Feigning memory impairment in a forced-choice task: Evidence from event-related potentials

Strategies of malingering detection have brought about a wealth of neuropsychological studies in the last decades. However, the investigation of physiological measures to reliably differentiate between authentic and manipulated symptom presentations is still in its infancy. The present study examined event-related potentials (ERP) to identify feigned memory impairment. We tested instructed malingerers (n = 25) and control participants (n = 22) with a recognition task similar to the Test of Memory Malingering. No differences between groups were found for P1 (70-110 ms) but for N1 (120-170 ms) and P300 components, with lower amplitudes for instructed malingerers. Behavioral data showed a typical pattern of unrealistically high errors in a forced-choice recognition task and less overall recalled stimuli in instructed malingerers. We also found study-phase repetition and old/new effects in the P300, but no interactions with groups (control vs. malingering). Post-hoc analyses revealed that the P300 effect is greater when participants reported an attention-based faking strategy, as opposed to response-based malingerers and controls. The employment of physiological measures can yield additional information on the validity of test data without the need to perform additional tests.

Eye tracking as a mean to detect feigned cognitive impairment in the word memory test

Eye movements showed initial promise for the detection of deception and may be harder to consciously manipulate than conventional accuracy measures. Therefore, we integrated an eye-tracker with the Word Memory Test (WMT) and tested its usefulness for the detection of feigned cognitive impairment. As part of the study, simulators (n = 44) and honest controls (n = 41) performed WMT's immediate-recognition (IR) subtest while their eye movements were recorded. In comparison to the control group, simulators spent less time gazing at relevant stimuli, spent more time gazing at irrelevant stimuli, and had a lower saccade rate. Group classification using a scale that combined the eye movement measures and the WMT's accuracy measure showed tentative promise (i.e., it enhanced classification compared to the use of the accuracy measure as the sole predictor of group membership). Overall, integration of an eye-tracker with the WMT was found to be feasible and the eye movement measures showed initial promise for the detection of feigned cognitive impairment. Moreover, eye movement measures proved useful in enhancing our understanding of strategies utilized by the simulators and the cognitive processes that affect their behavior. While the findings are clearly preliminary, we hope that they will encourage further research of these promising psychophysiological measures.