Manipulation of body odour alters men’s self-confidence and judgements of their visual attractiveness by women

Beauty is in the nose of the beholder: Fragrance modulates attractiveness, confidence and femininity ratings and neural responses to faces of self and others

Previous research investigated cross-modal influence of olfactory stimuli on perception and evaluation of faces. However, little is known about the neural dynamics underpinning this multisensory perception, and no research examined perception for images of oneself, and others, in presence of fragrances. This study investigated the neural mechanisms of olfactory-visual processing using electroencephalography (EEG) and subjective evaluations of self- and other-images. 22 female participants evaluated images of female actors and themselves while being exposed to the fragrance of a commercially available body wash or clean air delivered via olfactometer. Participants rated faces for attractiveness, femininity, confidence and glamorousness on visual analogue scales. EEG data was recorded and event-related potentials (ERPs) associated with onset of face stimuli were analysed to consider effects of fragrance presence on face processing, and interactions between fragrance and self-other image-type. Subjective ratings of confidence, attractiveness and femininity were increased for both image-types in pleasant fragrance relative to clean air condition. ERP components covering early-to-late stages of face processing were modulated by the presence of fragrance. Findings also revealed a cross-modal fragrance-face interaction, with pleasant fragrance particularly affecting ERPs to self-images in mid-latency ERP components. Results showed that the pleasant fragrance of the commercially available body wash impacted how participants perceived faces of self and others. Self- and other-image faces were subjectively rated as more attractive, confident and feminine in the presence of the pleasant fragrance compared to an un-fragranced control. The pleasant fragrance also modulated underlying electrophysiological activity. For the first time, an effect of pleasant fragrance on face perception was observed in the N1 component, suggesting impact within 100 ms. Pleasant fragrance also demonstrated greater impact on subsequent neural processing for self, relative to other-faces. The findings have implications for understanding multisensory integration during evaluations of oneself and others.

Intrinsic and extrinsic factors affecting axillary odor variation. A comprehensive review

Humans produce odorous secretions from multiple body sites according to the microbiomic profile of each area and the types of secretory glands present. Because the axilla is an active, odor-producing region that mediates social communication via the sense of smell, this article focuses on the biological mechanisms underlying the creation of axillary odor, as well as the intrinsic and extrinsic factors likely to impact the odor and determine individual differences. The list of intrinsic factors discussed includes sex, age, ethnicity, emotions, and personality, and extrinsic factors include dietary choices, diseases, climate, and hygienic habits. In addition, we also draw attention to gaps in our understanding of each factor, including, for example, topical areas such as the effect of climate on body odor variation. Fundamental challenges and emerging research opportunities are further outlined in the discussion. Finally, we suggest guidelines and best practices based on the factors reviewed herein for preparatory protocols of sweat collection, data analysis, and interpretation.

Investigating the Crossmodal Influence of Odour on the Visual Perception of Facial Attractiveness and Age

We report two experiments designed to investigate whether the presentation of a range of pleasant fragrances, containing both floral and fruity notes, would modulate people’s judgements of the facial attractiveness (Experiment 1) and age (Experiment 2) of a selection of typical female faces varying in age in the range 20–69 years. In Experiment 1, male participants rated the female faces as less attractive when presented with an unpleasant fragrance compared to clean air. The rated attractiveness of the female faces was lower when the participants rated the unpleasant odour as having a lower attractiveness and pleasantness, and a higher intensity. In Experiment 2, both male and female participants rated the age of female faces while presented with one of four pleasant fragrances or clean air as a control. Only the female participants demonstrated a crossmodal effect, with the pleasant fragrances inducing an older rating for female faces in the 40–49-years-old age range, whereas a younger rating was documented for female faces in the 60–69-years-old age range. Taken together, these results are consistent with the view that while the valence of fragrance (pleasant versus unpleasant) exerts a robust crossmodal influence over judgements of facial attractiveness, the effects of pleasant fragrance on judgements of a person’s age appear to be less reliable. One possible explanation for the differing effect of scent in the two cases relates to the fact that attractiveness judgements are more subjective, hedonic, and/or intuitive than age ratings which are more objective, cognitive-mediated, and/or analytic in nature.

