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  • Connection w/HG “Bridge Too Far” – brain & education – need for cognition Related problems with brain and 0-3 (Myth) My metaphor “bridges”, yours “windows” works as well Behavior provides window on the mind Mind provides a window into the brain
  • Here a picture of behavior Father helping children with math homework Understanding this behavior in terms of the mental processing in dad and kids’ mind can contribute to improved learning and teaching Understanding this behavior in terms of mental processing also essential to understanding brain images and to advances in cognitive neuroscience.
  • Talk about 3 things tonight that Howard mentioned in intro Topics all address relation b’n behavior, mind, brain Together topics illustrate the danger of ignoring behavioral-cognitive data in making claims about the brain and show the importance of cognitive science not only for education, but also for brain science Read slide: Myth, cognitive and education, cognitive neuroscience
  • Popular interest in brain and child development that for reasons that will become clear I cal the Myth Myth can be stated simply as in the slide Based on three well-established findings from developmental neurobiology: Known since late 1970’s that in cats, monkeys, humans there is a period early in development where rate of synapse formation exceeds rate of synapse elimination. Critical periods do exist in human and animal development, originally behaviorally defined connected with neuroscience via work of Wiesel, and Le Vay of late 1970s on c.p for optical dominance columns in the visual system. Also long history (1950s, Hebb) of effects of complex environments on fine (synaptic) structure of rat brain. Hardly “new” neuroscience Problems with how each of these findings in used and interpreted in the Myth and can talk about them later Here, concentrate on key myth claim about meaning and significance of rapid synapse formation early in development..
  • Here is the phenomenon Shows Huttenlocher data for human visual cortex In cat, monkey, and humans following birth there is a period during which new synapses form faster than old synapses die. Synaptic density peaks early in development and then decrease, stabilizing at adult mature synaptic densities around the age of sexual maturity. When peaks occur varies from brain area to brain and also on the methods scientists use to compute synaptic densities (whole brain tissue vs. neuropil) Generally believed rapid synapse formation finished in all brain areas by age 3 years Educators claim time ob synaptic excess – birth to puberty is optimal time for learning Early childhood advocates claim that the time of rapid synapse formation is the time of most rapid learning, the unique time during which parents can help their toddlers build better brains. Problem: Neither educators nor early childhood advocates have looked at rates of learning and ability to learn and how these might relate to changes in synaptic density in the brain.
  • Not many neuroscientists (at least those that count the synapses) have done so either Relatively little attention given to how changes in brain’s fine structure relates to brain function. An exception to this has been interest some brain scientists and cognitive psychologists have taken in how changes in the brain’s prefrontal cortex relates to changes in ability to remember past experiences. Best example, Adele Diamond and Pat Goldman-Rakic’s work on parallels in memory development between humans and infants. This research suggest that PFCx is involved in representational memory – our ability to remember what we have seen or experienced after the experience itself has disappeared How the brain might form and maintain mental representations of past experiences This ability develops and changes with age and with changes in synaptic density.
  • Scientist assess the ability to form representational memories and how they change with age by using “delay” task Common one is DNMS Animal is shown two objects. Object disappear from sight behind a screen during a delay period When screen is lifted two objects are visible. Animal or infant must pick the object in the second pair that was not in the first pair (non match) Assumption is that to do that task the subject must be able to keep a mental representation of the first pair “on-line” long enough to make a correct choice. At least two dimensions of development: (1) how quickly the animal or human can learn this task; (2) how long a delay they can tolerate and still perform correctly.
  • For monkeys, we have data on changes synaptic density in the prefrontal cortex over the life span. For monkeys, we also have behavioral data from a variety of studies using delay tasks that we can piece together to see changes in rate of learning and delays tolerated. Through the magic of PowerPoint we can plot these data against each other. One important dimension is how many trials it takes a subject to learn a task like DNMS The fewer trials it takes, the more quickly or efficiently we can say that the subject learns the task. Age: gestational age in log months Top graph: monkeys can first perform the task when synaptic density peaks Right axis: inverted trials to criterion -- fewer trials faster learning Rate of learning increases as synaptic density decreases Similarly for delays tolerated Mature levels of performance reached when mature levels of synaptic densities stabilize – decrease to -- mature levels.
