Can we shield ourselves from task disturbance by emotion-laden stimulation?

Contextual Modulation of Emotional Distraction: Attentional Capture and Motivational Significance

Emotional stimuli engage corticolimbic circuits and capture attention even when they are task-irrelevant distractors. Whether top–down or contextual factors can modulate the filtering of emotional distractors is a matter of debate. Recent studies have indicated that behavioral interference by emotional distractors habituates rapidly when the same stimuli are repeated across trials. However, little is known as to whether we can attenuate the impact of novel (never repeated) emotional distractors when they occur frequently. In two experiments, we investigated the effects of distractor frequency on the processing of task-irrelevant novel pictures, as reflected in both behavioral interference and neural activity, while participants were engaged in an orientation discrimination task. Experiment 1 showed that, compared with a rare distractor condition (20%), frequent distractors (80%) reduced the interference of emotional stimuli. Moreover, Experiment 2 provided evidence that emotional interference was reduced by distractor frequency even when rare, and unexpected, emotional distractors appeared among frequent neutral distractors. On the other hand, in both experiments, the late positive potential amplitude was enhanced for emotional, compared with neutral, pictures, and this emotional modulation was not reduced when distractors were frequently presented. Altogether, these findings suggest that the high occurrence of task-irrelevant stimuli does not proactively prevent the processing of emotional distractors. Even when attention allocation to novel emotional stimuli is reduced, evaluative processes and the engagement of motivational systems are needed to support the monitoring of the environment for significant events.

The Emotional Stroop Effect Is Modulated by the Biological Salience and Motivational Intensity Inherent in Stimuli

Prior research has found significant emotional Stroop effects for negative stimuli, but the results have been inconsistent for positive stimuli. Combining an evolutionary perspective of emotion with the motivational dimensional model of affect, we speculated that the emotional Stroop effect of a stimulus may be influenced by the biological salience and inherent motivational intensity of the stimulus. In the present study, we examined this issue with two experiments. The results indicated that both low- and high-withdrawal-motivation negative stimuli produced a robust emotional Stroop effect; however, the high-withdrawal-motivation negative stimuli produced a stronger emotional Stroop effect than the low-withdrawal-motivation negative stimuli. Regarding positive stimuli, only the high-approach-motivated positive stimuli produced the emotional Stroop effect, unlike the low-approach-motivation positive stimuli. These findings suggest that the emotional Stroop effect is modulated by the biological salience of stimuli and by the motivational intensity inherent in the stimuli. Biological salience and motivational intensity play an additive effect in the emotional Stroop effect.

Proactive control of affective distraction: Experience-based but not expectancy-based

Unpleasant stimuli disrupt ongoing information processing, even when they are entirely task-irrelevant. We examined whether such affective disturbances can be controlled explicitly and proactively. Specifically, we studied two different mechanisms to induce proactive control: the experience of frequent affective distraction and cueing of upcoming affective distraction. We predicted that both mechanisms would shield the attentional system from affective disturbance. Participants solved a letter classification task while being exposed to neutral or negative distractor pictures. We varied whether the proportion of negative distractors was low or high and whether cues for the upcoming type of distractor valence were informative or uninformative. In three experiments (N = 114), we found support for the notion that experience-based control shields information processing from affective disturbances, whereas distractor valence expectations were not helpful. These data suggest that there is no explicit top-down influence on attentional control settings of affective distraction, just adjustments to the context.

Affective distraction along the flexibility-stability continuum

This study explored whether conditions that promote flexibility in task processing enhance the detrimental impact of irrelevant negative stimulation on performance. We approached this flexibility from a transient and a sustained perspective, by manipulating whether participants repeated or switched between two tasks in consecutive trials and whether they performed the tasks in separate blocks or randomly mixed. Participants categorised either a letter or the colour of a bar, which were presented close to an irrelevant negative or neutral picture. Performance was worse in the presence of negative rather than neutral pictures. Repeating or switching tasks transiently did not modulate this detrimental impact of affective distraction in three experiments (n_Exp1 = 32, n_Exp2 = 32, n_Exp3 = 64). Attentional capture by negative content did decline in single compared to mixed task contexts, but only when these sustained task contexts also differed in the frequency of affective stimulation. When affective stimulation was the same in mixed and single task contexts, this modulation vanished. Overall, these results suggest that the influence of task-irrelevant negative stimulation on performance is surprisingly independent of cognitive states that favour either flexible or stable processing of task-relevant information.

The locus of the emotional Stroop effect: a study with the PRP paradigm

Stimuli that are clearly positive or negative (hence valence-laden stimuli) have the potential to interrupt unrelated task processing. A typical example is the emotional Stroop effect (ESE) in which responding to a certain task feature (e.g., color) is delayed by the presentation of task-irrelevant valent stimuli (e.g., negative pictures) compared to valence-neutral stimuli. Here we scrutinize which processes are slowed down by irrelevant but valent stimulation. In Experiment 1, participants performed in a Psychological Refractory Period (PRP) experiment with tone discrimination as Task 1 and color discrimination as Task 2. Importantly, colors in Task 2 were accompanied by valent or neutral pictures. Valent pictures delayed responding in Task 2 (thus an ESE) and this delay was additive to the time interval between tasks. In Experiment 2, task order was reversed and the ESE in Task 1 fully propagated to the Task 2 tone discrimination. These results imply that irrelevant valence-laden stimulation delays capacity-limited processes, and we suggest that this is a late perceptual process acting on stimulus categorization.