Perception of Hidden Confidence in Neutral Expressions: Interactions of Facial Attractiveness, Self-Esteem, and Names to Be Addressed by

Even when a person is portraying a neutral expression, their internal feelings can be reflected subtly on their face, and observers can perceive them. A previous study took facial photographs of female models while wearing attractive and unattractive clothing. Although the models displayed neutral expressions for both cases, their faces while wearing attractive clothing were perceived as more attractive because, it was argued, the attractive clothing raised their confidence, which was observable on the neutral faces. The present study aimed to replicate this. Envisaging being addressed by a specific name (given name, nickname, and formal title) are used to alter the models’ internal states instead of clothing. Twenty-one Japanese models took three photographs of their faces while imagining (1) being addressed by names they like, (2) being addressed by names they dislike, and (3) being addressed by their surnames with titles. A number of Japanese observers viewed three images of the same model at once and ordered them according to their attractiveness (Study 1) and confidence (Study 2). The images in condition (1) were perceived as more attractive/confident than other images. This suggests that being addressed by the name we like can raise our confidence momentarily, and it reflects subtly in neutral expressions.

A three-factor benefits framework for understanding consumer preference for scented household products: psychological interactions and implications for future development

Humans have deliberately scented their environment for purpose or pleasure for millennia. In the contemporary marketplace most consumers prefer and purchase scented versions of common household products. However, the drivers of this consumer preference have not been elucidated. To explain the attraction to scent in household products we propose a novel three-factor framework, comprising functional benefits (malodor mitigation, base odor coverage, freshening), in-use experience benefits (cleanliness, efficacy, pleasure), and emotional benefits (increasing in confidence, mood and nostalgia). To support this framework, we present new data from a market research survey on US consumer purchasing habits and attitudes towards home cleaning, laundry, and air freshening products. Further substantiating our framework, a focused review of olfactory psychological science illustrating the central role of scent in cognition, wellbeing, motivated behavior, and social behavior, as well as sensory marketing research highlights the benefits and implications of scent in consumer household products. Based on our three-factor framework we go on to discuss the potential for scent to influence health and raise issues to consider (such as potential negative responding to fragranced products). We conclude by showcasing new opportunities for future research in olfactory science and on scented household products that can advance the positive impacts of scent.

The role of fragrance and self-esteem in perception of body odors and impressions of others

Human sweat odor serves as social communication signal for a person’s traits and emotional states. This study explored whether body odors can also communicate information about one’s self-esteem, and the role of applied fragrance in this relationship. Female participants were asked to rate self-esteem and attractiveness of different male contestants of a dating show, while being exposed to male participant’s body odors differing in self-esteem. High self-esteem sweat was rated more pleasant and less intense than low self-esteem sweat. However, there was no difference in perceived self-esteem and attractiveness of male contestants in videos, hence explicit differences in body odor did not transfer to judgments of related person characteristics. When the body odor was fragranced using a fragranced body spray, male contestants were rated as having higher self-esteem and being more attractive. The finding that body odors from male participants differing in self-esteem are rated differently and can be discriminated suggests self-esteem has distinct perceivable olfactory features, but the remaining findings imply that only fragrance affect the psychological impression someone makes. These findings are discussed in the context of the role of body odor and fragrance in human perception and social communication.

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

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.

Development of a questionnaire to investigate socio-cultural differences in the perception of smell, taste and flavour

Objectives

Clinical experience and daily life indicate that the importance of smell, taste and flavour is variable among individuals. Therefore, the aim of this research was to develop a questionnaire to investigate the importance attributed to smell, taste and flavour and socio-cultural differences among individuals.

Methods

Cross-cultural adaptation of the questionnaire was executed by two professional translators and one bilingual investigator and pre-tested on a pilot group of 25 subjects with normal smell and taste abilities. The final version of the questionnaire was sent by e-mail to 850 healthy subjects. The Google form consisted of three parts: "The importance of olfaction" developed by Croy et al. in 2010, "The importance of taste and flavour" developed by our team and a section to collect demographic data. The questions were classified into "association", "application", "consequence" and "aggravation". Statistical differences were assessed using t-test with p ≤ 0.05. Correlations were calculated using Spearman's test. Internal consistency was assessed using the Cronbach's Alpha, while test-retest reliability was analysed by calculating the Intraclass Correlation Coefficients (ICC2k).

