Homeostatic relevance promotes access to visual awareness

Fear and disgust have been associated with opposite influences on visual processing, even though both constitute negative homeostatic emotions that motivate avoidance behavior and entail increased arousal. In the current study, we hypothesized that (1) homeostatic relevance modulates perception at early stages of visual processing, (2) through widespread physiological responses, and that (3) the direction of these modulations depends on whether an emotion calls for immediate regulatory behavior (fear) or not (disgust). Specifically, we expected that increased arousal should facilitate detection of fear-related stimuli, and inhibit detection of disgust-related stimuli. These hypotheses were tested in two pre-registered experiments run in September-October 2022 (total N = 120, ethnically-homogenous Polish sample). Using a novel, response bias-free version of the breaking continuous flash suppression paradigm, we examined localization and discrimination of fear- and disgust-conditioned stimuli at individually determined perceptual thresholds. Our first hypothesis was confirmed: Fear-conditioned stimuli were detected and discriminated better than neutral stimuli, and the magnitude of conditioning-related perceptual preference was related to arousal during conditioning acquisition. In contrast with our second hypothesis, arousal-mediated perception of disgust-conditioned stimuli was also enhanced, although the effects were weaker compared to those evoked by fear conditioning. The current study strengthens previous evidence for facilitated perception of threatening objects and shows for the first time that stimuli evoking disgust also gain preferential access to awareness. The results imply that stimuli associated with homeostatically relevant negative emotions are prioritized by the human visual system and that this preference is grounded in the underlying arousal levels.