The effect of intention to learn novel, environmental sounds on the novelty P3 and old/new recognition memory

Brain electrical activity was recorded while 32 young adults listened to frequent tones, infrequent target tones, and infrequent novel environmental sounds (some of which repeated). Subjects in the incidental group were not informed about the novel sounds, while subjects in the intentional group were informed and, in addition, were asked to memorize them for a subsequent memory test. Following the novelty oddball task, all subjects were given an old/new sound recognition memory task. The novelty P3 showed a more anterior scalp distribution and an effect of repetition in the incidental compared to the intentional group, suggesting that pre-categorizing the novel sounds influenced how they were processed. For the intentional group only, a subsequent memory effect was elicited by novel sounds that were subsequently recognized compared to those that were not, although both groups showed robust old/new ERP effects during the recognition task. The robust subsequent memory effects in the intentional group were associated with greater recognition accuracy of familiar environmental sounds relative to the incidental group. These data suggest that the encoding activity reflected in the ERP subsequent memory effect may have engendered an advantage in subsequent recognition memory performance.