Examples of Successful Proposals

The Development of Perception and Action Coupling in Early Childhood

Rick O. Gilmore, Ph.D.
Assistant Professor of Psychology; 865-3664; rog1@psu.edu

Semyon H. Slobounov, Ph.D.
Assistant Professor of Kinesiology; 865-3146; sms18@psu.edu

Richard L. Tutwiler, Ph.D.
ignal/Image Processing Group, Applied Research Laboratory

George H. Otto, Manager
Visualization Group, Center for Academic Computing

Elena S. Slobounov, Ph.D.
Senior Visualization Programmer, Center for Academic Computing

Abstract

Many forms of behavior depend upon information about spatial relationships, such as the direction, distance, and orientation of objects in the environment. One especially rich source of spatial information is the pattern of visual motion called optic flow. A variety of evidence, however, suggests that areas of the cerebral cortex that contribute to the perception of optic flow in adults are functionally immature at birth and develop rapidly in early childhood. Consequently, how children develop the capacity to perceive spatial relationships and plan actions based on optic flow, and how brain maturation shapes these abilities are important unanswered questions. This proposal requests $9,840 over 12 months from the CYFC in order to support the work of an interdisciplinary research group that aims to address these questions. The group will develop and test new tools to explore the development of children's sensitivity to complex patterns of optic flow, using both behavioral and physiological measures. One set of tools, based on high-end computer graphics or virtual reality (VR) technology, will be used to study visual perception and postural control in young children. A second set of tools, based on existing technology for conducting functional brain imaging with adults, will allow researchers to collect scalp electrical potentials (EEG) from children while they are perceiving and acting on realistic optic flow patterns. The results of the project will provide information about the normal development of perception and action coupling in early childhood and may ultimately contribute to early interventions for children who face developmental delays due to perceptual or motor deficits.

Specific Aims And Objectives

The ultimate goals of this collaborative project are to describe how the systems that guide the coupling of perception and action develop in childhood and to explain how these events are related to maturation of the brain. These goals motivate two specific aims:

1. Examine how young children develop the capacity to perceive optic flow patterns and use that information to influence two important behaviors: the perception of direction of motion, or heading, and the maintenance of postural stability. In achieving this aim, the project will focus on the following objectives:

   • Basic research will be conducted to assess the feasibility of using virtual reality (VR) technology to examine the development of heading perception and postural control in young children.
   • Software and hardware necessary for permitting simple actions-arm or foot movements-to change properties of a VR display will be developed and pilot-tested. By giving young children on-line control over the direction or speed of motion they experience in the VR environment, these tools will permit us to examine how quickly, flexibly, and robustly children learn that their own movements have discernible, immediate perceptual consequences.
   • Existing software and hardware used in measuring head and body movements that are associated with maintaining balance in adults and older children will be adapted for use with young children.
   • These tools will be used to conduct studies that will assess the development of children's abilities to perceive their direction of heading accurately from optic flow and to use visual information to control balance.
2. Relate the development of optic flow perception to maturation of the cerebral cortex. In achieving this aim, the project will focus on the following objectives:

   • Basic research will be conducted to assess the feasibility of using existing electroencephalography (EEG) technology to collect scalp electrical potentials from young children during studies of heading perception and balance control which are conducted in a VR environment.

   • These tools will be used to conduct studies that will describe the patterns of cortical activity, in both the time and frequency domains, which are associated with the development of children's abilities to perceive patterns of optic flow.

Background

Perceiving and planning actions based upon the direction, distance, and orientation of objects in the environment is a fundamental requirement of many forms of human behavior. However, areas of the cerebral cortex that carry out these functions in adults are immature at birth and appear to develop gradually over the first several months of life (Chugani & Phelps, 1986; Conel, 1939-1967; Huttenlocher, 1990). Accordingly, very young children may perceive space and plan actions quite differently than do older children or adults (Piaget & Inhelder, 1948; Yonas & Granrud, 1985). These differences may be due to dynamic changes that occur in the structure and function of spatial processing circuitry in the cerebral cortex (Gilmore & Johnson, 1997a, b; Held, 1985). Describing how the systems that guide perception and action develop in early childhood and how these events are related to changes in the brain function are central goals of this research project.

One especially rich source of spatial information is optic flow, the structured pattern of visual motion an observer or object generates by moving through the environment (Gibson, 1966). Perceiving optic flow permits animals to steer through the environment and avoid obstacles by detecting their direction of motion or heading; optic flow perception also contributes to balance control by specifying changes in body position or sway relative to gravity. Adult observers perceive their direction of heading from optic flow to within 1 deg under a variety of circumstances (Royden, Crowell, & Banks, 1994; Warren, Morris, & Kalish, 1988), and they are similarly sensitive to variations in optic flow in controlling posture (Lee & Lishman, 1975). Since optic flow selectively activates specialized circuits in the parietal lobe of adult primates, basic research into the emergence of optic flow perception may provide an instructive model for examining the role of brain maturation in the development of spatial processing in early childhood.

