High negative valence does not protect emotional event-related potentials from spatial inattention and perceptual load

Previous research suggests that intense, emotional pictures at fixation elicit an early posterior negativity (EPN) and a late
positive potential (LPP) despite manipulations of spatial inattention and perceptual load. However, if high emotional intensity
protects against such manipulations, then these manipulations should reduce emotional effects on EPN and LPP more strongly
for medium than for intense emotional pictures. To test this prediction, pictures that were high negative, medium negative,
or neutral were shown at fixation, and a small letter string was superimposed on the picture center. When participants attended
the pictures, there were clear emotional effects on EPN and LPP. When participants attended the letter string, the emotional
effects on LPP decreased; this decrease was smaller for medium than for high negative pictures. Thus, opposite of predictions,
spatial inattention reduced the emotional effects more strongly for high than for medium negative pictures. As a manipulation
of perceptual load, participants performed the letter task with one, three, or six relevant letters. Irrespective of load,
EPN and LPP were similar for high and medium negative pictures. Our findings suggest that high negative valence does not protect
EPN and LPP more strongly from effects of spatial inattention and perceptual load than does medium negative valence.