How do children learn? Developmental or educational psychologists would seem to be the experts to turn to in seeking answers to this question. Yet, for a long time, developmental psychologists devoted themselves to understanding how children's knowledge and understanding changes, but they did not directly examine the process by means of which these changes occur. Instead, the typical method was to study what children of one age understand and compare that to what children a few years older understand. Researchers then made inferences about what developed between the two ages. But clearly these inferences were indirect. No one had observed the change occurring within the individual child.
The microgenetic method has changed this. Its goal is direct observation of the change process as it occurs in individual children.
Its defining characteristic is that an individual encounters the same or similar problem over frequent occasions, allowing the researcher to observe how the individual's approaches to the problem change over time. Although the method has precursors in the work of Werner (1948), the first modern study featuring the microgenetic method was published by Kuhn and Phelps in 1982. They observed fourth grade students engaged in a scientific inquiry task. Students observed that one combination of liquid chemicals (e.g., A, B, and C) turned the mixture cloudy and another combination (e.g., B, C, and D) did not. The student's task was to experiment with the set of liquids to determine which of the individual liquids played a role in producing the chemical change and which did not.
Students of this age found the task difficult and typically did not succeed in drawing valid conclusions during their first attempt. But the critical feature of the method is that the student encounters the task not just once but a number of times, typically over a period of weeks or months. What Kuhn and Phelps observed is that over this course of time most student's performance improved in two ways. First, the conclusions got better. A student was more likely to correctly identify the components of the mixture that played a causal role in producing the outcome, as well as identify those components that played no causal role. But second, and equally important, the strategies by means of which a student generated those conclusions also underwent change. Specifically, the student displayed a number of different strategies to apply to the problem, and what changed over time was the frequency with which they were applied. More advanced and effective strategies—the ones that yielded valid conclusions—began to be used more frequently, while the less advanced, ineffective strategies that led to invalid conclusions became less frequent.
Exactly how did this change take place? Kuhn and Phelps found that some, but only a minority, of children showed an abrupt shift from predominant use of weak strategies to predominant use of strong strategies. These individuals discovered the best way to approach the problem quite suddenly, their approach took a sharp turn, and they rarely used the poorer strategies again. These children, however, were in the minority. For the majority of children, change took place much more gradually as better strategies increased in frequency and poorer ones decreased. Moreover, this change was not a smooth, continuous one. A better strategy might appear once but then not be used again until several sessions later. Or once this better strategy became predominant, a weak strategy that had not been used for some time might reappear. Change, in other words, was overall in a positive direction, but the progress was not even or constant.
An implication is that change entails two components— consolidation and mastery of the stronger strategies, leading to more frequent usage. and inhibition of the weaker strategies. Both are necessary for success. Much of the evidence from microgenetic studies suggests that the inhibition component may be the more challenging of the two. This conclusion is significant because it reverses previous conceptions of development.
Other studies since the one by Kuhn and Phelps have confirmed these basic findings over a wide range of cognitive tasks, including many that figure prominently in classroom instruction, and age groups. (For reviews of research see Siegler & Crowley, 1991; Kuhn, 1995; Miller & Coyle, 1999; Siegler, 2006). Chen and Siegler (2000), for example, observed changes in frequency of usage among 2-year-olds in the multiple strategies they exhibited to reach a desirable out-of-reach toy—reaching with their hands, asking for an adult's help or using an available tool. Siegler and Chen (1998) observed the strategies of 5-year-olds over time in making judgments about the operation of a balance scale. Alibali (1999) identified and followed over time ten different strategies that third and fourth graders used in solving mathematical equality problems (3 + x = 9). Thornton (1999) studied 5-year-olds playing the game of Twenty Questions.
Not only did she see strategy change over time; she also found that the type of strategy that was initially predominant was predictive of the degree of progress children showed. Children who initially asked only entirely specific questions (“Is it the red car?”) were less likely to progress than were those who initially included at least some less specific questions (e.g., “Is it the car?”) in their repertories. These were the children most likely to progress to consistent usage of the most effective strategies (e.g., “Is it one of the cars?”) Other studies have similarly found initial variability to be a predictor of change.
The microgenetic method has produced many of the kinds of changes with practice in school-related tasks that educators hope to see, making it possible to better understand them (Kuhn, 2005). Dean and Kuhn (2007) used a microgenetic method to follow changes over time in fourth graders' scientific reasoning. Students had to discover which of multiple potential variables did and did not make a difference to an outcome, as they worked on multiple problems over a number of months.
