Hunting down the source: how amnesic patients avoid fluency-based memory errors

Objective: The primary aim of this study was to test whether differences in the ability of amnesic and healthy participants to detect alternative sources of fluency can account for differences observed in the use of fluency as a cue for memory.
Method: Patients with severe memory deficits and matched controls were presented with three forced-choice recognition tests. In each test, an external source of fluency was provided by manipulating the perceptual quality of the studied items during the test phase. The detectability of the perceptual manipulation varied in each test (i.e., a 10%, 20%, or 30% contrast reduction were given).
Results: The results indicated that all participants were able to rely on fluency when making recognition decisions as long as the perceptual manipulation remained unnoticed. Interestingly, our data also revealed that the level of contrast reduction at which the alternative source is detected differs between healthy controls and amnesic patients. Specifically, patients with amnesia appeared to disqualify fluency as a cue for memory even when the contrast reduction was moderate while healthy participants only disqualified fluency when the contrast reduction was clearly visible.
Conclusion: Overall, our results seem to suggest that the ability to use fluency is probably not impaired in amnesia but undergo metacognitive changes resulting in the implementation of explicit or implicit strategies aiming at tracking alternative sources in order to reduce memory errors.