  • Sufficient data available to do similar plot for human data Huttenlocher 1982 study of prefrontal cortex (whole cortex) Here actual age in log mos Again ability to learn to do task at all appears when densities peak Learn more quickly and easily as one matures, learn most quickly in adulthood, after puberty. Similarly for delays tolerated. Children do not learn more DNMS more quickly or easily than adults. For those of you that know these data, by PowerPoint plots may seem silly, a waste of time Educators and early childhood advocates have not looked at learning rates or learning ease for any tasks or disciplines. They have looked at the the synaptic change curves and made up what appears to be a likely story – folk science, myth
  • Now turn to science of the mind and learning Father helping with math home work Number is a convenient domain to use as an example Cognitive and developmental psychologists have discovered a great deal about what must be going on inside the heads of kids and the father. Among them – read slide
  • 15 –20 years ago thought that this central conceptual structure and associated skills developed naturally. Have found since then that learning this structure depends on the experience one has with numbers, particularly with number words. There is a difference between people experienced with number words and people not experienced with number words. Data from 3 studies of experienced vs inexperienced No difference between experienced and inexperienced in solving simple problems when the physical objects present and visible. Substantial experience related differences in solving problems when physical objects not present – difference in ability to create mental representations of problems and ability to use number words and counting knowledge to solve the problems. (Oksapmin when confronted with the need to do simple calculations invent as adults, strategies typically invented by K and 1 grade children.--- not a critical period phenomenon.)
  • Case and Griffin found similar experience based difference in ability to make numerical comparisons. Also based on MNL – as you move along the line number names refer to larger numbers Comparison an important skill in inventing efficient strategies, e.g. counting on from the larger addend.
  • Cognitive diagnosis for a all too common educational problem: difficulty low SES children have in mastering first formal arithmetic. Also suggests a cognitive theory: teach the MNL explicitly to children who might not possess it at school entry.
  • Case and Griffin have done so. Treatment and control groups from neighborhood schools, Worcester, MA. Children chosen on the basis of the number knowledge test as those likely to fail in mastering first formal arithmetic. -- children predominantly low SES and minority. Normative group -- children attending city-wide magnet school -- best teachers, new curriculum, best resources -- approximate what one might expect in “middle class environment” Results: Pre-K treatment and control delayed Post-K and Post Grade 1 -- treatment same as normative,control group delayed Transfers to school like tests and math tasks. At end of Grade 1 “at risk” children perform comparably to Asian children on tests of computational skills used in international comparison.
  • Early brain imaging experiment: Roland & Firburg measured changes in rCBF while patients performed a task requiring “mathematical thinking” Task: Count backward from 3 -- standard test used in neurological and psychiatric evaluations. Found activations in left and right angular gyri and prefrontal cortex, activations that were”different” from “thinking about nothing” or “thinking about every third word” of a well known Danish jingle. Tells you something, but not much. From a cognitive viewpoint continuous subtraction involves many different complex subtasks: arithmetic fact retrieval, carrying, verbal working memory, counting, and comparing. With a more refined cognitive model one could ask: Which processes are responsible for which brain activations?
  • Consider just one simple, but important subtask: Numerical comparison. Cognitive psychologists have furthered analyzed numerical comparison into its subcomponents and developed testable cognitive models. Here is one simple, serial model of comparison (Dehaene): Three stage model (1) identify input stimuli, (2) compare magnitudes, (3) prepare and generate response. Explain Dehaene’s experiment.: Additive Factors Method Behavioral analysis of RT data show that at least at this level of analysis such serial model is adequate. Reliable imaging studies generally include such behavioral analysis .
