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.

Introduction

The ability to signal another person’s non-verbal cues is considered functional social behavior. For instance, an individual’s emotional expressivity may signal cooperative behavior and trustworthiness [1], and therefore receives more valuable social investments which in turn can benefit the social group at large on the longer term [2]. Information acquired via non-verbal communication promotes a more effective decision-making process by including whether these expensive individual investments in others are warranted [3]. This phenomenon is illustrated by the observation that people can judge personality traits predictive of future behavior from a face on first sight [e.g., 4–6], the tone of their voice [e.g., 7], or by the feel of a handshake [e.g., 8].

One important desirable social trait that fosters human interaction and cooperation pertains to people’s self-esteem [9,10]. Self-esteem is defined as a person’s appraisal of their value [10],and is often understood as sociometer: someone’s self-esteem is dependent on how they think other members of a group they belong to, value them, and thus critically depend on their relationships [11,12]. It is regarded as a basic social-emotional trait, having a more-or-less stable trajectory through life, with self-esteem increasing somewhat with age [13]. People with high (vs. low) self-esteem have been shown to be happier, feel more confident, and are more liked and successful in social life [13],and low self-esteem is linked to feelings of loneliness and depression [14,15]. In addition, perceptions of self-esteem and associated psychological features can be inferred from others’ appearance, facial expression or tone of voice [e.g., 6,7].

Recent research on the sense of smell shows that humans are sensitive to, and rely on, body odors for social communication. This so-called social chemosignaling [cf. 16], allows people, for example, not only to spot the tell-tale signs of inflammation from looking at a picture of an individual, but also to detect illness from the smell that person secretes [17]. In a similar vein, people can infer stable trait characteristics such as gender and relational status [e.g., 18,19], and personality traits such as dominance and extraversion from body odors [20]. In addition, body odors enable people to gauge more temporary emotional states, such as fear [e.g., 21,22], disgust [21], and anxiety [23]. Body odors may act as a signal, sent as a means for communication on purpose (e.g., when applying a perfume to make a particular impression when on a date), or as a cue that is understood in a particular way up by the perceiver, but not purposefully sent, (i.e., when someone gets a certain impression from someone else, by their particular body odor that is not directly manipulated [cf. 24]). Here, we investigate whether differences in self-esteem may lead to specific cues in body odors.

Differences in self-esteem could affect body odor in various ways. The trait might influence body odor in that high or low levels of self-esteem are associated with metabolic changes, which in turn are secreted onto the skin and result in different odors emanating from the body. Alternatively, people with differing levels of self-esteem might demonstrate typical behavior, e.g., they might interact with people more or less frequently, perform other types of sport, or have different hygiene routines, which might affect the body microbiome and in turn affect ones’ body odor [25,26]. Another alternative route in which self-esteem coincides with a different body odor is that a different response of the HPA axis in potentially stressful situations affects the composition of sweat [e.g., 27,28], and thus, ones’ body odor. In this latter mechanism, more general neurobiological mechanisms related to stress may affect self-esteem as well as body odor, such that body odor changes may coincide with both stress and self-esteem changes. This suggests that various mechanisms by which self-esteem might affect body odor of a sender are conceivable, and that these body odors may be picked up by perceivers through learning mechanisms, as having a communicative value about ones’ personality.

Here we hypothesize that body odor can carry information about a person’s self-esteem that can affect explicit social impressions, such as perceived personal attractiveness, acting as a cue. An important contribution of the present study therefore lies in exploring whether individuals with a low vs. high self-esteem secrete body odors that are distinctive and can influence subsequent impression formation. If such an effect would emerge then this provides crucial additional evidence of the human ability for social chemosignaling: Producing and sending body odors that represent self-worth that is fundamental to social interaction.

It is important to note that individuals are able to hide their temporal or chronic emotional states. For instance, making a poker face or speaking in a steady voice to mask personal feelings of insecurity or to increase perceived dominance [29,30]. More relevant for the present purpose, people might manipulate the odors they emit by applying perfumes, i.e., explicitly manipulating the cue. The practice of using perfume (“self-anointment”) to mask body odor is ancient and widespread [31], and is encountered even in non-human primates and other animals [32]. One of the drivers of self-anointment could be to make a better impression on others [33]. People tend to choose perfumes that match well with their natural body odor, and perceivers of these smells also experience this self-chosen combination of fragrance and body odor as more pleasant than a random combination of fragrance and body odor [34]. In similar vein, Dalton, Mauté, Jean and Wilson [35] demonstrated that when participants were exposed to sweat from female participants who applied antiperspirant–blocking sweat excretion from the underarm–they rated the female participants as more confident, trustworthy, and competent in a stressful situation, compared to when they were exposed to their ‘natural’ sweat odor. This suggests that body odors with and without fragrance convey different social signals, and that it is possible to actively change the signal a sender emits [36,37]. Interestingly, fragrances people wear can also have an effect on their own behavior: when male participants wore perfume during recording of videos compared to a control condition, female observers rated these male contestants on videos as more dominant, confident, and attractive, traits closely related to self-esteem [38,39], even when female participants were unable to smell the males’ body odors. Taken together, fragrances appear to change the impression we have on others in different ways.

In the present study, we examined for the first time whether self-esteem is a cue that can be inferred from body odor, and second, whether such signal changes social impressions. Furthermore, we explored how fragranced body spray applied by individuals affects these impressions. Our hypotheses were stated as follows (see https://osf.io/s9xpq/ for the pre-registration document):

If self-esteem is cued in body odor, exposure to sweat from male sender participants varying in self-esteem will modulate social judgments related to self-esteem, in female perceivers: exposure to sweat from low self-esteem male sender will cause lower perceived self-esteem compared to exposure to sweat from high self-esteem male senders.

If fragrance masks low self-esteem, sweat obtained from male senders with low self-esteem treated with fragrance will lead to higher perceived self-esteem in female perceivers.

These hypotheses were studied using a state-of-the-field sender-perceiver paradigm [e.g., 21,33,40,41], where first, sweat samples were collected from two groups of males, differing in self-esteem and either wearing fragrance or not, and second, where these samples were presented to a group of female perceivers.