Results

The questionnaire received a non-response rate of 10.7%. Calculation of Cronbach's alpha showed good internal reliability (a = 0.87). Test-retest evaluation was satisfactory for all subscales, with an overall ICC2k = 0.84 (CI 0.79-0.89). Statistical analysis showed that smell, taste and flavour appeared to be more important for women when compared to men (p < 0.001). No statistical differences were seen between individuals with various educational background (p > 0.05), and the importance of smell (r = 0.16; p < 0.01), taste and flavour (r = 0.08; p < 0.05) did not decline with age.

Conclusions

The development of this original test provides an overview into the importance of smell, taste and flavour among individuals. Although further research is needed, it can help in the evaluation and investigation of aspects that influence people to seek medical attention in the presence of sensory alterations.

Tooth brushing performance in adolescents as compared to the best-practice demonstrated in group prophylaxis programs: an observational study

BACKGROUND

Research indicates that adolescents may have difficulties to adopt the tooth brushing recommendations delivered in prophylaxis programs. However, it is not clear whether these difficulties are seen amongst the entire age range of adolescence (10-19 years) or only occur at certain developmental stages of the adolescence. The present study analyzes the tooth brushing performance of adolescents and compares it to the best-practice of tooth brushing demonstrated during prophylaxis programs.

METHODS

A random sample of N = 66 adolescents, comprising 10-year-olds (n = 42) and 15-year-olds (n = 24), were asked to perform oral hygiene to the best of their abilities in front of a tablet camera. Videos were analyzed for tooth brushing duration, location, and brushing movements, and the difference between the actual and expected behaviour was tested for consistency using repeated measures ANOVAs and Student's t-tests. For the direct comparison across different age groups, already available data from 12- and 18-year-olds were reanalysed.

RESULTS

The average brushing time (mean ± SD) of the 10-year-olds and 15-year-olds was 195.8 s (74.6 s) and 196.1 s (75.8 s), respectively. Regardless of age, the adolescents distributed their brushing time unevenly across the inner, outer and occlusal surfaces. The inner surfaces in particular were neglected to a considerable extent, as no age group spent more than 15.8% of the total brushing time on them. Furthermore, all age groups showed a high proportion of horizontal movements on the inner and outer surfaces, regardless of the movements instructed for the respective surfaces.

CONCLUSION

Even if adolescents brush to the best of their abilities, they neglect or skip one or many of the tooth surfaces. The reasons for the lack of compliance to tooth brushing instructions are discussed in light of the methods used in prophylaxis programs and the influence of parents.

The scent of attraction and the smell of success: crossmodal influences on person perception

In recent decades, there has been an explosion of research into the crossmodal influence of olfactory cues on multisensory person perception. Numerous peer-reviewed studies have documented that a variety of olfactory stimuli, from ambient malodours through to fine fragrances, and even a range of chemosensory body odours can influence everything from a perceiver's judgments of another person's attractiveness, age, affect, health/disease status, and even elements of their personality. The crossmodal and multisensory contributions to such effects are reviewed and the limitations/peculiarities of the research that have been published to date are highlighted. At the same time, however, it is important to note that the presence of scent (and/or the absence of malodour) can also influence people's (i.e., a perceiver's) self-confidence which may, in turn, affect how attractive they appear to others. Several potential cognitive mechanisms have been put forward to try and explain such crossmodal/multisensory influences, and some of the neural substrates underpinning these effects have now been characterized. At the end of this narrative review, a number of the potential (and actual) applications for, and implications of, such crossmodal/multisensory phenomena involving olfaction are outlined briefly.

Oral hygiene effects verbal and nonverbal displays of confidence

Although oral hygiene is known to impact self-confidence and self-esteem, little is known about how it influences our interpersonal behavior. Using a wearable, multi-sensor device, we examined differences in consumers' individual and interpersonal confidence after they had or had not brushed their teeth. Students (N = 140) completed nine one-to-one, 3-minute "speed dating" interactions while wearing a device that records verbal, nonverbal, and mimicry behavior. Half of the participants brushed their teeth using Close-Up toothpaste (Unilever) prior to the interactions, whilst the other half abstained from brushing that morning. Compared to those who had not brushed their teeth, participants who had brushed were more verbally confident (i.e., spoke louder, over-talked more), showed less nonverbal nervousness (i.e., fidgeted less), and were more often perceived as being "someone similar to me." These effects were moderated by attractiveness but not by self-esteem or self-monitoring.

