Ewww–Investigating the neural basis of disgust in response to naturalistic and pictorial nauseating stimuli

Abstract

Emotion induction in psychological and neuroscientific research has been mostly done by presenting participants with picture or film material. However, it is debatable whether this passive approach to emotion induction results in an affective state comparable to real-life emotions, and if the neural correlates of emotion processing are ecologically valid. To investigate the appropriateness of pictures for the induction of emotions, we presented 56 participants in a within-subjects design with naturalistic disgusting and neutral stimuli as well as with pictures of said stimulus material while recording continuous EEG data. We calculated asymmetry indices (AIs) for alpha power as an index of emotion processing and emotion regulation at the F3/4, F5/6, F7/8, and O1/2 electrode pairs. Participants reported higher disgust ratings for disgusting naturalistic compared to disgusting pictorial stimuli. Investigating changes in the EEG signal in participants with a pronounced disgust response (n = 38), we found smaller AIs for naturalistic stimuli compared to pictures. Moreover, in this disgusted sub-sample, there were smaller AIs in response to naturalistic disgusting stimuli compared to pictorial disgusting and neutral stimuli at the O1/2 electrode pair indicating stronger activation of the right relative to the left hemisphere by naturalistic stimuli. As the right hemisphere has been shown to display dominance in processing negative and withdrawal-associated emotions, this might indicate that naturalistic stimuli are more appropriate for the induction of emotions than picture stimuli. To improve the validity of results from emotion induction, future research should incorporate stimulus material that is as naturalistic as possible.

Walk the plank! Using mobile electroencephalography to investigate emotional lateralization of immersive fear in virtual reality

“…These crucial components of emotion are neglected by studies focusing solely on emotion perception. Although a recent study on naturalistic disgust induction confirmed such notions, the presentation of pictures was still highly effective in inducing disgust, highlighting that pictures are still a valid option to induce emotions [ 24 ]. Since a more naturalistic setting was nonetheless more effective in this study, aiming for high ecological validity to study emotional processing is likely to be advantageous.…”

Proactive and Reactive Control in Emotional States: an Investigation of Fear using the AX-Continuous Performance Task in Virtual Reality

“…VR is an effective method to induce visceral and realistic emotion, as it affords the ability to induce the phenomenon known as presence, or the feeling of 'being' in the virtual scene (Diemer et al, 2015;Slater, 2009). Furthermore, unlike the passive viewing of emotional stimuli, VR provides a multisensory experience which better encompasses the characteristics of our day-to-day lives (Berretz et al, 2023;Parsons, 2015). In this way, participants are more likely to genuinely feel like they are within a given scenario, briefly suspending their belief in reality, and bringing research closer to the real world.…”