Abstract
Errors in choice tasks are preceded by gradual changes in brain activity presumably related to fluctuations in cognitive control that promote the occurrence of errors. In the present paper, we use connectionist modeling to explore the hypothesis that these fluctuations reflect (mal-)adaptive adjustments of cognitive control. We considered ERP data from a study in which the probability of conflict in an Eriksen-flanker task was manipulated in sub-blocks of trials. Errors in these data were preceded by a gradual decline of N2 amplitude. After fitting a connectionist model of conflict adaptation to the data, we analyzed simulated N2 amplitude, simulated response times (RTs), and stimulus history preceding errors in the model, and found that the model produced the same pattern as obtained in the empirical data. Moreover, this pattern is not found in alternative models in which cognitive control varies randomly or in an oscillating manner. Our simulations suggest that the decline of N2 amplitude preceding errors reflects an increasing adaptation of cognitive control to specific task demands, which leads to an error when these task demands change. Taken together, these results provide evidence that error-preceding brain activity can reflect adaptive adjustments rather than unsystematic fluctuations of cognitive control, and therefore, that these errors are actually a consequence of the adaptiveness of human cognition.
Highlights
Human performance is error-prone even when simple tasks are considered
The N2 amplitude is typically larger for incompatible trials than for compatible trials—an effect presumably generated by increased activity in the anterior midcingulate cortex or rostral cingulate zone (RCZ), respectively, in the medial frontal cortex (Ridderinkhof et al, 2004; Huster et al, 2011)
In the present study, we investigated the hypothesis that the decline of N2 amplitude preceding errors reflects adaptive adjustments of cognitive control and, that it is the adaptivity of cognitive control that promotes the occurrence of errors in this type of task
Summary
Human performance is error-prone even when simple tasks are considered. This has typically been attributed to attentional lapses or control failures due to spontaneous fluctuations in attention and cognitive control (e.g., Weissman et al, 2006). In a recent study (Eichele et al, 2010), we examined eventrelated potentials (ERPs) preceding errors in the Eriksen-flanker task (Eriksen and Eriksen, 1974) In this task, participants have to categorize a target while ignoring simultaneously presented flankers that are associated with either the correct response (compatible trials) or an incorrect response (incompatible trials). Whereas high response conflict leads to higher levels of cognitive control, low response conflict leads to lower levels of cognitive control on the subsequent trial Evidence for this account has been provided by studies demonstrating a negative correlation between the amount of response conflict on the previous trial and the compatibility effect on the current trial in behavioral measures (e.g., Gratton et al, 1992; Ullsperger et al, 2005) and the N2 amplitude (e.g., Forster et al, 2011). This view implies that errors preceded by a decline of N2 amplitude are errors due to maladaptation of cognitive control and that this maladaptation is reflected by the time course of the N2 amplitude (and of response conflict) across trials
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