Exploring the science, safety, and benefits of air care products: perspectives from the inaugural air care summit

Seventy-one percent of US households purchase air care products. Air care products span a diverse range of forms, including scented aerosol sprays, pump sprays, diffusers, gels, candles, and plug-ins. These products are used to eliminate indoor malodors and to provide pleasant scent experiences. The use of air care products can lead to significant benefits as studies have shown that indoor malodor can cause adverse effects, negatively impacting quality of life, hygiene, and the monetary value of homes and cars, while disproportionately affecting lower income populations. Additionally, studies have also shown that scent can have positive benefits related to mood, stress reduction, and memory enhancement among others. Despite the positive benefits associated with air care products, negative consumer perceptions regarding the safety of air care products can be a barrier to their use. During the inaugural Air Care Summit, held on 18 May 2018 in the Washington, DC, metropolitan area, multidisciplinary experts including industry stakeholders, academics, and scientific and medical experts were invited to share and assess the existing data related to air care products, focusing on ingredient and product safety and the benefits of malodor removal and scent. At the Summit's completion, a panel of independent experts representing the fields of pulmonary medicine, medical and clinical toxicology, pediatric toxicology, basic science toxicology, occupational dermatology and experimental psychology convened to review the data presented, identify potential knowledge gaps, and suggest future research directions to further assess the safety and benefits of air care products.

Hyposmia and Disgust: Gender-Specific Effects

Reduced olfactory function is associated with altered trait disgust in men. This study sought to determine whether hyposmic women show similar changes in disgust responsiveness. We compared patients with hyposmia (25 men, 23 women) and 50 normosmic individuals (25 men, 25 women) with regard to their tendency to experience disgust across different disgust domains (disgust proneness), their self-disgust and their tendency to perceive their own disgust feelings as difficult to control and embarrassing (disgust sensitivity). We replicated the finding that male patients reported elevated self-disgust and disgust proneness toward a specific disgust domain (poor hygiene), whereas female patients obtained comparable disgust scores as the female control group. Both men and women of the patient group indicated disgust regulation difficulties in social contexts. In conclusion, we found greater changes in trait disgust in men with hyposmia. This gender-specific effect, which might be a result of more efficient compensatory behaviors in women, needs further investigation.

Effect of Biological Relatedness on Perfume Selection for Others: Preliminary Evidence

People tend to choose perfumes to complement their body odour. As kin share some body odour qualities, their ability to select complementary perfumes for relatives might be higher compared with selection for nonrelatives. We tested this in two studies, comparing selection of a perfume for a target man by himself and by either a familiar but unrelated individual (girlfriend; Study 1) or a relative (sister; Study 2). Target men applied the two perfumes (own or other's choice) to their axillae and then wore cotton pads for 12 hr. Collected perfume-body odour blends and perfumes alone were assessed by rater panels. In Study 1, the blends were rated as nominally more pleasant when body odours were mixed with the perfumes selected by girlfriends compared with those selected by target men themselves. In Study 2, body odours mixed with perfumes selected by sisters were rated significantly more attractive than those mixed with perfumes selected by target men. No significant differences were found for attractiveness and pleasantness ratings when perfumes were rated alone, suggesting that it was the resulting blends that were uniquely different. Our results indicate that sisters might be particularly tuned to select suitable perfumes for their siblings.

Effective axillary malodour reduction by polyquaternium-16-containing deodorants

OBJECTIVE

Worldwide, individuals apply deodorants to combat malodour formation originating from the axillary vault. Considering the globally increasing demand for efficacious, safe deodorants, we investigated the antimicrobial effectiveness of a polymeric quaternary ammonium compound (PQ-16) as a new active in a roll-on formulation against microbial growth and axillary malodour.

METHODS

We utilized an in vivo microbiological assessment to determine antimicrobial effects of the PQ-16-containing deodorant formulation (DEO1) (i) in comparison with a commercially available deodorant roll-on claiming a 24-h protection against body odour (DEO2) and (ii) in comparison with a roll-on containing the same formulation as DEO1 but comprising aluminium chlorohydrate instead of PQ-16 (DEO3) 1, 4, 8, 24 and 48 h after treatment. Also, the axillary malodour intensity 24 and 48 h after application of deodorants was investigated in a controlled in vivo study performed by a trained sniffer panel using direct sniffing.

