Effects of facial ugliness on the bad and ugly judgments of unethical behavior: an fMRI study

Abstract Objective: Unethical behavior has a powerful effect on an individual's overall judgment and is easily influenced by their looks. However, it remains unclear whether the unethical behavior of ugly-looking individuals is more likely to be judged as immoral and what the mechanisms behind it are. The present study investigates whether facial ugliness influences the bad and ugly judgments of unethical behavior from the perspective of neural mechanisms. Method: The experimental material consisted of scenarios describing different levels of unethical behavior committed by ugly-looking or non-ugly-looking people. Subjects were asked to rate the bad and ugly levels of behaviors on a 4-point scale while being scanned for brain activity. We conducted a parametric general linear model (GLM) to estimate neural responses to facial ugliness in morally bad and ugly judgments, which varied with the level of immorality. Results: The results showed that ugly-looking faces activated the anterior cingulate cortex and bilateral inferior occipital gyrus in both judgments, indicating a task-general pattern. Ugly-looking faces in morally ugly judgment showed stronger activity than in morally bad judgment in the ventromedial prefrontal cortex, left insula, left middle temporal gyrus, and cortical midline structures that characterize the emotional significance of events, suggesting a task-specific pattern. Conclusions: The results of the current study demonstrate that facial ugliness is task-specific as well as task-general in evaluating unethical behaviors. The findings provide more experimental and neurological evidence for the understanding of the essence between morality and aesthetics.