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Investigating gender differences based on emotional changes becomes essential to understand various human behaviors in our daily life. Ten students from the University of Vienna have been recruited by recording the electroencephalogram (EEG) dataset while watching four short emotional video clips (anger, happiness, sadness, and neutral) of audiovisual stimuli. In this study, conventional filter and wavelet (WT) denoising techniques were applied as a preprocessing stage and Hurst exponent Hur and amplitude-aware permutation entropy AAPE features were extracted from the EEG dataset. k -nearest neighbors kNN and support vector machine (SVM) classification techniques were considered for automatic gender recognition from emotional-based EEGs. The main novelty of this paper is twofold: first, to investigate Hur as a complexity feature and AAPE as an irregularity parameter for the emotional-based EEGs using two-way analysis of variance (ANOVA) and then integrating these features to propose a new CompEn hybrid feature fusion method towards developing the novel WT _ CompEn gender recognition framework as a core for an automated gender recognition model to be sensitive for identifying gender roles in the brain-emotion relationship for females and males. The results illustrated the effectiveness of Hur and AAPE features as remarkable indices for investigating gender-based anger, sadness, happiness, and neutral emotional state. Moreover, the proposed WT _ CompEn framework achieved significant enhancement in SVM classification accuracy of 100%, indicating that the novel WT _ CompEn may offer a useful way for reliable enhancement of gender recognition of different emotional states. Therefore, the novel WT _ CompEn framework is a crucial goal for improving the process of automatic gender recognition from emotional-based EEG signals allowing for more comprehensive insights to understand various gender differences and human behavior effects of an intervention on the brain.

Developing a brain mapping for emotional changes over the brain regions remains a crucial goal for improving the process of emotional recognition. The EEGs of forty volunteer individuals were gotten while the individuals were shown seven, short video clips (i.e. anger, anxiety, disgust, happiness, sadness, surprise and neutral). The motivation of this work is twofold. First, it aims to propose the brain electrical activity mapping using the effectiveness of the multiscale fuzzy entropy () feature. Second, it aims to detect the optimal EEG channels for anger, anxiety, disgust, happiness, sadness, surprise and neutral emotional states over the brain regions (i.e. frontal, temporal, parietal and occipital) using the differential evolution-based channel selection algorithm (DEFS_Ch). The results revealed that the frontal region was statistically significant from temporal, parietal and occipital. Moreover, anger emotional state was significantly different from the other emotional states. Furthermore, the anger, sadness and anxiety were significantly different from disgust, happiness, surprise and neutral at the occipital region. For more inspection, DEFS_Ch algorithm has been used to select the most effective emotional channels over the brain regions, anger and anxiety were shared the channels in the frontal, temporal and occipital regions. Disgust was identified by the frontal, temporal, parietal and occipital channels. Sadness and disgust were identified by the channels from the frontal and temporal regions. Surprise and happiness were identified by the left frontal, parietal and occipital channels. Finally, the neutral emotional states were identified by the channels from the lateral regions of the brain particularly in right and left frontal and temporal regions. The main novelty of this study was in building up an EEG brain mapping over the brain regions for different emotional changes to help the clinician for improving the procedure of emotional recognition from the EEG signals.

The motivation of this study was to perceive the gender variations by studying the emotional states (i.e. angry, anxiety, disgust, happiness, sadness and surprise). Emotional electroencephalography (EEG) data were recorded from ten healthful subjects whist the volunteers watched seven, short, emotional audio-visual video clips. Wavelet (WT) has been used as a denoising technique. The spectral relative power ratios ( $PR$ ) features including $(\delta/\theta), (\theta/\alpha), (\alpha/\beta), (\beta/\gamma)$ and ( $\theta/\gamma$ ) were extracted from each EEG channel. In the subsequent step analysis of variance (ANOVA) has been performed to characterize the emotional EEG based on gender differences. Moreover, K-nearest neighbors (KNN) and support vector machine (SVM) classifiers were used to classify the emotional EEG based on gender differences. The results revealed that a relatively high $PR$ for all emotional states in females compared to males particularly in anger, disgust, happiness and surprise emotional states compare to males' $PR$ . Moreover, the females show relatively higher $PR$ for anxiety, sadness and neutral in most cases. In contrast, the males show relatively higher $PR$ particularly in $\theta/\alpha$ and $\theta/\gamma$ for anxiety emotional state, higher $\delta/\theta$ and $\alpha/\beta$ for sadness emotional state, and $PR$ particularly had higher $\delta/\theta$ and $\alpha/\beta$ for neutral emotional state. The classification results were 90.4% for SVM and 92% for the KNN. Therefore, the proposed system using WT denoising method, spectral $PR$ features, SVM and KNN classifiers were crucial role in gender identification and characterizing the emotional EEG signals.

