Many moral buttons or just one? Evidence from emotional facial expressions

ABSTRACT

We investigated whether moral violations involving harm selectively elicit anger, whereas purity violations selectively elicit disgust, as predicted by the Moral Foundations Theory (MFT). We analysed participants’ spontaneous facial expressions as they listened to scenarios depicting moral violations of harm and purity. As predicted by MFT, anger reactions were elicited more frequently by harmful than by impure actions. However, violations of purity elicited more smiling reactions and expressions of anger than of disgust. This effect was found both in a classic set of scenarios and in a new set in which the different kinds of violations were matched on weirdness. Overall, these findings are at odds with predictions derived from MFT and provide support for “monist” accounts that posit harm at the basis of all moral violations. However, we found that smiles were differentially linked to purity violations, which leaves open the possibility of distinct moral modules.

KEYWORDS:

• Facial expression
• moral judgment
• moral foundations theory
• harm
• purity

Acknowledgements

We thank students who participated in our study and Ilaria Perrucci for her help in data collection and in coding facial expressions. The authors declare no conflict of interest.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1 We thank an anonymous reviewer for this suggestion.

2 The expressions classified as surprise were rare. However, there were several cases where one or two components of the surprise expression was present (e.g., AU1, AU1+AU2) (see Table 2). Because such cases are difficult to classify in terms of our similarity-based scheme (as the match with surprise was not higher than that with sadness or fear), we decided to leave them unclassified.

3 We thank an anonymous reviewer for pointing this limitation to us and for discussing its implications for the MFT hypotheses.

4 In the Introduction, we raised two issues with respect to measuring emotion through self-reports: (a) certain emotional words might be ambiguous and (b) the results could be influenced by post hoc rationalisations. With regards to (a) we found that five participants expressed doubts about the meaning of certain emotional words (e.g., “sdegno”, the Italian word for contempt). With regards to (b) since we asked directly about emotional judgments – these judgments were not preceded by moral judgments – the impact of post hoc rationalisations should be limited.