Methods

Participants

For the sender study, a total of 35 healthy male participants were invited to participate in the study. These were selected from a large sample (n = 216) of males in the appropriate age range (i.e., ranging 18–35), based on their self-reported self-esteem (as measured using the Dutch version of the Rosenberg Self-Esteem Scale, RSES [42]), so that half of the participants scored in the lower quartile (i.e., had low self-esteem), and the other half scored in the upper quartile of the population (i.e., had high self-esteem). The RSES is a short questionnaire with 5 positive phrased and 5 negative phrased statements on self-esteem, answered using a 4-point agreement scale (ranging ‘strongly agree’–‘strongly disagree’). An example item is “On the whole, I am satisfied with myself”. The Dutch version of the RSES has attested good validity and internal consistency [42]. Population quartile values of the RSES were determined by comparing larger scale population studies on self-esteem (See Supplementary Materials S2 in S1 File for an extensive description of the demographics in this sample including population study comparison). The selection criteria were being male in the appropriate age range (18–35) with no concurrent psychological disorders.

Invited participants completed the RSES a second time to check consistency of the measurement. Of the 35 invited participants, two participants did not show up for the second sweat donation session, and a third participant was excluded because of very inconsistent values on the RSES (e.g., one participant scored 14 during initial screening vs. 28 during the information session). We initially aimed to obtain samples from 32 male participants, and invited more participants to account for potential dropouts. This sample size of 32 sender participants was based on what was necessary for the perceiver study: per fragrance condition, a sender participant provided 2 sweat pads, one for each arm, that were cut into 8 pieces. Stimuli were composed of 4 different pieces from 4 donor participants in the same condition and group. Thus, 16 sender participants in each group would provide enough sweat pads for () 64 perceiver participants. See Fig 1 for a visualization of the procedure of the sender study.

Fig 1

Flow-chart of participant selection and procedure of the sender study.

Of these 32 participants, 16 participants (Mage = 26; SDage = 5.4) scored low on self-esteem (MRSES = 16.3; SDRSES = 2.6) compared to the population average (i.e., for men, MRSES = 22.4; SDRSES = 6.1, N = 242; [43]). The remaining 16 participants (Mage = 27; SDage = 5.1) scored high on self-esteem (MRSES = 26.9; SDRSES = 1.0).

During the sender study, additional measures of state self-esteem were collected during both fragrance conditions: the State Self-Esteem Scale [44], a measure of signature size [45,46], and the Name Initial Preference Task [47-49]. We did not find an effect of fragranced body spray on self-esteem in these measures. These are reported in full in the Supplementary materials S2 in S1 File.

In the perceiver study, 62 heterosexual healthy female participants were recruited. Sample size was determined through a power analysis (using G*Power 3.1 [50]) for within subjects ANOVA (power = .8, α = .05). The effect size was based on similar research on the effect of sweat with or without body spray applied on the judgment of perceived stress and the closely to self-esteem related construct of confidence [35,51]. The effects in this study corresponded to d = .41 for the difference between untreated stress sweat and stress sweat treated with an antiperspirant on confidence ratings, and d = .28 for the difference in overall social judgements between the two sweat conditions. These effect sizes were pooled (d = .35) and converted to eta2 (η2 = .0297), yielding n = 46 as group size sufficiently powered to find a within-subjects effect. To cope with potential drop-outs, 66 female participants were aimed for, of which 62 were actually tested. Participants were screened, recruited and tested by an external agency. See Fig 2 for a visualization of the procedure for the perceiver study.

Fig 2

Visualization of the procedure for the perceiver study.

Perceiver participants were recruited with an age-range of 18–35, with a mean age of 24.6 years (SD = 4.71). Perceivers were included based on their self-reported normal olfactory functioning, and completed a three Sniffin’ stick normosmia test to confirm normal sense of smell [52]. Hummel, Pfetzing and Lötsch [52] report that when using 3 sniffin’ sticks, a score of zero correctly identified smells sensitively indicates olfactory dysfunction. Five participants scored one out of three correctly identified smells, all other participants had either two (n = 16) or three (n = 41) correct. None of the participants was pregnant. Participants reported their use of hormonal contraceptives and were asked to estimate the number of days since most recent menstruation.

Stimuli

Body odors

Body odors were collected following previously established sweat collection protocols [21,40]. See Supplementary Materials S2 in S1 File for a detailed description of the donation procedure. In brief, sender participants came to the lab twice, once to donate sweat without body spray, and once with body spray applied under the underarm. Participants followed a protocol starting 3 days before the donation day, involving shaving instructions, personal care product restrictions, food restrictions, and completion of a diet diary. Sweat (including fragrance in that respective condition) was collected on cotton pads, and immediately vacuum-sealed and frozen at -20C.

After the collection phase was completed, four different types of sweat stimuli were made by pooling sweat together from sender participants in the four different conditions: from the sender participants high in self-esteem and low in self-esteem, and from the same participants wearing fragrance or not wearing fragrance. Each sweat pad was cut in 8 pieces, and each stimulus composed of 4 pieces from different senders in the same self-esteem group and body spray condition. Stimuli were prepared in opaque 250ml food grade PE jars and stored frozen until test.

Perceiver tasks

Odor discrimination and qualitative judgment

A two-alternative-forced-choice (2AFC) discrimination task was conducted to establish whether perceivers could discriminate between stimuli from senders high or low on self-esteem. Perceivers smelled one of the four different smell stimuli, and then smelled two smell stimuli, one of these being the same as the first. Participants had to indicate which of the two was the same as the first. Each smell was used as a target three times, with balanced alternative answer options, all presented in randomized order. Scores were added up for each smell (ranging 0 to 3, with 3 representing a perfect score). After the discrimination task participants were asked to rate each stimulus on pleasantness (a Likert scale ranging -4 ‘very unpleasant’ to 4 ‘very pleasant’), intensity (ranging 0 ‘I don’t smell anything’ to 7 ‘strongest I ever smelled’), and familiarity (ranging 0 ‘not at all familiar’ to 7 ‘very familiar’).