Investigating gender differences based on emotional changes using electroencephalogram (EEG) is essential to understand various human behavior in the individual situation in our daily life. However, gender differences based on EEG and emotional states are not thoroughly investigated. The main novelty of this paper is twofold. First, it aims to propose an automated gender recognition system through the investigation of five entropies which were integrated as a set of entropy domain descriptors (EDDs) to illustrate the changes in the complexity of EEGs. Second, the combination EDD set was used to develop a customized EEG framework by estimating the entropy-spatial descriptors (ESDs) set for identifying gender from emotional-based EEGs. The proposed methods were validated on EEGs of 30 participants who examined short emotional video clips with four audio-visual stimuli (anger, happiness, sadness, and neutral). The individual performance of computed entropies was statistically examined using analysis of variance (ANOVA) to identify a gender role in the brain emotions. Finally, the proposed ESD framework performance was evaluated using three classifiers: support vector machine (SVM), k-nearest neighbors (kNN) and random forest (RF), and long short-term memory (LSTM) deep learning model. The results illustrated the effect of individual EDD features as remarkable indices for investigating gender while studying the relationship between EEG brain activity and emotional state changes. Moreover, the proposed ESD achieved significant enhancement in classification accuracy with SVM indicating that ESD may offer a helpful path for reliable improvement of the gender detection from emotional-based EEGs.

Subtle nonverbal changes can influence perception, signal individual’s affective state and act as gateways in interpersonal communications. In this exploratory study, we investigated the effect of ...

Male parental investment can contribute to the fitness of both sexes through increased fertility and child survivorship. The level and intensity of parental investment are dependent upon ecological variations: in harsh and demanding environments, the need for biparental care increases. Moreover, when environmental pressures increase, uncertainty over paternity may lead to favoring stricter mate-guarding practices, thus directing males to invest more effort toward controlling and guarding their mates from infidelity. In this paper, we test the hypothesis that religious veiling, as a social and cultural practice which regulates and restricts sexuality, will be more important in harsher environments. Our results show that harsh and demanding environments are associated with the importance of religious veiling and the level of religiosity, providing a link between cultural practices such as religious veiling and ecological variation.

"CADDY - Cognitive Autonomous Diving Buddy" is an FP7 project that that is devoted to developing a cognitive underwater robotic system that will help divers during their activities in this hazardous environment. The envisioned resulting system will play a threefold role similar to those that a human buddy diver should have: buddy "observer", buddy "slave", and buddy "guide". During the second year of the project, validation trials were organized in Croatia with the purpose of testing all developed algorithms that will enable the three roles of the CADDY system. The trials were structured in five experiments. This paper is devoted to providing a concise overview of the conducted experiments and major results.

Humans tend to judge and sort parts of their social and non-social environment permanently into a few basic categories: those parts they like and those parts they do not. Indeed, we have developed aesthetic preferences for those things and people we are exposed to. Furthermore, needless to say, these preferences shape our behavioural choices—our tendency to seek out or avoid what the world has to offer to us. Humans and other animals have evolved preferences for food and habitats, for naturally occurring sensations such as smells and sounds, as well as for the broad array of culturally created artefacts

This paper described the basic concept behind the second and final validation trials of the Cognitive Autonomous Diving Buddy (CADDY) system. The CADDY system is composed of three components: autonomous surface vehicle (ASV), an autonomous underwater vehicle (AUV) named BUDDY, and a diver. CADDY aims to establish an innovative setup between a diver and companion autonomous robots (underwater and surface) that exhibit cognitive behaviour by adapting to diver's physical state, and actions, thereby improving overall diving experience by assisting the diver. Although certain problems were encountered during trials, the collected data and experience were valuable to identify potential improvements. Most importantly, divers felt safe and comfortable working and interacting with a robotic BUDDY thus achieving the primary goal.

