Stimuli In Man Research Articles

Pattern recognition reveals sex-dependent neural substrates of sexual perception.

Sex differences in brain activity evoked by sexual stimuli remain elusive despite robust evidence for stronger enjoyment of and interest toward sexual stimuli in men than in women. To test whether visual sexual stimuli evoke different brain activity patterns in men and women, we measured hemodynamic brain activity induced by visual sexual stimuli in two experiments with 91 subjects (46 males). In one experiment, the subjects viewed sexual and nonsexual film clips, and dynamic annotations for nudity in the clips were used to predict hemodynamic activity. In the second experiment, the subjects viewed sexual and nonsexual pictures in an event-related design. Men showed stronger activation than women in the visual and prefrontal cortices and dorsal attention network in both experiments. Furthermore, using multivariate pattern classification we could accurately predict the sex of the subject on the basis of the brain activity elicited by the sexual stimuli. The classification generalized across the experiments indicating that the sex differences were task-independent. Eye tracking data obtained from an independent sample of subjects (N=110) showed that men looked longer than women at the chest area of the nude female actors in the film clips. These results indicate that visual sexual stimuli evoke discernible brain activity patterns in men and women which may reflect stronger attentional engagement with sexual stimuli in men.

Increased pupil and heart-rate responses to sexual stimuli in men after physical exertion.

Physical stress has been found to enhance arousability by visual sexual stimuli on a short-term basis, as reflected in higher phasic pupil dilation responses, probably mediated by sympathetic nervous system (SNS)-related processes. However, previous research has not addressed the specificity of this effect in terms of emotional valence, that is, whether it reflects an instance of general excitation transfer or a more specific mechanism. Thus, to further investigate changes in sexual processing after acute stress exposure, 40 male participants underwent either a predominantly sympathetic stressor (3min sustained handgrip) or similar control procedure. After stress induction, pictures varying in valence as well as sexual versus non-sexual arousal were presented (for 5000 ms each). Using principal component analysis, pupillary responses during picture viewing were dissociated into fast and slow components (early vs. late response phases). In addition, startle eyeblink responses were elicited by bursts of white noise (50 ms, 105 dB) in half of the trials and recorded at the orbicularis oculi via electromyography. Skin conductance and heart rate were co-registered, as well. While affective startle modulation and skin conductance responses to emotional stimuli were unaffected by previous stress exposure, both evoked heart-rate deceleration (but not acceleration) and pupil responses were specifically enhanced with sexually arousing stimuli in stressed participants, and this effect was mediated by blood pressure reactivity as an index of preceding SNS activation. Taken together, our findings provide strong evidence for enhancement of sexual processing by acute stress exposure in men and suggest differential involvement of parasympathetic versus sympathetic mechanisms.

Disinhibition augments thirst perception from two dehydrating stimuli in men

Physiological systems controlling water and energy ingestion are coordinated. Whether maladaptive eating behavior and appetite for water are linked is unknown. Thus, we sought to investigate the association between maladaptive eating and both thirst and water drinking behavior with two dehydrating conditions. Twenty-two lean men and 20 men with obesity (mean age 32.3 ± 8.4 years and 30.0 ± 11.1 years, respectively) completed the Three-Factor Eating Questionnaire (TFEQ) and Gormally Binge Eating Scale. On separate days, volunteers were dehydrated by a 2-h hypertonic saline infusion and a 24-h water deprivation, and thirst was measured on a 100-mm visual analogue scale (VAS) during each procedure. After each dehydrating condition, ad libitum water intake was measured. In the saline infusion, higher Disinhibition on the TFEQ was associated with thirst in the lean group (β = 4.2 mm VAS, p = 0.03) but not in the group with obesity (p = 0.51). In the water-deprivation condition, higher Disinhibition was also associated with thirst in the lean group (β = 5.6 mm VAS, p = 0.01) with the strength of relationship being 3.5-fold stronger than that observed in the group with obesity (β = 1.6 mm VAS, p = 0.0003). Hunger, Restraint, and binge-eating scores were not associated with thirst in either dehydrating condition (all p > 0.05). Maladaptive eating behaviors were not associated with ad libitum water intake (all p > 0.05). Disinhibition is associated with higher thirst perception in healthy weight individuals and may be attenuated in obesity. The characteristics of disinhibition which typically includes a heightened readiness to eat, may reflect a more general phenotype that also reflects a readiness to drink.

