Saturday, October 01, 2005

The Learning Brain: Lessons for Education

Building a Bridge Between Brain Science and Education

By: Jay N. Giedd M.D.

In his widely quoted 1997 article “Education and Neuroscience: A Bridge Too Far?” John Bruer argued that, despite substantial progress in brain research, trying to use its discoveries to shape education policy is both uninformative and misleading. Two new books by prominent scientists, The Learning Brain and A Young Mind in a Growing Brain, take on the formidable challenge of beginning to build this bridge by linking advances in our understanding of the biology of brain maturation to phenomena in other domains, namely education and psychological development. In our era, the term “brain-based” education has been used in many books and has come to encompass many teaching approaches which, in fact, have little basis in brain science. Thus, it is refreshing to see a more rigorous approach to this important frontier.

PLASTICITY AND SENSITIVE PERIODS

rev_v7n4giedd_3The Learning Brain is written by neuroscientist Uta Frith, Ph.D., and Sarah-Jayne Blakemore, Ph.D., a rising star in the field of developmental neuropsychology. The authors strive to narrow the gap between brain science and education by synthesizing the relevant neuroscience literature, presenting concrete examples of some of its concepts, and mapping a plan of how greater integration with thinking about education could take place. Key principles noted in the book are plasticity (the ability of the brain to change and “fine-tune” itself in response to the demands of the environment) and “critical” or “sensitive” periods (the notion that during relatively brief stretches of our lives exposure to certain types of stimuli is necessary for optimal brain development).

A perennial question raised by these principles, one that the authors discuss but do not resolve, is whether early childhood environments need to be “enriched” with targeted interventions to improve a child’s brain development or whether typical environments are rich enough. Although extreme deprivation is clearly related to problems in a child’s development, adequate studies on what specific types of interventions at what specific ages might optimize brain development in normal environments have not yet been conducted. Available research does suggest that the learning environment is important not just for the early years; all ages are “sensitive” periods for some type of learning.

Specific topics addressed in The Learning Brain include mathematics, reading, social development, adolescence, memory, and optimization of learning. One of the authors’ observations about the acquisition of math skills seems particularly apropos for current educational approaches to advanced placement. It turns out that rote learning of the “times tables” involves brain circuitry associated with verbal performance, not with other math abilities. At what age and with what adeptness children can recite multiplication facts is an important (although not sole) factor in whether children will be placed in advanced math courses. Given that most school systems limit the number of advanced math placements, children who may thrive on non-rote-memory types of math challenges may be inappropriately excluded.

Another extrapolation made by the authors is that school placement criteria emphasizing the youngest age at which a cognitive milestone is reached may not be optimal; educational systems should have a more effective system for identifying late bloomers. Perhaps, as in the relationship between age of onset of puberty and ultimate adult height, earlier is not always better. This is not to imply, however, that the timing of instruction is not eminently important.

The most investigated aspect of the importance of timing has been in language acquisition. Wonderful work at the University of Oregon laboratory of Helen Neville, Ph.D., indicates that the age when a language is acquired affects both how readily it is learned and the cerebral localization of the skill. For instance, if people learned English between the ages of one and three, recordings later in life using an electroencephalograph (EEG) show that their left brain hemisphere is by far the most active when they are processing English grammar. If English was learned after three years of age, however, perhaps as a second language, the activation revealed by the EEG is in both brain hemispheres. In fact, the older the age of first exposure to English, the more bilateral the activation. An interesting nuance is that this holds true only for processing grammar, not vocabulary. Semantic (content or meaning) processing activates posterior regions of both hemispheres regardless of age of acquisition. The neurobiology of language acquisition may have relevance for curriculum development inasmuch as formal instruction in second languages is most often begun at about age 13, well past what is usually regarded as the sensitive period for language acquisition.

It is unlikely, from an evolutionary perspective, that the brain has had time to develop dedicated “hardware” for reading. Instead, the neural circuitry related to reading seems to be borrowed from brain systems related to human speech.

In the context of the neurobiology of reading, it is worth noting that most humans who have ever lived did not read. Since our evolutionary divergence from other hominids approximately 5 million years ago, there have been approximately 100 billion people. Writing is thought to have begun in Sumer (present-day Iraq) and perhaps independently in China approximately 5000 years ago. So it is unlikely, from an evolutionary perspective, that the brain has had time to develop dedicated “hardware” for reading. Instead, the neural circuitry related to reading seems to be borrowed from brain systems related to human speech. Accordingly, reading seems best learned by fostering insight into the correspondence of letters and sounds and by integrating that with attention to spoken words—the reading pedagogy broadly labeled “phonetics.” We owe thanks to the brain’s plasticity that so much of our present-day brain activity subserves a skill acquired so recently. But does this same evolutionary context help to explain why reading disabilities are the most common learning disorders in children?

