Worked Examples and Cognitive Load Theory

The Cognitive Load Theory, introduced by John Sweller in 1988, is concerned with the acquisition of knowledge while taking into account the limitations of short-term memory, as well as students’ mastery of lesson-related schema. Sweller maintains that since people have a limited amount of short-term memory, the more items in a lesson that aren’t mastered to the point of automation, the less likely a student will retain information being taught. The concept of worked examples states that when a student is learning a new skill, they will benefit more from analyzing worked-out examples of the skill than working through problems relating to instruction.

 

A practical example from my own seventh grade Career Technical Education – Business class follows:

 

Lesson: Where Does Your Food Dollar Go?

 

Objective: Upon completion of lesson, students calculate what percentage of the cost of food goes where with 100% accuracy, and will be able to explain why the farmer doesn’t get all the money consumers pay for food.

 

Assessment: Where Does My Food Dollar Go? worksheet and class discussion

 

Note: The point of the lesson is not student mastery of finances for the food industry, rather an understanding of the concept that not all of the money we spend on food goes to the farmer because other businesses/industries are involved in getting the food to consumers.

 

Relevant automatic skills students have before lesson:

 

Relevant skills students have before lesson that aren’t automatic yet:

 

Relevant skills I need to teach students so they can interpret/solve the problem:

 

Cognitive load theory would suggest that I might have too many skills in this lesson that the students haven’t mastered to the point of automatic behavior for absorption of the new skills to be really effective. The theory of worked examples suggests that I need to show at least one product already broken down by where money goes before I have students solve this problem relating to other products.

 

Since I taught this lesson to five class periods this week, for the first and second I taught as I normally would. I reminded students of how we had previously briefly looked at a dollar broken down by where the money we spend on food goes. I then showed them different products and discussed the ingredients, weight, packaging and price of each product, speculating with the students what part of the development of each the farmer had a part in and which of the ingredients/packaging s/he provided for the product. We looked over where each part of the money went and then worked through examples of calculating the percentage of the money that would go to off-farm labor, rent and taxes, leaving the other percentages for them to calculate by themselves.

 

Some of the students who excelled already at many of the relevant skills that I needed to teach most of the other students caught on pretty quickly, but for the most part there were a lot of blank stares and questions along the lines of: “So, um, what are we doing??”

 

For the remaining three periods I relied less on explaining every facet of breaking down a food dollar. I stated more generally that farmers do not get all of the money that comes from the sale of food because so many other hands are involved in the process of getting food from the farm to the shelf of grocery stores and therefore into the hands of consumers (less deductive reasoning on the part of the students). I simplified my presentation and relied more heavily on prior knowledge, such as knowing that marketing people figure out how to package food and have to get paid for their efforts, rather than explaining exactly where each percentage of money for food goes (that’s part of where the money goes).

 

I then showed an example of Pirouette Cookies broken down by the percentages of where the food money goes and asked the students to help me figure out how I got the answers that I did. By working backward from this solved example, we were able to figure out a formula that would hold true no matter what product or price percentage we were trying to figure out (cost * percent = how much of the money goes to this business/industry). Only then did I turn the students lose on completing the rest of the worksheet.

 

Not surprisingly, the number of students reaching the original objective (complete entire worksheet with 100% accuracy) was much higher for the classes where there was less ‘clutter’ in the lesson. Teaching the lesson the way I always have, about one student in 30 completed the lesson accurately, and teaching it keeping worked examples and cognitive load in mind led to about 20 students in 30 reaching the objective. I would like to have closer to 100% of my students reaching the objective, so will continue to refine exactly how to reach my objective without unnecessary clutter in my presentation.