Previous studies have documented links between sub-clinical narcissism and the active pursuit of short-term mating strategies (e.g., unrestricted sociosexuality, marital infidelity, mate poaching). Nearly all of these investigations have relied solely on samples from Western cultures. In the current study, responsesfrom a cross-cultural survey of 30,470 people across 53 nations spanning 11 world regions (North America, Central/South America, Northern Europe, Western Europe, Eastern Europe, Southern Europe, Middle East, Africa, Oceania, Southeast Asia, and East Asia) were used to evaluate whether narcissism (as measured by the Narcissistic Personality Inventory; NPI) was universally associated with short-term mating. Results revealed narcissism scores (including two broad factors and seven traditional facets as measured by the NPI) were functionally equivalent across cultures, reliably associating with key sexual outcomes (e.g., more active pursuit of shortterm mating, intimate partner violence, and sexual aggression) and sex-related personality traits (e.g., higher extraversion and openness to experience). Whereas some features of personality (e.g., subjective well-being) were universally associated with socially adaptive facets of Narcissism (e.g., self-sufficiency), most indicators of short-term mating (e.g., unrestricted sociosexuality and marital infidelity) were universally associated with the socially maladaptive facets of narcissism (e.g., exploitativeness). Discussion addresses limitations of these cross-culturally universal findings and presents suggestions for future research into revealing the precise psychological features of narcissism that facilitate the strategic pursuit of short-term mating. Creative Commons CC-BY-SA licence.

Attractive facial features in women are assumed to signal fertility, but whether facial attractiveness predicts reproductive success in women is still a matter of debate. We investigated the association between facial attractiveness at young adulthood and reproductive life history—number of children and pregnancies—in women of a rural community. For the analysis of reproductive success, we divided the sample into women who used contraceptives and women who did not. Introducing two-dimensional geometric morphometric methodology, we analysed which specific characteristics in facial shape drive the assessment of attractiveness and covary with lifetime reproductive success. A set of 93 (semi)landmarks was digitized as two-dimensional coordinates in postmenopausal faces. We calculated the degree of fluctuating asymmetry and regressed facial shape on facial attractiveness at youth and reproductive success. Among women who never used hormonal contraceptives, we found attractive women to have more biological offspring than less attractive women. These findings are not affected by sociodemographic variables. Postmenopausal faces corresponding to high reproductive success show more feminine features—facial characteristics previously assumed to be honest cues to fertility. Our findings support the notion that facial attractiveness at the age of mate choice predicts reproductive success and that facial attractiveness is based on facial characteristics, which seem to remain stable until postmenopausal age.

It was recently shown that Austrians associate car front geometry with traits in a way that could be related to face shape geometry mapping to those same overall suites of traits. Yet, possible confounding effects of familiarity with the car models, media coverage and entertainment could not be ruled out. In order to address this, the current study uses a cross-cultural comparison. Adult subjects in two countries (Austria and Ethiopia, n=129) were asked to rate person characteristics of 46 standardized front views of automobiles on various trait scales. These two countries differ substantially with regard to their experience with car models and brands, as well as car marketing and media coverage. Geometric morphometrics was then used to assess the shape information underlying trait attribution. Car shapes for perceived maturity, maleness and dominance were highly similar in both countries, with patterns comparable to shape changes during facial growth in humans: Relative sizes of the forehead and windshield decrease with age/growth, eyes and headlights both become more slit-like, noses and grilles bigger, lips and air-intakes are wider. Austrian participants further attributed various degrees of some interpersonal attitudes and emotions, whereas neither Austrians nor Ethiopians congruently ascribed personalities. Morphological correlates of personal characteristics are discussed, as are person perception and its overgeneralization to inanimate objects. Cross-cultural similarities and differences are addressed, as well as implications for car styling, follow-up studies on driving and pedestrian behavior, and fundamental dimensions in inference from (human) faces.

A number of recent studies use body odor samples to study how odor affects various human social interactions. However, the methods used vary considerably, and only limited attention has been paid to the validity of the particular approaches adopted. One of the crucial points in body odor sampling is its length. Here we report the results of a study that tested the effects of using two different sampling periods, namely 12 and 24 h, on subsequent odor perception. Our results show significantly higher ratings of pleasantness and attractiveness, and lower ratings of intensity and masculinity, for the 12-h sampling condition. Further analysis of the data distribution suggests higher skew and a potential floor effect in hedonic ratings derived from the 24-h condition. These data imply that sampling length has a significant impact on perceived body odor quality and should thus be considered when designing studies in this area and in interpretation of results across studies.

