That stinks: There may be a link between moral judgement and bad smells

  • A study was designed to test whether the brain's response to disgust is influenced by moral judgement
  • Results showed that reading about an unpleasant dilemma affected participants' response to odours
  • The dilemmas did, however, not influence their response to pain 

The role of the brain in moral judgement has increasingly become a subject of research.

According to a team of researchers from the University of Geneva, “both disgust and pain are unpleasant, arousing experiences with strong relevance for survival, but with distinctive sensory qualities and neural channels”.

The theme of the study was the relationship between the experiences of pain and disgust and moral judgement.  

The experiments

Researchers from the University of Geneva (UNIGE) conducted two experiments where participants were exposed to either bad odours (high or low disgust levels) or thermal stimulus (of high or low pain). The experiments consisted of 76 trials, and each trial began with a picture cue predicting either a pain or disgust stimulus.

In 50% of the trials, these stimuli were delivered after a predicted cue, and participants had to rate the unpleasantness. In the remaining half of the trials, after the cue, participants were presented with a text-based morally challenging dilemma, and then the stimulus.

For the first experiment, galvanic skin response (GSR) was used to make an analysis. MRI was used to analyse the brain response in the second experiment.

According to the researchers, the purpose of these analyses was to test whether the brain's response to disgust was influenced by moral judgement.

The results

Behavioural responses to the stimuli in the experiments were measured. Results of the experiments showed that reading the unpleasant dilemma affected the participants' response to the odours they smelled and brought about feelings of disgust, whereas the texts did not influence their experience of pain in any way. 

What do these results mean?

Overall, participants' disgust response to the smells was consistently stronger when followed by an unpleasant moral dilemma. This means that feelings of disgust may be increased when subjects are exposed to bad behaviour or behaviour that is considered morally challenging. 

Image credit: iStock
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