The aim of the present research was to investigate how reflection might affect causal reasoning and the accuracy of metacognitive awareness. In an initial phase, a random sample of 202 sixth grade students classified in 4 groups according to their dominant conceptions about electrical circuits. Fifteen students from each of the above groups (N=60) were selected to solve 2 tasks with simple electrical circuits of different level of difficulty and to estimate task difficulty and confidence about the solution provided to each task. Right after they had provided their solution, they were individually asked to reflect on the procedure of problem solving through prompting and to estimate again task difficulty and their confidence about their solutions. Protocol analysis indicated the impact of reflection and causal reasoning produced by students on the accuracy of metacognitive experiences about task difficulty and confidence about their solutions in regard to their actual cognitive performance.