Men and women score differently on some personality traits and people’s behavior reflects who they are. Therefore, males and females could be expected to express themselves differently on a behavioral level. To test this idea we turned the public performances of speakers (20 female and 20 male) into stick figure movies. Students of the University of Vienna ( n = 150) rated these movies on scales measuring the Big Five personality traits. The participants experienced difficulties in ascribing the correct sex to the stick figures. Nevertheless, stick figures representing male speakers received higher ratings for extraversion and emotional stability than stick figure animations of female speakers. In addition, gender stereotypes seemed to influence the participants’ ratings. Agreeableness, for instance, was preferably classified as female trait. In conclusion, our results suggest that body motion conveys social information, that men and women present themselves differently, and that people’s judgments are influenced by gender stereotypes.

Inclusive fitness theory presumes a human ability to discriminate between kin and nonkin. The present study investigated to what extent computer-generated similarity or dissimilarity can be discerned as phenotypic resemblance or dissimilarity, respectively, on a conscious level. Furthermore, sex differences assumed from female dispersal theory were examined. Three warps, one of computed similarity and one of computed dissimilarity of varying degree to a reference face among them, were presented to subjects, who were asked to indicate the image that they perceived as the most similar or dissimilar, respectively, to the source face. Higher degrees of (dis-)similarity led to higher recognition rates, which, however, never exceeded 80 percent. Women achieved higher recognition rates than men and (dis-)similarity was recognized more easily in female faces by both male and female subjects. We hypothesize that these sex differences are due to an evolutionary adaptation enabling women to recognize potentially remote relatives when they have left their natal groups and joined others to avoid inbreeding.

Human saliva not only helps control oral health (with anti-microbial proteins), but it may also play a role in chemical communication. As is the case with other mammalian species, human saliva contains peptides, proteins, and numerous volatile organic compounds (VOCs). A high-throughput analytical method is described for profiling a large number of saliva samples to screen the profiles of VOCs. Saliva samples were collected in a non-stimulated fashion. The method utilized static stir bar extraction followed by gas chromatography-mass spectrometry (GC-MS). The method provided excellent reproducibility for a wide range of salivary compounds, including alcohols, aldehydes, ketones, carboxylic acids, esters, amines, amides, lactones, and hydrocarbons. Furthermore, substantial overlap of salivary VOCs and the previously reported skin VOCs in the same subject group was found in this study by using pattern recognition analyses. Sensitivity, precision, and reproducibility of the method suggest that this technique has potential in physiological, metabolomic, pharmacokinetic, forensic, and toxicological studies of small organic compounds where a large number of human saliva samples are involved.

When people form impressions about others, they are mostly influenced by non-verbal cues. Thus, politicians and other leaders are judged by the behavior they display. To analyze the relation between non-verbal behavior and impression formation body movements of politicians giving a speech were transformed into animated stick figures. Subjects then rated the stick-figure movies on the five factor model of personality. Motion analysis revealed that observers associate extraversion, agreeableness, conscientiousness, emotional stability and openness with different motion qualities such as the amount of motion and its flow. Additionally, we found significant correlations between these personality traits and dominant activation of different body parts. The current study underlines that body motion is a powerful signal in human communication.

255 instances of “brow raise” filmed in three cultures in unstaged social interactions were analyzed on different levels using the “Facial Action Coding System” (FACS, Ekman & Friesen 1978). Contraction and slackening of the M. frontalis, pars medialis et lateralis are involved, and show temporal constancy in all three cultures, creating a pattern with a typical movement configuration. This configuration is discussed as a universal prerequisite for stimulus generation perception. The total time of contraction varies with contextual features, and brow raise in openings is longer than during interactions. An analysis of co-occurrence of other facial movements showed universal patterns occurring in all three cultures. Brow raise is most often accompanied by a smile. The antithesis of this “eyebrow flash”, both in neuromuscular and semantic aspect, is brought about by the action of the M. corrugator supercilii, lowering the brows and pulling them together. In addition, a set of functional patterns could be identified in all three cultures, ranging from a factual “yes” to a “yes to social contact”. Thus, the eyebrow flash can be interpreted as a “social marking-tool” which emphasizes the meaning of other facial cues, head movements and even verbal statements.