Psychological judgments

A task was designed to elicit affective psychological judgements in a setting in which self-esteem and olfaction plays a role, i.e., interpersonal romantic interaction. Short videos showing interactions between a male contestant and a female contestant going on a first date were used as relevant test material, as self-esteem and body odor may modulate these interactions in an implicit manner. eighteen videos from a television dating show were selected, based on a pilot study (see the Supplementary table S3 in S1 File for a list of the videos used, and Supplementary materials S5 for a report on the pilot study in S1 File). Videos were selected portraying male contestants that were in the middle ranges of rated self-esteem, so that effect of sweat odor could or fragrance stimuli in either direction could be assessed. The videos were presented as embedded video with a width of 560 pixels and height of 315 pixels. All videos were played without sound (see Supplementary materials S5 in S1 File for a discussion on this), and lasted for approximately 30 seconds.

After watching each video, participants were asked to rate the male contestant on three characteristics (‘given your impression of the man, how would you rate the man in the video on:’, or ‘Afgaande op jouw indruk van de man, in hoeverre vond je de man in het filmpje:’, in Dutch), i.e., self-esteem (‘zelfverzekerd’ in Dutch), attractiveness (‘aantrekkelijk’), and extraversion (‘extravert’ in Dutch), using a 0–100 visual analog scale ranging “not at all” to “very much”.

As a brief training, before the odor conditions, participants watched two videos with male contestants that in the pilot-test were rated respectively higher and lower than the stimulus materials used during the conditions, to implicitly anchor participants in their choice and to make them familiar with the task. These videos are marked A and B in the Supplementary table S3 in S1 File. Then, the actual experiment started. Four trials with different scenes were used for each of the four smell conditions, making a total of 18 trials for the entire procedure (training and experiment–see S1 File). Scenes were presented in counter-balanced fashion using a Latin square randomized design, ensuring that every participant watched a different set of videos in each sweat type condition. The scores on each of the three questions were averaged over the four different videos in the same condition and taken as dependent measures.

Mood and arousal

Mood and arousal was measured using six semantic differentiation scale questions after the statement “I would like to know how you feel at this moment. Could you indicate below whether how you feel matches with:” (“graag zou ik willen weten hoe je je op dit moment voelt. Kun je hieronder aangeven in hoeverre je gevoel overeenkomt met:”), with the pairs: good-bad (“goed-slecht”); sad-happy (“bedroefd-vrolijk”); pleased-displeased (“tevreden-ontevreden”); calm-excited (“kalm-opgewonden”); tired-energetic (“vermoeid-energiek”); sedate-aroused (“rustig-opgewekt”). People indicated their response by selecting their answer on a ten-point scale. The first three questions reflected mood, and the latter three questions measure arousal. These questions were taken from Aarts and Dijksterhuis [53], who based it on the Affect-Arousal Scale from Salovey and Birnbaum [54]. The two sets (reflecting mood and arousal respectively) of three questions were averaged per condition/baseline, scores for the four conditions were subtracted from a baseline measure taken before onset of the first odor trial to reflect change from baseline.

Procedure

All methods were carried out in accordance with the declaration of Helsinki, and the Netherlands code of conduct for research integrity. The study was approved by the Ethics Committee of the Faculty of Social and Behavioral Sciences of Utrecht University, and filed under number FETC18-076. Written informed consent was obtained from all participants, who were all over 18 years old. All participants were instructed and tested in Dutch.

After signing the informed consent, perceiver participants were seated in a soundproof cubicle, with their head mounted in a fixed chinrest (see for detailed descriptions of the sender study procedure Supplemental materials S2 in S1 File, for a visual overview see Fig 1). They first did two practice trials of the video rating task with videos portraying a dating situation different from the videos used in the odor conditions, including the mood-arousal questions, to establish their mood-arousal baseline. They were then instructed to knock on the door to alert the experimenter, who would place the first odor stimulus. The four stimulus jars for each participant were thawed 30 minutes before the start of the experiment. Just before the onset of the condition at hand, the lid was removed, and the 250ml PE container for that condition was fixed in a clamp attached to the chin-rest at a fixed distance of 2 cm from their nose.

After every four trials of the rating task within one condition, a screenshot from one of the four previously presented videos was presented in counter-balanced fashion using a Latin square design. Participants were asked to answer the question how much they agreed with the statement “I would date this male” on a 7 point scale ranging “not at all” to “very much”. Data analysis from this question is presented in the Supplementary materials S4 in S1 File. After this, they rated their mood and arousal using the Mood-Arousal questionnaire. See Fig 2 for a visualization of the procedure of the perceiver study.

After going through all 4 odor conditions, they moved to a different location in the lab, and performed the discrimination task and gave qualitative judgments (i.e., pleasantness, intensity and familiarity) for each of the 4 stimuli in a randomized order. Finally, participants were tested for their normal olfactory functioning.

After their participation, participants were debriefed by means of a funneled interview. Most participants answered that they had an idea about the type of stimuli used. Several participants answered they thought the study was to test the effectiveness of a new type of deodorant, but none of the participants guessed the research question or hypotheses correctly.

Design and statistical analyses

The perceiver study follows a within-subject design with the presentation order of the conditions counterbalanced (see Fig 2). Both experimenter and participant were blind to the odor condition. The dependent measures were analyzed by means of fully within participant 2*2 repeated measures ANOVAs, with Sender type (low vs. high self-esteem) and Fragrance (no vs. yes) as within participant factors. Since ANOVA is relatively robust against violations of normality, only in cases of severe violations appropriate transformations were applied [55]. Pairwise comparisons to follow up ANOVA tests were Bonferroni corrected.

Outliers were replaced following the median-absolute-deviation (MAD; [56]) outlier procedure, meaning that outliers, i.e., scores > 2.5 times the average median (i.e., the median absolute deviation) above or below the median score were replaced by scores one unit above or below the most extreme score still within 2.5 times the average median.

The main analyses were informally pre-registered by means of a time stamped, internally circulated PDF document (see Supplementary materials S1 in S1 File).

We also report Bayesian repeated measure analyses as an additional source of information about the evidence for the alternative hypothesis versus the null-hypothesis given the data. A uniform prior was used. Bayes factors for null versus the alternative (BF10) or vice-versa (BF01) are reported depending on whichever is > 1. Main analyses were performed in IBM SPSS Statistics, and Bayes factors were calculated using jamovi [57-59].

