Imagine a toddler, perhaps 10 months old, sitting in a high chair in a kitchen, watching and listening as her parents prepare a meal and, in the process, speak to each other and to the child. Even such a seemingly simple, everyday event presents this small child with an enormous amount of information to interpret. Her parents move rapidly from place to place, handling many different objects that they manipulate in diverse ways, all the while maintaining a steady stream of conversation with one another. Despite the complexity of her environment, in the coming months and years this child will somehow find ways to make sense of the flow of language and action. She will accurately link words to thousands of objects and actions, and thus add rich levels of meaning to her furiously expanding capacity for knowledge.

Psychologist Dare Baldwin's research is dedicated to solving the riddle of what she calls humans' "phenomenal ability to acquire knowledge." A recipient of an NSF Young Investigator Award, which is designed to support the work of outstanding young faculty in science and engineering, Baldwin has been focusing much of her attention on how young children, and even infants, can amass and synthesize as much information as they do. Baldwin's studies to date suggest that even at a very young age, infants and children possess a remarkable ability to accumulate knowledge by inference, from seemingly subtle clues, as activity and language swirls around them.

On a larger scale, Baldwin says, "I would like to understand all the different sorts of mechanisms that children can recruit for the purpose of acquiring knowledge, and in turn learn how knowledge acquisition affects children's performance across a variety of domains." Baldwin, who has also been awarded the Distinguished Scientific Award for Early Career Contribution to Psychology by the American Psychological Association, recently has been involved in a number of NSF-funded studies related to knowledge-acquisition:

Social Cues
Baldwin and various colleagues investigated young children's sensitivity to social cues - such as gaze direction, body posture, gestures, emotional expression and more - as a source of information about word meaning. The research shows, for instance, that children as young as 12-18 months spontaneously check where a speaker is looking when she utters a word that is new to them, and link the word with the object the speaker is looking at. In this way, infants avoid many potential word learning errors. They link words with the correct objects - the ones speakers are indeed referring to - rather than to whatever objects happen to be capturing their own attention when new words are heard. "Being so active in using social cues," notes Baldwin, "radically facilitates children's language learning."

In more recent research, Baldwin and a team of colleagues found that autistic children lack these skills for making use of social cues to guide word learning, which leaves them prone to errors in the word learning process. This research provides evidence for a connection between autistic children's known deficits in social understanding and their known delays in acquiring language.

Knowledge vs. Ignorance
With doctoral student Mark Sabbagh, Baldwin has also been studying whether three and four year old children evaluate another person's apparent level of knowledge when acquiring a new word. "Understanding the distinction between knowledge and ignorance, enables one to be a better world learner," Baldwin explains. "For example, imagine you've got a three-year-old who's fascinated by dinosaurs, and she asks her parents to name this or that dinosaur. The adult might say, "I'm not sure, but it might be a pteranodon." The child should really not learn that label, because the adult is not sure. At the very least, she should peg it with some uncertainty." The two researchers have found that, indeed, young children are less likely to remember a word linked to an object if an adult speaker expresses uncertainty about whether the label is correct.

Intentions
Baldwin's previous research suggests that infants as young as 12-18 months are able to understand something about the intentions that underlie people's behavior. Infant's abilities in this respect are remarkable given that human behavior tends to occur in a complex, rapid and continuous stream. Baldwin is now investigating the origins of these impressive abilities.

Baldwin wondered if infants, even younger than one year of age, might have the capacity to identify structure within complex activity. Would infants recognize the "units of action" in the behavior of the person they are observing? Would the infants recognize these units even when the units are not demarcated, in any simple way, by pauses in the flow of behavior? "For example," she says, "many of our behaviors fall into a similar pattern: we fix our gaze on an object, touch it or otherwise manipulate it, release it, and move our gaze and body-orientation elsewhere, then repeat the process with another object. If infants can identify each goal-directed action as a discrete unit, they would have a leg up on discovering the intentions motivating such activities."

By running a series of experiments with infants, Baldwin and colleagues collected evidence that infants indeed segment continuously flowing behavior into units that coincide with the initiation and completion of intention. The scientists used a series of videotapes of adults performing simple actions, such as grasping a towel. Sometimes, the tapes were freeze-framed at the completion of the action; other times, the tapes were freeze-framed in the middle. The infants showed only moderate interest in the tapes that showed the complete action. But they were transfixed by tapes that interrupted the expected sequence in mid-stream. That, says Baldwin, appears to be "the first evidence out there that infants this young are sensitive to the structure inherent in intentional action."

Taken as a whole, Baldwin's research contributes significantly to our understanding of how social cognition, language, and knowledge acquisition are linked in the developing brain.