003). Initially this effect is quite broad such that infants map both count nouns and adjectives onto both category-based (e.g., animals) and property-based (e.g., color) commonalities among objects. However, by 14 months of age, infants' are sensitive to subtle cues in adult speech that allow them to distinguish between these grammatical categories. They come to attend exclusively to category-based commonalities when hearing count nouns, but attend either to property-based commonalities exclusively or to a broader range of commonalities when hearing adjectives (Waxman & Booth, 2001, Booth & Waxman, 2003).
Interestingly, the influence of count noun naming on categorization is evident with completely novel objects in 18-, but not 14-month-olds (Booth & Waxman, 2002). The null results obtained for the younger age group appear to be due to infants' inability to detect a meaningful referent for the novel names presented to them. Because the stimuli were completely novel, and no conceptual properties were detectible, infants had no 'core meaning' to attach the novel words to. When infants were given a 'hint' regarding the deeper conceptual properties of the objects (i.e., their function), naming did facilitate categorization at 14 months. In more recent work, we confirmed infants’ ability to map nouns onto object categories using a fully automated design that minimized potential experimenter error (Booth & Waxman, 2009).
Early word learning
Because we believe that early linguistic and conceptual development are inextricably linked, many of our projects have focused on word learning in infants, toddlers, and preschoolers. We are particularly interested in the role that conceptual information plays in supporting the acquisition and extension of new words. Much of this work is described in our current projects section, but older research is summarized here.
Knowledge of ontological kind
In some of our foundational work, we demonstrated that young children's ontological knowledge about labeled objects influences their extension of novel words applied to those objects (Booth & Waxman, 2002, 2003). Three-year-olds extended novel words on the basis of similarities in shape alone when labeled objects were described as having conceptual properties typically associated with artifacts (e.g., has a special use, is kept in a particular location). In contrast, children extended labels on the basis of similarities in both shape and texture when the very same objects were described as having conceptual properties typically associated with animate kinds (e.g., has emotions, eats). Because the same objects were presented in both conditions, only the conceptual information provided could be responsible for the differences in extension patterns. We have since extended this important finding to 2-year-olds and have shown similar effects in infants as young as 18- to 22-months of age who have minimal productive vocabularies (Booth, Waxman, Huang & Hackenberg, 2005). We have also better articulated the origins of these effects. Specifically, we demonstrated that toddlers were more likely to develop a precocious shape bias after several weeks of training on categories defined by shape-function relations rather than on categories defined by shape alone (Ware & Booth, 2010). This research has generated considerable theoretical controversy. To learn more, see Booth & Ware, 2010, Booth & Waxman, 2008; Booth & Waxman, 2003; Booth & Waxman, 2006).