GREATER EFFECT OF AUDITORY STIMULI THAN VISUAL STIMULI ON ANTICIPATORY POSTURAL ADJUSTMENTS INCREASE

Purpose: The role of visual stimuli as the primary stimulus and the effect of auditory stimulus before external perturbation on Anticipatory Postural Adjustments (APAs) releases has been investigated, but which type of stimulus (auditory or visual) before perturbation has a more significant effect on initial APAs release, needs to be investigated. So, this study aimed to investigate the role of visual-auditory contributions before external perturbation on APAs and the effect of stimulus presentation on the release of APAs at different time intervals.
 Methods: Participants in this study were fourteen physical education students (Meanage 22.4 ± 2.14 years) exposed to five trials of visual stimulus and five trials of an audible stimulus (80 dB) while standing on the Biodex balance sheet. Then, 1.4 seconds after presenting the stimulus, external perturbation was applied. Electromyography (EMG) activity of the postural muscles was recorded during all trials. APAs were extracted at intervals of -100 to 50 ms (APA1), 50 to 200 ms (APA2), and 200 to 350 ms (APA3). The mixed ANOVA and repeated measures analysis of variance with Bonferroni correction test were used for data analysis.
 Results: The results showed that the presentation of visual and auditory stimuli increased the APAs of the postural muscles. According to these results, APA3 was greater than APA2 and APA2 than APA1(P≤0.05). Also, the results showed that auditory stimulus increased the APAs of the postural muscles more than the visual stimulus (P≤0.05).
 Conclusion: Generally, the researchers concluded that providing an auditory stimulus before perturbation has a greater effect on APA than a visual stimulus in healthy young girls. Therefore, it is suggested that in order to prevent imbalance or maintain greater balance, auditory stimuli with appropriate intensity can be used. Furthermore, subsequent research on this topic could include comparing APA release under the influence of visual and auditory stimuli in men and women, athletes and non-athletes, and healthy individuals with individuals with mobility impairments.

Distended Seminal Vesicles Are Involved in Specific Cerebral Sexual Arousal: A Pilot Study Using Functional Brain Imaging in Young Healthy Men

BackgroundWhether seminal vesicles play a role in sexual activity in men is unknown. No study so far has compared the neural processing of visual sexual stimuli in men depending on the filling state of the seminal vesicles. ObjectiveTo evaluate potential specific cortical activation by visual sexual stimuli with distended and empty seminal vesicles. Design, setting, and participantsA prospective case-control trial was conducted. Six male individuals underwent two visits on 2 consecutive days for hormone analyses; Derogatis Interview for Sexual Functioning (DISF) questionnaire; functional magnetic resonance imaging (fMRI) with passively viewing sexual, neutral, positive, and negative emotional pictures; and structural pelvic MRI. After the first visit, the participants had to empty seminal vesicles by masturbation. During fMRI, every participant viewed alternating blocks of sexual, neutral, positive, and negative emotional pictures. Outcome measurements and statistical analysisComparisons between days 1 and 2 were evaluated using paired t tests. Results and limitationsNo significant differences were observed regarding hormone analyses, DISF questionnaire score, and arousal scoring between days 1 and 2. Seminal vesicle volume was significantly lower on day 2 (p = 0.003). Significantly higher activation was observed in the right precentral gyrus, middle frontal gyrus, and right superior temporal sulcus when contrasted for sexual over neutral (p < 0.05). ConclusionsIn response to pictures with sexual emotional content, significantly higher activation was detected in brain areas involved in motor preparation (arousal) and coding of desirability of visual sexual stimuli in men with distended seminal vesicles than in the same men with emptied seminal vesicles. This suggests that the filling state of the seminal vesicles may influence sexual desire in men. Patient summaryWe compared brain activity of men with filled and emptied seminal vesicles by functional magnetic resonance imaging. We found that men with filled seminal vesicles had higher activation of brain areas involved in arousal and sexual desire.

Evidence of attentional bias toward body stimuli in men.

Over the past 30 years, attentional bias for body shape and weight content has been implicated in the precipitation and maintenance of body dissatisfaction and eating disorders. Although the existence of this bias toward body stimuli is well-established in female populations, it is comparatively understudied in men. This review aimed to examine the nature of this visual attentional bias toward male bodies in male samples across a range of different attentional paradigms, including eye-tracking, dot-probe, and the visual search task. Results were heterogenous, finding some evidence that men with higher body dissatisfaction and eating disorder symptoms demonstrated an attentional bias toward desirable bodies of other men, and undesirable features of their own bodies. These results suggest that schematic cognitive models of body dissatisfaction and eating disorders body may also be applicable to men, however more research is needed.