  • Brain recording experiment - record ERPs while subjects doing comparison task (64 electrodes) - significant changes in electrical activity might give general indications about neural circuitry underlying 3-stage cognitive model of comparison - spatial plus temporal data allows tracing of neural circuitry underlying comparison - Results: - notation effect 146 ms after stimulus: verbal numbers negative activation at left posterior occipital-temporal brain areas Arabic digits similar negative wave bilaterally in posterior occipital-temporal brain areas - distance effect 218 ms before response right inferior parietal brain area later PET student bilateral inferior parietal brain area Independent of input notation Different neural systems for identifying different inputs Single distinct neural system for making comparison
  • Temple and Posner found same area of activation during comparions in 5-year old children However, for input used Arabic numerals and dot patterns. Comparison seems to rely on abstract, pre-verbal magnitude representation Adult pattern present by age 5 years (unlike word recognition in reading)
  • What do we learn from this about the brain? See how the 3 distinct systems for representing quantity are organized in the brain. Understand which representations are used for which tasks. (comparison versus arithmetic fact retrieval) Suggests additional questions and hypotheses for studying the brain: Study r. hemisphere as well as l. hemisphere patients for number processing deficits. (only bi-lateral parietal lesion should result in permanent inability to make numerical comparisons. Animals (and infants)can also make comparisons – analogous/same brain area? How are brain circuits for numerical processing modified as children learn verbal, then Arabic representations? As they acquire the mental number line structure? As they learn arithmetic? That is we can ask and answer with some specificity: How does experience contribute to brain organization, formation of neural circuitry, changes in brain connectivity? Possible only if we first understand behavioral-cognitive level.
  • Deeper understanding of the brain requires a deeper understanding of the mind’s cognitive workings. Future challenge: refine our cognitive models.
  • JSMF is taking this challenge seriously Basis for new programmatic effort over the next 10 years that will encompass previous interests in cognitive neuroscience, education, and rehabilitation. Attempt to fund work that bridges the brain, mind, behavior and recognizes mind and behavior as window onto better understanding of structure-function relations in the brain.
  • Recent book review in Science by Gallistel contained this statement Captures my intent and belief, once clear about “behavior” Tenet of cognitive science: any theory to explain human behavior must analyze behavior carefully Any adequate theory of human behavior must include claims about covert mental constructs, processes, and representations This cognitive theory foundation for work at neural level.
  • One final aspect to Myth where lack of attention to behavior undermines case Birth to 3 as important age group arises from attachment theory Secure attachment contributes to life-long cognitive, mental, and emotional health Lack characterization of specific care-taking practices that lead to secure attachment Little understanding in terms of cognitive science of what kinds of mental processes are involved in the hypothesized attachment system No research linking attachment theory and human brain development. Particularly strong deterministic claims as found for example in I AM YOUR CHILD also overstates what many attachment theorists appear to believe about the life-long impact of early experience and their skepticism about the existence of a CP for attachment.
  • Integrate these findings in mental number line, what Robbie case calls the central conceptual structure for elementary arithmetic. Explain structure . Resnick: MNL provides the conceptual structure that under-girds children’s ability to invent counting strategies to solve simple arithmetic problems.
  • Deeper understanding of the brain requires a deeper understanding of the mind’s cognitive workings. Future challenge: refine our cognitive models.
  • Actually those neurobiological findings figure in both education and child development discussion. In education, period of rapid synapse formation and of excess neural connections (0-19) is the critical period during which children learn most quickly and easily. In child development, period of rapid synapse formation (0-3) is the critical period during which the brain becomes permanently wired for thinking and learning and early childhood experience dictates how efficiently the brain learns for life.
  • Now turn to science of the mind and learning Father helping with math home work Number is a convenient domain to use as an example Cognitive and developmental psychologists have discovered a great deal about what must be going on inside the heads of kids and the father. Among them – read slide
  • Modern technology has given us possible windows on the brain PET, fMRI, ERP, MEG Left Marcus Raichel at PET Scanner Right: Geodesic sensor not for recording neural activity via electrical fields neurons generate at the scalp surface. Continuing with the number example, show how cognitive analysis of that domain – understanding what was going on around the kitchen table – is fundamental to our exploiting these windows on the brain. Our view of the brain is constrained by our view of the mind.

