Metacognition and false recognition in patients with frontal lobe lesions: the distinctiveness heuristic.

The distinctiveness heuristic is a response mode in which participants expect to remember vivid details of an experience and make recognition decisions based on this metacognitive expectation. Whereas much is known about the cognitive processes that are involved in using the distinctiveness heuristic, little is known about the corresponding brain processes. Because such metacognitive processes that involve the evaluation and control of one's memory are believed to be dependent upon the frontal lobes, the authors examined whether the distinctiveness heuristic could be engaged to reduce false recognition in a repetition lag paradigm in patients with lesions of their frontal lobes. Half of the participants studied pictures and corresponding auditory words; the other half studied visual and auditory words. Studied and novel items were presented at test as words only, with all novel items repeating after varying lags. Controls who studied pictures were able to reduce their false recognition of repeated lag items relative to those controls who studied words, demonstrating their use of the distinctiveness heuristic. Patients with frontal lobe lesions showed similar levels of false recognition regardless of whether they studied pictures and words or words only, suggesting that they were unable to use the distinctiveness heuristic. The authors suggest that the distinctiveness heuristic is a metacognitive strategy, dependent upon the frontal lobes, that may be engaged by healthy individuals to reduce their false recognition.