Hormones and visual attention to sexual stimuli in older men: an exploratory investigation

Background Testosterone is associated with sexual desire and performance in men, but little is known about cognitive mechanisms underlying this relationship. Even less is known about the influence of estradiol, despite its production from testosterone, and high receptor density in brain regions related to male sexual behavior. Method We used eye-tracking to compare men’s visual attention to images of fully clothed (i.e. neutral) and minimally clothed (i.e. sexy) models in three groups: androgen-deprived (n = 6) and not androgen-deprived with prostate cancer (n = 11), and healthy controls (n = 7). We also assessed effects of serum testosterone, estradiol, and sex hormone-binding globulin levels. Results We found no group effect for fixations to sexy compared to neutral images, and no influence of testosterone on either total fixations, or proportion of fixations to sexy images. In contrast, we found that sex hormone binding globulin positively predicted total fixations, and estradiol positively predicted proportion of total fixations on sexy images--regardless of androgen treatment status. Conclusion Our results suggest that visual attention to sexual stimuli in men may be significantly affected by hormones. This has potential implications for clinical populations that experience sexual side effects, such as prostate cancer patients on androgen deprivation therapy.

Kinetics of oxytocin effects on amygdala and striatal reactivity vary between women and men.

Accumulating evidence suggests that intranasal oxytocin (OXT; 24 IU) reduces amygdala responses to fear-related stimuli in men, while exerting inverse effects in women. However, OXT enhances activity of the brain reward system in both sexes. Importantly, a crucial and still open question is whether there are sex-specific dose-response relationships for the amygdala and striatal regions. To address this question, a total of 90 healthy women participated in a double-blind, placebo-controlled crossover functional magnetic resonance imaging (fMRI) study and the results were compared with our previous findings from men. Participants were randomly assigned to three doses of OXT (6 IU, 12 IU, and 24 IU) and completed an emotional face recognition task including fearful and happy faces of varying emotional intensities. Across doses, OXT enhanced amygdala reactivity to low fearful faces compared to placebo and increased responses to happy faces in the dorsal striatum in women. While treatment effects on amygdala reactivity were evident at each given dose, the OXT effect on striatal responses to social stimuli was more pronounced with higher doses, but this dose-dependent effect did not survive correction for multiple comparisons. Importantly, OXT effects on amygdala and striatal activation significantly differed between sexes and striatal baseline sexual-dimorphic response patterns were diminished after administration of OXT. Our findings suggest that OXT increases the salience of social signals by strengthening the sensitivity for these signals in the amygdala and in the striatum in women, while OXT may primarily induce anxiolysis by reducing amygdala responses in men.

Observing Erotic Videos with Heterosexual Content Induces Different Cerebral Responses in Homosexual and Heterosexual Men

ABSTRACT To determine the cerebral functionality associated with the perception and processing of erotic stimuli in men with different sexual orientation, this work evaluated the electroencephalographic activity (EEG) from several cortical areas, as well as subjective arousal in homosexual and heterosexual men during observation of an erotic film with heterosexual content. The heterosexual men rated the erotic video with higher general and sexual arousal than the homosexual participants. During observation of the neutral and erotic videos, both groups showed a decreased amplitude of the alpha band in prefrontal and parietal cortices, indicating increased attention. When watching the erotic video, the homosexual men showed an increased amplitude of the theta and fast bands only in the prefrontal cortex, which could be related to the cognitive processing of the erotic stimulus. These EEG results should broaden our knowledge of the cortical mechanisms related to the different perception and processing of erotic stimuli in men with different sexual orientations.

