Studies Included in the Analysis
For the purpose of the planned analyses, and to minimize potential confound effects, all the data used in the main analyses were recorded in the Rosenfeld Lab, with the same hardware and with the same version of P300-CIT – the Complex Trial Protocol, which is the most modern and countermeasure-resistant version of the P300-based CIT (Rosenfeld et.al., 2004; Rosenfeld et. al. 2008). Since 2008, many studies have demonstrated high sensitivity and specificity in the CTP (over 90% for autobiographical information and over 80% for incidentally acquired information; with the AUC typically over .9) (see Rosenfeld et.al, 2013 for review).
In the Complex Trial Protocol (CTP), contrary to the traditional three-stimulus protocol, the probe, irrelevant and target are separated into two parts (Rosenfeld, et.al., 2008). In the first phase, probes and irrelevants are presented and the participants are asked to make a button response to indicate that they saw the stimulus (same button for both stimuli). In the second phase, targets and non-targets are presented during which the participants are instructed to respond differently to targets compared to non-targets. These targets and non-targets are usually a series of digits that are not relevant to the first phase (e.g., “11111” is the target, and “22222”, “33333”, “44444”,”55555”, “66666” are non-targets), such that more cognitive resources can be dedicated to phase 1, where the diagnostic analysis takes place. This protocol is to be used as an example throughout the paper. So, data collected from the CTP can further be analyzed through statistical tools like Bootstrapping to make classification results more accurate and effective.
Critically, we reanalyzed the data from Rosenfeld et al. (2017b) using our rBS technique, specifically regarding the following two studies:
1) Rosenfeld, et.al (2017a) (Experiment 2 - n=52 guilty participants with semantic stimuli) – this study explored the possibility of a memory suppression effect on P300 amplitude while using the Complex Trail Protocol with semantic stimuli. No differences in amplitude or latency were found between suppression versus non-suppression groups, so all participants were pooled in Rosenfeld et al. (2017b). Consequently, we also merged suppression and non-suppression groups in the current analysis. 2) Ward, Rosenfeld (2017) (n=29 guilty participants with episodic stimuli) – this experiment also verified the memory suppression effect on P300 amplitude in the CTP, however with episodic memory. Since there were no differences in P300 amplitude or latency between experimental groups, data were pooled in Rosenfeld et al. (2017b) and also in the current analysis.
Please refer to Rosenfeld et al., (2017a) and Ward & Rosenfeld (2017) for details on participant recruitment and EEG/ERP data processing methods.