Acute stress reduces affective habituation to unpleasant odors in men with blunted cortisol reactivity.

Habituation to pleasant or unpleasant odors may reflect a dynamic affective process influenced by individuals' physiological and psychological states. This study investigated the effects of acute stress on habituation patterns to odors with varying valence. Forty male participants from an ethnically homogeneous Chinese sample completed the socially evaluated cold pressor task and a control task in randomized order. Participants then performed two olfactory habituation tasks, which involved 20 consecutive presentations of positive-valence odors (phenethyl alcohol or orange oil) and negative-valence odors (4-methylpentanoic acid or 1-butanol; NVO). Generalized linear mixed-effects model analyses revealed that acute stress reduced affective habituation to NVO, F(1, 51) = 4.6, p = .037, but accelerated habituation to positive-valence odors, F(1, 41) = 29.1, p < .001. Higher cortisol responses were marginally associated with faster habituation to NVO (r = .33, p = .055). Exploratory analyses indicated that stress-related reductions in affective habituation to NVO were observed among cortisol nonresponders, but not responders. These findings suggest that acute psychosocial stress alters affective habituation to odors in a valence-dependent manner, with cortisol responses potentially contributing to this modulation. Future research with larger, mixed-gender samples is needed to examine the generalizability of these results. (PsycInfo Database Record (c) 2026 APA, all rights reserved).