“知道自己知道”与“知道自己不知道”——一项有关知道感（FOK）的脑成像研究

采用事件相关功能性磁共振成像技术（event-related fMRI）以及在FOK（feeling-of-knowing）研究中常用的“线索回忆-FOK判断-再认测验”（Recall-Judgment-Recognition，RJR）程序，以汉字词对为识记材料，研究了FOK判断中的大脑活动区域。根据FOK判断的正负以及其后的再认测验的对错，实验将FOK判断的项目分为四类：PP项目（正性FOK判断，正确再认），NN（负性FOK判断，错误再认），NP（负性FOK判断，正确再认）以及PN（正性FOK判断，错误再认）。脑成像的分析结果显示：准确的FOK预测（即PP与NN项目）与不准确的FOK预测（即NP与NP项目）在脑活动上没有显著的差异。而进一步分析表明，这种“无差异”的现象可能是由于PP项目与NN项目激活了不同的脑活动模式所造成的。具体地讲，相对于NN项目而言，PP项目伴随有明显的左侧前额叶（BA 8区）的活动。这一观察提示我们：知道感（PP）与不知道感（NN）可能是由不同的脑神经网络所支持、并通过不同的认知过程来实现的。

Knowing that You Know and Knowing that You don't Know:A Fmri Study on Feeling-of-Knowing(FOK)

Neural correlates of feeling-of-knowing (FOK) were investigated by event-related fMRI and unrelated word-pairs in a standard Recall-Judgment-Recognition (RJR) procedure. According to performance in post-scan criterion test, FOK trials were categorized as "PP" (positive-FOK, positive/"hits"-recognition), "NN" (negativeFOK, negative/" misses"-recognition), "NP" (negative-FOK, negative-recognition), and "PN" (positive-FOK,negative-recognition). Contrasts between accurate FOK predictions (PP, NN) and inaccurate ones (NP, PN) revealed no difference. Further analysis indicated PP and NN were different; combining them together might conceal differences. Specifically, PP was associated with left prefrontal activities in BA 8 or BA 47 relative to NN or NP respectively. This observation queried the conventional view that regarded PP and NN as the same kind of "accurate FOK predictions", and called for dissociations between feeling-of-knowing (PP) and feeling-of-not-knowing (NN).