Do not neglect small troubles: moderately negative stimuli affect target processing more intensely than highly negative stimuli.

Though the humans are more susceptible to unpleasant stimuli of higher intensity, how the valence intensity of unpleasant stimuli impacts subsequent cognitive processing, and whether this impact increases with the unpleasantness, require clarification. For this purpose, event-related potentials (ERPs) were recorded for highly negative (HN), mildly negative (MN) and neutral cueing pictures, and subsequently for the non-emotional target picture while subjects were required to discriminate the location of the target. Cue-induced ERPs showed more negative deflections for the HN than for the neutral pictures in the 450-650 ms time interval. The emotion effect for the MN cueing stimuli, however, was non-significant in this interval. In contrast, target-induced P3 amplitudes were significantly more negative following MN versus neutral cueing pictures, while the P3 amplitudes were not significantly different between HN and neutral conditions, irrespective of cueing validity. Thus, despite weak immediate impact, MN stimuli influenced subsequent target processing more heavily than HN stimuli. This suggests that the impact of unpleasant events on cognition doesn't necessarily increase with the unpleasantness. Mild unpleasant stimulus, which is weak in immediate emotion arousal, should not be neglected due to the likelihood of producing a sustained impact.