Olfaction in the Multisensory Processing of Faces: A Narrative Review of the Influence of Human Body Odors

Abstract

A recent body of research has emerged regarding the interactions between olfaction and other sensory channels to process social information. The current review examines the influence of body odors on face perception, a core component of human social cognition. First, we review studies reporting how body odors interact with the perception of invariant facial information (i.e., identity, sex, attractiveness, trustworthiness, and dominance). Although we mainly focus on the influence of body odors based on axillary odor, we also review findings about specific steroids present in axillary sweat (i.e., androstenone, androstenol, androstadienone, and estratetraenol). We next survey the literature showing body odor influences on the perception of transient face properties, notably in discussing the role of body odors in facilitating or hindering the perception of emotional facial expression, in relation to competing frameworks of emotions. Finally, we discuss the developmental origins of these olfaction-to-vision influences, as an emerging literature indicates that odor cues strongly influence face perception in infants. Body odors with a high social relevance such as the odor emanating from the mother have a widespread influence on various aspects of face perception in infancy, including categorization of faces among other objects, face scanning behavior, or facial expression perception. We conclude by suggesting that the weight of olfaction might be especially strong in infancy, shaping social perception, especially in slow-maturing senses such as vision, and that this early tutoring function of olfaction spans all developmental stages to disambiguate a complex social environment by conveying key information for social interactions until adulthood.

Influence of the human body odor compound HMHA on face perception

“…Perception and behavioral effects of the acid fraction of human body odor remains poorly explored, compared to other families of compounds such as androstenes (in the field of face processing, see Damon et al, 2021). Here, we investigated whether HMHA, produced in larger proportions by men (Troccaz et al, 2009) could play a role in human interactions, either through intersexual processes (attraction) or intrasexual competition, which are two nonexclusive components of the sexual selection process.…”

“…However, the influence of (body) odors is likely to remain below the level of consciousness, without the odor being explicitly perceived (e.g., Richard Ortegón et al, 2022) and with possible disruption of the effect if the odor reaches conscious perception (Li et al, 2007). Additionally, whether the level of HMHA concentration used in the current study corresponds to the level naturally produced at the surface of the body is unknown, thus limiting the ecological validity of the approach (see discussion of this issue in Burke et al, 2012, and Damon et al, 2021). Third, the sample used in this study was rather small, which limits the generalizability and reliability of the conclusions.…”

Food preference acquired by social transmission is altered by the absence of the olfactory marker protein in mice

“…It has been shown that human mothers influence the hedonic polarity of their neonates’ initial olfactory responses and acquisition of food preference through their diet ( 52 ). OMP could thus participate in these early influences of general social cognition and therefore in the development of food preferences in humans ( 53 ).…”

Olfactory-to-visual facilitation in the infant brain declines gradually from 4 to 12 months

“…Maternal odor could even be progressively dissociated from the perception of faces, as the proportion of faces in the infant's visual environment linearly decreases during the first year while the proportion of other body parts, especially hands, increases (Fausey et al, 2016). However, accumulating evidence shows that human odors are still associated with faces in adulthood (see Damon et al, 2021 for a recent review), indicating that body odor influence on face perception is not restricted to the maternal odor effect in the youngest infants.…”