The influence of olfactory stimuli on social cognition, prejudice and emotions: a systematic review of the literature.

This review synthesizes research on how olfactory stimuli influence social cognition, emotions, and prejudice, an area that remains understudied despite the olfactory system's direct neural connections to limbic regions like the amygdala and hippocampus. Following PRISMA 2020 guidelines, the authors systematically searched PubMed and Web of Science (2000-2025), identifying 21 eligible studies from 569 records. The literature reveals three core mechanisms through which odors exert their effects: (1) early perceptual modulation of social stimuli, (2) affective priming via disgust and valence systems, and (3) higher-order modulation of social judgments and moral evaluation. Unpleasant odors (e.g., sweat, rotten smells) increase vigilance, bias emotion perception, and amplify both implicit and explicit prejudices against marginalized groups such as gay men or immigrants. Putative human chemosignals like androstadienone and hedione subtly modulate mood, attention, and social judgments in context-dependent ways. Individual differences-including disgust sensitivity, neuroticism, and religiosity-systematically moderate these effects. Neuroimaging (EEG/fMRI) shows that odors engage distributed networks involving the amygdala, insula, and frontal regions, affecting early and late-stage emotional processing. The authors conclude that olfactory stimuli act as powerful, often subconscious modulators of social cognition. They propose that odors function as contextual priors that bias social inference, especially under conditions of ambiguity or uncertainty. These findings highlight the need to integrate olfactory dimensions into models of social behavior and bias formation. Future research should employ ecologically valid paradigms such as virtual reality to better understand how smells shape real-world interpersonal and intergroup dynamics.