Discrepancy between feedback negativity and subjective evaluation in gambling.

Feedback negativity is a negative event-related potential elicited by feedback indicating incorrect performance or monetary loss. It is unclear whether this negativity is elicited by neutral feedback (e.g. a draw in gambling) or is affected by the subjective rating of punishment. To investigate these issues, we performed a modified and computerized game of 'rock-paper-scissors' as a gambling task and measured feedback negativity in response to feedback indicating the outcome, which was accompanied by a monetary reward. The data demonstrated that feedback negativity was elicited not only by a monetary loss but also by an even outcome and was independent of the magnitude of monetary loss. Our results suggest feedback negativity is not always specific to both monetary loss and subjective rating of punishment.