Wednesday, August 6, 2014

Learning from examples: how to do it right

This survey of the learning-from-worked-examples literature highlights some best practices for using worked examples as a learning aid.

Learning from examples is most effective in stages 1 and 2 of the four-stage ACT-R cognitive framework:

  1. learners solve problems by analogy

  2. learners develop abstract declarative “rules” to guide problem solving (some generalization from step 1)

  3. learners no longer need to consciously invoke the “rules script” to solve problems

  4. learners have practiced many types of problems, so can instantly “retrieve a solution template”

Throughout the survey, “A is more effective than B”  is generally measured by pre/post testing to measure transfer in controlled experiments. In some cases a hypothesis is proposed to explain the result in terms of one or another theoretical cognitive framework; in other cases no interpretation of result is offered.

A key finding is that students who engage in “self explanation” [Chi et al., many many cites], in which a learner pauses while inspecting an example to construct the omitted rationale for a particular step, outperform those who don’t.  Here are several ways to stimulate this behavior (*) along with other best practices for creating and using worked examples:

  1. * Identify subgoals within the task.

  2. * Several partially-worked examples of varying complexity and illustrating various strategies/approaches, with enough “missing” to stimulate some self-explanation, are more effective than fewer but more-thoroughly-worked examples.

  3. * Don’t mix formats in one example, eg, use either a labeled diagram showing some concepts or a textual explanation of those concepts, but not both: the “split attention” cost actually retards learning.

  4. Don’t assigning an “explainer” role to stimulate self-explanation: it actually hinders learning, possibly because of increased stress and reduced intrinsic motivation for the learners.

  5. Visuals accompanied or immediately followed by aural comments are more effective than either visuals or comments alone.

  6. Alternate worked examples with practice problems, rather than showing N examples followed by N problems.

  7. Novices tend to overfocus on problem context rather than underlying conceptual structure; to compensate, use the same context/background for a set of different problem types.

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