Family Scents: Developmental Changes in the Perception of Kin Body Odor?

There is increasing evidence that human body odors are involved in adaptive behaviors, such as parental attachment in infants or partner choice in adults. The aim of the present study was to investigate changes in body-odor perception around puberty, a period largely ignored for odor-mediated behavioral changes, despite major changes in social needs and in odor emission and perception. Nine families with two children (8 pre-pubertal, aged 7-10, and 10 pubertal, aged 11-18) evaluated body odors of family members and unfamiliar individuals for pleasantness, intensity, and masculinity, and performed a recognition task. The hypothesized emergence of a parent-child mutual aversion for the odor of opposite-sex family members at puberty was not found, contradicting one of the few studies on the topic (Weisfeld et al., J. Exp. Child Psychol. 85:279-295, 2003). However, some developmental changes were observed, including reduced aversion for odor of the same-sex parent, and increased ability of adults, compared to children, to recognize odor of family members. Sex and personality (depressive and aggressive traits) also significantly influenced odor judgments. Further research with larger samples is needed to investigate the poorly explored issue of how olfactory perception of self and family members develops, and how it could correlate with normal reorganizations in social interactions at adolescenc

Digit ratio (2D:4D) predicts facial, but not voice or body odour, attractiveness in men

There is growing evidence that human second-to-fourth digit ratio (or 2D:4D) is related to facial features involved in attractiveness, mediated by in utero hormonal effects. The present study extends the investigation to other phenotypic, hormone-related determinants of human attractiveness: voice and body odour. Pictures of faces with a neutral expression, recordings of voices pronouncing vowels and axillary odour samples captured on cotton pads worn for 24 h were provided by 49 adult male donors. These stimuli were rated on attractiveness and masculinity scales by two groups of 49 and 35 females, approximately half of these in each sample using hormonal contraception. Multivariate regression analyses showed that males' lower (more masculine) right 2D:4D and lower right-minus-left 2D:4D (Dr2l) were associated with a more attractive (and in some cases more symmetrical), but not more masculine, face. However, 2D:4D and Dr2l did not predict voice and body odour masculinity or attractiveness. The results were interpreted in terms of differential effects of prenatal and circulating testosterone, male facial shape being supposedly more dependent on foetal levels (reflected by 2D:4D ratio), whereas body odour and vocal characteristics could be more dependent on variation in adult circulating testosterone levels

Revisiting the relation between language and cognition:A Cross-cultural Study with odors

Nous avons étudié la relation entre la codabilité des odeurs et leur représentation en mémoire dans trois groupes culturels, français, américain et vietnamien. Dans une première expérience, nous avons demandé à des participants des trois cultures d’identifier par deux fois un ensemble de 40 odorants. A partir de cette tâche, nous avons calculé la codabilité de chacun des 40 odorants. Dans une deuxième expérience, nous avons demandé à un autre groupe de participants de chaque culture de réaliser une tâche de reconnaissance par oui/non sur le même ensemble d’odorants. Les résultats de l’expérience 1 suggèrent que la codabilité des odeurs (1) est une dimension pertinente car certaines odeurs sont plus codables que d’autres au sein d’une même culture, (2) peut être mesurée de manière équivalente par des indices d’accords intra et interpersonnels, et (3) varie entre les cultures en fonction de l’environnement olfactif et de la structure du langage. Les résultats de l’expérience 2 montrent que les scores de codabilité en France prédisent les performances de mémoire de reconnaissance dans les trois cultures mais que les scores aux Etats-Unis et au Vietnam n’en prédisent aucun des scores de reconnaissances.We investigated the relationship between odor codability and odor memory representation in three cultural groups: French, American, and Vietnamese. In a first experiment, we asked participants from the three cultures to identify twice a set of 40 common odorants. From this task, we computed the codability of each of the 40 odorants. In a second experiment, we asked another group of participants from each culture to perform a yes/no recognition task on the same set of odorants. Results from Experiment 1 suggest that odor codability (1) is a meaningful dimension because some odors are more codable than others within a culture, (2) is equivalently measurable by several inter- and intrapersonal agreement indices, and (3) varies between cultures as a function of both the olfactory environment and language structure. Results from Experiment 2 show that the French codability scores predict recognition memory performance in all three cultures but that the American and Vietnamese codability scores predict none of the recognition performances

