Disgust Versus Fear: Comparing the Generalization Pattern of Disgust and Fear

Abstract A major limitation of fear generalization research entails the confusing unconditional stimulus—it can often induce not only fear but also disgust. Differences between the two threat-related emotions during conditioning and generalization are currently unknown. To address this issue, 32 college students completed threat conditioning tasks including conditioned stimuli paired with fear or disgust images. A block design was used to divide fear and disgust into two randomly ordered blocks, enabling examination of differences between fear and disgust by recording subjective expectations and eye movement in the generalization process. The results revealed that participants reported larger subjective expectations of fear-related GS1 (generalized stimuli) and GS2 than disgust-related GS1 and GS2, and fear led to longer reaction times than disgust in both conditioning and generalization phases. The pupil size and fixation duration for fear stimuli were larger than for disgust stimuli, suggesting that fear generalization has a steeper gradient than disgust generalization. Participants paid more attention to fear and were more inclined to avoid disgust stimuli. These findings provide new, albeit preliminary, evidence of the differences between fear and disgust stimuli in generalization, and may offer insight into the treatment of clinical anxiety and other fear- or disgust-related disorders.