Homeliness is in the disgust sensitivity of the beholder: relatively unattractive faces appear especially unattractive to individuals higher in pathogen disgust

Pathogen-relevant variables (e.g., regional variation in pathogen prevalence, individual differences in sensitivity to pathogen disgust) have been found to be associated with judgments and preferences surrounding physical attractiveness, in line with the view that certain morphological features and configurations indicate health and/or immunocompetence. In three studies, we administered the three-domain disgust scale and obtained ratings of attractiveness of faces to examine whether associations emerged between perceivers' disgust sensitivity and their ratings of attractive and/or unattractive targets. The results across the three studies showed that for unattractive targets, perceivers higher in pathogen disgust tended to assign lower attractiveness ratings; for attractive targets, pathogen disgust was uncorrelated with attractiveness ratings. Sexual disgust and moral disgust were not associated with perceptions of unattractive or attractive target faces. These results indicate that disgust-dependent attractiveness perceptions may motivate avoidance of potentially unfit interaction partners.     

Haptic categorical perception of shape

Categorization and categorical perception have been extensively studied, mainly in vision and audition. In the haptic domain, our ability to categorize objects has also been demonstrated in earlier studies. Here we show for the first time that categorical perception also occurs in haptic shape perception. We generated a continuum of complex shapes by morphing between two volumetric objects. Using similarity ratings and multidimensional scaling we ensured that participants could haptically discriminate all objects equally. Next, we performed classification and discrimination tasks. After a short training with the two shape categories, both tasks revealed categorical perception effects. Training leads to between-category expansion resulting in higher discriminability of physical differences between pairs of stimuli straddling the category boundary. Thus, even brief training can alter haptic representations of shape. This suggests that the weights attached to various haptic shape features can be changed dynamically in response to top-down information about class membership.     

Waist to hip ratio and breast size modulate the processing of female body silhouettes: An EEG study

Waist-to-hip ratio (WHR) and breast size are considered important biological features defining female body attractiveness; but their neurophysiological correlates remain largely unknown. To shed light on this issue, behavioral and electroencephalographic responses were recorded while healthy heterosexual men and women completed an oddball task, which was then followed by an attractiveness judgement task. In both cases participants were presented with female body forms that combined 0.6, 0.7 or 0.8 WHRs with small or large breast sizes. Brain activity dynamics were explored using temporal principal component analysis of the event-related potentials data. Variance in the data was explained mostly by eight temporal factors for the oddball task and six for the attractiveness judgement task. Lower WHRs seemed to gather larger processing resources than higher WHRs at early perceptual-related processes during the oddball task. The less attractive WHRs and breast sizes, in contrast, seemed to boost allocation of resources later in the processing stream, which may be due to a negativity bias enhancing evaluation and decision-making processes. This inference is supported by results from the attractiveness judgement task, although the observer's gender may also play a role. Finally, LORETA analysis of the temporal factors indicate that variations in WHR may modulate activation of frontal regions, such as the anterior cingulate and orbitofrontal cortex, that are related with reward processing and decision-making; while variations in breast size may influence activity in posterior parietal regions involved in human body perception. This paper highlights the biological importance of female body physical features in defining attractiveness, and the neurophysiological correlates that are implicated.     

Walking in Fourier’s space: algorithms for the computation of periodicities in song patterns by the cricket Gryllus bimaculatus

Is discrimination of the envelope of an acoustic signal based on spectral or temporal computations? To investigate this question for the cricket Gryllus bimaculatus, pattern envelopes were constructed by the addition of several sine waves and modified by systematic phase changes. The phonotactic response of female crickets towards such sinusoidal but also rectangular pulse patterns was quantified on a locomotion compensator. Envelope patterns that exhibited a modulation frequency of 25 Hz as the dominant frequency were attractive and although changes of phase modified the temporal pattern, the values of attractiveness remained unaffected. Removal of the 25-Hz component reduced the phonotactic scores. Patterns in which other frequency components exhibited a larger amplitude than the 25-Hz component were less attractive. However, the combination of an unattractive pulse period with the attractive modulation frequency of 25 Hz in a pattern revealed that such stimuli were unattractive despite the presence of the 25-Hz component. A comparison of the attractiveness of all patterns revealed that female crickets evaluated the duration of pulse period over a wide range of duty cycles. The combined evidence showed that pattern envelopes were processed in the time- and not in the spectral domain.     