Odor Perception in Children with Autism Spectrum Disorder and its Relationship to Food Neophobia

Atypical sensory functioning in Autism Spectrum Disorder (ASD) has been well documented in the last decade for the visual, tactile and auditory systems, but olfaction in ASD is still understudied. The aim of the present study was to examine whether children with ASD and neuro-typically (NT) developed children differed in odor perception, at the cognitive (familiarity and identification ability), sensorimotor (olfactory exploration) and affective levels (hedonic evaluation). Because an important function of the sense of smell is its involvement in eating, from food selection to appreciation and recognition, a potential link between odor perception and food neophobia was also investigated. To these ends, 10 children between 6 and 13 years old diagnosed with ASD and 10 NT control children were tested. To compare performance, 16 stimuli were used and food neophobia was assessed by the parents on a short food neophobia scale. Results revealed that (i) significant hedonic discrimination between attractive and aversive odors was observed in NT (p=0.005; d=2.378) and ASD children (p=0.042; d=0.941), and (ii) hedonic discrimination level was negatively correlated with food neophobia scores in ASD (p=0.007) but not NT children. In conclusion, this study offers new insights into odor perception in ASD children, highlighting a relationship between odor hedonic reactivity and eating behavior. This opens up new perspectives on both (i) the role of olfaction in the construction of eating behavior in ASD children, and (ii) the measurement and meaning of food neophobia in this population

Variability of Affective Responses to Odors: Culture, Gender, and Olfactory Knowledge

Emotion and odor scales (EOS) measuring odor-related affective feelings were recently developed for three different countries (Switzerland, United Kingdom, and Singapore). The first aim of this study was to investigate gender and cultural differences in verbal affective response to odors, measured with EOS and the usual pleasantness scale. To better understand this variability, the second aim was to investigate the link between affective reports and olfactory knowledge (familiarity and identification). Responses of 772 participants smelling 56-59 odors were collected in the three countries. Women rated odors as more intense and identified them better in all countries, but no reliable sex differences were found for verbal affective responses to odors. Disgust-related feelings revealed odor-dependent sex differences, due to sex differences in identification and categorization. Further, increased odor knowledge was related to more positive affects as reported with pleasantness and odor-related feeling evaluations, which can be related to top-down influences on odor representation. These top-down influences were thought, for example, to relate to beliefs about odor properties or to categorization (edible vs. nonedible). Finally, the link between odor knowledge and olfactory affect was generally asymmetrical and significant only for pleasant odors, not for unpleasant ones that seemed to be more resistant to cognitive influences. This study, for the first time using emotional scales that are appropriate to the olfactory domain, brings new insights into the variability of affective responses to odors and its relationship to odor knowledg

Affective semantic space of scents. Towards a universal scale to measure self-reported odor-related feelings

Measuring self-reported affective feelings to odors and odorous products is a recent challenge for the food and cosmetic field, requiring the development of suited instruments. This paper finalizes a line of studies aimed at developing Emotion and Odor Scales (EOSs) in several cultures. Previously available for Switzerland, the United Kingdom and Singapore, new EOSs are presented here for the United States, Brazil, and China. These scales, developed with 350-540 participants per country, have been conceived to allow the measurement of affective feelings (e.g., emotions, moods, attitudes) in response to a wide range of odors including pleasant and unpleasant, food and non-food ones. Several affective categories were recurrent in the countries examined here: Disgust/Irritation, Happiness/Well-being, Sensuality/Desire, Energy, but also Soothing/Peacefulness and Hunger/Thirst, indicating a potential link between emotion and adaptive universal functions of olfaction such as danger avoidance, ingestion and social communication. For these common categories, similarity in affective responses generally reflected geographic proximity indicating also a strong influence of cultural aspects. Exceptions to this pattern were Singapore and China, with affective responses of Singaporeans being closer to those of Europeans. This series of studies allows us to propose a universal scale (UniGEOS) that might be used in the future for examination of other cultures. This scale comprises affective categories that we found to be culturally shared, enclosing the most frequently shared affective terms, and several culture-specific aspects that may be relevant in other cultures. This tool can be used in its complete form (25 affective terms) or as a short version with nine categories entitled Unpleasant feelings, Happiness/Delight, Sensuality/Desire, Energy, Soothing/ Peacefulness, Hunger/Thirst, Interest, Nostalgia and Spirituality

