We record EEG from the scalp using the Geodesic EEG system (GES) 400 by Electrical Geodesics, Inc. (EGI). This is a safe, non-invasive methodology for recording EEG from the surface of the scalp and extracting event related potentials (ERPs). Research using this system is examining in detail the nature of the brain's response to events, such as errors, rare events, and corrective feedback. With this tool, Arbel and the CNG group are studying various aspects of typical and impaired learning.