Electrophysiology of Non-Conscious Memory Contributions to Free Recall

SMSU Event Center BC

In traditional episodic memory paradigms, free recall tasks are widely used to investigate memory processes between explicit memory (i.e., declaratively recollecting information) and implicit memory (i.e., recognizing information based on familiarity). This approach for contrasting recollection to recognition has provided key insights into memory system dissociations in neuropsychological patients (e.g.: Yonelinas et al., 2002). However, recent research has yielded conflicting results. For instance, in a free recall task, individuals correctly recalled and recognized words that were studied beforehand (hits); while on other occasions individuals correctly recalled words, but, failed to recognize that these words were from a list studied beforehand (misses) (Ozubko et al., submitted). Thus, these recognition failures or “misses” represent a unique paradox in recall; were words recollected by their recall success or were words forgotten by their recognition – and what processes underlie this paradoxical combination of responses? The current study was designed to directly test these questions by simultaneously recording electrophysiological (EEG) signals from the scalp during memory judgements. In this novel and innovative cued semantic associated paradigm, we included a voice-key response device to time lock EEG signals during memory. In our task, participants studied a list of words during an encoding phase and were subsequently tested on a new list of semantically associated words intermixed with new words during the retrieval phase. This pilot study, identified key factors required for implementing this innovative approach in next-stage studies, currently being conducted. Furthermore, pilot data enabled us to form new hypotheses for EEG effects of explicit and implicit memory.