RESULTS

Treatment with DEO1 in comparison with application of DEO2 significantly reduced the log 10 bacterial count at all points in time. After 24 and 48 h, sniffers rated malodour production in the DEO1-treated axillae significantly lower than in the DEO2-treated armpits. Application of DEO1 in comparison with DEO3 decreased the log 10 bacterial count after 1, 4, 8 and 24 h (significant for 4 and 8 h). After 48 h, the log 10 bacterial count showed similar values for both DEO1 and DEO3. The sniffer panel reported no significant differences between axillary malodour in DEO1-treated compared to DEO3-treated armpits after 24 and 48 h.

CONCLUSION

We identified polyquaternium-16 (PQ-16, copolymers of 1-vinyl-2-pyrrolidone and 1-vinyl-3-methylimidazolium chloride) as a highly effective deodorant active. Results showed that a newly developed PQ-16-containing deodorant roll-on formulation (i) significantly reduced axillary malodour 24 and 48 h after treatment, (ii) significantly decreased the amount of axillary bacteria, (iii) compared to a commercially available deodorant claiming a 24-h odour protection significantly lowered axillary malodour 24 h and 48 h after application, and (iv) was well tolerated by the study population. PQ-16 represents an innovative and skin-friendly deodorant active.

Body Odor Based Personality Judgments: The Effect of Fragranced Cosmetics

People can accurately assess various personality traits of others based on body odor (BO) alone. Previous studies have shown that correlations between odor ratings and self-assessed personality dimensions are evident for assessments of neuroticism and dominance. Here, we tested differences between assessments based on natural body odor alone, without the use of cosmetics and assessments based on the body odor of people who were allowed to use cosmetics following their daily routine. Sixty-seven observers assessed samples of odors from 113 odor donors (each odor donor provided two samples - one with and one without cosmetic use); the donors provided their personality ratings, and the raters judged personality characteristics of the donors based on the provided odor samples. Correlations between observers' ratings and self-rated neuroticism were stronger when raters assessed body odor in the natural body odor condition (natural BO condition; r s = 0.20) than in the cosmetics use condition (BO+cosmetics condition; r s = 0.15). Ratings of dominance significantly predicted self-assessed dominance in both conditions (r s = 0.34 for natural BO and r s = 0.21 for BO+cosmetics), whereas ratings of extraversion did not predict self-assessed extraversion in either condition. In addition, ratings of body odor attractiveness and pleasantness were significantly lower in natural BO condition than in BO+cosmetics condition, although the intensity of donors' body odors was similar under both conditions. Our findings suggest that although olfaction seems to contribute to accurate first impression judgments of certain personality traits, cosmetic use can affect assessments of others based on body odor.

Concordant Cues in Faces and Voices

Information from faces and voices combines to provide multimodal signals about a person. Faces and voices may offer redundant, overlapping (backup signals), or complementary information (multiple messages). This article reports two experiments which investigated the extent to which faces and voices deliver concordant information about dimensions of fitness and quality. In Experiment 1, participants rated faces and voices on scales for masculinity/femininity, age, health, height, and weight. The results showed that people make similar judgments from faces and voices, with particularly strong correlations for masculinity/femininity, health, and height. If, as these results suggest, faces and voices constitute backup signals for various dimensions, it is hypothetically possible that people would be able to accurately match novel faces and voices for identity. However, previous investigations into novel face–voice matching offer contradictory results. In Experiment 2, participants saw a face and heard a voice and were required to decide whether the face and voice belonged to the same person. Matching accuracy was significantly above chance level, suggesting that judgments made independently from faces and voices are sufficiently similar that people can match the two. Both sets of results were analyzed using multilevel modeling and are interpreted as being consistent with the backup signal hypothesis.

Human Body Scents: Do they Influence our Behavior?

Pheromonal communication in the animal world has been of great research interest for a long time. While extraordinary discoveries in this field have been made, the importance of the human sense of smell was of far lower interest. Humans are seen as poor smellers and therefore research about human olfaction remains quite sparse compared with other animals. Nevertheless amazing achievements have been made during the past 15 years. This is a collection of available data on this topic and a controversial discussion on the role of putative human pheromones in our modern way of living. While the focus was definitely put on behavioral changes evoked by putative human pheromones this article also includes other important aspects such as the possible existence of a human vomeronasal organ. If pheromones do have an influence on human behavior there has to be a receptor organ. How are human body scents secreted and turned into odorous substances? And how can con-specifics detect those very odors and transmit them to the brain? Apart from that the most likely candidates for human pheromones are taken on account and their impact on human behavior is shown in various detail.