Results

Data statement

All data of this project, including syntax, can be found at https://osf.io/xwtnq.

Discrimination task

First, we analyzed the data from the discrimination task, to test whether participants were able to discriminate between high self-esteem and low self-esteem sweat (see Table 1). The total numbers of correct answers for high self-esteem sweat versus low self-esteem sweat trials were set against the total amount of trials (i.e. the ratio of correct answers). Sensitivity (d’; [60]) was calculated and tested against chance level, i.e., (0), for the relevant trials.

Table 1

Sensitivity values (d’) and summary statistics for discrimination between sweat from low and high self-esteem sender participants.

	% correct	Sensitivity (d’)	SE	95% Confidence interval for d’	p-value for t-test against chance
Low-No vs High-No	61.2	.40	.12	.16–.64	.017*
Low-Yes vs High-Yes	52.8	.33	.14	.11–.54	.533
Low-No vs Low-Yes	94.8	2.30	.19	1.93–2.68	< .001*

Note: ‘Low’ denotes sweat from low self-esteem men, whereas ‘High’ denotes sweat from high self-esteem men. ‘No’ denotes that no fragrance was used, whereas ‘Yes’ denotes fragrance was applied. To illustrate, ‘Low-Yes’ denotes a stimulus originating from men with low self-esteem, who had applied fragrance.

Participants correctly discriminated low self-esteem sweat from high self-esteem sweat in 61.2% of the trials, which was significantly above chance (p = .017). For sweat masked with fragrance, participants were unable to discriminate between low and high self-esteem sweat, with performance around chance level (i.e., 52.8% correct, p = .533). To get a sense of the difference between pure sweat and sweat with fragrance, participants correctly discriminated between sweat from the same senders with and without fragrance in 94.8% of the cases (p < .001).

Odor ratings

2-way ANOVAs with Sender type (low vs. high self-esteem) and Fragrance (no vs. yes) as within participant factors were performed on the ratings of pleasantness, intensity, and familiarity (see Table 2 for summary statistics). Normality tests indicated that the assumption of normality was violated for every condition (all ps < .02). However, no clear pattern of abnormality emerged for the four conditions, making a single transformation that corrected the different shifts from normality difficult, and distributions looked close to normal. Relative normality was further confirmed by skewness values, that were between [-.721; 1.064] for all ratings, and by kurtosis ratings, that were between [-.1.209; .265], and were thus all between the cutoff values for normality of -1.96 and +1.96 [58]. It was decided to proceed with the ANOVAs as planned.

Table 2

Summary statistics for perceivers’ (n = 62) body odor ratings of pleasantness, intensity, familiarity, with and without fragrance.

	Low self-esteem senders		High self-esteem senders
	Without fragrance M (SD)	With fragrance M (SD)	Without fragrance M (SD)	With fragrance M (SD)	Significant effects p < .05
Pleasantness	-1.19 (1.54)	1.62 (1.69)	-0.39 (1.48)	2.00 (1.34)	Frag.; Send.
Intensity	2.44 (1.67)	4.11 (1.21)	1.50 (1.21)	4.32 (1.10)	Frag.; Send.; Frag*Send.
Familiarity	2.63 (2.12)	4.02 (1.75)	2.15 (2.09)	4.09 (1.75)	Frag.

Note: Pleasantness was rated on a Likert scale ranging -4 to 4, and intensity and familiarity were rated on a 0 to 7 Likert scale. Abbreviations: Frag. Means a significant main effect of fragrance use. Send. Means a significant main effect of Sender type. Int. means a significant interaction between Fragrance use and Sender type.

For pleasantness, there was a main effect for Sender type: F(1, 61) = 14.46, p < .001, η = .192, BF10 = 2.0, providing evidence that sweat from higher self-esteem men was rated as being more pleasant, independent of fragrance application. There was also a main effect for Fragrance: F(1, 61) = 126.07, p < .001, η = .674, BF10 > 100, providing strong evidence that sweat samples from men who wore fragrance were rated as more pleasant, independent of Sender type. There was no evidence for a Sender type by Fragrance interaction, F(1, 61) = 2.06, p = .157, η = .033, BF01 = 2.7.

For intensity, there was a significant main effect for Sender type: F(1, 61) = 3.23, p = .015, ηp2 = .093, BF01 = 1.9, suggesting that sweat from higher self-esteem men was perceived as being somewhat more intense. There was decisive evidence that Fragrance made the stimuli perceived as more intense: F(1, 61) = 176.33, p < .001, ηp2 = .743, BF10 > 100. However, these effects should be interpreted in light of a Sender type by Fragrance interaction, F(1, 61) 12.68, p = .001, ηp2 = .172, BF10 = 73.4. Without fragrance, sweat from high self-esteem men was rated as significantly less intense compared to sweat from low self-esteem men, p = .001, d = .64. Fragrance application removed this effect, making both sweat types comparably intense, p = .211, d = .18 (means and standard deviations are reported in Table 2).

Finally, for familiarity, there was no main effect for Sender type: F(1, 61) = 1.62, p = .208, η = .026, BF01 = 5.2. However, there was a main effect for Fragrance: F(1, 61) = 32.16, p < .001, ηp = .345, BF10 > 100, indicating that sweat samples containing fragrance were rated as more familiar compared to no-fragrance samples. There was no significant Sender type by Fragrance interaction, F(1, 61) 2.53, p = .117, ηp = .040, BF01 = 2.6.

In line with the results from the discrimination task, these results suggest sweat from men with high self-esteem smells different, i.e., less intense and more pleasant, compared to sweat from men low on self-esteem. However, fragrance application masked this effect. Next, we investigated whether different types of body odors also impacted on the affective judgments of the perceivers.

Psychological judgments

To further investigate the effects of low and high self-esteem sweat on perceiver judgements of self-esteem, attractiveness, and extraversion, of videos showing male dating show contestants different to the sender participants, 2-way ANOVAs were done, again with Sender type and Fragrance as within participant factors (see Fig 3).

Fig 3

Ratings for self-esteem, attractiveness and extraversion, under different stimulus conditions (sweat from low and high self-esteem donors, without and with fragrance).

