Reliability of the N2-component in a modified 3-stimulus concealed information test: On the importance of excellent measurement accuracy.

Research on deception focused on the investigation of event-related potentials (ERP) to facilitate our knowledge on cognitive-motivational processes underlying deception. We investigated the reliability of the frontal N2 amplitude in a modified Concealed Information Test (CIT) (N = 64 participants). Variations of Cronbach's Alpha coefficients were examined for number of epochs per stimulus type, task modality and types of ERP quantification. Cronbach's Alpha coefficients of the N2 increased with the number of epochs across task modality, stimulus types and electrode positions. In a pictorial CIT, the frontal N2 indicated excellent Cronbach's Alpha coefficients (≥ 0.90) across electrode positions and quantification methods for 25 epochs per stimulus type. At least 15 epochs were necessary to achieve excellent Cronbach's Alpha coefficients (≥ 0.90) of the peak-to-peak N2 in a modified CIT across electrode positions and stimulus types. We provide best-practice advises for the necessity to assess N2 in a modified CIT with excellent reliability.