Teresa Wilcox - US grants

Recent research indicates that infants can draw on at least two sources of information to individuate objects involved in occlusion events: (a) featural (i.e., the shape, size, color, or pattern of an object) and (b) physical (i.e., knowledge about the lawful ways that objects move and interact). However, whether infants demonstrate this ability depends on the task used. When an event monitoring task is used (i.e., infants must judge whether successive portions of an event are consistent), infants demonstrate the ability to use featural information by 4.5 months of age, and some forms of physical information by 3.5 months of age (Aguiar & Baillargeon, 1997; Wilcox & Baillargeon, 1997). In contrast, when an event mapping task is used (i.e., infants must retrieve a representation of one event and compare it to a subsequent event), older infants often fail (Wilcox & Baillargeon, in press; Xu & Carey, 1996). The goal of the proposed research is to examine more closely the mapping problem and to identify the processes that infants engage in when they attempt to retrieve representations of occlusion events. The proposed research has been organized into two sections. The first section investigates infants ability to map occlusion events that involve two featurally distinct objects. These experiments address the question of how infants organize and map events that require binding features to individuals. The second section investigates infants ability to map occlusion events that involve two identical objects. These experiments address two issues: (a) infants ability to draw on different forms of physical knowledge to individuate objects and (b) event ambiguity and how it contributes to mapping difficulties. Together, the results of the proposed research will provide new insight into the way that infants form representations of occlusion events and how infants use these representations when reasoning about other physical events. The results will also provide direction for future research that will focus on the investigation of event representations in infancy.

[unreadable] DESCRIPTION (provided by applicant): [unreadable] Object individuation- the ability to determine whether an object is the same object, or a different object, than experienced previously - is one of our most basic cognitive capacities. Most current research has focused on the kinds of visual features (e.g., size, shape, color, pattern) infants use to individuate objects and how this changes with time and experience. What has been left open to speculation is the extent to which infants use information from other modalities to individuate objects. In light of the fact that infants live in a multimodal world - they see, touch, taste, and listen to the objects with which they come in contact - this gap in knowledge is problematic. Without this knowledge we cannot fully understand how infants solve the individuation problem in everyday situations. The research proposed in this application will move object individuation research in a new direction, by investigating infants' capacity to use auditory information as the basis for object individuation. Looking time methods will be used with infants 4.5 to 11.5 months of age. The objective of this application is to identify the types of auditory information infants use to individuate objects. The specific aims are to (1) assess the extent to which infants' use two kinds of sounds, those produced by shaking containers filled with different substances and those produced electronically, to individuate objects and (2) identify the underlying basis for the sensitivities observed. The central hypothesis for the proposed research is that young infants will demonstrate greater sensitivity to sounds that reveal something about the physical structure of the objects making them (e.g., containers filled with different substances), than sounds that are not clearly linked to the physical properties of objects (e.g., electronic tones). The outcome of this research will be used to develop theories of object individuation that focus on how infants go about individuating objects in a complex, multimodal world. These theories eventually will be used by parents, educators, and daycare providers to create environments that are most likely to facilitate learning about the physical nature of objects in healthy and at-risk infants. [unreadable] [unreadable]

As infants look around them, objects disappear and reappear from view. For example, a ball rolls behind the sofa, a toy gets covered by a blanket, or a bowl is placed in the cupboard. One of infants' most challenging tasks is to keep track of the identity of these objects as they move in and out of view. How do infants' determine whether an object currently in view is the very same object they saw before or a different object? What parts of the brain process this information? Are some parts of the brain more important than others for tracking object identity? In the past, questions about the neural basis of object identity were difficult to answer because non-invasive techniques were not available to measure brain activity in human infants. With support from the National Science Foundation, Dr. Teresa Wilcox will help apply a new technology, near-infrared spectroscopy (NIRS), to the study of the infant brain. Near-infrared spectroscopy measures changes in cerebral blood flow from the scalp of the infant, and changes in blood flow are used an indicator of neural activation. This highly innovative approach will allow Dr. Wilcox and her colleagues to measure neural activation during object identity tasks.

The broader impact of this funded project is that the successful application of NIRS, which is non-invasive, affordable, and relatively easy to use, will open the door for investigators to study the neural basis of other cognitive functions in infants, such as language or spatial memory. In addition, this project will enhance the neuroimaging resources and infrastructure at Texas A&M University and provide a unique educational resource for undergraduate and graduate students interested in neuroimaging of the human brain.