There was a main effect of fragrance (denoted by an asterisks) for ratings of self-esteem and attractiveness, no other differences were significant. NB: Box-and-whisker plots display the median and 1st and 3rd quartiles ranges, and whiskers indicate range of the data. Diamonds denote individual data points. Perceiver participants rated videos that portrayed males (i.e., dating show contestants) who were not the sender participants (see the Psychological Judgments paragraph in the Methods section).

There was no main effect for Sender type on perceived ratings of self-esteem, F (1,61) = 1.71, p = .196, η2 = .027, with substantial evidence for the null-hypothesis of no effect, BF01 = 3.4. However, there was a main effect for Fragrance, F (1,61) = 4.04, p = .049, η2 = .062, BF10 = 1.3, suggesting perceived self-esteem was higher when sweat of senders wearing fragrance was presented (M = 51.65, SD = 11.45) compared to sweat from the same senders without fragrance (M = 49.03, SD = 8.85). There was no significant Sender type by Fragrance interaction, F (1,61) = 0.89, p = .348, η2 = .014, with evidence for the null-hypothesis, BF01 = 3.3.

For perceived attractiveness, there was a similar pattern of results: the ANOVA showed no main effect for Sender type, F (1,61) = .092, p = .763, η2 = .001, with substantial evidence that self-esteem levels of sweat senders did not impact attractiveness ratings during the perceiver phase, BF01 = 7.1. There was, however, evidence for a main effect for Fragrance, F (1,61) = 5.53, p = .022, η2 = .083, BF10 = 3.0, indicating that sweat collected while wearing fragrance (M = 34.45, SD = 14.97) resulted in higher attractiveness ratings during the perceiver phase than sweat without fragrance (M = 31.58, SD = 14.28). There was no significant Sender type by Fragrance interaction, F (1,61) = 1.17, p = .284, η2 = .019, with evidence for the null-hypothesis of no interaction effect, BF01 = 3.5.

Turning to ratings of extraversion, there was no significant main effect of Sender type on rated extraversion, F (1,61) = 3.56, p = .064, η2 = .055, BF01 = 1.3. There was also no main effect for Fragrance: F (1,61) = 3.87, p = .054, η2 = .060, BF01 = 1.6, and substantial evidence for the null-hypothesis of no interaction between Sender type and fragrance on rated extraversion, F (1,61) = 0.08, p = .784, η2 = .001, BF01 = 5.4.

The results of these analyses show perceivers rated men differently on their self-esteem and attractiveness, given their smell. However, the perceivers were not so much affected by the type of sender who had donated the sweat, but were by whether or not the sender wore fragrance. We next investigated whether perceivers’ self-reported mood was affected by the body odors they were exposed to.

Mood and arousal

Change-from-baseline scores were calculated for the mood and arousal questionnaire scores. For mood, the analysis showed no effect of Sender type, F (1,61) = .023, p = .880, ηp2 = .000, BF01 = 7.3, no effect of Fragrance, F (1,61) = .126, p = .724, ηp2 = .002, BF01 = 6.8, and no significant interaction between Sender type and Fragrance, F (1,61) = .611, p = .437, ηp2 = .010, BF01 = 4.3.

The same analysis was repeated for arousal scores. There was no effect of Sender type, F (1,61) = 1.41, p = .239, ηp2 = .023, BF01 = 3.4, no effect of Fragrance, F (1,61) = .037, p = .847, ηp2 = .001, BF01 = 6.6, and no significant interaction, F (1,61) = 2.29, p = .135, ηp2 = .036, BF01 = 2.3.

These results suggest that although perceivers judge senders differently based on whether they wear fragrance or not, and can discriminate between the sweat of men with low or high self-esteem, these odors do not affect their mood or arousal state.

Discussion

The present study investigated the social chemosignaling of self-esteem, according to which people with a high vs. low self-esteem produce perceivably different body odors that impact on social impressions related to self-esteem. Employing a sender-receiver paradigm, the data showed that female perceivers rated the body odors of male senders with high self-esteem as more pleasant and intense than body odors of male senders with low self-esteem, confirming the distinctiveness of body odor related to levels of self-esteem. However, these effects of chemosignaling of self-esteem did not alter ratings of male contestants who appeared in dating scenarios evaluations. Furthermore, applying fragrance to the body revealed that smelling sweat masked with scent led to higher ratings of potential dating partners.

Although low self-esteem body odor was perceived as less pleasant and more intense, this did not translate into negative social impressions. This suggests that feeling negative or positive about oneself, as indicated by self-reported self-esteem, does not necessarily translate into a social cue that affects others. One underlying mechanism for chemical signaling of personality traits is that they may be traced to socio-biological characteristics that in turn influence the composition of sweat [34]. For example, trait dominance has been suggested to be related to individual differences in testosterone levels [e.g., 61], and in turn, testosterone levels drive the neurobiochemical composition of sweat [cf. 62]. Consequently, dominant men might be more attractive to women in specific contexts [63]. However, self-esteem is often seen as a mediator of situational biochemical responses rather than as being under direct neurobiochemical control. For instance, self-esteem is related to cortisol response when people are socially challenged (i.e., social rejection; [64]). Thus, self-esteem might serve a social chemosignaling function when body odor is secreted under specific conditions. A possible way to follow this up could be to ask participants to donate sweat in an ostracism paradigm [65], to see whether social exclusion is signaled in sweat (e.g., in the form of stress) and perceptions of attractiveness, moderated by level of self-esteem.

