An integrated entropy-spatial framework for automatic gender recognition enhancement of emotion-based EEGs.

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.

Complexity and Entropy Analysis to Improve Gender Identification from Emotional-Based EEGs.

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.

Electroencephalogram Profiles for Emotion Identification over the Brain Regions Using Spectral, Entropy and Temporal Biomarkers.

Identifying emotions has become essential for comprehending varied human behavior during our daily lives. The electroencephalogram (EEG) has been adopted for eliciting information in terms of waveform distribution over the scalp. The rationale behind this work is twofold. First, it aims to propose spectral, entropy and temporal biomarkers for emotion identification. Second, it aims to integrate the spectral, entropy and temporal biomarkers as a means of developing spectro-spatial ( S S ) , entropy-spatial ( E S ) and temporo-spatial ( T S ) emotional profiles over the brain regions. The EEGs of 40 healthy volunteer students from the University of Vienna were recorded while they viewed seven brief emotional video clips. Features using spectral analysis, entropy method and temporal feature were computed. Three stages of two-way analysis of variance (ANOVA) were undertaken so as to identify the emotional biomarkers and Pearson's correlations were employed to determine the optimal explanatory profiles for emotional detection. The results evidence that the combination of applied spectral, entropy and temporal sets of features may provide and convey reliable biomarkers for identifying S S , E S and T S profiles relating to different emotional states over the brain areas. EEG biomarkers and profiles enable more comprehensive insights into various human behavior effects as an intervention on the brain.

Effective EEG Channels for Emotion Identification over the Brain Regions using Differential Evolution Algorithm.

The motivation of this study was to detect the most effective electroencephalogram (EEG) channels for various emotional states of the brain regions (i.e. frontal, temporal, parietal and occipital). The EEGs of ten volunteer participants without health conditions were captured while the participants were shown seven, short, emotional video clips with audio (i.e. anger, anxiety, disgust, happiness, sadness, surprise and neutral). The Savitzky-Golay (SG) filter was adopted for smoothing and denoising the EEG dataset. The spectral features were performed by employing the relative spectral powers of delta (δRP), theta (θRP), alpha (αRP), beta (ßRP), and gamma (γRP). The differential evolution-based channel selection algorithm (DEFS_Ch) was computed to find the most suitable EEG channels that have the greatest efficacy for identifying the various emotional states of the brain regions. The results revealed that all seven emotions previously mentioned were represented by at least two frontal and two temporal channels. Moreover, some emotional states could be identified by channels from the parietal region such as disgust, happiness and sadness. Furthermore, the right and left occipital channels may help in identifying happiness, sadness, surprise and neutral emotional states. The DEFS_Ch algorithm raised the linear discriminant analysis (LDA) classification accuracy from 80% to 86.85%, indicating that DEFS_Ch may offer a useful way for reliable enhancement of the detection of different emotional states of the brain regions.

Sex differences and similarities in urban home ranges and in the accuracy of cognitive maps.

Former research has examined potential human sex differences in spatial abilities or home range size. Both are assumed to have an adaptive function. In this study we combined the investigation of home range size in an urban environment and spatial abilities by accuracy analysis of cognitive maps. Participants (n = 87) drew a sketch of their home range in Vienna depicting all places regularly visited in every-day life. We used the sketches' geographical locations to calculate the size of the home range. With the Geometric Morphometric Methodology, we quantified the accuracy of cognitive maps by measuring Euclidean distances between corresponding landmarks in the sketches and the geographical maps of home ranges. Our results showed a non-significant trend for men to have a larger home range. Overall, participants' cognitive maps were fairly accurate. However, men sketched their home range more precisely than women. Female map accuracy increased as a function of residency duration. In addition, accuracy of cognitive maps was influenced by home range size and number of frequently visited places. In summary, findings indicate that sex differences in home range size and spatial abilities may still persist in humans living in urbanized Western societies, but are also influenced by environmental experience.

The case of Moulay Ismael--fact or fancy?

