4.1 Conflict-monitoring N200
Although some studies have found a more negative N200 for the probe
compared to the irrelevant stimuli, some studies have reported null or
opposite results (Gamer and Berti, 2010, 2012, Ganis et al., 2016,also
see a review Sai et al. 2023). One possible reason for this discrepancy
maybe due to N200 overlapping with neighboring components such as P200
and P300. In our current study, we used PCA to separate the N200 from
other components and found that the probe indeed elicited a more
negative N200 than the irrelevants in guilty group. This may be because
guilty participants need to conceal their knowledge about the probe
stimuli, which required more control monitoring compared to
truth-telling about irrelevant stimuli. However, caution is advised when
utilizing the N200 as an indicator to detect concealed information, as
highlighted by Ganis et al. (2016). Their research suggests that the
N200 elicited by probes larger than irrelevant stimuli might be
attributed to differences in the stimuli, potentially leading to the
absence of the CIT effect under controlled conditions (Gamer and Berti,
2010, Ganis et al., 2016). It’s worth noting that our experiment
differed from theirs, as our stimuli exclusively consisted of
traditional Chinese names with two or three words, ensuring uniformity
in the stimulus presentation. In contrast to their study, where N200
yielded null results, our findings demonstrated a significant CIT effect
for N200. This discrepancy might be attributed to our utilization of
PCA, which effectively isolated the genuine N200 response from other
components, such as P200 and P300, (Daffner et al., 2015; Kayser et al.,
1998). Additionally, it should be noted that the stimuli used in this
study were autobiographical information, further studies should use the
PCA method to examine whether the effect of N200 can also be found in
mock-crime situations.