Why do people engage in self-sniffing? A new study published in Physiology & Behavior concluded that olfactory self-inspection serves numerous functions, which varies based on the specific body part being sniffed.
Various studies have found that people touch their face without a particular reason. This type of behavior might serve a regulatory or odor-inspection function. Sniffing hands, especially after shaking hands, seems to be a way of checking one’s own body odor or that of the other person. Frequency of self-sniffing varies with culture, gender, and age, and there are also variations in the frequency of sniffing different body parts.
Self-sniffing could help monitor health and hygiene status or manage one’s appearance. Body odor can convey information about a person’s physiological and emotional state, and this information can likewise be perceived by others. In this work, Dagmar Schwambergová and colleagues “investigated the frequency of olfactory self-inspection and its possible functions.”
A pilot study was conducted to determine the relevant body parts and contexts for self-sniffing. Participants included 124 Czech individuals recruited through emails and lectures at Charles University. They responded to questions assessing the incidence and frequency of indirectly sniffing various body parts or worn clothes, such as through hand contact, on a scale of 1 (never or almost never) to 7 (several times a day). They also responded to open-ended questions assessing the context of such behavior (e.g., “In what situations do you smell your own armpits?”). This qualitative data was used to adapt the self-sniffing inventory that was used.
The final sample for the main study included a total of 209 participants. Participants completed a socio-demographic survey (e.g., age, gender, education, and occupation) and a self-sniffing inventory of 35 items assessing the frequency of self-sniffing various body parts (e.g., “Do you ever smell your hand after touching your genitals?”) and clothes, and the context in which they engaged in that behavior.
The study included other measures as well, such as a health-related survey (e.g., “Do you use any medication prescribed by your practitioner?”), hygiene inventory (e.g., “When you wash your hands, approximately how long do you wash them for?”), Three Domain Disgust Scale (including moral, sexual, and pathogen disgust), and Body Odor Disgust Scale assessing internal (e.g., “You are alone at home and notice that your feet are very smelly”) and external (e.g., “You are sitting next to a stranger and notice that his feet are very smelly”) odor sources.
A Principal Component Analysis revealed three distinct dimensions of self-sniffing, including social acceptability self-inspection (involving areas like armpits, breath, and worn clothes), intimate self-inspection (covering private parts like genitals and anus), and cosmetic self-inspection (related to areas where fragranced products are applied, like hair and hands).
The researchers observed no gender differences in the social acceptability and cosmetic dimensions of self-inspection. However, men engaged in more intimate self-inspection than women. Participants with health issues more often engaged in social acceptability self-inspection, likely to monitor changes in odor due to illness. Further, those with lower hygiene standards were more inclined towards intimate self-inspection. The most frequently sniffed body parts were hands and worn t-shirts.
This study suggests that self-sniffing serves different functions depending on the body part, with potential roles in health monitoring, hygiene checks, as well as social and sexual contexts.
A limitation to this work is that data collection relied on self-reports. Participants may not be fully aware of the self-sniffing behavior they engage in, or may be influenced by the social desirability bias. Future research may consider direct observation for the social acceptability and cosmetic dimensions of self-inspection.
The study, “Olfactory self-inspection: Own body odour provides cues to one’s health and hygiene status”, was authored by Dagmar Schwambergová, Jitka Třebická Fialová, and Jan Havlíček.