Comment by d-us-vb

Trial and error is necessary and beneficial, but not after the student becomes frustrated or anxious/bewildered by the complexity. The research shows that striking a balance between teacher intervention and trial and error is the optimal approach. If a teacher notices that a student is way off course but they keep persisting in one branch of the trial-and-error search space, it’ll be best if they intervene and put the student on the right branch. The student can still use the knowledge of what wasn’t working to find the solution on the right branch, but just persisting would be ineffective.

Gaining true understanding/insight is necessarily trial and error. Teachers cannot teach insight. But they can present the optimal path to gain insight.