Body odor quality predicts behavioral attractiveness in humans

Growing effort is being made to understand how different attractive physical traits co-vary within individuals, partly because this might indicate an underlying index of genetic quality. In humans, attention has focused on potential markers of quality such as facial attractiveness, axillary odor quality, the second-to-fourth digit (2D:4D) ratio and body mass index (BMI). Here we extend this approach to include visually-assessed kinesic cues (nonverbal behavior linked to movement) which are statistically independent of structural physical traits. The utility of such kinesic cues in mate assessment is controversial, particularly during everyday conversational contexts, as they could be unreliable and susceptible to deception. However, we show here that the attractiveness of nonverbal behavior, in 20 male participants, is predicted by perceived quality of their axillary body odor. This finding indicates covariation between two desirable traits in different sensory modalities. Depending on two different rating contexts (either a simple attractiveness rating or a rating for long-term partners by 10 female raters not using hormonal contraception), we also found significant relationships between perceived attractiveness of nonverbal behavior and BMI, and between axillary odor ratings and 2D:4D ratio. Axillary odor pleasantness was the single attribute that consistently predicted attractiveness of nonverbal behavior. Our results demonstrate that nonverbal kinesic cues could reliably reveal mate quality, at least in males, and could corroborate and contribute to mate assessment based on other physical traits

Cross-modal associations of human body odour attractiveness with facial and vocal attractiveness provide little support for the backup signals hypothesis: A systematic review and meta-analysis

Assessing the attractiveness of potential mating partners typically involves multiple sensory modalities, including the integration of olfactory, visual, and auditory cues. However, predictions diverge on how the individual modalities should relate to each other. According to the backup signals hypothesis, multimodal cues provide redundant information, whereas the multiple messages hypothesis suggests that different modalities provide independent and distinct information about an individual's mating-related quality. The backup signals hypothesis predicts a positive association between assessments based on different modalities, whereas no substantial correlation across modalities is expected under the multiple messageshypothesis. Previous studies testing the two hypotheses have provided mixed results, and a systematic evaluation is currently missing. We performed a systematic review and a meta-analysis of published and unpublished studies to examine the congruence in assessments between human body odour and facial attractiveness, and between body odour and vocal attractiveness. We found positive but weak associations between ratings of body odours and faces (r = 0.1, k = 25), and between body odours and voices (r = 0.1, k = 9). No sex differences were observed in the magnitude of effects. Compared to judgments of facial and vocal attractiveness, our results suggest that assessment of body odour provides independent and non-redundant information about human mating-related quality. Our findings thus provide little support for the backup signals hypothesis and may be better explained by the multiple messages hypothesis

Smell and taste changes are early indicators of the COVID-19 pandemic and political decision effectiveness

In response to the COVID-19 pandemic, many governments have taken drastic measures to avoid an overflow of intensive care units. Accurate metrics of disease spread are critical for the reopening strategies. Here, we show that self-reports of smell/taste changes are more closely associated with hospital overload and are earlier markers of the spread of infection of SARS-CoV-2 than current governmental indicators. We also report a decrease in self-reports of new onset smell/taste changes as early as 5 days after lockdown enforcement. Cross-country comparisons demonstrate that countries that adopted the most stringent lockdown measures had faster declines in new reports of smell/taste changes following lockdown than a country that adopted less stringent lockdown measures. We propose that an increase in the incidence of sudden smell and taste change in the general population may be used as an indicator of COVID-19 spread in the population

Relationship between odor intensity estimates and COVID-19 prevalence prediction in a Swedish population

International audienceIn response to the coronavirus disease 2019 (COVID-19) pandemic, countries have implemented various strategies to reduce and slow the spread of the disease in the general population. For countries that have implemented restrictions on its population in a stepwise manner, monitoring of COVID-19 prevalence is of importance to guide the decision on when to impose new, or when to abolish old, restrictions. We are here determining whether measures of odor intensity in a large sample can serve as one such measure. Online measures of how intense common household odors are perceived and symptoms of COVID-19 were collected from 2440 Swedes. Average odor intensity ratings were then compared to predicted COVID-19 population prevalence over time i