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Chapter 2: What Brain Research Tells Us About Learner Differences

Strategic Networks

It is through strategic networks that we plan, execute, and monitor our internally generated mental and motor patterns-actions and skills as diverse as sweeping the floor, deciding a chess move, or choosing a college. During some activities, such as playing sports, orchestrating an April Fool's joke, or composing an essay, we may be conscious of applying strategy. What most of us do not realize is that conscious or not, strategy is involved in essentially everything we do.

The strategic components of everyday tasks serve to illustrate the centrality of strategy for cognition and learning. Take another look at "The Unexpected Visitor" (Figure 2.5). Try to identify the type of room in which the scene is set.

Painting entitled The Unexpected Visitor
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- Figure 2.5 -
Another Look at The "Unexpected Visitor"
Reprinted by permission of the publisher from Eye Movements and Vision by Alfred L. Yarbus 1967 by Plentum Publishers, Inc.

Most likely you glanced at the image and had no trouble determining that it shows a living room or a parlor. Without being aware of it, you relied on your strategic networks to figure this out. You identified the goal of the task, came up with a plan to achieve it, executed that plan, and evaluated its outcome, all the while avoiding distractions that might carry you off track. This underlying strategy is evident in Figure 2.6, which shows eye movements of someone examining "The Unexpected Visitor."

Painting entitled The Unexpected Visitor
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- Figure 2.6 -
Eye Movement: Three Viewing Strategies
Reprinted by permission of the publisher from Eye Movements and Vision by Alfred L. Yarbus 1967 by Plentum Publishers, Inc.

Notice that Figure 2.6 shows three eye movement maps. Each reflects the same individual looking at the same image, yet the patterns of movement are different. Why? The answer is different goals. First, the viewer was told to look at the image, but was given no specific instructions about what to look for (map 1, at the top of the figure). Second, he was instructed to identify the ages of the people in the picture (map 2, at the lower left). Third, he was asked to determine what the people in the picture were doing before the visitor arrived so unexpectedly (map 3, at the lower right). Each instruction required a different viewing strategy, and each new strategy resulted in a different pattern of eye movement.

As this example shows, even a simple action like searching a picture involves a multi-step strategic process:

  • Identify a goal.
  • Design a suitable plan.
  • Execute the plan.
  • Self-monitor.
  • Correct or adjust actions.

Skilled readers use this kind of strategic process whether they are reading to locate a particular fact, skimming to get the "gist," or relishing the literary language. Remarkably, our brains can plan, organize, and monitor patterns of action such as these, often while just barely engaging our conscious minds and usually while we are doing other things. How do our brains do this? The answer is that strategic networks operate in the same highly efficient fashion as recognition networks do.

Strategic Processes Are Distributed

The neural networks responsible for generating patterns of mental and motor action occupy their own unique territory, located primarily in the part of the brain called the frontal lobes (see Figure 2.7). Research into the effects of selective damage to the frontal lobes has revealed that like recognition, the ability to think and act strategically is distributed across specialized modules.

Schematic drawing of the brain showing the regions responsible for strategy.
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- Figure 2.7 -
Strategic Networks
This schematic drawing of the lateral surface of the human brain shows the regions primarily responsible for strategy.

Neurological and brain imaging studies tell us that within the frontal lobes, the prefrontal cortex oversees complex strategic capacities and is critical for identifying goals, selecting appropriate plans, and self-monitoring. If we were to show "The Unexpected Visitor" to a person with damage to this area of the brain, a map of his eye movements might not reveal the distinctive tracing patterns shown in Figure 2.6. Instead, the map might show random movements, indicating a focus on seemingly unrelated details. Even if this viewer's eye movements did suggest some kind of plan, he would not be able to alter this plan in response to unexpected variables, such as a change of instructions. For example, a directive to figure out the visitor's age and another to speculate on the prior activities of the woman in the foreground might produce no difference in pattern.

Background Knowledge Background Knowledge: Explore the Web site of The Brain Injury Association of Washington. Click "Brain Injury 101".

The pattern of activity distributed across the modules of the frontal lobes shapes how we plan and execute actions. These modules function in parallel, enabling us to perform highly complex actions with ease. Consider, for example, what's involved in playing the organ. If it were not for parallel processing within strategic networks, organists would never be able to simultaneously coordinate not one but several different keyboards and numerous pedals and switches!

Strategic modules, although operating in parallel, are also interdependent. The connections between modules enable modules doing different things to influence one another. In fact, elements of our plans-of-action that come later in a series can influence those that come before (Fowler, 1981). This is why, for example, you will pick up a bowling ball one way if you intend to bowl the ball yourself and another way if you intend to hand it to a friend. Similarly, when we speak, separate but connected modules process syllables and words simultaneously, so that the pronunciation of any syllable or word is highly influenced by those that follow it. That's why prerecorded "voices" like the automated flight-arrival information broadcast in airports sound so odd to us: Both the words and sentences are spliced together from prerecorded individual sounds, and each sound is articulated the same way regardless of the linguistic context. Cursive writing provides yet another example: When we write, we form individual letters differently depending on which letters precede and follow them.

