Susan J. Hespos, PhD - US grants

Previous behavioral work on the cognitive development of human infants has illuminated many aspects of the system that children use to adapt to their new world. However, relatively little is known about the neural activity that supports these new ways of thinking. With NSF support, Dr. Susan Hespos of Northwestern University will examine the development of perceptual and cognitive processing in infancy through the use of near infrared spectroscopy (NIRS). This technique, currently being implemented in a few laboratories around the world, allows the measurement of brain activation by means of the tiny amounts of light that pass through the skull. By amplifying this natural phenomenon, it is possible to measure brain activity safely and noninvasively, even with infants. NIRS will provide key information regarding the developmental trajectory of visual cognitive maturation. The localization of brain functions provided by NIRS will be verified by first testing the well-understood basic motor and sensory functions, and then moving on to more complicated issues regarding visual cognition. It is hoped that this progression will clarity the ambiguous results previous efforts have yielded on localization. The first of the extensions will be exploring the neural correlates of responding to familiar versus novel stimuli. Next, the neural development of object perception (discrimination of shapes, faces, size changes, orientation changes, categorization, etc.) will be studied.

Having a reliable and feasible method for studying the neural bases of behavior in infants will greatly facilitate the field of developmental cognitive neuroscience. This project will provide a new avenue for discovering developmental changes in brain activation during the first year of life. It has so far been difficult to study the neural correlates of higher-order cognitive processing in infants and how these interact with cognitive development. By mapping out the brain activity in typically developing infants, it will provide a baseline from which to examine individuals who are developing atypically. Clinical work on atypical development demonstrates that early diagnosis is generally of great benefit. Ultimately, NIRS imaging could be used for early diagnosis of language, motor, and/or visual disorders.

The research will clarify the effect of words on categorization in the first months of life and trace the developmental trajectory of this effect over the first year of life. The starting point for these studies is a recent demonstration by the investigators that words promoted object categorization in infants as young as 3 months, and do so in a way that carefully matched tones do not. This result opens several new avenues for investigation, each of which will bear on fundamental questions concerning the relation between language and conceptual organization in the first year of life. The project will identify what it is about speech stimuli that promote object categorization over and above the effect of tone sequences in infants so young. The proposed experiments test the hypothesis that human speech engenders in very young infants a heightened attention to the surrounding objects, and that this very general attentional effect later becomes more specific as infants become attuned to the speech sounds of their own ambient language. Pursuing this hypothesis requires an examination of 3- to 12-month-old infants' treatment of a broad range of auditory stimuli. To discover whether the facilitative effect of words on categorization is specific to linguistic stimuli or evident for other complex stimuli as well, the proposed experiments use a preferential-looking task. In this task, the infant is presented with a series of individual pictures followed by a test trial in which the infant is presented with a novel and a familiar picture side-by-side, and the investigators measure how much time the infant spends looking at each picture. The project investigates the effects of auditory stimuli including naturalistic speech from a range of languages, filtered speech, backwards speech, mammal vocalizations, and bird calls. Another focus of this project is to investigate the developmental trajectory for infants growing up in bilingual homes.

The project, focused on typically-developing infants, will have broad impact on theories of normative development in monolingual and bilingual infants and will have implications for interventions with atypically-developing infants and young children. The research focuses on two uniquely human capacities -- language and conceptual development -- and explores an emerging link between them. By mapping out the development of this link, the proposed studies will put practitioners in a better position to identify patterns that deviate from typical development. Moreover, by considering infants growing up bilingual, this work will address crucial questions about consequences of processing two languages in the first years of life, and will advance efforts to promote positive developmental outcomes for the ever-increasing number of bilingual infants and young children in the United States. Finally, this basic research can also serve as a springboard for developing targeted interventions for young children diagnosed with language delay and impairments, as well as those diagnosed with autistic spectrum disorders.

Learning by analogy is a powerful and efficient method for acquiring new information. The goal of this research program is to trace the origins of analogical ability in human infants, using the simplest and most basic relation--that of sameness and difference between two things. The proposed research will identify the scope of infants' ability to detect same-different relations. Certainly infants do not have the same higher-order relational abilities of children and adults. This research will 1) identify the earliest evidence of relational learning processes in the first months of life; 2) trace its developmental trajectory over the first year; and 3) characterize the interplay between language and early relational ability.

The research addresses the key question of when children begin to think abstractly and how this ability can be fostered. Studies of early relational learning processes will provide insight into the conceptual capacities that are critical to higher-order learning in childhood and beyond. Further, the studies of interactions with language may lead to better understanding of the role of cultural and linguistic experience in conceptual development. The patterns revealed by these experiments will give parents and educators the requisite knowledge to support relational learning in STEM disciplines. They may also enable practitioners to identify patterns that deviate from typical development and suggest targeted interventions for children with cognitive or linguistic impairments.

Analogical ability is the ability to make relational comparisons between objects, events, or ideas, and to see common relational patterns across them. It is a cornerstone of higher reasoning ability, and is essential for learning mathematics and science. This project investigates the nature of this ability and how it develops in infants, tracing its development over the first year of life. Delineating the conditions that promote relational learning in young infants, will lead to insights into how best to promote relational learning in children and in adults who show lags in abstract learning. One result of the proposed studies will be a set of methods and tools that can be used by teachers and caregivers to support relational learning. For example, this research can serve as a springboard for developing targeted interventions for young children diagnosed with language delay, as well as those diagnosed with autistic spectrum disorders. Another result will be a better understanding of how to build artificial intelligence systems that learn more like people, with far less data than today's systems require.

The starting point for this proposal is a recent demonstration that 7- and 9-month-old infants can form abstract same and different relations, and apply them to new objects. The preliminary studies suggest that even 3-month-old infants are capable of relational learning; however, they are highly vulnerable to distraction by the interestingness of the objects in the pairs. The new research will use four series of experiments to trace infants' ability to learn abstract relations. The first will examine the processes that promote relational learning in 3-month-olds. The second will investigate the conditions that support spontaneous comparison and learning in 7- and 9-month-olds. The third series will test how language influences relational learning- specifically, whether naming relations can improve learning, and whether naming objects can impede relational learning. The fourth series of experiments will investigate the generalizability of these effects by testing a variety of abstract relations. Computational modeling of the learning patterns found in our studies will provide complementary insights on these processes. Taken together, these studies will reveal information critical to understanding analogical processes and the origin and evolution of higher-order cognition.