Transcript

  • 1. Windows 1999: Seeing the Brain through Windows on the Mind
  • 2. Behavior  Mind  Brain
  • 3. Looking Through the Windows: Outline
    • Popular views about brain science and child development fail to recognize the importance of the behavioral level.
    • Understanding mind and behavior can contribute to improved learning and teaching.
    • Understanding mind and behavior is essential to advancing our understanding of the brain.
  • 4. The Myth of the First Three Years
    • The first three years of life is a period of rapid synapse formation .
    • This is the critical period in brain development.
    • During the critical period, environmental enrichment (depravation) has profound, irreversible effects on the brain.
  • 5. Synaptic Density over the Lifespan (human visual cortex) Birth Age 1 Age 11 Redrawn from P. Huttenlocher 1987
  • 6. Prefrontal Cortex and Representational Memory From Gazzaniga 2000, Plate 31 PFCx
  • 7. Delayed Non-Match to Sample
  • 8. Synapses and Learning: Monkeys Training to Criterion Delays Tolerated From Bourgeouis 1994, Bachevalier 1990 Gestational age (log mos) % Max Syn Den Training Blocks % Max Syn Den Gestational age (log mos) Delay
  • 9. Synapses and Learning: Humans Training to Criterion Delays Tolerated From Huttenlocher 1987, Diamond 1990, Overman 1990 % Max Syn Den % Max Syn Den Age (log mos) Age (log mos) Training Blocks Delay
  • 10. The Brain and Birth to Three
    • Myth advanced primarily by policy advocates and propagated in the popular media.
    • Myth fails to make appropriate, well-founded connections between brain and behavior.
    • Await a serious scientific and scholarly discussion of current understanding of behavior, mind, and brain and what that means for policy, practice, and research.
  • 11. What Children Know About Number
    • Three systems: pre-verbal magnitudes, number words, Arabic numerals.
    • Most children learn these systems and how they inter-relate prior to school entry. 4.
    • Most children arrive at school able to use this understanding to count, compare, and invent strategies for solving simple number problems.
  • 12. Solving Addition Problems
    • Jordan et al.: Middle-income vs. low-income kindergarten children
    • Case & Griffin: High-SES vs. low-SES kindergarten children
    • Saxe: Oksapmin trade store owners vs. Oksapmin adults
    High Experience Low Experience With Physical Objects Without Physical Objects
  • 13. Comparison: Which is Bigger? From Griffin, Case & Siegler 1994 % Correct
  • 14. Solving an Educational Problem
    • Cognitive Diagnosis: Some children begin school without knowing how the verbal representation of number relates to their innate magnitude representation of quantity.
    • Cognitive Therapy: Use curricula that explicitly teach how the three representations of number inter-relate.
  • 15. Mean Scores (s.d) on Number Knowledge Test Pre- and Post Number Worlds Instruction Group Pre-K Post-K Post-Gr. 1 Treatment 1 6.3(2.5) 11.2(2.7) 16.5(3.0) Treatment 2 5.7(2.5) 12.1(1.9) 17.4(2.0) Control 1 7.2(2.4) 8.9(2.4) 12.5(2.8) Control 2 7.2(2.0) 9.3(2.8) 14.3(2.9) Norm 1 9.8(3.2) 11.4(2.8) 16.9(4.0) Norm 2 10.6(1.7) 13.5(2.9) 18.8(2.9) Expected Score: K = 9 - 11; Grade 1 = 16 -18 From S. Griffin and R. Case, Teaching Number Sense, Table 3, Yr. 2 report, August 1993
  • 16. Imaging: A Window on the Brain Roland & Friberg (1985) J. of Neurophysiology 53(5):1227 Counting backward from 50 by 3s
  • 17. Prepare & Execute Response [right] Identification Comparison Response Notation effect Distance effect Response-side effect (arabic vs. verbal) (close vs. far) (left vs. right) (S. Dehaene, J. Cognitive Neuroscience, 8(1), p49, 1996) Arabic Comprehension [8] Verbal Comprehension [EIGHT] Magnitude Comparison 5 < 8?