As teachers, being mindful of the parallel nature of strategic processing can help us better understand individual learners and design optimal supports for each. For example, school requires students to learn discrete strategic skills (such as listening, extracting relevant information, and writing down the information) and to execute these skills simultaneously (as when taking notes in class). From what we know about strategic networks, we can appreciate that these patterns of actions are not "built" by putting together a step-by-step sequence. Different layers of an action are added on at the same time and mutually influence one another. For this reason, skill instruction is often more effective when the various components of the process are learned simultaneously rather than one at a time (Gopher, 1996). Thus, a tennis instructor may model the whole serve and encourage the learner to try it out, only analyzing individual steps (ball toss, backswing, step forward, swing, and follow-through) when particular aspects must be corrected. Likewise, each subcomponent of a task like writing an essay makes the most sense to our students if it is taught in the context of the whole task.

Strategy Involves Bottom-Up and Top-Down Processing

Like recognition modules, strategic modules form part of a two-way hierarchical pathway. Neural signals travel from higher-order regions in the cortex down to the spinal cord, where the neurons that innervate muscles are found, enabling internally driven strategies ("I will pick up this pencil") to influence how we act on-and in-the world (picking up the pencil). Modules specialized to carry out different steps within a skills sequence reside at different levels along that path.

The top of the hierarchy orders the steps, "commands" our muscles to act, and keeps track of whether or not the goal is reached, modifying the plan as needed. As actions are practiced and perfected, they require decreasing amounts of monitoring from the top. Anyone who knows how to touch-type will remember that as a beginner, you had to rely heavily on conscious monitoring capacities to check finger placement and letter sequence. With practice, though, the pattern of movements necessary to hit the right keys became automated, requiring little if any conscious monitoring.

The top-down flow of information in strategic networks makes intuitive sense. We can understand that top-down processing enables us to carry out a plan formed high up in the neural hierarchy. When we as teachers express goals clearly, give verbal instructions, or offer models for students to work from, we are supporting students' top-down processing by stressing the importance of strategic skills and encouraging students to be guided by clear goals129 and plans.

Within strategic networks, information travels not only down from the cortex to the muscles, but also up from the muscles to the cortex. One source of bottom-up strategic pathways is the cerebellum, the cauliflower-shaped structure located at the back and base of the brain, overlaying the brainstem (see Figure 2.8). Pathways from the cerebellum to strategic modules in the cortex serve an important role in learning skills and strategies. The cerebellum takes sensory feedback, which clues it in to how actions are being executed, and compares it to other signals that convey the actions we intended. Then, through these bottom-up projections, the cerebellum informs our strategic networks about whether our actions are "on target." Although this is best described for motor patterns, bottom-up processing operates in a similar way to refine mental patterns. It works much like a thermostat, but regulating skills and strategies rather than temperature.

Drawing of the cerebellum.
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- Figure 2.8 -
The Cerebellum
Illustration by Lyida Kibiuk. Reprinted by permission of the Society of Neuroscience.

Thus, to acquire skills, students need support for both top-down and bottom-up strategic processing. They learn best when they have not only good instruction and good models but also plenty of opportunities to practice and to receive ongoing, relevant feedback. The kinds of models and supports most suitable for individual learners depend on the students' particular strategic strengths and weaknesses.

Individual Differences in Strategic Networks

The distributed organization of strategic networks introduces a level of complexity that would not exist in a homogeneous network in which all tissue looks and acts the same and a deficit in one part of the network has the same effect as a deficit in another. In reality, deficits and strengths can affect very specific aspects of strategic skills. For example, a student may be skilled at making a plan but have difficulty self-monitoring when executing the plan. Another student might be an expert at finding information, but have difficulty organizing and keeping track of that information. Recent brain imaging experiments provide a novel illustration of individual differences in strategy. When two people are confronted with the same problem but solve it using different cognitive strategies, the brain images reveal two very different patterns of activity (Burbaud et al., 2000).

Differences in strategic networks manifest themselves in various ways in the classroom. For example, learners differ dramatically in their abilities to acquire and automate pattern-based routines such as forming letters, typing, spelling, and multiplying. Learners also differ in their ability to enact higher-level strategies such as planning, organizing, monitoring progress, devising alternative approaches, and seeking help when they need it. For example, students with executive-function disorders (disorders affecting reasoning, logic, hypothesis-testing, and similar high-level abilities) can have difficulty at all levels of reading. When decodingwords, they may make impulsive guesses rather than apply their phonics knowledge or search for context cues. When reading a paragraph, they may fail to use organizing strategies to help them focus on the key points.

Variation within students' strategic networks also influences their abilities to use different kinds of learning tools. Students with motor difficulties may be marginally able or unable to use a keyboard or a mouse, to scan a line of text, or to turn the pages of a book. Speech difficulties may impede oral presentations, and students with language and learning difficulties may find that they expend so much energy attending to the mechanics of producing written text that they have difficulty communicating effectively in that medium. These are just a few of the obvious examples; often the strengths and weaknesses in strategic networks are more subtle.

Variations in the degree of bottom-up and top-down processing influence how students acquire skills. We have all seen students with the uncanny ability to watch someone else do something and then do it almost perfectly the first time; this is an indication of strong top-down strategic processing. On the other hand, we also know students who seem to learn best by doing; these are the students who achieve expertise only after lots of practice and feedback-an indication of strong bottom-up strategic processing. Awareness of these subtle differences can help teachers design optimal strategic teaching for different kinds of learners.

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