Although memory of episodic associations is generally considered to be recollective in nature, it has been suggested that when stimuli are experienced as a unit, familiarity-related processes might contribute to their subsequent associative recognition. Furthermore, intradomain associations are believed to be unitized more readily than interdomain associations. To assess these claims, we tested associative recognition following two types of pair associate learning. In the unimodal task, stimulus pairs were pictures of common objects, whereas in the cross-modal task, stimulus pairs consisted of an object picture and an unrelated environmental sound. At test, participants discriminated intact from recombined pairs while ERPs were recorded. In the unimodal task only, associative recognition was accompanied by a robust frontal deflection reminiscent of a component commonly interpreted as related to familiarity processes. In contrast, ERP correlates of associative recognition observed at more posterior sites, akin to a component that has been related to recollection, were apparent in both tasks. These findings indicate that retrieval of unimodal associations can be supported by familiarity-related processes that are dissociable from recollective processes required for the retrieval of cross-modal associations.

Failed knowledge recall attempts are sometimes accompanied by a strong feeling of imminent success, giving rise to a “tip-of-the-tongue” (TOT) experience. Similar to successful retrieval (i.e., the Know state, K), a TOT commences with strong cue familiarity but involves only partial retrieval of related information. We sought to characterize the cognitive processes and temporal dynamics of these retrieval states and to extend the applicability of previous findings about TOT to the auditory modality. Participants heard 3-sec initial segments of popular songs and were asked to recall their names. EEG was recorded while participants indicated their retrieval state via button press. Stimulus-locked analyses revealed a significant early left fronto-central difference between TOT and K, at 300–550 msec postcue onset. Post hoc analysis revealed that, in this time window, TOT also differed from DK (Don't Know) responses, which themselves were similar to the K responses. This finding indicates that neural processes, which may reflect strategy selection, ease of semantic processing, familiarity-related processes, or conflict monitoring, are indicative of the fate of our knowledge judgments long before we actually execute them.