Are Humans Constantly but Subconsciously Smelling Themselves?

Abstract

All primates, including humans, engage in self-face-touching at very high frequency. The functional purpose or antecedents of this behaviour remain unclear. In this hybrid review we put forth the hypothesis that self-face-touching subserves self-smelling. We first review data implying that humans touch their own face at very high frequency. We then detail evidence from the one study that implicated an olfactory origin for this behaviour: This evidence consists of significantly increased nasal inhalation concurrent with self-face-touching, and predictable increases or decreases in self-face-touching as a function of subliminal odourant tainting. Although we speculate that self-smelling through self-face-touching is largely an unconscious act, we note that in addition, humans also consciously smell themselves at high frequency. To verify this added statement, we administered an online self-report questionnaire. Upon being asked, ~94% of ~400 respondents acknowledged engaging in smelling themselves. Paradoxically, we observe that although this very prevalent behaviour of self-smelling is of concern to individuals, especially to parents of children overtly exhibiting self-smelling, the behaviour has nearly no traction in the medical or psychological literature. We suggest psychological and cultural explanations for this paradox, and end in suggesting that human self-smelling become a formal topic of investigation in the study of human social olfaction.

Sex differences in social odor discrimination by southern giant pouched rats (Cricetomys ansorgei)

“…A self‐odor will inherently be more familiar than that of an unrelated conspecific. Because our animals are single housed and often soil their bedding within their home cages, females serving in this study clearly had prior experience with their own scent (Gallup & Anderson, 2018; Perl et al, 2020). This increased the potential for saturating habituation to their own scent, which might have made self‑other discrimination easier.…”

Frequency of Face and Mask Contacts Before and After Quarantine During COVID-19 Pandemics

“…It is also presumed that face touching as a way of self-smelling is largely an unconscious act, for instance, a study in 400 participants, found 94% of them admitted having smelled of themselves [21].…”

Different armpits under my new nose: olfactory sex but not gender affects implicit measures of embodiment

“…By comparison, the fact that humans are able to extract biological and social cues from body odors has long been dismissed outright (Lundström & Olsson, 2010). Yet, humans permanently produce and process body odors, even if largely on a subconscious level (Perl et al, 2020; Prehn et al, 2006; Zhou & Chen, 2008, 2009). These odors seem to play a role in the perception of self and others and in self-other distinction (Perl et al, 2020).…”

“…Yet, humans permanently produce and process body odors, even if largely on a subconscious level (Perl et al, 2020; Prehn et al, 2006; Zhou & Chen, 2008, 2009). These odors seem to play a role in the perception of self and others and in self-other distinction (Perl et al, 2020). Humans can indeed distinguish their own body odor from that of other persons’.…”

“…Body as compared to non-body odors in humans are linked to specific neural substrates including multisensory integration areas such as the angular gyrus (Lundström et al, 2008), a network associated to bodily self-perception (Blanke et al, 2002, 2004). One’s own body odor is considered to be a quite stable and unique “signature” of the bodily self (Lundström & Olsson, 2010), and it has been argued that humans partake in self-smelling behaviors as a way of reassuring the self (Perl et al, 2020). In fact, body odors deliver a great range of information about the person, from individual/kin identity, age, illness, reproductive state, attraction, to transient emotional states (Chen & Haviland-Jones, 2000; Ferdenzi et al, 2020; Mallet & Schaal, 1998; Porter, 1998, 1998; Semin & Groot, 2013, for a review).…”