Knowing what you don't know makes failure productive

• Problem-solving prior to instruction can prepare students for learning.
• When working on unfamiliar problems, students become aware of their knowledge gaps.
• Building on student ideas during instruction specifies students' knowledge gaps.
• Our results indicate that awareness of specific knowledge gaps promotes learning.

To progress from intuitive ideas to deep conceptual understanding, students need to become aware of gaps in their ideas. Attempting to solve problems prior to instruction may lead to a global awareness of knowledge gaps (i.e., awareness without being able to identify which specific component is lacking). These gaps may subsequently be specified by comparing students' solutions to the canonical solution. In our first experiment, the teacher highlighted specific gaps by comparing typical student solutions to the canonical solution before or after problem solving. The second experiment varied the factors form of instruction (with or without student solutions) and timing of instruction (problem-solving prior to or after instruction). Problem-solving prior to instruction triggered a global awareness of knowledge gaps. While this was beneficial for learning when combined with instruction with student solutions, our results indicate that comparing student solutions during instruction to specify the gaps is the most relevant factor.