Objective: Body dissatisfaction is of high prevalence among women all over the Western world. It is often suggested that sociocultural processes are the main cause of such widespread dissatisfaction. Here, we consider how perceptual effects may influence ideas of body normality and body ideals. Method: Women who varied on a measure of body dissatisfaction rated a range of bodies for how normal and ideal they looked. They were exposed to either thin or fat bodies, and then they rerated the bodies. Results: Women’s perceptions of body normality and ideal were easily malleable by exposure. In addition, greater body dissatisfaction and internalization of the thin Western ideal were related to (i) a smaller most normal and ideal body, (ii) a greater discrepancy between the most normal and most ideal-rated body, and (iii) a reduced effect of exposure to fat bodies. Discussion: Reduced updating of perceptions of body normality and body ideals in response to experience may be one mechanism that maintains body dissatisfaction. V C 2008 by Wiley Periodicals

The evolutionary constraints that lead to the evolution of sexual reproduction are framed by the better repair mechanisms that repair fatal mutations, as well as the need for variable immune systems imposed on large organisms by parasites, such as viruses and bacteria. Besides the evolution of sexual reproduction, these factors also affect mate choice, especially as regards the gene complex that encodes the immune system. The need to increase both the likelihood of gametes to encounter each other as well as sufficient provision of nutrition for the offspring then leads to the evolution of two sexes: large numbers of small mobile sperms ensure that gametes meet, whereas large egg cells full of energy provide for the zygote, thus leading to a developmental advantage. The asymmetric investment in the offspring then affects not only mate choice criteria, but also cognitive strategies. Men place more importance on youthfulness and fertility than women, who regard resource holding potential as a more relevant criterion. Consequently, female jealousy is connected to endangered access to resources, whereas male jealousy is rooted in paternal uncertainty. Cognitive adaptations developed to ensure reproductive success show sex differences, such as in error management. The most obvious function of sexual behavior is reproduction. To foster the benefits for the offspring, reproduction partners should also develop an emotional bond, which is mediated by hormones connected to sexual intercourse. With increasing age, reproduction loses importance, while pair bonding functions remain relevant. Therefore, sexuality never ceases to be part of a relationship.

Over evolutionary time, humans have developed a selective sensitivity to features in the human face that convey information on sex, age, emotions, and intentions. This ability might not only be applied to our conspecifics nowadays, but also to other living objects (i.e., animals) and even to artificial structures, such as cars. To investigate this possibility, we asked people to report the characteristics, emotions, personality traits, and attitudes they attribute to car fronts, and we used geometric morphometrics (GM) and multivariate statistical methods to determine and visualize the corresponding shape information. Automotive features and proportions are found to covary with trait perception in a manner similar to that found with human faces. Emerging analogies are discussed. This study should have implications for both our understanding of our prehistoric psyche and its interrelation with the modern world.

Divers operate in harsh and poorly monitored environments, in which the slightest unexpected disturbance, technical malfunction, or lack of attention can have catastrophic consequences. Motivated by these considerations, the “CADDY—Cognitive Autonomous Diving Buddy” FP7 project sets forth the main goal of developing a cooperative autonomous underwater robotic system to monitor and assist human divers, thus affording them increased levels of safety during the execution of challenging scientific and commercial missions. This article presents the main results obtained in the first 2 years of the project along the following main research topics: Seeing the Diver, where the focus is placed on the 3D reconstruction of a diver's model (pose estimation and recognition of hand gestures) through remote and local sensing technologies, thus enabling behavior interpretation; Understanding the Diver, with the objective of interpreting the model and physiological measurements of the diver in order to determine the state of the diver; and Diver-Robot Cooperation and Control, aimed at investigating the interaction of the diver with underwater vehicles endowed with rich sensory motor skills, focusing on cooperative control and optimal formation with the diver as an integral part of the overall vehicle-diver formation.

Evolutionary psychology suggests that skin signals aspects of mate value, yet only limited empirical evidence exists for this assertion.We sought to study the relationship between perception of skin condition and homogeneity of color/chromophore distribution.Cropped skin cheek images from 170 girls and women (11-76 years) were blind-rated for attractiveness, healthiness, youthfulness, and biological age by 353 participants. These skin images and corresponding melanin/hemoglobin concentration maps were analyzed objectively for homogeneity.Homogeneity of unprocessed images correlated positively with perceived attractiveness, healthiness, and youthfulness (all r0.40; P.001), but negatively with estimated age (r = -0.45; P.001). Homogeneity of hemoglobin and melanin maps was positively correlated with that of unprocessed images (r = 0.92, 0.68; P.001) and negatively correlated with estimated age (r = -0.32, -0.38; P.001).Female skin only was studied.Skin color homogeneity, driven by melanin and hemoglobin distribution, influences perception of age, attractiveness, health, and youth.

