Abstract: Recent neuroimaging studies implied that feeling-of-knowing (FOK) and feeling-of-not-knowing (FOnK) might be subserved by different cognitive and neural processes (Chinese Science Bulletin 2002, 47：1876-9；Progress in Natural Science 2003, 13: 263-8；Acta Psychologica Sinica 2004, 36: 426-33). Although this hypothesis challenged the traditional view that regarded FOK as a continuum, the neuroimaging study cannot provide causal inference given this kind of study is correlation in nature. In this behavioural study, we examined the effects of level-of-processing (LOP) on FOK and FOnK respectively. Our results showed deep LOP promoted the prediction accuracy of FOK but not that of FOnK, in fact, deep LOP deteriorated the accuracy of FOnK. This result was obtained in both of the within-subject design and the between-subject design; it was also tenable when we excluded the recognition that was realized through familiarity heuristic.

Key words: feeling-of-knowing (FOK), feeling-of-not-knowing (FOnK), level-of-processing (LOP)