2012 by Oxford University Press, Inc. All rights reserved. We review two decades of research on the error-related negativity (ERN or Ne), a component of the event-related brain potential that accompanies errors in speeded performance. Theories of the ERN must contend with a wealth of experimental data, both in healthy subjects and in individuals with neurological and psychiatric conditions. Data regarding a number of other components, including the error positivity, feedback-related negativity, correct response negativity, and theta oscillations are thought by many to also constrain ERN theorizing. We attempt to characterize the past highlights and current trajectory of theorizing, computational modeling, and empirical research. We consider how the way in which ERN research is conducted affects its success, and we discuss some promising trends for the future. Although two decades have resulted in impressive theories and data, the ERN community awaits breakthrough developments by new investigators.
