Studies of information processing biases in social anxiety suggest abnormal processing of negative and positive social stimuli. It is unclear, however, if and how these biases manifest together during the processing of motivationally relevant information. The current study employed event related brain potentials (ERPs) to investigate the nature and time course of these potentially dynamic biases. High and low socially anxious individuals performed a modified version of the flanker task comprised of negative and positive facial expressions. Results revealed vacillations between a lack of positive bias and the presence of a negative bias beginning during early stimulus processing and continuing through early response monitoring stages in socially anxious participants. These results begin to shed light on how and when different information processing biases emerge and interact in social anxiety.