Two dissociable aspects of feeling-of-knowing: knowing that you know and knowing that you do not know.

Feeling-of-knowing judgement is traditionally regarded as a unitary cognitive process. However, recent research suggests that knowing that you know (positive feeling-of-knowing) and knowing that you do not know (negative feeling-of-knowing) have different neural substrates (Luo, Niki, Ying, & Luo, 2004). In the present study, we used a paradigm adapted from Koriat and Levy-Sadot (2001) to examine whether positive feeling-of-knowing and negative feeling-of-knowing were mediated by distinct cognitive processes. We found that positive and negative feeling-of-knowing were dissociated during immediate feeling-of-knowing judgements (i.e., preliminary feeling-of-knowing) and delayed feeling-of-knowing judgements (i.e., postretrieval feeling-of-knowing). At the judgement intervals, positive feeling-of-knowing was based on partial recovery of the nonrecalled targets, whereas negative feeling-of-knowing was determined by familiarity with the retrieval cues. Our results suggest that feeling-of-knowing is a heterogeneous process.