Reciprocal competition between cognitive tasks and emotional processing revealed by EEG and eye tracking

Processing of engaging stimuli triggers increases in visual exploration, enhances the centroparietal late positive potential (LPP) and produce larger posterior alpha desynchronization (a-ERD), suggesting orienting and attention allocation. It has been shown that a salient arousing image in the background of a cognitive task consumes processing resources from the superimposed task, producing a deleterious effect on performance. On the other hand, experiments designed to change the focus of attention during the processing of emotional stimuli have shown a reduction of the emotional response, indicating an attentional competition between significant stimuli simultaneously presented. This research aimed to describe the competition between the performance on a cognitive task presented in a reduced space of the image (1.2 %) and the processing of emotional images displayed at the background using EEG and Eye Tracking. Results showed that the superimposition of the task had an early attractor effect, evidenced by an above-chance decoding accuracy (about 180 ms since the image onset) and an enhancement in the N1 component. This engagement in the task reduced the processing of the images as evidenced by a decrease in the LPP amplitudes, an enhancement in the a-ERD and a greater dwell-time over the task. Additional analysis showed that the unpleasant pictures were visually explored and emotionally processed after participants responded to the task. In conclusion, the present study supports the competition model of selective attention, highlighting the dominance of top-down control in shaping perceptual and cognitive processing.