We investigated the electrophysiological correlates of proactive interference and similarity-based interference in visual working memory for gratings and faces. Using a multivariate approach we assessed the joint effects of reaction time and interference on oscillatory power. These analyses revealed significant and distinct electrophysiological correlates of proactive interference and similarity-based interference. For faces, trials with high proactive interference yielded increased occipital gamma oscillations. Gratings did not exhibit behavioral or electrophysiological proactive interference effects, but an electrophysiological correlate of lag instead. Trials with high similarity-based interference yielded decreased low frequency (2-8 Hz) oscillations for both stimulus types. The marked differences in the electrophysiological correlates of the two types of interference, even when controlling for accuracy and RT differences, lends support to theories that posit separate informational dimensions for temporal and similarity based information (e.g., Brown, Neath, and Chater (in preparation)). |