Are There Costs to Using Incorrect Worked Examples in Mathematics Education?

Using incorrect worked examples during mathematics instruction can improve student learning. However, teachers worry that students may confuse correct and incorrect examples over time, and memory research supports this fear. To examine if this forgetting occurs, we had undergraduates rate the correctness of correct and incorrect worked examples immediately and one week later (Experiment 1). Previously studied incorrect examples were rated as slightly more correct after the delay, but this did not affect ratings of unstudied examples or problem-solving accuracy. In Experiment 2, we more closely mimicked how incorrect worked examples are used in classroom settings. Again, we found only small changes in students' memory for studied worked examples after the delay, and no changes for unstudied examples or problem-solving accuracy. Our findings suggest the costs of teaching with incorrect worked examples are limited to the specific studied problems, and do not affect learning of the underlying mathematical rule.