Indirect benefits for choosy female grasshoppers (Chorthippus biguttulus)?

Since direct benefits are likely to be absent in the grasshopper Chorthippus biguttulus, indirect genetic benefits are a potential explanation for costly female preference. Choosy females may improve their fitness in terms of enhanced attractiveness of sons alone or additionally by improved viability of offspring. We tested the predictions of these two hypotheses by comparing attractiveness-related song traits and viability in offspring of attractive and unattractive grasshopper males. The experiment was conducted with larvae reared under semi natural lab conditions in one year and under natural conditions in the field in the following year. If reared under natural conditions no significant differences in viability and song traits between offspring of attractive and unattractive males could be found. Offspring reared in the lab produced calling songs with a significantly more exact song rhythm when sired by attractive males than offspring of unattractive males. Offspring of attractive males should thus have a theoretical advantage in mate choice, which, however, did not translate into higher attractiveness values in acoustic female choice experiments. Therefore our experiments could not resolve whether female choice in C. biguttulus evolved according to the sexy son hypothesis. Since viability in offspring of attractive males did not differ from offspring of unattractive males, “good genes” seems unlikely to be the underlying mechanism of female choice.     

Energetic cost of sexual attractiveness: ultrasonic advertisement in wax moths

Pair formation in the lesser wax moth,Achroia grisella(Lepidoptera: Pyralidae), is initiated by male ultrasonic signals that attract receptive females. Individual males vary in attractiveness to females, and the most attractive males are distinguished by exaggeration of three signal characters: pulse rate, peak amplitude and asynchrony interval (temporal separation between pulses generated by movements of the left and right wings during a given wing upstroke or downstroke). Using flow-through respirometry, we measured the resting and signalling metabolic rates of males whose relative attractiveness was known. Acoustic recordings and metabolic measurements were made simultaneously, and we calculated net metabolic rates and factorial metabolic scopes as measures for the energetic cost of signalling. On average, attractive males had higher net metabolic rates and factorial metabolic scopes than unattractive ones, but many unattractive males also had high values. Thus, high expenditure of energy on signalling is necessary but not sufficient for attractiveness. This may result because only one of the three signal characters critical for female preference, pulse rate, is correlated with energy expenditure. Although the results are consistent with the good genes model of sexual selection, they do not conflict with other indirect or direct mechanisms of female choice.     

Body Shape Preferences: Associations with Rater Body Shape and Sociosexuality

There is accumulating evidence of condition-dependent mate choice in many species, that is, individual preferences varying in strength according to the condition of the chooser. In humans, for example, people with more attractive faces/bodies, and who are higher in sociosexuality, exhibit stronger preferences for attractive traits in opposite-sex faces/bodies. However, previous studies have tended to use only relatively simple, isolated measures of rater attractiveness. Here we use 3D body scanning technology to examine associations between strength of rater preferences for attractive traits in opposite-sex bodies, and raters’ body shape, self-perceived attractiveness, and sociosexuality. For 118 raters and 80 stimuli models, we used a 3D scanner to extract body measurements associated with attractiveness (male waist-chest ratio [WCR], female waist-hip ratio [WHR], and volume-height index [VHI] in both sexes) and also measured rater self-perceived attractiveness and sociosexuality. As expected, WHR and VHI were important predictors of female body attractiveness, while WCR and VHI were important predictors of male body attractiveness. Results indicated that male rater sociosexuality scores were positively associated with strength of preference for attractive (low) VHI and attractive (low) WHR in female bodies. Moreover, male rater self-perceived attractiveness was positively associated with strength of preference for low VHI in female bodies. The only evidence of condition-dependent preferences in females was a positive association between attractive VHI in female raters and preferences for attractive (low) WCR in male bodies. No other significant associations were observed in either sex between aspects of rater body shape and strength of preferences for attractive opposite-sex body traits. These results suggest that among male raters, rater self-perceived attractiveness and sociosexuality are important predictors of preference strength for attractive opposite-sex body shapes, and that rater body traits –with the exception of VHI in female raters– may not be good predictors of these preferences in either sex.     

