Deontological morality can be experimentally enhanced by increasing disgust: A transcranial direct current...

Area of Science:

• Neuroscience
• Psychology
• Moral Cognition

Background:

• Deontological guilt is associated with disgust and obsessive-compulsive (OC) symptoms.
• The insula, a brain region, is implicated in both disgust and deontological guilt.
• Transcranial direct current stimulation (tDCS) offers a non-invasive method to modulate brain activity.

Purpose of the Study:

• To investigate if indirect stimulation of the insula using tDCS can enhance disgust and deontological morality.
• To explore the relationship between disgust, deontological moral judgments, and obsessive-compulsive disorder (OCD) symptoms.

Main Methods:

• A randomized, sham-controlled, within-subject design was employed with 37 healthy participants.
• Participants received anodal tDCS or sham tDCS over T3 for 15 minutes.
• Measures included word completion tasks (disgust-related), moral vignette ratings, and heart rate variability (HRV) to assess autonomic nervous system activity.

Main Results:

• Active tDCS over T3 significantly increased HRV, indicating enhanced parasympathetic activity.
• Participants completed more disgust-related words and reported higher subjective disgust levels after active tDCS compared to sham.
• Moral vignettes in the deontological domain were rated as significantly more wrong after active tDCS; no significant difference was found for altruistic vignettes.

Conclusions:

• Results preliminarily support the hypothesis that insula stimulation enhances disgust and deontological morality.
• The findings suggest a significant association between disgust sensitivity and deontological moral judgments.
• This research has potential implications for understanding and treating obsessive-compulsive disorder (OCD) using non-invasive brain stimulation.