The P300 brain signal can verify a user selection in a Brain Computer Interface (BCI). Its presence indicates the selection was what the user wanted, and its absence indicates a selection error that can be automatically undone. Automatic recovery increases information transfer rate as the user does not need to select undo, and then reattempt the selection. This technique was used in responses to controlled goal items in an evoked potential BCI used to control a virtual apartment.
Bayliss, J. D., Inverso, S. A., and Tentler, A., “Changing the P300 Brain-Computer Interface.” Journal of CyberPsychology & Behavior 7.6:694-704, 2004.
Inverso, S. A. “Automatic Error Recovery Using P3 Response Verification for a Brain Computer Interface.” Rochester Institute of Technology, Rochester, NY, USA (2004).