Dean and Kuhn found not only that students' knowledge and the strategies used to generate that knowledge improved over time, but also that this improvement was better maintained, compared to a condition involving brief direct instruction of the effective strategy. Finally, Kuhn, Goh, Iordanou, and Shaenfield (in press) observed change over time in sixth graders' argumentation strategies as they worked in pairs debating a social issue with a pair of peers who held an opposing view. Although they received no formal instruction, their argumentation skills showed improvement when assessed individually (without peer support) on a new topic.
How and why does the microgenetic method work? Ideally, frequent exercise serves simply to speed up the change process, allowing the researcher to examine it, without altering its essential characteristics. A concern is that this acceleration might change characteristics of the process, if so limiting what can be learned about such changes as they occur in an entirely natural environment. Studies that have compared change patterns under micro-genetic conditions with those observed over a much longer time period using longitudinal methods, however, find that the patterns observed under the two conditions are comparable (Siegler & Svetina, 2002). What differs is the length of time over which they take place.
But this does not mean that there is no difference between the comparatively rapid cognitive changes that have typically been called learning and the slower changes that have been referred to as development. The distinction between development and learning is a long-standing one that has been important to developmental psychologists, and there is no indication that it should be discarded.
While the microgenetic method has contributed to making the dividing line between learning and development less firm than it was once thought to be, it does not follow that there remain no useful distinctions at all. Learning what songs are on this week's Top 10 List and learning that conflicting ideas can both be right are different kinds of learning in numerous important respects (among them generalizabilty, reversibility, and universality of occurrence). What is important is recognizing the process of change as one that has multiple parameters. When the process is examined microgeneti-cally, it becomes possible to begin to characterize it in terms of many such parameters. The distinction between development and learning is also indicated by the fact that microgenetic studies have typically shown change to occur more rapidly in older children or adults than in their younger counterparts (Kuhn & Pease, 2006; Kuhn, Garcia-Mila, Zohar, & Andersen, 1995). The older individuals apparently bring something to the learning process that the younger ones have not yet developed.
Another important question that has been asked about the strategy change that microgenetic studies reveal is the degree to which it occurs under the individual's conscious monitoring and control. Because inhibition of less effective strategies is involved, the development of conscious awareness, monitoring, and management of one's own learning processes—executive or metastrategic functions—have been suggested as playing an important role. Some micro-genetic researchers, such as Siegler (2000, 2006; Siegler & Jenkins, 1989), emphasize the need for associations with the more frequent, less effective strategies to be weakened, as well as associations with more effective strategies strengthened. Others, such as Kuhn and colleagues (Kuhn, 2001; Kuhn & Dean, 2004) emphasize relinquishment of less effective strategies as a more formidable obstacle than strengthening new ones. These researchers propose that knowledge at a meta-level is as important as that at the performance level and plays a major role in what happens there. If so, the changes that occur at the strategic level in microgenetic studies should be accompanied by changes at the metastrategic level and studies by Kuhn and colleagues provide evidence that this is the case (Dean & Kuhn, 2007; Kuhn & Pearsall, 1998; Kuhn, Garcia-Mila, Zohar, & Andersen, 1995).
In the study by Kuhn and Pearsall, for example, during repeated engagement over several months with a scientific investigation task students were asked at several points to explain to a new student how to do the task. This measure of metastrategic understanding showed advances over time, as did measures of strategic performance. Kuhn and Pease (2006) showed that metastrategic monitoring and management of performance also increase over longer periods of time, as a part of normal cognitive development. They studied the performance of 12-year-olds and young adults in learning a simple set of causal relations, and they attributed the adults' superior performance to enhanced meta-level monitoring and management.
Although classroom teachers are unlikely to use it to conduct formal research studies, the microgenetic method clearly has a place in the classroom. Teachers are using the microgenetic method in an informal, naturalistic way when they assign their students the same or a similar task repeatedly over a period of time, for example, to carry out two-digit multiplication or to select a book to read and to write a book report on it. Teachers expect to see changes over time in the strategies a student brings to bear on the task and in the product that results. The findings from more formal microgenetic research offer teachers a framework for conceptualizing and monitoring such changes. They suggest that teachers have many strategies they might usefully consider in observing a student's progress over time. These include not only the product of the student's efforts—the work the student submits for a grade—but also what strategies the student has applied to generate this product, how the individual has changed over time, whether the student needs more help in inhibiting ineffective strategies or in consolidating the use of effective ones, and, perhaps most significant of all, what progress the student is making in coming to monitor and manage his or her own learning.
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