“I can see you”: The impact of implied social presence on visual attention to erotic and neutral stimuli in men and women

The watchful eye of others often leads people to alter their behaviour. Eye tracking methodology has been used to create implied social presence, as well as to examine gaze patterns to erotic stimuli, but the effects of implied social presence on visual attention to erotic and neutral stimuli remains largely unknown. In the present study, we examined precisely this issue. We compared looking behaviour of men and women who were either aware that their gaze patterns were being monitored (implied social presence) and those who lacked this knowledge (no implied presence). Women in the aware condition made significantly fewer fixations than men, whereas no such gender differences were found in the unaware condition. Across both conditions, men made significantly more fixations to the erotic stimuli compared to the neutral stimuli and the background. For women, no significant differences were found in the number of fixations to the erotic stimuli and the background, although women look at these areas more than the neutral stimuli. These results demonstrate that eye tracking creates an implied social presence, and this differentially affects the looking behaviour of women versus men. Moreover, gendered sexual norms coupled with the need to manage self-presentation may influence women’s sexual urges and expressions. The inhibition of sexuality displayed by women indicates that sexual double standards still exist in society and need to be addressed. As well, theoretical, methodological, and clinical implications of eye tracking methodology should be taken into consideration in future research.

Functional Magnetic Resonance Imaging Detects Between-Group Differences in Neural Activation Among Men with Delayed Orgasm Compared with Normal Controls: Preliminary Report

BackgroundMechanisms underlying delayed orgasm (DO) are poorly understood; however, known effects of psychotropic medications on sexual function provides a rationale for aberrant central nervous system signaling as a cause. AimTo compare brain activation between men with normal orgasm and those with lifelong DO during sexual stimulation using brain fMRI algorithms. Methods3 subjects with self-reported life-long DO and 6 normal controls were included in this study. The International Index of Erectile Function, Male Sexual Health Questionnaire, and self-reported time to orgasm were used to assess sexual function. Subjects underwent a 3-T fMRI study while viewing 3 video clips: a neutral control (NC), a positive emotional control (EC), and a sexual condition (SC). Each video sequence was repeated 5 times, with 50-second clips presented in a randomized fashion. fMRI data were analyzed in a block design manner to determine areas of differential brain activation between groups. The Allen Brain Atlas of gene expression in the human brain was used to identify signaling pathways in the areas of differential fMRI activation between the DO and control groups. OutcomesThe primary outcome was differential activation of fMRI neural activation between groups. ResultsAnalysis of differential activation in the SC compared with the NC and EC revealed increased activation in the right frontal operculum (P = .003), right prefrontal gyrus (P = .003), and inferior occipital gyrus (P = .003). Increased activation in the right fusiform gyrus of the occipital lobe and the right hippocampus (P = .0004) was seen in the DO group compared with controls. Using the Allen Atlas of Human Brain Expression, we identified corresponding neurotransmitter receptors to this region, including adenosine receptors, muscarinic and nicotinic cholinergic receptors, cannabinoid receptors, and dopamine receptors, among others. Clinical ImplicationsLifelong DO in men may be due to abnormal neurotransmitter signaling leading to poor progression of arousal due to aberrant processing of sexual cues. Identification of neurotransmitter pathways by fMRI will aid the development of pharmacotherapeutic agents. Strengths & LimitationsStrengths of this study include the novel application of functional neuroimaging to investigate the pathogenesis of DO. Limitations include the small sample size, making this study exploratory in nature. ConclusionThis study revealed differences in brain activation on visualization of sexual stimuli in men with a history of DO compared with controls. Identified regions are rich in numerous neurotransmitter receptor subtypes and may be amenable to pharmacologic targeting to identify novel therapies for these men.Flannigan R, Heier L, Voss H, et al. Functional Magnetic Resonance Imaging Detects Between-Group Differences in Neural Activation Among Men with Delayed Orgasm Compared with Normal Controls: Preliminary Report. J Sex Med 2019:16;1246–1254.

Observing Erotic Videos With Heterosexual Content Induces Different Cerebral Responses in Homosexual and Heterosexual Men

ABSTRACT To determine the cerebral functionality associated with the perception and processing of erotic stimuli in men with different sexual orientation, this work evaluated the electroencephalographic activity (EEG) from several cortical areas, as well as subjective arousal in homosexual and heterosexual men during observation of an erotic film with heterosexual content. The heterosexual men rated the erotic video with higher general and sexual arousal than the homosexual participants. During observation of the neutral and erotic videos, both groups showed a decreased amplitude of the alpha band in prefrontal and parietal cortices, indicating increased attention. When watching the erotic video, the homosexual men showed an increased amplitude of the theta and fast bands only in the prefrontal cortex, which could be related to the cognitive processing of the erotic stimulus. These EEG results should broaden our knowledge of the cortical mechanisms related to the different perception and processing of erotic stimuli in men with different sexual orientations.