  • 18. (S. Dehaene, J. Cog. Neuroscience, 8(1), p.56, 1996) Arabic Verbal Notation Effect Arabic Verbal Distance Effect 210 ms before key press
  • 19. Temple & Posner 1998, PNAS 95: 7837 Distance effect adults Dehaene (1996) Distance effect 5-year-olds
  • 20. Mapping Cognitive Functions onto Neural Structures Dehaene & Cohen 1995 Comparison
  • 21. The Future Challenge for Mind-Brain Science
    • The challenge for the future is to understand at a deeper level the actual mental operations assigned to the various areas of [brain] activation. Before this goal can be achieved, the experimental strategies used in PET studies must be refined so that more detailed components of the process can be isolated.
    • - M. Posner & M. Raichle, 1994
  • 22. The Bridging Brain, Mind, and Behavior Program provides support for inter- and cross-disciplinary research explicitly addressing questions whose investigation requires spanning the different levels of analysis characterizing neurobiological or cognitive studies with observations obtained from behavioral research.   Examples of projects the Foundation would consider within the scope of the program include, but are not limited to:          Research in new or under-developed areas of cognitive neuroscience that integrates behavioral, cognitive, and neural analysis in studies of human behavior and higher-cognitive functions.           Applied research in areas such as training , education , and rehabilitation that attempts to conduct and integrate research across the behavioral and cognitive levels, and, where appropriate, the neural level of analysis to develop research-based tools, methods, and protocols to improve teaching, learning, and clinical practice.           Research on the genetic bases of behavior and on genetic factors affecting brain development that integrates behavioral, cognitive, and neural studies of patients and human subjects.           Work that addresses how to integrate research that takes social and cultural groups as the unit of analysis with research that takes the individual mind-brain as the unit of analysis. 21st Century Science Initiative - Bridging brain, mind, and behavior
  • 23.  
  • 24. For additional information on the foundation and for the PowerPoint version of this talk, please visit our website at: www.jsmf.org
  • 25. Brain and Behavior
    • An analysis at the behavioral level lays the foundation for an analysis at the neural level. Without this foundation, there can be no meaningful contribution from the neural level.
    • - Randy Gallistel
  • 26. Birth to Three and Attachment
    • Lack precise characterization of specific care-taking practices that lead to secure attachment.
    • Lack adequate cognitive understanding of the attachment system.
    • No research linking attachment theory and brain development.
  • 27. The Brain and Birth to Three
    • Myth advanced primarily by policy advocates and propagated in the popular media.
    • Myth fails to make appropriate, well-founded connections between brain and behavior.
    • Critique has been welcomed by brain and cognitive scientists, not so by pediatric psychiatrists.
    • Await a serious scientific and scholarly discussion of current understanding of behavior, mind, and brain and what that means for policy, practice, and research.
  • 28. Integrating the Representations: the Mental Number Line
  • 29. The Future Challenge for Mind-Brain Science
    • The challenge for the future is to understand at a deeper level the actual mental operations assigned to the various areas of [brain] activation. Before this goal can be achieved, the experimental strategies used in PET studies must be refined so that more detailed components of the process can be isolated.
    • - M. Posner & M. Raichle, 1994
  • 30.  
  • 31. The Myth and Synapse Formation
    • Education: The period of rapid synapse formation and excess neural connectivity (ages 0-10) is the period during which children learn most quickly and easily.
    • Early Child Development: When rapid synapse formation ends (age 3), the brain is permanently hard-wired as an organ of thinking and learning.
  • 32. What Children Know About Number
    • Three systems: pre-verbal magnitudes, number words, Arabic numerals.
    • Infants use the pre-verbal system to make simple numerical judgments.
    • Children begin to learn the sequence of number words at age 2.
    • Children learn what the number words and counting means around age 4.
    • Children use counting knowledge to invent strategies for solving simple arithmetic problems.
  • 33. Windows on the Brain