Textbooks on evolutionary psychology and biology cite the case of the Sharifian Emperor of Morocco, Moulay Ismael the Bloodthirsty (1672-1727) who was supposed to have sired 888 children. This example for male reproduction has been challenged and led to a still unresolved discussion. The scientific debate is shaped by assumptions about reproductive constraints which cannot be tested directly-and the figures used are sometimes arbitrary. Therefore we developed a computer simulation which tests how many copulations per day were necessary to reach the reported reproductive outcome. We based our calculations on a report dating 1704, thus computing whether it was possible to have 600 sons in a reproductive timespan of 32 years. The algorithm is based on three different models of conception and different social and biological constraints. In the first model we used a random mating pool with unrestricted access to females. In the second model we used a restricted harem pool. The results indicate that Moulay Ismael could have achieved this high reproductive success. A comparison of the three conception models highlights the necessity to consider female sexual habits when assessing fertility across the cycle. We also show that the harem size needed is far smaller than the reported numbers.

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

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

Laying eyes on headlights: eye movements suggest facial features in cars.

Humans' proneness to see faces even in inanimate structures such as cars has long been noticed, yet empirical evidence is scarce. To examine this tendency of anthropomorphism, participants were asked to compare specific features (such as the eyes) of a face and a car front presented next to each other. Eye movement patterns indicated on which visual information participants relied to solve the task and clearly revealed the perception of facial features in cars, such as headlights as eyes or grille as nose. Most importantly, a predominance of headlights was found in attracting and guiding people's gaze irrespective of the feature they were asked to compare--equivalent to the role of the eyes during face perception. This response to abstract configurations is interpreted as an adaptive bias of the respective inherent mechanism for face perception and is evolutionarily reasonable with regard to a "better safe than sorry" strategy.

Analysis of volatile organic compounds in human saliva by a static sorptive extraction method and gas chromatography-mass spectrometry.

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.

A neural signature of anorexia nervosa in the ventral striatal reward system.

OBJECTIVE: Animal studies assessing mechanisms of self-starvation under conditions of stress and diet suggest a pivotal role for the mesolimbic reward system in the maintenance of core symptoms in anorexia nervosa, which is corroborated by initial empirical evidence in human studies. The authors examined activity in the ventral striatal system in response to disease-specific stimuli in women with acute anorexia nervosa. METHOD: Participants were 14 women with acute anorexia nervosa and 14 matched healthy comparison women who underwent functional magnetic resonance imaging (fMRI) during evaluation of visual stimuli depicting a female body with underweight, normal weight, and overweight canonical whole-body features according to standardized body mass indices. Participants were required to process each stimulus in a self-referring way. Ratings for each weight category were used as the control task. RESULTS: Behaviorally, women with anorexia nervosa provided significantly higher positive ratings in response to underweight stimuli than in response to normal-weight stimuli, while healthy comparison women showed greater preference for normal-weight stimuli relative to underweight stimuli. Functionally, ventral striatal activity demonstrated a highly significant group-by-stimulus interaction for underweight and normal-weight stimuli. In women with anorexia nervosa, activation was higher during processing of underweight stimuli compared with normal-weight stimuli. The reverse pattern was observed in healthy comparison women. CONCLUSIONS: These findings are consistent with predictions in animal studies of the pivotal role of the human reward system in anorexia nervosa and thus support theories of starvation dependence in maintenance of the disorder.

Body dissatisfaction and attentional bias to thin bodies.

OBJECTIVE: Evidence for attentional biases to weight- and shape-related information in women with eating concerns is inconclusive. METHOD: We investigated whether body dissatisfaction is associated with an attentional bias toward thin bodies using a modified dot probe task. RESULTS: In three studies, we found that undergraduate females were faster to discriminate the direction of an arrow cue when it appeared in the location previously occupied by a thin than a fat body. This attentional bias toward thin bodies was found using extreme stimuli (thin and fat bodies) presented for 500 ms (Experiment 1), extreme stimuli presented for 150 ms (Experiment 2), and less extreme stimuli that were equated for perceived extremity, presented for 150 ms (Experiment 3). When the stimuli were equated on perceptual extremity, the more dissatisfied a woman was with her body, and the larger her own BMI, the less of an attentional bias she showed toward thin bodies. DISCUSSION: Our results indicate that women have an attentional bias to thin bodies, which appears to be automatic. Contrary to prediction, this bias was weaker in women with greater BMI and body dissatisfaction. This result offers no support for the view that selective attention to thin bodies is causally related to body dissatisfaction.