Relación entre la excitación sexual subjetiva y la respuesta genital: diferencias entre hombres y mujeres

ObjectiveThe level of agreement between subjective and objective measures of sexual arousal is referred as sexual concordance. Sex is one of the principal moderators and there is a higher level of correspondence in men than in women. The aim of this study is to evaluate the predictive validity of the scales Ratings of Sexual Arousal (RSA) and Ratings of Genital Sensations (RGS), relating their scores with the genital response to visual sexual stimuli in men and women. Material and methodA sample of 159 young heterosexuals was used (69 men and 90 women) which completed, firstly, a sociodemographic and sexual story questionnaire, the Sexual Inhibition/Sexual Excitation Scales Short-Form and the SOS-6. At the laboratory, they were exposed to a neutral film and to an explicit sexual content film. The subjective sexual arousal was evaluated with the RSA and RGS scales and the genital response was registered through a plethysmography (men) and a photo-plethysmography (women). ResultsSignificant correlations were obtained between subjective and objective sexual arousal only in men. The RGS scale has the capacity to predict the erection response toward sexual stimuli. ConclusionsThe theory of differences in sexual concordance between men and women was endorsed. Modest evidence about the predictive validity of the subjective sexual arousal evaluation scale was found only in men. It arises the need for subjective and objective assessment of sexual arousal, in clinical settings and research area.

Identifying the neural signature of thermic comfort sensation: neuroergonomic evaluation of a new ventilating system integrated in car seat

Identifying the neural signature of thermic comfort sensation: neuroergonomic evaluation of a new ventilating system integrated in car seat

Androgen Deprivation Alters Attention to Sexually Provocative Visual Stimuli in Elderly Men.

IntroductionTestosterone is known to regulate male sexual interest, but the exact way that androgens influence men's sexual cognition remains unclear.AimTo investigate the influence of androgen deprivation (AD) on visual responses to sexually suggestive stimuli in men treated for prostate cancer with AD therapy.MethodsPatients with AD-treated prostate cancer, patients with prostate cancer not on AD therapy, and age-matched healthy control participants were exposed to images of male and female runway models fully or minimally clothed. Eye tracking was used to compare looking behavior among groups.Main Outcome MeasuresProportion of fixations on fully clothed vs minimally clothed models and proportion of fixations on target areas of interest (ie, legs, chest, pelvis, and face) of fully clothed and minimally clothed models were analyzed and compared among groups.ResultsAlthough men not on AD exhibited a larger proportion of fixations on the minimally clothed compared with the fully clothed images, there was no difference between the 2 image types for men on AD. This was true regardless of whether the images depicted male or female models. Groups did not differ in their fixations to target areas of interest.ConclusionThese results suggest that testosterone can influence men’s visual attention to sexual stimuli; specifically, AD can attenuate the time spent fixated on sexualized targets.Palmer-Hague JL, Tsang V, Skead C, et al. Androgen Deprivation Alters Attention to Sexually Provocative Visual Stimuli in Elderly Men. Sex Med 2017;5:e245–e254.

Gender Differences in Spontaneous and Evoked Activities of the Human Brain

The purpose of this study was to analyze sex-related differences in spontaneous and evoked brain activity. The study included 11 women and 10 men aged between 18 and 27 years; the subjects were adapted to the conditions of electrophysiological experiment. Differences in spontaneous activity were estimated by EEG spectral characteristics in frequency ranges corresponding to θ, α, β1, β2, γ1, and γ2 rhythms at rest with the eyes open and closed. The differences in evoked activity were estimated by the parameters of evoked potentials (EP) recorded upon the presentation of different types of stimuli (images and words) and categories (“fruits” and “vessels”). Behavioral differences were estimated by the efficiency of stimuli recognition. No gender differences were observed in the efficiency of stimuli recognition (number of errors, time of reaction). In the EEG of male subjects at rest, fast frequencies (β and γ) were less marked than in the female subjects, which may indicate a higher level of activation of CNS structures in women. Regardless of stimuli type and category, the amplitude of EP components in men is lower than that in women, which may be caused by lower level of CNS activation. However, the difference in the latency of EP components depended on the type of stimuli used. During the recognition of visual images, the latency of earlier EP components (N1, P2) in men was longer mostly on back and/or right electrodes. The latencies of the later EP components (P3, N3) in male subjects were longer on the back electrodes and shorter on the front electrodes than those in female ones. During the recognition of words, the latency of P1, N1, P2 and N2 components in men were shorter on temporal and temporoparietal electrodes of the left hemisphere. This may indicate that visual image in men are perceived slower but comprehended faster than in women. On the other hand, verbal stimuli in men were perceived faster but comprehended slower than in women.