Judging the Difference between Attractiveness and Health: Does Exposure to Model Images Influence the Judgments Made by Men and Women?

Recent research has shown facial adiposity (apparent weight in the face) to be a significant predictor of both attractiveness and health, thus making it an important determinant of mate selection. Studies looking at the relationship between attractiveness and health have shown that individuals differentiate between the two by preferring a lower weight for attractiveness than for health in female faces. However, these studies have either been correlational studies, or have investigated weight perceived from only the face. These differences have been discussed with regard to sociocultural factors such as pressure from parents, peers and also media, which has been seen to have the highest influence. While exposure to media images has been shown to influence women’s own-body image, no study has yet directly tested the influence of these factors on people’s preferred weight in other women’s bodies. Here we examine how a short exposure to images of models influences men’s and women’s judgments of the most healthy looking and attractive BMI in Malaysian Chinese women’s bodies by comparing differences in preferences (for attractiveness and health) between groups exposed to images of models of varying attractiveness and body weight. Results indicated that participants preferred a lower weight for attractiveness than for health. Further, women’s but not men’s preferred BMI for attractiveness, but not health, was influenced by the type of media images to which they were exposed, suggesting that short term exposure to model images affect women’s perceptions of attractiveness but not health.     

Sexual conflict and cryptic female choice in the black field cricket, Teleogryllus commodus

The prevalence and evolutionary consequences of cryptic female choice (CFC) remain highly controversial, not least because the processes underlying its expression are often concealed within the female reproductive tract. However, even when female discrimination is relatively easy to observe, as in numerous insect species with externally attached spermatophores, it is often difficult to demonstrate directional CFC for certain male phenotypes over others. Using a biological assay to separate male crickets into attractive or unattractive categories, we demonstrate that females strongly discriminate against unattractive males by removing their spermatophores before insemination can be completed. This results in significantly more sperm being transferred by attractive males than unattractive males. Males respond to CFC by mate guarding females after copulation, which increases the spermatophore retention of both attractive and unattractive males. Interestingly, unattractive males who suffered earlier interruption of sperm transfer benefited more from mate guarding, and they guarded females more vigilantly than attractive males. Our results suggest that postcopulatory mate guarding has evolved via sexual conflict over insemination times rather than through genetic benefits of biasing paternity toward vigorous males, as has been previously suggested.     

Facial Attractiveness and Physical Health

Previous research has documented that more facially attractive people are perceived by others to be physically healthier. Using self-reports, observer ratings, daily diary methodology, and psychophysiological assessments, this study provides limited empirical evidence that more facially attractive people (N = 100) may be physically healthier than unattractive people. Discussion suggests the value of an evolutionary psychological perspective for understanding the relationship between facial attractiveness and physical health.     

The effects of facial attractiveness and perceiver's mate value on adaptive allocation of central processing resources

Faces capture cognitive resources, and more attractive faces capture more resources. But to be of adaptive value this proportionality should be modulated by properties of the perceiver, including their own level of attractiveness. Here we investigated the allocation of central processing resources for perceivers at different levels of mating market value (high, low) in response to target faces of different levels of attractiveness (attractive, unattractive). We tracked attention allocation by measuring event-related brain potentials (ERPs) from the scalp of men while they viewed and rated images of women's faces. As expected, a main effect of attractiveness was found such that attractive faces garnered the largest brain responses. However, perceiver's market value and target face attractiveness interacted, as brain responses to unattractive faces were significantly larger in the low-market-value condition compared to the high-market-value condition, whereas responses to attractive faces were stable across market values. Thus, for men at least, allocation of attention is adaptively modulated by both the attractiveness of a target face and their own market value. The more attractive an individual perceives themselves to be, the less processing resources they appear to devote to the unattractive faces in their environment.     

