Week 3 Readings

Chase & Simon

Chase and Simon designed an experiment to test how people of varying skill levels in a particular subject absorb and retain new information, utilizing chess players as a model.  Their experiments showed that master level players see the board as a group of interrelated chunks and are able to reconstruct parts of the board they may have forgotten based on what they did remember.

• There was no difference between the master, experienced, and beginner players’ number of tries when reproducing randomized boards, indicating that the master does not have greater memory than the other two, but is able to place unremembered pieces where they “should” be based on the remembered pieces.
• All players perceived the board in chunks; the difference is that the master perceived larger chunks as well as more chunks than the others.
• In short, the master is confident enough, based on past experience, to apply past experience to new information and extrapolate to draw conclusions.

Chi et al

In this study, Chi attempted to differentiate the ways in which experts and novices approach a problem, using problems from physics textbooks as a model.  He found that experts tend to focus on the underlying principles of the problems while novices focused on the surface features of the problem.

•  Done through 4 experiments.  First, sorting the problems into different categories without prompting.  Second, sorting a second group of problems with surface similarities into groups.  Third, determining the schemata, or way in which problems are approached, based on what is seen.  Fourth, identifying features of the problem that determine its classification.
• 1) Novices focused on surface features like pulley, inclined plane, rotation, etc. while experts focused on relevant laws of physics like F=MA, Conservation of Energy, etc. 2) Novices grouped problems with surface similarities together while experts differentiated based on underlying principles.  3) Novices’ schemas focused on physical characteristics, but while the experts’ schemas included those aspects, the focus was on the physical laws which may directly lead to answers.  4) Key features of the problems differed greatly between the experts and novices, again based on physical similarities versus features that directly relate to laws of physics.
• 2 hypotheses for why
• 1) Reading problem leads to representation of problem which leads to categorization.  4 stages of representation: a) Literal representation, b) Spatial relationships between the literal objects & a diagram (“naïve”), c) Idealized objects and physical concepts necessary to arrive at equations for solving (“scientific”), d) Algebraic representation of problem.  Experts categorize based on (c) instead of (b).  Alternative: problem may be tentatively categorized immediately.
• 2) Problem representation is constructed in context of knowledge available for problem type which constrains and guides final form of representation (called “schema”).  In other words, experts possess a larger base of knowledge from which to represent and categorize a problem.  Tested in experiment 3.

·         Experts approach a problem qualitatively while novices approach it through the lens of the unknown.

Both of these papers compare how experts and novices approach problems.  As categorization of problems can be described as a form of the “chunking” described in Chase and Simon’s paper, these papers are describing the same phenomena: experts draw upon their greater base of experience to categorize problems and make connections.  The burning question is how do I use this in a science classroom, assuming that I am the expert (Hopefully a fair assumption)?  First, I think understanding that the student is unable to make the connections that are second nature to me is essential.  Second, helping students see the common threads that run between several questions that superficially appear different can help them start to transition towards expert thinking (I am, of course, assuming that expert thinking is desirable.  I don’t believe that point needs defending).  Finally, giving students and walking students through questions that force them to think qualitatively about the situation can help them start drawing those connections for themselves.