Post-Error Slowing May Not Be Proactive: Electrophysiological evidence favours a disorienting account

Abstract

The slowing down of a response after committing an error in speeded response tasks has been reliably observed over the last 60 years, but no explanation has yet been articulated to account for it. Post-error slowing (PES) is thought to reflect a proactive mechanism to improve one’s chances of successfully inhibiting a response or selecting the correct response from an array of possibilities. Recently, Dutilh and colleagues (2012a) used computational modelling to compare how well several accounts of PES fit real and simulated data. They concluded that PES is the result of participants widening their response boundaries, which they assumed corresponds to increased caution. This explanation supports a proactive account of PES. We used EEG to test the same four accounts modelled by Dutilh and colleagues to provide direct neural evidence to supplement their simulated data. In a Go/NoGo task administered to N = 100 healthy young adults (24.3 ± 4.8 yrs), we mapped ERP parameters to the theoretical drift parameters established by Dutilh and colleagues. Their hypothesis would predict larger N2 after errors and that the amplitude of the N2 should correlate with magnitude of PES. Our results did not support these predictions (N2 amplitude was smaller after errors, p = .015, and there was no correlation between N2 amplitude and PES, p = .523). Our findings support another common account of PES, a disorienting account, that supposes errors disrupt attentional processing. The post-error anterior N1 was significantly disrupted by errors (p = .020) and was correlated with the magnitude of PES (p = .016). We, therefore, suggest that PES is not completely proactive, but rather is partially the consequence of disruptions to attentional processing that only incidentally improve response inhibition by offsetting the initiation of response execution. Interestingly, the post-error N1 in older adults was diminished (p = .0008), but higher general intelligence rescued such disruptions to attention (p < .0001), indicating a partial compensatory mechanism in ageing that is supported by general intelligence.