Washing away your sins in the brain: Physical cleaning and priming of cleaning recruit different brain networks after moral threat

Abstract

The association betweenmoral purity and physical cleanliness has been widely discussed recently. Studies found thatmoral threat initiates the need of physical cleanliness, but actual physical cleaning and priming of cleaning have inconsistent effects on subsequent attitudes and behaviors. Here, we used resting-state functionalmagnetic resonance imaging to explore the underlying neuralmechanismof actual physical cleaning and priming of cleaning. After recallingmoral transgression with strong feelings of guilt and shame, participants either actually cleaned their faces with a wipe or were primed with cleanliness through viewing its pictures. Results showed that actual physical cleaning reduced the spontaneous brain activities in the right insula and MPFC, regions that involved in embodiedmoral emotion processing, while priming of cleaning decreased activities in the right superior frontal gyrus andmiddle frontal gyrus, regions that participated in executive control processing. Additionally, actual physical cleaning also changed functional connectivity between insula/MPFC and emotion related regions, whereas priming of cleaningmodified connectivity within bothmoral and sensorimotor areas. These findings revealed that actual physical cleaning and priming of cleaning led to changes in different brain regions and networks, providing neural evidence for the inconsistent effects of cleanliness on subsequent attitudes and behaviors.