Worked Examples Theory and Practice Worked examples is an approach that is used in a variety of techniques. This presentation outlines the reasons for taking the approach of worked examples.

Problems with Problem Solving A big part of computing is problem solving So let's get novices problem solving early….. Cognitive overload is often the result frustration low levels of learning Why does the computer hate me? Hmmm… I’ve created a program. Why doesn’t it work? Which of these do I need to solve the problem? What do these things do? What is the problem with problem solving? Cognitive overload occurs when we are asked to cope with too many bits of information at the same time. Though it is traditional to ask pupils to start solving problems early, this often results in cognitive overload, leading to frustration and low levels of learning. What’s an if statement, variable, loop, sequence,……??? What can I get the computer to do? What do I want the computer to do?

Research Study Asked students to talk about experience of completing programming assignments What do you think they told the researchers? Nothing!!! – beyond emotional responses When students were asked about their experience of completing programming assignments, such as the parts that they got stuck on. they told the researchers about their emotional state rather than the content of the assignment. Kinnunen & Simon, Experiencing Programming Assignments in CS1: The Emotional Toll, ICER 2010

The students couldn't remember the detail Problem solving cognitively very demanding Have you ever had this experience with pupils? pupil is not stupid or lazy, their poor brain is acutely overloaded Students couldn't remember the detail as there was no way for them to remember all aspects of the demanding task. Working memory has 7 +- 2 slots to hold things we need. This can be full for a novice because every aspect of the problem is important and new. This means that there is too much to keep in mind when also trying to learn. This is something many of us experience on a daily basis.

What is going on? Expert can, novice can't. Why? *** Patterns *** Novices don't have the experience, hence no patterns and worse – problem solving as a learning exercise is very inefficient and very painful! What is going on? Experts are able to store more information about a problem than novices. This is because they can see related problems and patterns. They have solutoins for those parts of the problem, so this is less taxing to think about than it can be for a novice. Because novices don't have the experience, they are less likely to be able to find patterns, leadin to more difficuly attempts to remember aspects of the problem.

Ok, I get it. Solving problems to learn problem solving is no good for novices So how can novices efficiently learn the patterns? Knowing this is a problem doesn't solve it - how can novices efficiently learn the patterns?

Actually – it's not a new problem…. It's why we have apprenticeship Novice watches craftsman at work picks up much of the subtlety of a complex skill almost subliminally! Not much good for an intellectual discipline you can't see the brain at work This realisation has spawned a whole area: cognitive apprenticeship Worked examples are one instance of cog. app. Congitive apprenticeship is an approach that allows pupils to take the knowledge of the expert and apply it to the novice's situation. Worked examples is one example of this.

Applying cognitive apprenticeship in computing Novices gain first exposure from you in class or through reading. They study/try out worked examples instead of solving problems Novices focus on structure of, and approach to solve, this problem - this is the pattern Once novices are exposed to something new, they can consult worked examples to see how each stage of a problem can be solved. Novices can focus on the structure of the problem and see the patterns in the approach used.

By the way, what is a worked example? Process for solving a particular problem broken down into steps Each step: represents one or more actions required at this point in the solution process has an explanation of how/why the expert chose these actions at this point, and how they work shows the intermediate solution reached at this point – could be a diagram or text, depending on what the expected output of the problem is. Worked examples can be more or less detailed A worked example is a process for solving a particular problem. Each step represents one or more actions required at each point in the process. The steps should be explained so that novices can see the reason for the step. Intermediate solutions should be visible because then novices can understand where they have "got to" in the process. The level of detail of a worked example will depend on the activity and the learner. It can be varied to target the necessary level.

Best practice use Follow a worked example immediately with a related practice problem minimum time for novice to forget the process forces the novice to exercise what they have just seen/learned Practice problem needs to be closely related

Data Representation Suggested worked example steps: Find the area in pixels Calculate the number of bits taken to store the pixels (Calculate the number of bytes required) (Convert the answer to an acceptable number of units) 400 Colour depth: 24 bit. This is an example of a worked example for data representation. Though the steps are simple, a worked example can elaborate on each step to whatever level of detail is required to make it easy to understand for a novice. 300

Techniques to Investigate Subgoal Labelling Calculation Worked Examples Incremental Software Development Worked Examples Relational Database Design Worked Examples For more on worked examples, have a look at any of the following techniques: Subgoal labelling, calculation