The contribution of stimulus frequency and attention to the N2 and P3 in Go/Nogo: A multilab replication and new analyses

Numerous EEG studies have found that stimuli that require withholding a response (Nogo stimuli) elicit two scalp-recorded event-related potentials (ERPs), the frontal N2 and the frontocentral P3, that are larger than for stimuli that require a response (Go stimuli). The functional significance of these ERPs is not entirely clear, with some accounts focusing on inhibitory processes, and others focusing on a conflict monitoring explanation. Our understanding of the role of these components is further complicated by the presence of potential confounds in traditional Go/Nogo tasks. One important confound present in many studies is the lower frequency of Nogo stimuli relative to Go stimuli. Since the N2 and P3 are generally modulated by stimulus frequency and novelty, the Nogo enhancement could reflect an automatic mismatch process elicited by infrequent Nogo stimuli. A seminal study by Eimer (1993) involved matching the probability of Go/Nogo stimuli to test the contribution of stimulus frequency and manipulating spatial attention to test the explanation that an automatic stimulus mismatch process could be driving these differences. Such an explanation for the frontal N2 predicts that there should be no modulation of frontal N2 Go/Nogo effects by spatial attention. Results showed a larger N2 and P3 for Nogo than Go stimuli, indicating that stimulus frequency is not the determinant factor for these effects. Furthermore, N2 and P3 Go/Nogo effects were modulated by the attentional cue, suggesting that they are not the result of an automatic mismatch process. Subsequent research has also shown larger N2 and P3 amplitudes for Nogo stimuli when Go and Nogo stimuli are equiprobable, but the results have not been entirely consistent because of variability in the paradigms used. The purpose of the present study is to directly replicate the original study by Eimer (1993) and to test the robustness of the results to variations in the analysis pipelines. As part of the #EEGManyLabs project, 5 labs will independently replicate the original study, resulting in a multisite replication with high statistical power. Individual replications will also be integrated via a meta-analysis. Together, these studies will provide important information about the replicability of classic EEG findings and advance our understanding of the role of the frontal N2 and frontocentral P3 during inhibition tasks.