The Worked Example Effect

The Worked Example Effect

Before I spent a good chunk of last year reading about Cognitive Load Theory I would find myself falling into the trap of telling my physics students who are struggling to do more problems.  It is probably in part due to the pervasive view in education that it is always better if a student figures something out for themselves (if the student discovers it). 

The worked example effect (one of the many ‘effects’ that have come out of research into Cognitive Load Theory) stands opposed this the view that it is always better for learners (and particularly novice learners), to discover something for themselves, and suggests instead that it is always better for a learner to be presented with multiple clear, well-structured and logically sequenced worked examples.  Simply put, novice learners benefit more from studying worked examples than spending the equivalent time on problem solving.

The reason that the worked example effect is more effective than problem solving comes down to schema, and the way that experts and novices approach problems.  When experts are faced with a novel problem they use existing schema, which is a large store of procedural and content knowledge in long-term memory that they draw on.  This leads to automated complex thought processes where the correct set of moves to make seems clear.  The experts understand how and why they have achieved the goal.

In contrast novices, when faced with a novel problem, tend to start by focusing the goal (in physics this is finding the answer), and then work backwards using means-end analysis.  A nice example of means-end analysis is finding your way through a maze for the first time, using trial-and-error to find a path through the maze. You may achieve the goal, but not know how or why you got there.  This process puts extraordinary burdens of working memory, and often means that students fail to build schema beyond the surface structure of a problem.

Problem Solving: Novices vs Experts

I think you can see this happening where students appear to be successfully solving lots of problems in class and at home, but in a test or exam can’t solve similar problems. What is happening is the students are using means-end analysis problem solving techniques for each question, eventually solving the problem, but not having a clear idea of how or why they solved the problem.  They are essentially memorising how to solve a variety of different problems, without building a strong schema of understanding.

The goal then, when providing students with worked examples, is to build expert schema (a large store of procedural and content knowledge).  This is only achieved if the worked examples reduce the students extraneous cognitive load.  The worked examples have to be clear, well structured, logically sequenced, and expose expert schema.

Its not enough to provide students with example after example, lesson after lesson, because there is no way for you as a teacher to check for understanding; to check that schema has been built, so time needs to be allocated for students to work independently on similar questions, and for teachers to use this time to check and correct student understanding.

In my teaching practice I have found that finding time to check for understanding has been difficult, as a complex worked example could take the better part of a lesson, when allowing for my explanations and student questions along the way.  To overcome this I have been providing pre-written worked examples that I discuss with the students in class.  I find that this takes about half the time that doing the same question on the board because I don’t have to write the information down, and I don’t have to wait for students to catch up with their notes.  I have also observed the following advantages:

• Students can focus on how the question was answered, rather than copying down notes.
• When one student answers a question, all students hear and engage with the answer, rather that just those who are caught up with their notes.
• The example is laid out in a way that I would do it, and no information is lost whilst students are copying off the board.

Below are some examples of my pre-written worked examples.  I think that the steps taken to solve a problem need to be clearly identified, so I sequence my examples using the steps I took as headings.  I also provide explanatory notes to clarify where I feel that this needs to be written down.

Electric Fields Worked Example

Magnetic Fields and Forces on electric currents/charges

See here If you want to learn more about cognitive load theory

I hope you find this blog post useful.

Dan (@dan_braith) 


References:

Clark, R.E., Kirschner, P.A., Sweller, J. (2012). Putting Students on the Path to Learning: The Case for Fully Guided Instruction. American Educator, v36 n1 p6-11 Spr 2012

Sweller, J., Ayres, P. L., & Kalyuga, S. (2011). Cognitive load theory. New York: Springer.