In their chapter on social and emotional development the authors discuss what are called autism spectrum disorders. Social competence is an enormously important skill for reproduction (if only because one has to meet the opposite sex) and the evolutionary centrality of this is reflected in the amount of brain circuitry dedicated to these skills. As suggested by the intriguing work of Robin Dunbar, FBA, an evolutionary psychologist at the University of Liverpool, the evolutionary rewards of adeptly navigating complex social situations may have been the driving force behind our species’ expanding brain volume. Dunbar notes high correlations between neocortical volume and measures of social complexity across species.

The chapter on adolescence highlights the ongoing maturation of the prefrontal cortex—critical for judgement, decision making, and impulse control—domains of obvious educational and behavioral relevance during the teenage years. As a brain area responsible for integrating all current sensory input, emotional states, context, memory, and hopes and dreams for the future in the process of decision making, the prefrontal cortex is amongst the latest to mature.

The enduring plasticity of the brain is featured in the section on lifelong learning. The effects of specific activities on brain structure or physiology are provided as examples of the “use it or lose it” principle. The relationship between physical and mental activity is also discussed.

OPTIMIZING LEARNING

The final chapters of The Learning Brain explore memory and how to optimize learning. The memory section nicely summarizes the different types of memory, a highly significant discovery of recent neuroscience, but it would have benefited from a brief discussion of the molecular underpinnings of memory formation, which is so central to learning. A thought-provoking aspect of the discussion is whether imaging the brain one day might be useful to objectively measure the effectiveness—the output, as it were— of different educational approaches, enabling educators to demonstrate what is optimal. Other intriguing questions addressed by the authors are: Might rote learning bypass the brain circuitry required for understanding? Does learning by imitation stifle creativity or tap into powerful brain mechanisms?

Overall, The Learning Brain admirably realizes the authors’ stated aim of synthesizing a wide body of the neuroscience literature relevant (or possibly relevant) for education and presenting it in a readable and even entertaining format. Although the subtitle, “Lessons for Education,” suggests the unidirectional intention of the authors, future steps to improve education will benefit from a bidirectional approach, asking, as well, what brain science can learn from the field of education.

EXCERPT

From The Learning Brain: Lessons for Education by Uta Frith and Sarah-Jayne Blakemore. © 2005 by Uta Frith and Sarah-Jayne Blakemore. Reprinted with permission of Blackwell Publishers.

Everyone would agree that education changes minds. Teaching someone to read means that they can take meaning from a page covered in scribbles or from a stone covered in runes. Once you have learned to multiply numbers, your mind treats numbers as multipliable. But education changes your brain and not just your mind. Every time you learn something new, whether it is a new face, a new word, or a new song, something in your brain has changed. Education is to the brain what gardening is to a landscape. Not just education, but culture in a broader sense changes brains. The examples we have considered in any detail are literacy and music, but many more exist.

What happens when the brain develops according to a faulty program, and learning cannot proceed normally? A theme developed in this book is that brains can compensate for, but rarely reverse, faulty programs that stem from birth or before. When considering disorders of development where learning is impaired, we had occasion to consider a breakdown in one or more modules of the mind. In the normal case, modules can hardly be distinguished, because brains develop and operate as an orchestra of many interacting parts. In the abnormal case, different members of the orchestra, by their absence, or their playing out of tune, can become conspicuous. Research on how the brain learns has particular uses in designing remedial education programs for such cases.

Can education make better brains? The answer is emphatically yes. The past knowledge of generations can be transmitted to us so that we can store and access more knowledge, learn and use more skills, and be more aware of what affects our mental life. Education can also ameliorate problems of the growing brain.

How can we use our brain power more effectively? We passionately believe that brain science will eventually give us answers to this important question. At the very least this belief can enhance our desire to learn and to teach.



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Carolyn Asbury, Ph.D., consultant

Scientific Advisory Board
Joseph T. Coyle, M.D., Harvard Medical School
Kay Redfield Jamison, Ph.D., The Johns Hopkins University School of Medicine
Pierre J. Magistretti, M.D., Ph.D., University of Lausanne Medical School and Hospital
Robert Malenka, M.D., Ph.D., Stanford University School of Medicine
Bruce S. McEwen, Ph.D., The Rockefeller University
Donald Price, M.D., The Johns Hopkins University School of Medicine

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