Immune reactivity and attractiveness.

Over the past decades, information about the characteristics of attractiveness has accumulated. We know about eight pillars of beauty, among them youthfulness, symmetry, hormone markers and body odor. But what is the biological function of these attractive signals? Is there one common function to be found in all eight beauty markers? In this paper, we argue that attractiveness signals immune resistance. Being attractive would thus be an honest signal for an immune system that coped well with the environmental challenges it was exposed to during ontogeny. This is a prerequisite for developmental stability, which again affects the differentiation of beauty characteristics. We argue that human preferences and mate choice criteria have evolved in coevolution with parasites, and that the current parasite load modulates our decision making.

Ageing, mate preferences and sexuality: a mini-review.

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.

Face gender and emotion expression: are angry women more like men?

Certain features of facial appearance perceptually resemble expressive cues related to facial displays of emotion. We hypothesized that because expressive markers of anger (such as lowered eyebrows) overlap with perceptual markers of male sex, perceivers would identify androgynous angry faces as more likely to be a man than a woman (Study 1) and would be slower to classify an angry woman as a woman than an angry man as a man (Study 2). Conversely, we hypothesized that because perceptual features of fear (raised eyebrows) and happiness (a rounded smiling face) overlap with female sex markers, perceivers would be more likely to identify an androgynous face showing these emotions as a woman than as a man (Study 1) and would be slower to identify happy and fearful men as men than happy and fearful women as women (Study 2). The results of the two studies showed that happiness and fear expressions bias sex discrimination toward the female, whereas anger expressions bias sex perception toward the male.

Body dissatisfaction and the effects of perceptual exposure on body norms and ideals.

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.

Visual attention to variation in female facial skin color distribution.

OBJECTIVES: Visible skin condition of women is argued to influence human physical attraction. Recent research has shown that people are sensitive to variation in skin color distribution, and such variation affects visual perception of female facial attractiveness, healthiness, and age. METHODS: The eye gaze of 39 males and females, aged 13 to 45 years, was tracked while they viewed images of shape- and topography-standardized stimulus faces that varied only in terms of skin color distribution. RESULTS: The number of fixations and dwell time were significantly higher when viewing stimulus faces with the homogeneous skin color distribution of young people, compared with those of more elderly people. In accordance with recent research, facial stimuli with even skin tones were also judged to be younger and received higher attractiveness ratings. Finally, visual attention measures were negatively correlated with perceived age, but positively associated with attractiveness judgments. CONCLUSIONS: Variation in visible skin color distribution (independent of facial form and skin surface topography) is able to selectively attract people's attention toward female faces, and this higher attention results in more positive statements about a woman's face.

Face to Face : The Perception of Automotive Designs.

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.

Color homogeneity and visual perception of age, health, and attractiveness of female facial skin.

BACKGROUND: Evolutionary psychology suggests that skin signals aspects of mate value, yet only limited empirical evidence exists for this assertion. OBJECTIVES: We sought to study the relationship between perception of skin condition and homogeneity of color/chromophore distribution. METHODS: 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. RESULTS: Homogeneity of unprocessed images correlated positively with perceived attractiveness, healthiness, and youthfulness (all r > 0.40; 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). LIMITATIONS: Female skin only was studied. CONCLUSIONS: Skin color homogeneity, driven by melanin and hemoglobin distribution, influences perception of age, attractiveness, health, and youth.

Application of dissimilarity indices, principal coordinates analysis, and rank tests to peak tables in metabolomics of the gas chromatography/mass spectrometry of human sweat.

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.