The majority of works in metabolomics employ approaches based on principal components analysis (PCA) and partial least-squares, primarily to determine whether samples fall within large groups. However, analytical chemists rarely tackle the problem of individual fingerprinting, and in order to do this effectively, it is necessary to study a large number of small groups rather than a small number of large groups and different approaches are required, as described in this paper. Furthermore, many metabolomic studies on mammals and humans involve analyzing compounds (or peaks) that are present in only a certain portion of samples, and conventional approaches of PCA do not cope well with sparse matrices where there may be many 0s. There is, however, a large number of qualitative similarity measures available for this purpose that can be exploited via principal coordinates analysis (PCO). It can be shown that PCA scores are a specific case of PCO scores, using a quantitative similarity measure. A large-scale study of human sweat consisting of nearly 1000 gas chromatography/mass spectrometry analyses from the sweat of an isolated population of 200 individuals in Carinthia (Southern Austria) sampled once per fortnight over 10 weeks was employed in this study and grouped into families. The first step was to produce a peak table requiring peak detection, alignment, and integration. Peaks were reduced from 5080 to 373 that occurred in at least 1 individual over 4 out of 5 fortnights. Both qualitative (presence/absence) and quantitative (equivalent to PCA) similarity measures can be computed. PCO and the Kolomorogov-Smirnoff (KS) rank test are applied to these similarity matrices. It is shown that for this data set there is a reproducible individual fingerprint, which is best represented using the qualitative similarity measure as assessed both by the Hotelling t2 statistic as applied to PCO scores and the probabilities associated with the KS rank test.

Several studies have shown that microbial action is responsible for many compounds responsible for human odour. In this paper, we compare the pattern of microbial profiles and that of chemical profiles of human axillary odour by using multivariate pattern matching techniques. Approximately 200 subjects from Carinthia, Austria, participated in the study. The microbial profiles were represented by denaturing gradient gel electrophoresis (DGGE) analysis and the axillary odour profiles were determined in the sweat samples collected by a stir-bar sampling device and analysed by gas chromatography/mass spectrometry (GC/MS). Both qualitative and quantitative distance metrics were used to construct dissimilarity matrices between samples which were then used to represent the patterns of these two types of profiles. The distance matrices were then compared by using the Mantel test and the Procrustean test. The results show that on the overall dataset there is no strong correlation between microbial and chemical profiles. When the data are split into family groups, correlations vary according to family with a range of estimated p values from 0.00 to 0.90 that the null hypothesis (no correlation) holds. When 32 subjects who followed four basic rules of behaviour were selected, the estimated p-values are 0.00 using qualitative and

Pattern recognition studies are performed on the gas chromatography mass spectrometry of extracts of human sweat of 182 subjects sampled 5 times (over 5 fortnights), in an attempt to determine whether it is possible to classify samples into those arising from males and females. All methods were applied to peak tables of square root normalised GC-MS peak areas. Potential markers were identified using both a univariate (t-statistic) and multivariate (Partial Least Squares Discriminant Analysis: PLS-DA) method, on each fortnight separately, selecting those peaks that have high ranks each fortnight. Classification was performed using PLS-DA, selecting the model using 100 repetitions for each fortnight dividing the data into test and training sets randomly, and using the bootstrap to find the number of significant components for each of the 100 models. Contingency tables can be drawn up for the number of misclassified samples, using three error criteria, namely autoprediction, bootstrap and test set. The decision threshold for which sample is assigned to a group can be adjusted and Receiver Operator Characteristic curves were used to visualise the influence on changing this threshold. It is shown that by using the entire set of 910 measurements there is a closer correspondence between autoprediction and test set error rates than for 182 measurements where there is less agreement, suggesting that sample size has a key role. A general strategy for studying large metabolomics datasets is proposed.

Facial expressions of emotions are important in nonverbal communication. Although numerous neural structures have been identified to be involved in emotional face processing, the amygdala is thought to be a core moderator. While previous studies have relied on facial images of humans, the present study is concerned with the effect of computer-generated (avatar) emotional faces on amygdala activation. Moreover, elicited activation patterns in response to viewing avatar faces are compared with the neuronal responses to human facial expressions of emotions. Twelve healthy subjects (five females) performed facial emotion recognition tasks with optimized 3T event-related fMRI. Robust amygdala activation was apparent in response to both human and avatar emotional faces, but the response was significantly stronger to human faces in face-sensitive structures, i.e. fusiform gyri. We suggest that avatars could be a useful tool in neuroimaging studies of facial expression processing because they elicit amygdala activation similarly to human faces, yet have the advantage of being highly manipulable and fully controllable. However, the finding of differences between human and avatar faces in face-sensitive regions indicates the presence of mechanisms by which human brains can differentiate between them. This mechanism merits further investigation.