Efficient sweat reduction of three different antiperspirant application forms during stress-induced sweating

OBJECTIVES

Stress sweating can occur in everyday situations independently of thermally-induced perspiration. It is triggered by emotionally challenging situations and leads to underarm wetness and a characteristic unpleasant malodor. In this study, we aimed to determine the long-term efficacy of three unperfumed antiperspirant (AP) formulas for different application forms (roll-on, stick, aerosol) against stress-induced sweating and malodor formation.

METHODS

We utilized the widely accepted Trier Social Stress Test (TSST) to induce psychosocial stress in female and male volunteers (18 - 40 years) and determined physiological stress parameters. To additionally assess the efficacy of the test AP roll-on against thermally-induced sweating, a hot room study was performed.

RESULTS

Increasing heart rates and an augmentation of saliva cortisol levels during the TSST indicated a substantial stress reaction which was paralleled by a pronounced sweat production in the untreated axillae of both males and females. Forty-eight hours after application, all three test APs significantly decreased the amount of sweat in the treated axillae independent of gender. With respect to AP effects on malodor production, trained sniffers assessed sweat samples collected during the TSST from the untreated axillae as significantly more malodorous than comparable samples from the AP-treated axillae. Also, independent of gender the test AP roll-on significantly decreased the thermally-induced sweat in the AP-treated axilla.

CONCLUSION

We show for the first time a highly effective reduction of emotionally-induced axillary sweating and malodor production for three different application forms 48 h after the last product use. The specially developed roll-on, stick, and aerosol AP provide long-term protection against stress-induced sweat which is of high relevance in everyday life.

Psychology of fragrance use: perception of individual odor and perfume blends reveals a mechanism for idiosyncratic effects on fragrance choice

Cross-culturally, fragrances are used to modulate body odor, but the psychology of fragrance choice has been largely overlooked. The prevalent view is that fragrances mask an individual's body odor and improve its pleasantness. In two experiments, we found positive effects of perfume on body odor perception. Importantly, however, this was modulated by significant interactions with individual odor donors. Fragrances thus appear to interact with body odor, creating an individually-specific odor mixture. In a third experiment, the odor mixture of an individual's body odor and their preferred perfume was perceived as more pleasant than a blend of the same body odor with a randomly-allocated perfume, even when there was no difference in pleasantness between the perfumes. This indicates that fragrance use extends beyond simple masking effects and that people choose perfumes that interact well with their own odor. Our results provide an explanation for the highly individual nature of perfume choice.

Population genetic segmentation of MHC-correlated perfume preferences

It has become difficult to find a matching perfume. An overwhelming number of 300 new perfumes launch each year, and marketing campaigns target pre-defined groups based on gender, age or income rather than on individual preferences. Recent evidence for a genetic basis of perfume preferences, however, could be the starting point for a novel population genetic approach to better match perfumes with people's preferences. With a total of 116 participants genotyped for alleles of three loci of the major histocompatibility complex (MHC), the aim of this study was to test whether common MHC alleles could be used as genetic markers to segment a given population into preference types. Significant deviations from random expectations for a set of 10 common perfume ingredients indicate how such segmentation could be achieved. In addition, preference patterns of participants confronted with images that contained a sexual communication context significantly differed in their ratings for some of the scents compared with participants confronted with images of perfume bottles. This strongly supports the assumption that genetically correlated perfume preferences evolved in the context of sexual communication. The results are discussed in the light of perfume customization.

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.

Cognitive facilitation following intentional odor exposure

This paper reviews evidence that, in addition to incidental olfactory pollutants, intentional odor delivery can impact cognitive operations both positively and negatively. Evidence for cognitive facilitation/interference is reviewed alongside four potential explanations for odor-induced effects. It is concluded that the pharmacological properties of odors can induce changes in cognition. However, these effects can be accentuated/attenuated by the shift in mood following odor exposure, expectancy of cognitive effects, and cues to behavior via the contextual association with the odor. It is proposed that greater consideration is required in the intentional utilization of odors within both industrial and private locations, since differential effects are observed for odors with positive hedonic qualities.

