Individual differences in ERPs during deception: Observing vs. demonstrating behavior leading to a small social conflict.

The present study investigated individual differences modulating P300 and MFN amplitudes in a concealed information test (CIT). Some participants were offered candy and either denied (n = 41) or ate it (n = 31), while others witnessed an examiner eating it (informed condition; n = 34). Afterwards it was suggested that the candy was not meant for them. During the CIT, participants saw the candy (probe) and similar unknown items (irrelevants) and indicated that they did not know them. P300 and MFN amplitudes differed for probe and irrelevant items, revealing that known items were more salient and deception was accompanied by response conflicts. Larger differences between P300s for probe versus irrelevant items occurred for women. Furthermore, especially for women, response conflicts diminished when being in the informed condition. Different patterns of MFN amplitudes appeared for informed women depending on the Machiavellianism score, suggesting that gender and Machiavellianism could be related to different cognitive processing during deception.