© 2015 Elsevier Inc. There is more to female attractiveness than a pretty face. Human mate choice decisions are guided by different cues, which in combination may give a better estimate of a general condition. We hypothesized that such signal redundancy might be true for vocal and visual cues of human female attractiveness. To test this we used photographs of women's faces, recorded their voices and asked men to rate both types of stimuli on attractiveness. We found a significant relationship between males' ratings of female faces and voices. Moreover, low levels of fluctuating asymmetry of women's bodies and faces were associated with high ratings on facial and vocal attractiveness. Applying the Geometric Morphometric Methodology we performed a multivariate regression analysis of attractiveness ratings with landmark data obtained from women's faces. We found similar facial shape changes for ratings of facial and vocal attractiveness that are both negatively related to facial and body FA. Findings suggest that females with an attractive face also tend to have an attractive voice and that this redundant information is reflected in female facial shape.

Individuals are thought to have their own distinctive scent, analogous to a signature or fingerprint. To test this idea, we collected axillary sweat, urine and saliva from 197 adults from a village in the Austrian Alps, taking five sweat samples per subject over 10 weeks using a novel skin sampling device. We analysed samples using stir bar sorptive extraction in connection with thermal desorption gas chromatograph–mass spectrometry (GC–MS), and then we statistically analysed the chromatographic profiles using pattern recognition techniques. We found more volatile compounds in axillary sweat than in urine or saliva, and among these we found 373 peaks that were consistent over time (detected in four out of five samples per individual). Among these candidate compounds, we found individually distinct and reproducible GC–MS fingerprints, a reproducible difference between the sexes, and we identified the chemical structures of 44 individual and 12 gender-specific volatile compounds. These individual compounds provide candidates for major histocompatibility complex and other genetically determined odours. This is the first study on human axillary odour to sample a large number of subjects, and our findings are relevant to understanding the chemical nature of human odour, and efforts to design electronic sensors (e-nose) for biometric fingerprinting and disease diagnoses.

Evolutionary psychologists have proposed that preferences for facial characteristics, such as symmetry, averageness, and sexual dimorphism, may reflect adaptations for mate choice because they signal aspects of mate quality. Here, we show that facial skin color distribution significantly influences the perception of age and attractiveness of female faces, independent of facial form and skin surface topography. A set of three-dimensional shape-standardized stimulus faces—varying only in terms of skin color distribution due to variation in biological age and cumulative photodamage—was rated by a panel of naive judges for a variety of perceptual endpoints relating to age, health, and beauty. Shapeand topography-standardized stimulus faces with the homogeneous skin color distribution of young people were perceived as younger and received significantly higher ratings for attractiveness and health than analogous stimuli with the relatively inhomogeneous skin color distribution of more elderly people. Thus, skin color distribution, independent of facial form and skin surface topography, seems to have a major influence on the perception of female facial age and judgments of attractiveness and health as they may signal aspects of underlying physiological condition of an individual relevant for mate choice. We suggest that studies on human physical attractiveness and its perception need to

Bilateral symmetry of physical traits is thought to reflect an individual’s phenotypic quality, especially their ability to resist environmental perturbations during development. Therefore, facial symmetry may signal the ability of an individual to cope with the challenges of their environment. Studies concerning the relationship between symmetry and attractiveness lead to the conclusion that preferences for symmetric faces may have some adaptive value. We hypothesized that if symmetry is indeed indicative of an individual’s overall quality, faces high in symmetry should receive higher ratings of attractiveness and health, but also be perceived as demonstrating certain positive personality attributes. College students’ attributions of a set of 20 female faces varying in facial symmetry were recorded. As predicted, faces high in symmetry received significantly higher ratings of attractiveness, health, and certain personality attributes (i.e., sociable, intelligent, lively, self-confident, balanced). Faces low in symmetry were rated as being more anxious. These differences were not caused by an attractiveness stereotype. The present results lend further support to the notions that (i) facial symmetry is perceived as being attractive, presumably reflecting health certification

