Danger and disease: electrocortical responses to threat- and disgust-eliciting images

Previous research suggests facilitated processing of evolutionarily significant stimuli (e.g., depictions of erotica, mutilation, threat), as reflected by augmented event-related potentials (ERPs), including the early posterior negativity (EPN) and late positive potential (LPP). Evolutionary models suggest that images that evoke disgust should be high in motivational salience, but evidence that the EPN and LPP are enhanced by disgusting images is lacking. Prior studies have employed only a small number of disgusting images that were limited in the types of content depicted. In the current study, participants viewed larger sets of disgusting, threatening, and neutral images with more varied content while electroencephalography (EEG) was recorded. Results showed that disgusting and threatening images elicited equivalent LPPs, which were both significantly increased relative to LPPs elicited by neutral images. EPN amplitudes were augmented for both disgusting and threatening relative to neutral images, though significantly more for disgust. These findings offer initial evidence that the EPN and the LPP are sensitive to disgust-eliciting pictures and that these pictures may receive processing that is at least on par with that of threatening images. Limitations of the current study and implications for future research are discussed.