Regression of Face-Gabor ssVEP differences on stimulus arousal, valence, and the interaction between arousal and valence. A follow-up on the trend-level interaction between arousal and valence demonstrated a significant positive relationship between arousal and ssVEP differences, but only among more negatively valenced stimuli (i.e. angry faces). This suggests that participants devote more attentional resources to highly arousing (task-irrelevant) stimuli when they are negative, but that arousal has no influence on attention when viewing neutral or positive task-irrelevant stimuli.