A hypothesis derived from evolutionary theory and previous qualitative observation is that male and female subordinates deploy different interpersonal signals to obtain concessions from powerful males. The present study tested this hypothesis by means of a quantitative naturalistic observational method. Would-be patrons were videotaped approaching the entrance of an exclusive nightclub in Munich, Germany, where doormen control entry. Patrons' dominance, affiliative, and sexual signals in gestures and dress were coded for conditions of low and high doorman threat. Although both sexes used appeasing gestures of smiles and greetings, females deployed many appeasements using affiliative and courtship signals while males tended to withhold appeasements by masking agonistic affect. Moreover, when approaching larger numbers of doormen, males accelerated while females slowed down. The evolutionary hypothesis was confirmed, at least for our German sample, that males and females use some different strategies for minimizing threat from powerful males.

The average human male face differs from the average female face in size and shape of the jaws, cheek-bones, lips, eyes and nose. It is possible that this dimorphism is determined by sex steroids such as testosterone (T) and oestrogen (E), and several studies on the perception of such characteristics have been based on this assumption, but those studies focussed mainly on the relationship of male faces with circulating hormone levels; the corresponding biology of the female face remains mainly speculative. This paper is concerned with the relative importance of prenatal T and E levels (assessed via the 2D : 4D finger length ratio, a proxy for the ratio of T/E) and sex in the determination of facial form as characterized by 64 landmark points on facial photographs of 106 Austrians of college age. We found that (i) prenatal sex steroid ratios (in terms of 2D : 4D) and actual chromosomal sex dimorphism operate differently on faces, (ii) 2D : 4D affects male and female face shape by similar patterns, but (iii) is three times more intense in men than in women. There was no evidence that these effects were confounded by allometry or facial asymmetry. Our results suggest that studies on the perception of facial characteristics need to consider differential effects of prenatal hormone exposure and actual chromosomal gender in order to understand how characteristics have come to be rated ‘masculine’ or ‘feminine’ and the consequences of these perceptions in terms of mate preferences.

The present study investigated possible associations between facial symmetry and actual personality as assessed by the 'big-five' personality factors: neuroticism (N), extraversion (E), openness (O), agreeableness (A), and conscientiousness (C). Digital photographs were taken of male and female faces, volunteers also completed the NEO-FFI personality inventory. Facial images were analysed for horizontal symmetry by means of digital image processing. Following previous reports we predicted that facial symmetry should be negatively related to neuroticism but positively related to extraversion, openness, agreeableness, and conscientiousness. In general, our data on actual personality confirmed previous reports on perceptions of personality for neuroticism and extraversion. Neuroticism was found to be negatively but not significantly related to facial symmetry whereas extraversion was positively associated. In contrast to previous data, we found significant negative associations between facial symmetry and openness and agreeableness. Conscientiousness was non-significantly related to facial symmetry. The strongest associations with facial symmetry were found for extraversion and openness. Our results suggest that behavioural perceptions of an individual may reflect an individual's actual personality, and facial symmetry is a correlate of personality. However, because of some inconsistencies between this and previous studies we suggest that (1) the associations between facial symmetry and personality traits require further investigation, and (2) future studies should urge for methodological consistency to make results comparable.

Olfactory communication is very common amongst animals, and since the discovery of an accessory olfactory system in humans, possible human olfactory communication has gained considerable scientific interest. The importance of the human sense of smell has by far been underestimated in the past. Humans and other primates have been regarded as primarily 'optical animals' with highly developed powers of vision but a relatively undeveloped sense of smell. In recent years this assumption has undergone major revision. Several studies indicate that humans indeed seem to use olfactory communication and are even able to produce and perceive certain pheromones; recent studies have found that pheromones may play an important role in the behavioural and reproduction biology of humans. In this article we review the present evidence of the effect of human pheromones and discuss the role of olfactory cues in human sexual behaviour.

Evolutionary behavioral biology suggests that certain characteristics of the human face and body are important for mate preferences and are therefore subject to sexual selection. J. Weeden and J. Sabini identify a number of weaknesses in the association between traits' attractiveness and health. In contrast, the authors argue that (a) studies on preferences for physical characteristics that rely on 1 trait permit only limited interpretation, (b) limitations placed on J. Weeden and J. Sabini's review exclude important associations, (c) there are misconceptions in their treatment of some traits, and (d) their selected literature provides an inaccurate picture regarding effect size. The authors suggest that future research in this field should seek conceptual and methodological constancy in trait selection and in the evaluation of attractiveness- and health-related traits.