The absence of a relationship between how people rate their own self-esteem and how their body odor influences ratings of self-esteem or attractiveness is nevertheless in line with previous findings on self-esteem and perceived attractiveness [66,67]. These studies suggest that while self-esteem is linked to how people judge their own attractiveness, this is of little influence on how attractive others rate their appearance from videos. In addition, only small correlations between ratings of own self-esteem and peer-rated self-esteem have been demonstrated [68], and a weak cue of self-esteem in the sweat may have been obscured by other cues or the provided dating context. Nevertheless, we do find that body odors of men with high self-esteem are rated as more pleasant than those of men with low self-esteem. These results are somewhat contradictory. One possible explanation is that the receiver participants were implicitly distracted by a mismatch between the pooled sweat stimuli obtained from the male senders, and the contestants in the videos they were rating. In the current experiment, the videos portrayed contestants different from the body odor senders. The results may have been different if the videos of men portrayed the participants who donated the body odors, since that would align appearance with odor. Whether particular features of someone’s appearance, e.g., one’s eye or hair color or skin pigmentation, can be congruent or incongruent with someone’s body odor is unknown, although this may be expected based on findings that very specific features such as relational status, age and gender are detectable in body odors [18,69,70]. Following the learning hypothesis of social chemosignaling [71], if particular appearance features are systematically paired with a particular chemical sweat profile, these features may be linked to that profile.

Another possible explanation for the absence of self-esteem body odor effect on social perception and behavior concerns the nature of our test setting. Previous research on social chemosignaling [21,23] mostly established effects of body odors on implicit measures of social evaluation or communication (such as facial electromyography or speeded classification of emotional facial expressions). In this case female participants provided explicit ratings of attractiveness and self-confidence. It is possible that social chemosignalling manifests at an implicit level of information processing as this rarely reaches consciousness [72]. Accordingly, although differences between high and low self-esteem were perceivable on explicit evaluative responses to the body odor itself (i.e. intensity, pleasantness and ability to discriminate), these difference did not affect the participants’ social judgments in a social setting.

Our findings reveal that fragranced body odor can affect judgments of self-esteem and attractiveness. Dating show contestants were rated as more confident and more attractive when body odor with a fragrance was presented during the task compared to natural body odor. Fragrance, in this case, may be seen as communicative cue, since fragrance generally is applied intentionally, with a purpose. After all, fragrances have been designed carefully to contain molecules such as aldehydes, found in nature as part of the aromas flowers emit to attract pollinators like bees [73]. As such, it could be maintained that fragrances have been created precisely to mimic natural attractiveness cues. People tailor their impressions for particular audiences to show off their best self [29,34]. The present results show that this intentional signal, i.e., a fragrance applied on the body, is also picked up as such by perceivers. Previous studies indicate that using fragrance alters how people behave, affecting how others perceive their level of self-esteem and attractiveness in a test setting that did not allow for smelling the fragrance men had applied [74]. Similarly, previous work has also shown that using fragranced cosmetics can improve judgments of attractiveness and pleasantness based on body odors, and at the same time can partly obscure the perception of certain personality traits [33]. In line with these and other studies [37,74,75], the results suggest that just as people alter their voice, facial expression and face appearance to convey a particular impression to someone else [3,29], fragrances are effectively employed to alter one’s chemical impression.

Whereas previous studies on chemosignaling (e.g., [76,77]) find mostly implicit effects of body odors, and no explicit perception effects, we found no implicit effects of odors, but only explicit perception effects of body odors. These perceivable differences in natural body odors did not affect the participants. In psychology, implicit measures are generally preferred as evidence for a specific effect, as they are believed to provide more meaningful information than explicit judgments (e.g., [78,79]). Indeed, smells do not always receive overt attention, with many people not noticing but the most extreme changes in their surrounding smellscape [79,80]. At the same time, some people are much more aware of the smells in their surroundings. There are cultural differences in (social) odor awareness, but within country factors also play a large role [81,82]. For example wine and coffee experts are more aware of their sense of smell [83], and perfumers, women, and hunter-gatherers (see [84] for a review). This raises the question of what the effects of awareness on chemosignaling are. If one person barely takes notice of the strongest smells, while the next person is able to volitionally sniff out the subtlest differences in body odors (e.g., the smell of Parkinson’s disease [85]), that raises questions whether there are individual differences in the effects of chemosignaling. An interesting alley for future studies would be to investigate whether particular social chemosignaling effects are only present when perceived unattentively (i.e., implicitly), or whether they lose, or—equally likely—gain, power when their presence is attentively noticed, for example by a highly aware and trained perfumer.

The present study was limited by a number of issues. Men and women differ in their ability to smell. Here, we have tested only female perceivers, smelling sweat from male senders. To be able to generalize to larger populations and to understand the underlying mechanisms of social chemosignaling, future research needs to include experimental groups including male perceivers, and female senders. The results suggest that female perceivers are able to discriminate between sweat from participants with high versus low self-esteem, but that this effect disappeared when the body odor was masked with fragrance. But interpreting these results should be done carefully, since sweat was pooled, every 8 of 64 stimuli contained sweat from the same individual, to mitigate individual differences in the sweat. However, particularly strong smelling sweat from one or a few individuals in one condition may have given a distinctive cue to many perceivers when discriminating the sweat, despite the efforts and hygiene standards applied in the sender protocol. Future studies with larger samples, collected using more ecological methods, may be able to overcome this limitation (cf. [86]). Another limitation is the use of the quick smell test [52], instead of a full test battery for olfactory function, to assess whether our perceiver participants were not impaired in their sense of smell (i.e., hyposmic or anosmic). By not excluding participants that did not score three correct identifications, it is possible that some of the participants in our perceiver experiment were hyposmic or even anosmic, even though they did not report this themselves. One methodological explanation for the absence of an effect of self-esteem status of the senders on rated self-esteem could lie in the fact that perceiver participants were not sensitive enough to detect these subtle differences in sweat. To investigate this possibility, the main analyses were repeated, including only the participants that scored 3 out of 3 correct (n = 41; the syntax for this analysis is available on https://osf.io/xwtnq/). This analysis yielded the same results, suggesting that in our sample, hyposmia does not explain the absence of an effect of sender self-esteem status on perceiver behavior.

In conclusion, we show that fragrance and self-esteem can affect sweat odor profiles of senders, in such a way that perceivers can pick up on those differences: men with low self-esteem smell different than men with high self-esteem. In addition, we show fragrance can have a substantial impact on how chemical cues are perceived by others (cf. [34]). In light of the widespread de-odorization and re-odorization in society, this provides important steps in understanding what the effect of fragrance on the non-verbal communicative function of body odors in social situations are. The results suggest that applying a fragranced olfactory layer onto one’s body odor can mask sweat smells and alters the social impressions we make on others. The use of fragrances is pervasive, profound and widespread, and this study demonstrates that this is not without reason.

