Reward Associations Reduce Behavioral Interference by Changing the Temporal Dynamics of Conflict Processing

Abstract

Associating stimuli with the prospect of reward typically facilitates responses to those stimuli due to an enhancement of attentional and cognitive-control processes. Such reward-induced facilitation might be especially helpful when cognitive-control mechanisms are challenged, as when one must overcome interference from irrelevant inputs. Here, we investigated the neural dynamics of reward effects in a color-naming Stroop task by employing event-related potentials (ERPs). We found that behavioral facilitation in potential-reward trials, as compared to no-reward trials, was paralleled by early ERP modulations likely indexing increased attention to the reward-predictive stimulus. Moreover, reward changed the temporal dynamics of conflict-related ERP components, which may be a consequence of an early access to the various stimulus features and their relationships. Finally, although word meanings referring to potential-reward colors were always task-irrelevant, they caused greater interference compared to words referring to no-reward colors, an effect that was accompanied by a relatively early fronto-central ERP modulation. This latter observation suggests that task-irrelevant reward information can undermine goal-directed behavior at an early processing stage, presumably reflecting priming of a goal-incompatible response. Yet, these detrimental effects of incongruent reward-related words were absent in potential-reward trials, apparently due to the prioritized processing of task-relevant reward information. Taken together, the present data demonstrate that reward associations can influence conflict processing by changing the temporal dynamics of stimulus processing and subsequent cognitive-control mechanisms.

The influence of monetary incentives on context processing in younger and older adults: an event-related potential study

“…Thus, the neural activity required for the successful preparation (here, encoding) of an upcoming event seems to be enhanced by the motivation to gain reward. This modulation of the P3b by reward expectancy is in line with results from other studies showing larger P3b amplitudes for reward trials than for trials without reward (Begleiter, Chou, & Aunon, 1983;Krebs et al, 2013;Parvaz, Konova, Tomasi, Volkow, & Goldstein, 2012), as well as for high-as compared to lowreward conditions (Capa, Bouquet, Dreher, & Dufur, 2013;Goldstein et al, 2006). Recently, Krebs and colleagues applied a Stroop task and found increased P3b amplitudes to reward-predicting cues, which were interpreted as increased preparatory attention toward critical features of the upcoming Stroop stimulus that were essential to obtain later reward.…”

“…In line with the literature, larger P2 amplitudes to gain and loss cues have been linked to automatic attention capture by salient information (Carretié et al, 2004; for a review, see Olofsson et al, 2008), whereas larger P3b amplitudes to salient cues might indicate strategic processes of updating task-relevant stimulus information and the amount of attentional resources available for stimulus processing (Briggs & Martin, 2009;Donchin & Coles, 1988;Krebs et al, 2013;Olofsson et al, 2008;Polich, 2007). In the present study, the updating of task-relevant information provided by motivationally salient cues may have been useful for the gating of the following context information (Braver & Barch, 2002;Gruber & Otten, 2010).…”

“…Furthermore, in a task-switching paradigm, larger P3b amplitudes during response execution on reward trials were associated with a greater investment in WM benefiting fast reaction times (Capa et al, 2013). In addition, the CNV has also been shown to be linked to reward expectancy, since trials indicating reward for fast and correct responses produced larger CNV amplitudes (Capa et al, 2013;Falkenstein, Hoormann, Hohnsbein, & Kleinsorge, 2003; but see Goldstein et al, 2006 Krebs et al, 2013; or the sustained potential [SP] by West & Alain, 2000;West et al, 2005), in that they peaked earlier during trials with than in those without reward, where no amplitude differences were reported. This temporal shift has been interpreted as an earlier start of conflict processing, which was triggered by enhanced attention toward relevant features of the Stroop stimulus, linked to the preceding P3b in Krebs et al's study.…”

“…Yet the precise mechanisms underlying this benefit and the control processes affected by motivational salience remain unclear. ERPs can help to determine whether the influence of reward and penalty on cognitive control is associated with processes of context updating, task reconfiguration, or maintenance, linked to proactive control (Lenartowicz et al, 2010;, or to processes of conflict detection and response selection, linked to reactive control (Krebs, Boehler, Appelbaum, & Woldorff, 2013;Schmitt, Wolff, et al, 2014;West & Alain, 2000;West et al, 2005), or to both.…”

“…The selections of the time interval and the electrodes for statistical analyses of the EEG components were based on the literature and on visual inspection (Karayanidis, Coltheart, Michie, & Murphy, 2003;Krebs et al, 2013;Liotti et al, 2000;West et al, 2005). In the motivational cue interval, we analyzed P2 and P3b amplitudes at three midline electrodes over frontal (Fz), central (Cz), and parietal (Pz) areas.…”