I see people: The presence of human faces impacts the processing of complex emotional stimuli

Both emotional images and human faces are particularly salient compared to other categories of visual stimuli. The late positive potential (LPP) is larger for emotional than neutral images, and some evidence suggests that the LPP is further enhanced for images containing people. Studies of emotion frequently compare pleasant and unpleasant IAPS pictures to neutral, without an explicit understanding of how the presence of faces in these images may affect attentional allocation and psychophysiological response. The present experiment examined the effect of faces on the LPP elicited by neutral and threatening IAPS images. The LPP was enhanced by faces in neutral images, but no difference was observed between threatening images with and without faces. These results demonstrate that the inclusion of faces in IAPS images significantly impacts the LPP; however, this effect is unique to neutral images.