(PDF)

Click here for additional data file.

22 Feb 2021

PONE-D-20-36466

The smelly self: The role of self-esteem and fragrance in body odor and social impressions

PLOS ONE

Dear Dr. Croijmans,

Thank you for submitting your manuscript to PLOS ONE. The manuscript was reviewed by two independent reviewers who both believed that it has merit and is methodologically sounded. However, they both highlighted some changes that need to be addressed before proceeding for publication. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Apr 08 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

We look forward to receiving your revised manuscript.

Kind regards,

Maria Serena Panasiti

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. Please include captions for your Supporting Information files at the end of your manuscript, and update any in-text citations to match accordingly. Please see our Supporting Information guidelines for more information: http://journals.plos.org/plosone/s/supporting-information.

3.Thank you for providing the following Funding Statement:

"The research has been funded by Unilever. Researchers from Unilever provided input to the design of this study. Of the 5 authors listed, author Gortemaker was employed by Unilever during her contribution to the manuscript, and first author Smeets has a dual affiliation, working at Utrecht University and Unilever. Other authors are all affiliated with Utrecht University. The data reported in this paper have not been used for product development, and no intellectual property has been filed. Unilever authors were not involved in relevant statistical analyses. The design of the study, study implementation, and statistical analyses was led by authors from Utrecht University. Unilever would like to see these results published to help accelerate scientific progress in the area of sweat odor, and the impact of reodorization and deodorization. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript."

We note that one or more of the authors is affiliated with the funding organization, indicating the funder may have had some role in the design, data collection, analysis or preparation of your manuscript for publication; in other words, the funder played an indirect role through the participation of the co-authors.

If the funding organization did not play a role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript and only provided financial support in the form of authors' salaries and/or research materials, please review your statements relating to the author contributions, and ensure you have specifically and accurately indicated the role(s) that these authors had in your study in the Author Contributions section of the online submission form. Please make any necessary amendments directly within this section of the online submission form.  Please also update your Funding Statement to include the following statement: “The funder provided support in the form of salaries for authors [insert relevant initials], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.”

If the funding organization did have an additional role, please state and explain that role within your Funding Statement.

Please also provide an updated Competing Interests Statement declaring this commercial affiliation along with any other relevant declarations relating to employment, consultancy, patents, products in development, or marketed products, etc.

Within your Competing Interests Statement, please confirm that this commercial affiliation does not alter your adherence to all PLOS ONE policies on sharing data and materials by including the following statement: "This does not alter our adherence to  PLOS ONE policies on sharing data and materials.” (as detailed online in our guide for authors http://journals.plos.org/plosone/s/competing-interests). If this adherence statement is not accurate and  there are restrictions on sharing of data and/or materials, please state these. Please note that we cannot proceed with consideration of your article until this information has been declared.

Please know it is PLOS ONE policy for corresponding authors to declare, on behalf of all authors, all potential competing interests for the purposes of transparency. PLOS defines a competing interest as anything that interferes with, or could reasonably be perceived as interfering with, the full and objective presentation, peer review, editorial decision-making, or publication of research or non-research articles submitted to one of the journals. Competing interests can be financial or non-financial, professional, or personal. Competing interests can arise in relationship to an organization or another person. Please follow this link to our website for more details on competing interests: http://journals.plos.org/plosone/s/competing-interests

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: No

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: In this study, the authors explored whether body odors can communicate information about one’s self-esteem, and the role of applied fragrance in this relationship. Even though high self-esteem sweat was rated more pleasant and less intense than low self-esteem sweat, there was no difference in perceived self-esteem and attractiveness of males in videos, hence explicit differences in body odor did not transfer to judgments of related person characteristics. When fragrance was added to the body odor, males were rated as having higher self-esteem and being more attractive.

The research question is well explained and related to the previous literature. Experiments have been conducted rigorously, with appropriate controls and sample sizes. I particularly appreciated the use of Bayesian analyses in support of frequentist analyses. The discussion is properly supported by the results. I have just few points that need to be addressed.

- I would suggest to change the title in order to give a sense of the findings. Right now, it sounds like body odors can communicate self-esteem

- At the end of the introduction, authors should present their hypotheses

- In the perceiver study, participants are women rating their impression of men. Did the authors control for the use of hormonal contraception and menstrual cycle? Previous literature has shown that these can affect the perception of body odors as well as social preferences so it might particularly relevant for the present study (Endevelt–Shapira et al., 2020; Derntl et al., 2013; Havlicek et al., 2005). If the authors collect this information it might be interested to see if the results are affected by these aspects.

- The procedure is a bit complicated, maybe a figure would help the reader to understand the different steps, odor stimuli and tasks.

Reviewer #2: Thank you for a possibility to review this submission. I believe that the topic is worth investigation and I found the study interesting and methodologically excellent. However, I also believe that the manuscript needs some work before it is published. My comments are mostly related to the writing style, missing details of the study and problems related to references (missing or erroneously applied). For example, the literature review in the introduction is good, but this section needs a bit of a reorganization and some shortening. One major change I would suggest is adding an analysis comparing baseline self-esteem assessments of the videos with the ratings performed during odor stimulation. Please find my detailed comments below.

Specific comments:

Abstract -

Please specify that the fragrance you mention in the abstract was a fragranced body odor.

„This suggests body odors associated with self-esteem have distinct perceivable features, but only fragrance affects the psychological impression someone makes.” - please rephrase, this sentence is not clear.

Introduction -

Please reorganize the introduction. The first paragraph (currently lines 29-38) should be placed after the paragraph on self-esteem (currently ending at line 63).

Paragraph on signal vs. cue (l. 64-76) is overly complicated and not entirely necessary. Please remove it (you can shorten the content and add it to the next paragraph).

The Sorokowska et al reference in line 77, Croy et al reference in line 86 and Roberts et al reference in line 123 are not well-matched to the content. Sorokowska et al study should be discussed in the paragraph on fragrances.

In the summary of the introduction „ In the present study, we examined for the first time whether self-esteem is a signal that can be inferred from body odor, and second, whether such signal changes social impressions.” - I believe you suggested that you referred to odors as cues?

