Abstract:

Task-irrelevant negative emotional stimuli can divert attention away from the current task, thus resulting in lower performance on the current task. This attentional bias to task-irrelevant emotional stimuli was explained by the hypothesis in the aspects of the automatic processing of emotional information, the attentional biased competition, or the perceptual load. Despite increasing studies showed that attention could be caught by task-irrelevant representations maintained in working memory (i.e., memory-driven attentional capture), there have been few, if any, studies specifically examining attentional capture by representations of negative emotional stimuli in working memory. Such an issue is helpful for better understanding the mechanism of visual attentional capture of unwanted memory (such as intrusive memory), which has important clinical implications for individuals with traumatic experiences or emotional disorders.
In this study, a dual-task paradigm consisting of a working memory task and a visual search task was performed with emotional pictures as stimuli. Beyond the end-of-search manual reaction times, the first fixation proportion was used to investigate the effects of the representations of task-irrelevant negative emotional stimuli on attentional selection at the early stage of the visual search task. In Experiment 1, the effects of the valence (negative vs. neutral) of task-irrelevant emotional stimuli on attentional capture were investigated. In Experiment 2, neutral emotional stimuli were used as the target in order to eliminate the competitive priority for emotional targets over the distractors. In addition, such manipulation could get an opportunity to compare the difference in attentional capture induced by negative emotional distractors between perceptual level and working memory level.
The results showed that (1) negative emotional distractors elicit stronger attentional capture than neutral ones when no memory-matched distractor was included in the visual search display; (2) memory-matched distractors caught more attention than those that do not match the representations in working memory, indicating memory-driven attentional capture; (3) the memory-driven attentional capture was not affected by the emotional valence of representations in working memory; and (4) as indicated by the dwell time of the first fixation, after being caught by the memory-matched distractors, attention was accelerated to disengage from those distractors, so that the attentional capture effect indicated by the reaction time was suppressed (in Experiment 1) and even reversed (in Experiment 2).
It can be concluded that (1) in the early attentional selection stage, memory-driven attentional capture is not affected by the valence of task-irrelevant emotional stimuli in working memory; and (2) after the early attentional capture stage, cognitive control prompts attention to quickly disengage from the memory-matched distractors, and its effect is modulated by the emotional valence of the target.

Key words: cognitive control, emotional working memory, attentional capture effect, attentional suppression effect, eye tracking technique