Sex-dependent neural effect of oxytocin during subliminal processing of negative emotion faces

In line with animal models indicating sexually dimorphic effects of oxytocin (OXT) on social-emotional processing, a growing number of OXT-administration studies in humans have also reported sex-dependent effects during social information processing. To explore whether sex-dependent effects already occur during early, subliminal, processing stages the present pharmacological fMRI-study combined the intranasal-application of either OXT or placebo (n = 86–43 males) with a backward-masking emotional face paradigm. Results showed that while OXT suppressed inferior frontal gyrus, dorsal anterior cingulate and anterior insula responses to threatening face stimuli in men it increased them in women. In women increased anterior cingulate reactivity during subliminal threat processing was also positively associated with trait anxiety. On the network level, sex-dependent effects were observed on amygdala, anterior cingulate and inferior frontal gyrus functional connectivity that were mainly driven by reduced coupling in women following OXT. Our findings demonstrate that OXT produces sex-dependent effects even at the early stages of social-emotional processing, and suggest that while it attenuates neural responses to threatening social stimuli in men it increases them in women. Thus in a therapeutic context OXT may potentially produce different effects on anxiety disorders in men and women.

Research of visual evoked potentials (VEPs) to emotionally charged stimuli in men with different levels of aggression

Research of visual evoked potentials (VEPs) to emotionally charged stimuli in men with different levels of aggression

Gender-Specificity of Initial and Controlled Visual Attention to Sexual Stimuli in Androphilic Women and Gynephilic Men.

Research across groups and methods consistently finds a gender difference in patterns of specificity of genital response; however, empirically supported mechanisms to explain this difference are lacking. The information-processing model of sexual arousal posits that automatic and controlled cognitive processes are requisite for the generation of sexual responses. Androphilic women’s gender-nonspecific response patterns may be the result of sexually-relevant cues that are common to both preferred and nonpreferred genders capturing attention and initiating an automatic sexual response, whereas men’s attentional system may be biased towards the detection and response to sexually-preferred cues only. In the present study, we used eye tracking to assess visual attention to sexually-preferred and nonpreferred cues in a sample of androphilic women and gynephilic men. Results support predictions from the information-processing model regarding gendered processing of sexual stimuli in men and women. Men’s initial attention patterns were gender-specific, whereas women’s were nonspecific. In contrast, both men and women exhibited gender-specific patterns of controlled attention, although this effect was stronger among men. Finally, measures of attention and self-reported attraction were positively related in both men and women. These findings are discussed in the context of the information-processing model and evolutionary mechanisms that may have evolved to promote gendered attentional systems.

Androstadienone’s influence on the perception of facial and vocal attractiveness is not sex specific

The androgen steroid androstadienone, an odorous compound emitted from the human axillary region, has recurrently been considered as a candidate compound involved in human chemical communication and mate choice. Although perception of androstadienone has been shown to influence several affective (mood), attentional, physiological and neural parameters, studies investigating its impact on human attractiveness remain unpersuasive because of incomplete designs (e.g., only female participants) and contradictory results. The aim of this study was to investigate how androstadienone may influence others’ attractiveness. Specifically, we used a complete design (male and female raters, male and female faces and voices) to determine whether androstadienone influences the perception of social stimuli in a sex-specific manner, which would favor pheromonal-like properties of the compound, or in a more general manner, which would suggest that the compound has broader influences on human psychological responses. After comparing the ratings of men and women who were exposed to androstadienone masked in clove oil with those of men and women who were exposed to clove oil alone, we found that androstadienone enhanced the perceived attractiveness of emotionally relevant stimuli (opposite-sex stimuli in men and in fertile women). Response times for categorizing the stimuli as attractive or not were also affected by androstadienone, with longer response times in men and in fertile women and shorter response times in non-fertile women, irrespective of the stimulus sex. The results favor the hypothesis of general effects over sex-specific effects of androstadienone, thus questioning the relevance of focusing on that particular compound in the study of human attractiveness through body odor and encouraging the search for other semiochemicals that might be significant for human mate choice.