The well-known experiments of Nisbett and Wilson lead to the conclusion that we have no introspective access to our decision-making processes. Johansson et al. have recently developed an original protocol consisting in manipulating covertly the relationship between the subjects' intended choice and the outcome they were presented with: in 79.6% of cases, they do not detect the manipulation and provide an explanation of the choice they did not make, confirming the findings of Nisbett and Wilson. We have reproduced this protocol, while introducing for some choices an expert guidance to the description of this choice. The subjects who were assisted detected the manipulation in 80% of cases. Our experiment confirms Nisbett and Wilson's findings that we are usually unaware of our decision processes, but goes further by showing that we can access them through specific mental acts.