Nevertheless, surprisingly little is known about the development of optic flow perception in early childhood. Previous developmental studies have examined the infants' abilities to use optic flow to perceive impending collisions (Na?ez, 1987; Na?ez & Yonas, 1994), control posture (Bertenthal & Bai, 1989; Bertenthal, Dunn, & Bai, 1986; Bertenthal, Rose, & Bai, 1997), and discriminate object form (Kellman, 1993). For example, many species produce defensive eye, head, or body movements in response to radially expanding optic flow patterns that specify an object approaching the face on a collision course. In humans, however, collision avoidance behavior develops slowly. Infants do not blink reliably in response to a perceived collision until approximately three months of age (Yonas, Pettersen, & Lockman, 1979). These behaviors become increasingly sensitive and selective in the following months. Similarly, optic flow begins influences balance control from a relatively early age, but adult-like abilities emerge gradually. Lee and Aronson (1974) initially demonstrated that oscillating patterns of optic flow presented in a moving room apparatus could induce body sway or falling in 13 to 16-month-old children. Subsequent research has shown that infants' synchronize postural sway to oscillating patterns of optic flow as early as five months of age, and show increasingly systematic coupling between perception and action over the next several months (Bertenthal, Dunn, & Bai, 1986; Bertenthal & Bai, 1989; Bertenthal, Rose, & Bai, 1997). Furthermore, previous research has emphasized the importance of experience derived from self-produced actions, such as sitting erect, crawling, and walking, but has ignored the potentially important role of brain maturation in accounting for developmental change in this system. Finally, while the perception of heading direction in young children has not been previously explored, preliminary data from one of the lead investigators' laboratories (Rettke, Gilmore, & Pupik, submitted) suggest that four to six-month-old infants are surprisingly insensitive to changes in heading direction that adults can detect easily. How the perception of heading direction approaches adult levels and whether changes in this ability are associated with functional maturation of optic flow circuitry in the cortex are important unresolved questions.

In sum, previous research indicates that sensitivity to optic flow patterns that specify collisions, indicate postural stability, or specify an observer's direction of heading emerges gradually in early childhood. The existing data do not, however, address whether or how these perception-action systems might be related to similar optic flow mechanisms, nor how perception and action systems sensitive to optic flow might be related to the development of specific regions in the cerebral cortex. Systematic studies which examine the development of several different forms of optic flow in the same children and across a broader age span are needed to answer these questions. Moreover, in order to address questions regarding the role of brain development in the emergence of mature perception- action systems, reliable and non-invasive recordings of functional brain activity during task performance are necessary. This project seeks to meet both of these needs.

Rationale

Why virtual reality (VR)? This project will integrate graphics and measurement hardware and software to allow visual perception and postural control experiments to be run using existing computer graphics and VR technology located in the Visualization and Immersive Environments Testbed of the Center For Academic Computing (CAC). The CAC's ImmersaDesk VR display system includes a large format (4x6 foot) high-resolution graphics display and programmable magnetic tracking devices which permit real-time interactive control over computer generated three-dimensional environments. The wide field of view and interactivity offered by the Immersadesk provide an ideal venue to allow and observe user interactions with simulated environments. To our knowledge, this project will be the first time that VR will be used to answer basic research questions about perceptual and motor development in children.

Beyond the excitement associated with breaking new ground, the use of VR technology is actually necessary for several reasons. Previous research has indicated that some forms of optic flow sensitivity may be greatest in the visual periphery (Stoffregen, 1987). Consequently, making progress in research on optic flow perception in children will require the use of large visual displays which permit control over a large fraction of the visual environment visible to the participant. CAC's existing large screen display is directly suitable for this purpose. Moreover, in order to examine which aspects of optic flow are crucial for behavioral performance, it is necessary to create a visually rich, but carefully controlled visual environment. This requires specialized computer graphics software, hardware, and technical assistance, which CAC is able and willing to provide. Finally, the VR technology provides researchers an opportunity to allow participants, even the youngest infants, to interact with and control the display with their own head, arm, trunk or leg movements. Extensive developmental research indicates that giving children contingent control over some aspect of the environment may provide an especially sensitive measure of their abilities. Quite simply, by allowing young children to control virtual visual environments, we hope to learn whether they have more sophisticated perceptual and motor abilities than their relatively limited action repertoires would indicate.

Why EEG? This project will develop hardware and software tools that will allow brain electrical potentials (EEG) to be recorded from children who are participating in studies of optic flow perception. Functional brain imaging is a powerful and widely used tool in cognitive neuroscience, but it is relatively rare in studies of child development for several reasons. Whole-brain imaging methods, including functional magnetic resonance imaging (fMRI), are expensive and technically difficult. These methods have limited temporal resolution, which is critically important for measuring rapid mental processes. Moreover, whole brain imaging methods are not available to researchers at the University Park campus and are currently not suitable for use with young children due to the potential risks. On the other hand, older, more established functional brain imaging technologies like EEG do not suffer from these limitations. EEG is safe and suitable for use with children, has exceptionally high temporal resolution, and with the use of newly developed algorithms, may have satisfactory spatial resolution, as well. Moreover, there are several Penn State faculty, including two of the cooperating investigators (Slobounov and Tutwiler), who have extensive experience with EEG data collection and analysis procedures, including the modifications necessary for children.