DESCRIPTION (provided by applicant): The capacity to represent the world in terms of numerically distinct objects is a milestone in early cognitive development and forms the foundation for more complex thought and behavior. Failure to develop this capacity places infants at significant risk for later developmental difficulties. Recent research has revealed important developmental changes in infants' ability to use featural information to individuate objects. However, relatively little is known about the neural mechanisms that underlie these changes, in large part because there are a limited number of non-invasive techniques available to measure brain function in infants. Hence, there is a critical need to identify new methods to specify the relation between behavior and brain function in object processing. One (1) such method is near-infrared spectroscopy (NIRS), an optical imaging technique that uses changes in cerebral blood volume as an indicator of neural activation. Because NIRS is safe and non-invasive, can be used during behavioral tasks, and provides spatial and temporal information about neural activation, it is ideal for infant research of this kind. The research proposed in this application will use NIRS to identify changes in neural activation during an object processing task. The objective of this application is to identify the neural basis of infants' ability to use 2 kinds of featural information, shape and color, to individuate objects. The central hypothesis is that infants' capacity to individuate objects using shape and color differences will be associated with unique, well-defined patterns of neural activation. This hypothesis has been formulated on the basis of behavioral and neuroimaging data collected in our lab. The rationale for the proposed research is that once we have identified the neural substrates that support featurally-based object individuation in the infant, it will be possible to formulate a developmental model of object processing that focuses on brain-behavior relations. This information can be used to help guide the development of diagnostic and intervention techniques that can be used with infants at risk for object processing difficulties, and will provide the impetus for new research that examines the extent to which normal patterns of behavior and brain function can be altered by differences in early experience.

As infants look around them, objects routinely disappear and the later reappear. For example, a toy gets covered by a blanket, an electric train moves through a tunnel, or a cup is placed in the sink. One of infants' most challenging tasks is to keep track of these objects as they move in and out of view. How do infants' determine whether an object currently in view is the same object they saw before or a different object? What parts of the brain process this information? In the past, questions about the neural basis of object processing were difficult to answer because non-invasive techniques were not available to measure brain activity in awake, attending human infants. With support from the National Science Foundation, Dr. Teresa Wilcox will apply an optical imaging technique, near-infrared spectroscopy (NIRS), to the study of the infant brain. Near-infrared spectroscopy measures changes in cerebral blood flow from the scalp of the infant, and changes in blood flow are used an indicator of neural activation. This highly innovate approach will allow Dr. Wilcox and her colleagues to measure neural activation during object processing tasks. For example, these researchers will measure activation in the parietal cortex, an area that processes object motion in the adult, while infants watch an event in which an object changes its speed or path of motion. The broader impact of this funded project is that the successful application of NIRS, which is non-invasive, affordable, and relatively easy to use, will open the door for investigators to study the neural basis of other cognitive functions in infants, such as language or number processing. In addition, this project will enhance the neuroimaging resources and infrastructure at Texas A&M University and provide a unique educational resource for undergraduate and graduate students interested in neuroimaging of the human brain.

Description (provided by applicant): The capacity to represent the world in terms of numerically distinct objects is a milestone in early cognitive development and forms the foundation for more complex thought and behavior. Failure to develop this capacity places infants at significant risk for later developmental difficulties. Recent research has revealed important developmental changes in infants'ability to use featural information to individuate objects. However, relatively little is known about the neural mechanisms that underlie these changes, in large part because there are a limited number of non-invasive techniques available to measure brain function in infants. Hence, there is a critical need to identify new methods to specify the relation between behavior and brain function in object processing. One such method is near-infrared spectroscopy (NIRS), an optical imaging technique that uses changes in cerebral blood volume as an indicator of neural activation. Because NIRS is safe and non-invasive, can be used during behavioral tasks, and provides spatial and temporal information about neural activation, it is ideal for infant research of this kind. The research proposed in this application will use NIRS to identity changes in neural activation during object processing tasks. The objective of this application is to identify the neural basis of infants'ability to (a) use shape, size, color, and luminance information to individuate objects and (b) extract shape from a variety of perceptual cues (e.g., coherent motion and contour). The central hypothesis is that infants'capacity to individuate objects using shape, color, and luminance differences will be associated with unique, well-defined patterns of neural activation in higher level object processing areas. In addition, infants'capacity to perceive the shape of an object on the basis of coherent motion and connected contour will be associated with unique patterns of neural activation in extrastriate cortex. This hypothesis has been formulated on the basis of behavioral and neuroimaging data collected in our lab. The rationale for the proposed research is that once we have identified the neural substrates that support featurally-based object representation and individuation in the infant, it will be possible to formulate a developmental model of object processing that focuses on brain-behavior relations. PUBLIC HEALTH RELEVANCE: The information that will be gained by the proposed research can be used to help guide the development of diagnostic and intervention techniques that can be used with infants at risk for object processing difficulties. Early detection of object processing difficulties, and appropriate intervention, can be expected to significantly reduce the extent to which later emerging cognitive dysfunction is observed in at risk infants. The information gained by the proposed studies will also provide the impetus for new research that examines the extent to which normal patterns of behavior and brain function are affected by specific medical conditions and differences in early experience.