Experimental Strategies and Conceptual Change The article The Development of Scientific Reasoning in Knowledge-Rich Contexts written by Leona Schauble relates a series of experiments which give some insight as to how conceptual change and experimental strategies effect subjects of varying ages, ten fifth and sixth graders and ten non college adults. The conclusions drawn from the article are relevant in determining the cognitive strengths and weaknesses in the subjects as well as how these strengths and weaknesses vary as a result of differing ages. The objective of the study was to track changes in both the theories and reasoning strategies used by participants who conduct and interpret repeated cycles of experiments over several sessions to learn about the causal structure of two physical science systems. The exact experiments are not needed to understand the results of the experiments as long as the experimentation strategies and conceptual changes are understood.

The experimentation strategies approach tends to emphasize concern for logical validity, (i. e. how the problem pieces together and why). The conceptual change approach tends to be more concerned with the plausibility and explanatory coherence as tests for deciding whether knowledge should be adopted. Schauble (1996) states that 'because previous work focused either on the validity of strategies or the coherence of conceptions, it has tended to mask these close interrelations' (p. 102).

Therefore the results of the experiments are incredibly useful in determining how validity and coherence play complementary roles. As stated earlier, it is not important that the exact nature of the experiments be listed as long as the reader understands their validity. Each subject was asked to solve a series of complex tasks in which the subjects attempted to 'discover the causal relationships between variables and outcomes in multi variable contexts' (Schauble, 1996, p. 102). The adults conducted more informative experiments, giving them an advantage, yet both groups showed some improvement in understanding domain context.

The intrigue surrounding these experiments is centered on what can be inferred from the learning habits observed in both the children and the adults. Even though the adults had barely any more schooling than the children, it is not surprising that the adults had more complex and comprehensive experimentation strategies. Such strategies can be obtained through personal experience. It makes sense that the adults would still have a wider knowledge base to choose from, helping them to be more systematic. However, its interesting that both groups continued to use incorrect strategies long after they had proved invalid. Both groups tended to favor a particular strategy and attempted to manipulate the other variables to make sense of that favored strategy.

The article does not explain this phenomena, it simply states that it did happen. The subjects even went as far as reverting back to old strategies that failed on similar experiences. This may be due to favored heuristics that determine an individuals problem solving skills. However, if this were true it would seem that adults would prove even more persistent in their incorrect strategies as their heuristics are more fully developed. The study shows just the opposite.

On repeated experimentation the the adults demonstrated 79% 'comprehension', or possible variation in the task explored, and the children only demonstrated 66% comprehension (Schauble, 1996, p. 110). This tends to argue against the notion because both groups began at approximately the same comprehension levels. These results seem to lend to the formerly discussed view of a wider knowledge base for adults than exist in children. These findings do not completely discredit the heuristic notion as the study does not touch on the use of heuristics and therefore was not very comprehensive itself. It is interesting that the plan structures of the adults began as more complex but leveled off with that of the children upon repeated experimentation.

By the second task half of the children were using the more complex plan structures and the children and adults no longer differed significantly. It can be inferred by these results that our reasoning capacity is something that is inherent and varies little through out our lifetimes. This can a lot of ambiguity in the classroom. Teacher's can take the findings of this experiment and focus less on working on plan structures and more on and eliminating inefficiency due to emphasis on invalid, favored strategies.

The results of the experiments listed in the article are useful in their own right but they can also act as feeder experiments for later research. Now that the learning strategies have been somewhat determined in relation to age studies can delve deeper into what motivates these decisions. If the motivations are found they can be fueled or inhibited depending on the positive or negative effects on learning. Schauble (1996) states that there is a positive relationship between the kind of plan structure adopted and the percentage of valid inferences made' (p.

110). The article itself presented a workable plan structure and evoked valid inferences to be used in later research. ReferencesShauble, L. (1996). The Development of Scientific Reasoning in Knowledge-Rich Contexts. Developmental Psychology 32.

p. 102-119.