Tip-of-the-tongue experiences are not merely

Often when one answers a question, one feels or has a sense that one knows the answer, but it is not forthcoming. Examples of such instances are feeling-of-knowing (FOK) and tip-of-the-tongue (TOT) experiences. It is often assumed that TOT experiences are merely strong FOK experiences. In the present study, the authors examined this hypothesis. They observed that participants with deficient prefrontal cortex (PFC) functioning reported fewer and less accurate FOKs than did participants with intact PFC functioning (Experiment 1). In contrast, the authors observed no contribution of PFC functioning in the reporting of TOT experiences (Experiment 2). That is, the level of PFC functioning did not have an impact on the frequency or accuracy of TOT reports. These data support the assertion that TOTs are not merely strong FOKs but that the two experiences are qualitatively different phenomena.