Effective prevention of stress-induced sweating and axillary malodour formation in teenagers

Emotional sweating and malodour production represent a relevant challenge to today's antiperspirant (AP) and deodorant products as stress in everyday life increases continuously. The aim of this study was to investigate stress-induced sweating in teenagers who are known to experience various stressful situations, e.g. exams at school or job interviews. To induce emotional sweating in 20 female and 20 male adolescents (16-18 years of age), we applied the Trier Social Stress Test (TSST), considered today to be the most reliable and standardized stress protocol. In this study, we demonstrate that the TSST induces high amounts of sweat and strong axillary malodour in the tested age group. Notably, male teenagers showed significantly higher stress-induced odour scores than female subjects, although no gender differences were detected concerning other physiological stress markers. Testing of a novel deodorant/AP product developed to specifically address the needs of adolescent consumers revealed excellent deodorant and AP efficacy under the challenging conditions of the TSST.

How do pairs matched in physical attractiveness form if people are unaware of their own attractiveness?

The correlation of physical attractiveness in romantic partners has been widely documented. However, it has also repeatedly been demonstrated that people are largely unaware of their own attractiveness, which raises the question about the mechanism responsible for the within-pair matching. One hitherto unexplored possibility is that low accuracy in attractiveness self-assessments results from methodological drawbacks. Participants were usually asked to rate their attractiveness on a numeric scale, and independent judges evaluated them on the basis of facial photographs. We hypothesized that the accuracy of self-assessment may be increased if (1) participants and judges evaluate the same characteristic, e.g., both groups assess facial attractiveness, (2) own attractiveness is estimated in a comparative manner (with reference to attractiveness of other individuals) rather than by abstract numbers, (3) judges rate attractiveness of people as seen in video clips rather than in photographs. To test these hypotheses we photographed and videotaped faces of 96 women and 78 men. Independent judges rated attractiveness from these photographs and video clips, and the participants assessed own attractiveness in several ways. None of the above hypotheses was confirmed by statistical analysis. We discuss how the within-pair matching in attractiveness can arise, given such poor awareness of own appeal.

The Future of an Applied Evolutionary Psychology for Human Partnerships

There has been significant recent progress in our understanding of human mate choice. We outline several frontiers of rapid cultural change which may increasingly directly affect individual self-evaluation in the mating market, formation and maintenance of long-term partnerships, and potentially reproductive outcome and child health. Specifically, we review evidence for the effects of (1) increasing exposure to mass media, (2) the advent of novel ways to meet potential partners, and (3) cultural influences which may disrupt or alter the expression of evolved mate preferences. We comment on the potential for these effects to influence self-perception and partner-perception, with downstream effects on relationship satisfaction and stability. A common theme emerges, which is that these effects may contribute to relationship dissatisfaction and dissolution, with negative implications for societal change. We then address how we envisage evolutionary psychology research may focus on and offer informed approaches to ameliorate these effects in the future. We picture the development of a field of applied evolutionary psychology, and we suggest that this will increasingly become a central focus for many researchers.

Distinguishing between Perceiver and Wearer Effects in Clothing Color-Associated Attributions

Recent studies have noted positive effects of red clothing on success in competitive sports, perhaps arising from an evolutionary predisposition to associate the color red with dominance status. Red may also enhance judgments of women's attractiveness by men, perhaps through a similar association with fertility. Here we extend these studies by investigating attractiveness judgments of both sexes and by contrasting attributions based on six different colors. Furthermore, by photographing targets repeatedly in different colors, we could investigate whether color effects are due to influences on raters or clothing wearers, by either withholding from raters information about clothing color or holding it constant via digital manipulation, while retaining color-associated variation in wearer's expression and posture. When color cues were available, we found color-attractiveness associations when males were judged by either sex, or when males judged females, but not when females judged female images. Both red and black were associated with higher attractiveness judgments and had approximately equivalent effects. Importantly, we also detected significant clothing color-attractiveness associations even when clothing color was obscured from raters and when color was held constant by digital manipulation. These results suggest that clothing color has a psychological influence on wearers at least as much as on raters, and that this ultimately influences attractiveness judgments by others. Our results lend support for the idea that evolutionarily-derived color associations can bias interpersonal judgments, although these are limited neither to effects on raters nor to the color red.