Individual experiences often overlap in their content, presenting opportunities for rapid generalization across them. In this study, we show in 2 independent experiments that integrative encoding-the ability to form individual and across memory representations during online encoding-is supported by 2 distinct neurophysiological responses. Brain potential is increased gradually during encoding and fit to a trial level memory measure for individual episodes, whereas neural oscillations in the theta range (4-6 Hz) emerge later during learning and predict participants’ generalization performance in a subsequent test. These results suggest that integrative encoding requires the recruitment of 2 separate neuralmechanisms that, despite their co-occurrence in time, differ in their underlying neural dynamics, reflect different brain learning rates and are supportive of the formation of opposed memory representations, individual versus across-event episodes.