The capacity to adjust behavior and evaluate performance in a changing environment is highly related to taking feedback into account. Using feedback is, hence, crucial for different cognitive capacities. The present study focused on feedback processing in hypothetico-deductive reasoning. Electroencephalographical (EEG) activity was recorded while participants performed a hypothesis-testing task in which a feedback signal allowing the evaluation of performance was delivered at each trial. To ameliorate the spatial resolution of EEG signals, the surface Laplacian was estimated. Results showed three distinct patterns of activation. At central and centro-parietal electrodes, the activity was sensitive to participants' expectancies in a binary and a gradual way, respectively. At the parieto-occipital electrode, the activity was sensitive to the evaluation of performance itself: correct versus false. In conclusion, the processing of feedback signal depends on at least three separate processes.