Methods:

„This sample size of 32 sender participants was based on what was necessary for the perceiver study: 2 groups of 16 sender participants would provide enough sweat pads for 64 perceiver participants.” - please explain the rationale behind the selection of this sender sample size - how did you calculate that?

Please add a few words about the RSES in this section.

„During the sender study, additional measures of state self-esteem were collected.” - do you mean that the body odor donors were subject to one more measurement?

„Participants were screened” - screened for what?

„Five participants scored one out of three correctly identified smells” - were they eliminated from the study?

Please describe the videos in the „stimuli” section. Did the videos present the odor senders? You should also provide some references in the body odor section, showing that the procedure you used was valid and well-established.

Affective judgments are rather psychological judgments - please come up with a more exact name for this section.

“Affective judgments. A task was designed to elicit affective judgements in a setting in which self-esteem and olfaction plays a role, i.e., interpersonal romantic interaction.” - this is completely unclear.

Mood and arousal - can you provide more details on the original scale?

L. 240 - how were the odors presented?

Please provide a reference for the median-absolute-deviation (MAD) outlier procedure.

Results

“distributions looked close to normal” - this is oddly phrased. Maybe you can refer to skeweness and kurtosis here?

I understood from the methods that you have the baseline ratings of perceived self-esteem of the males in the videos? Please provide an additional analysis, comparing these ratings to the ratings performed in a presence of an odor.

Discussion

“ The observation that low self-esteem body odor was perceived as less pleasant and more intense, did not lead to negative social impressions, suggests that feeling negative about oneself, or positive, for that matter, does not necessarily produce a smell that serves a basic social chemosignaling function.” - please rephrase, this is very difficult to follow.

“One possible explanation is that the receiver participants were implicitly distracted by a mismatch between the pooled sweat stimuli, and the males in the videos they were rating.” - I do not understand this rationale.

“while explicit measures (such as attractiveness ratings) usually do not show differences.” - please provide some references here - I do not find this sentence convincing.

“Our findings do reveal fragranced body odor affects females’ judgments of self-esteem and attractiveness of males.” - please rephrase.

L. 459-476 Sorokowska et al 2016 also reported differences in conveyed impressions for natural vs. fragranced samples. Please discuss.

L. 476-490 - this paragraph is difficult to follow. Please rephrase or remove it.

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

6 May 2021

Please see the 'response to reviewers' document attached for a point-by-point response to the reviewers' comments

Submitted filename: Response to reviewers 20210413.docx

Click here for additional data file.

28 Jul 2021

PONE-D-20-36466R1

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

PLOS ONE

Dear Dr.Croijmans,

Thank you for submitting your manuscript to PLOS ONE, as you will see from the comments below, both reviewers were happy with your revisions. One of the two reviewers still have few remaining comments, once you will carefully adress them I will be happy to accept the paper for pubblicaiton.

Please submit your revised manuscript by August 17th. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Maria Serena Panasiti

Academic Editor

PLOS ONE

Journal Requirements:

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: (No Response)

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: I thank the authors for taking the time to revise the manuscript according to previous comments. My concerns have been satisfied. I believe that the MS is now much stronger and worthy of publication in PlosOne.

Reviewer #2: This is my second review of the paper entitled “The role of fragrance and self-esteem in perception of body odors and impressions of others". I find the revised version of this manuscript improved and clearer and there are only a few issues I would suggest addressing.

Introduction:

p. 6 l. 111: “– blocking sweat excretion from the underarm, and thus any –“ – there is a word missing here.

p. 6 l. 116-120: the reference “(Craig Roberts et al., 2009)” is not relevant and incorrectly formatted.

p. 6 l. 122-123: “the psychological reasons underlying fragrance use, and the effects of this, has not been extensively investigated.” – This statement is not true, as there is a large body of literature showing multiple connections between psychological factors and fragrance use. Please reword or remove this sentence altogether.

Methods:

p. 8 l. 161: please clarify that you aimed to obtain 32 samples and invited more male senders to account for potential dropouts. Thank you for presenting the process in Figure 1, it is very useful.

p. 9 l. 193: “yielding n = 46 as group sizes” – group size per condition or a total sample size? Please verify and correct. The study is significantly underpowered if this is the required sample size per condition (I hope this is not the case).

p. 9 l. 201-203: you wrote that “Perceivers were included based on their self-reported normal olfactory functioning, and completed a three Sniffin’ stick normosmia test to confirm normal sense of smell (Hummel, Pfetzing, & Lötsch, 2010).” To confirm normal sense of smell based on the q-stics you would need to obtain the score of 3 for each participant, which means that many of your perceivers could have been hyposmic or even anosmic (self-reports are not very reliable, as shown by several publications). Please discuss this problem as a limitation of your study.

Results

p.15-16 l. 354-359: please move this part to the Discussion.

Table 2: Please modify this table to present the rated characteristics in consecutive rows, and columns low self-esteem donors (no deo-deo) followed by high self-esteem donors (no deo-deo) in columns. Perhaps you could also add a column “significant effects” and just briefly state, e.g., “Frag”, “Send”, “Frag*Send” This will help the reader grasp all your findings (I must admit I needed to read the whole section a few times to get the overall picture).

l. 409-448: Please write clearer that the psychological judgments refer to ratings of videos of men other than your senders.

Discussion

Please present the limitations of your study in a separate paragraph.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

16 Aug 2021

Please find the comments to the reviewer's points in the attached document titled 'Letter to reviewers R2 20210816.docx'

Submitted filename: Letter to reviewers R2 20210816.docx

Click here for additional data file.

6 Oct 2021

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

PONE-D-20-36466R2

Dear Dr. Croijmans,

I am pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Please take care of making the last correction indicated by reviewer 2 in Table 2, you can do that during the proof process.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Maria Serena Panasiti

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: (No Response)

Reviewer #2: Thank you for adressing all my previous comments. I am satisfied with the responses you provided and I endorse this manuscript for publication. I would only suggest replacing “int.” in Table 2 with “frag*send”.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

3 Nov 2021

PONE-D-20-36466R2

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

Dear Dr. Croijmans:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Maria Serena Panasiti

Academic Editor

PLOS ONE