On scientific grounds, the addition of functional brain measures to behavioral studies of optic flow perception will add a vital dimension to this work, and potentially, to the capabilities of other developmental researchers at University Park. These data will permit the relationship between changes in behavioral performance and developments in brain activity to be assessed directly.

Methods and Timeline

The project will consist of four phases:

1. PHASE I: Feasibility assessment (February - April, 1999)
   • Secure IRB approval for project.
   • Identify and recruit graduate and undergraduate research assistants.
   • Assess feasibility of adapting CAC VR system hardware and software and existing EEG system.
   • Develop a work plan to make the necessary adaptations, and begin making adaptations.
      
2. PHASE II: Pilot testing (May - August, 2000)
   • Complete hardware and software adaptations.
   • Recruit participants and conduct pilot tests.
   • Modify software, hardware, and procedures as necessary.
      
3. PHASE III: Data collection (September - November, 2000)
   • Carry out full scale testing and data collection.
   • Conduct data analyses.
   • Travel to Washington, DC to meet with Federal grant making officials to discuss proposal submissions.
      
4. PHASE IV: Grant writing (December, 1999 - January, 2001)
   • Prepare and submit grant proposals to NSF and NICHD.

Relevance to the CYFC

This project helps to fulfill the primary mission of the CYFC in several ways. The project will promote the basic research activities of an interdisciplinary group of scientists from four separate administrative units in the university. These activities will contribute to the education and research training of a small number of graduate and undergraduate students by involving them directly in a cutting edge research effort. The work is part of an innovative basic research program into the earliest origins of visual perception and action planning which has strong potential for external support. Finally, the results from this project may provide a foundation of basic research that may be useful in guiding early intervention or prevention efforts for children at risk of perceptual or motor delays.

Anticipated outcomes

This project is expected to

• Demonstrate the feasibility of using VR technology for studies of optic flow perception and balance control in young children.
   
• Demonstrate the feasibility of recording functional brain activity (EEG) from young children performing perception and action tasks; and
   
• Provide pilot data for and facilitate the preparation of proposals for external research support. We expect to submit an application to the Child Learning and Development Program at NSF for the January 15, 2001 deadline and to submit an R01 proposal to the NICHD for the February 1, 2001 deadline. It is also possible that grant making foundations such as the March of Dimes or the Foundation to Prevent Blindness may be interested in providing funding for some aspects of this work. Those possibilities will also be explored.

Personnel

Rick O. Gilmore, Ph.D., Lead Investigator. Dr. Gilmore will devote the equivalent of 5% of his time to this project over the 12-month grant period. He and Dr. Slobounov will direct all aspects of the project. Dr. Gilmore's salary and benefits will be contributed by the Psychology Department.

Semyon Slobounov, Ph.D., Lead Investigator. Dr. Slobounov will devote the equivalent of 5% of his time to this project over the 12-month grant period. Dr. Slobounov's salary and benefits will be contributed by the Kinesiology Department.

Richard Tutwiler, Ph.D., Collaborating Investigator. Dr. Tutwiler will provide in-kind training and technical assistance to the graduate and undergraduate research assistants on an as-needed basis.

George H. Otto, Collaborating Investigator. Mr. Otto will devote up to 5% of his time to the project over the 12 month grant period. Salary and benefits for Mr. Slobounov will be contributed by CAC (see attached letter).

Elena S. Slobounov, Ph.D., Collaborating Investigator. Dr. Slobounov will devote up to 5% of her time to the project. Salary and benefits for Dr. Slobounov will be contributed by CAC (see attached letter).

Graduate and Undergraduate Research Assistant. The research assistants who will work on this project have not yet been identified.

Budget With Justification

Matching and In-kind support. As part of the CAC's mission to support faculty led research initiatives of this type, CAC staff will provide technical assistance for modeling and programming the interactive 3D worlds for use in the study (see attached letter). In addition to the Immersadesk VR system, several graphics workstations and related software will be made available for project development. The project will have access to EEG and force plate equipment provided by a matching grant of $10,000 from the Kinesiology Department (see attached letter) and from Dr. Slobounov's laboratory. Moreover, Dr. Tutwiler will provide in-kind technical assistance to the project.

Requested support. We request a total of $9,840 needed to support a graduate and undergraduate research assistant, for supplies related to adapting the existing VR and EEG systems for use children, and for a trip to Washington, DC to meet with Federal funding agencies. Detailed information about the request follows.

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