EEG correlates of false information processing
Human memory is not a literal record of our experiences but a fallible and malleable cognitive process. Because of the reconstructive nature of memory, we are often prone to accept false events and recall them as truthful (Bartlett, 1932). One easy and reliable method to create and study false memories in the laboratory is the misinformation paradigm. In this paradigm participants are presented with a story (original information). After some time, parts of this story are presented again but now including some modifications (misinformation). Finally, the memory is measured for the original information, the misinformation, and, as control, some other incorrect information never presented before. The misinformation effect occurs when the percentage of misinformation accepted is higher than the acceptance of control incorrect information. This effect has been largely studied in relation to its applied relevance in eyewitness testimony research. Yet, the neural substrates and temporal dynamics of processing correct and false information remain scarcely studied. In this study the neural activity was recorded using EEG while participants performed a memory recognition test which comprised misinformation, true, and simply incorrect items. The only previous EEG study on neural correlates focused on misinformation pointed to the P3b and LPC (late positive component) ERPs components as the key to distinguishing between memories for correct and false memories. High P3b is linked with a strong match between the expectation and the stimuli presented. LPC is a late component around 400 to 800 ms after the stimulus presentation, associated with the recollection of accurate information.
Our results show that for the contrasts of misinformation accepted vs rejected, and false information accepted vs rejected (correct rejections), P3b was significantly more positive when the inaccurate information was accepted. These differences suggest a larger cognitive workload on accepting this type of information than when it is correctly rejected. Furthermore, in both contrasts we found differences in P600 which is linked to reprocessing of detected anomalies in the input. Here, we found a more expressed P600 for accepted than for rejected misinformation. P600 was also stronger for correct rejections than false alarms. In this latter case, the higher P600 amplitude may reflect the detection and reanalysis of the rejection of this false information. Interestingly, in the case of acceptance of misinformation, the higher P600 amplitude suggest that participants are not totally blind to the inaccuracy of the misinformation, though still they accept it.
The work was supported by the Russian Science Foundation (project №19-18-00534).