The role of cuticular hydrocarbons in male attraction and repulsion by female Dawson's burrowing bee, Amegilla dawsoni

Cuticular hydrocarbons (CHCs) are long-chain fatty acids and their derivatives that protect insects from desiccation. They can also be important semiochemicals in insect reproduction. We used behavioural and chemical assays to examine the potential role of CHCs in sexual communication in a solitary burrowing bee, Amegilla dawsoni. Washing CHC blends from the cuticle of emerging virgin females made them unattractive to mate-searching males. Returning the CHC blends restored their attractiveness. Nesting females were unattractive to mate-searching males, whether they were washed or not. Chemical analysis identified significant differences between male and female CHC blends and between virgin female and nesting female blends. Some of these differences were due to specific compounds. Loss of attractiveness is unlikely to be due to antiaphrodisiac compounds delivered by males, because male-specific compounds were not found on nesting females, and because recently mated females with intact CHC blends were attractive to searching males. Nesting females could not be made attractive to searching males by removing their CHC blends. Adding virgin female CHC blends tended to improve attractiveness but the effect was weak, suggesting that some form of volatile compound may also be involved in signalling unreceptivity.     

The Impact of Psychological Stress on Men's Judgements of Female Body Size

Background

Previous work has suggested that the experience of psychological stress may influence physical attractiveness ideals, but most evidence in favour of this hypothesis remains archival. The objective of this study was to experimentally investigate the impact of stress on men''s judgements of female body size.

Methods

Men were randomly assigned to either an experimental group, in which they took part in a task that heightened stress (experimental group, n = 41) or in which they did not take part in such a task (control group, n = 40). Both groups rated the attractiveness of female bodies varying in size from emaciated to obese, completed a measure of appetite sensation, and had their body mass indices (BMIs) measured.

Results

Between-groups analyses showed that the experimental group was matched with the control group in terms of mean age, BMI, and appetite sensation. Further analyses showed that men in the experimental group rated a significantly heavier female body size as maximally attractive than the control group. Men in the experimental group also rated heavier female bodies as more attractive and idealised a wider range of female figures than did the control group.

Conclusion

This study found that the experience of stress was associated with a preference among men for heavier female body sizes. These results indicate that human attractiveness judgements are sensitive to variations in local ecologies and reflect adaptive strategies for dealing with changing environmental conditions.     

Feeling Bad and Looking Worse: Negative Affect Is Associated with Reduced Perceptions of Face-Healthiness

Some people perceive themselves to look more, or less attractive than they are in reality. We investigated the role of emotions in enhancement and derogation effects; specifically, whether the propensity to experience positive and negative emotions affects how healthy we perceive our own face to look and how we judge ourselves against others. A psychophysical method was used to measure healthiness of self-image and social comparisons of healthiness. Participants who self-reported high positive (N = 20) or negative affectivity (N = 20) judged themselves against healthy (red-tinged) and unhealthy looking (green-tinged) versions of their own and stranger’s faces. An adaptive staircase procedure was used to measure perceptual thresholds. Participants high in positive affectivity were un-biased in their face health judgement. Participants high in negative affectivity on the other hand, judged themselves as equivalent to less healthy looking versions of their own face and a stranger’s face. Affective traits modulated self-image and social comparisons of healthiness. Face health judgement was also related to physical symptom perception and self-esteem; high physical symptom reports were associated a less healthy self-image and high self-reported (but not implicit) self-esteem was associated with more favourable social comparisons of healthiness. Subject to further validation, our novel face health judgement task could have utility as a perceptual measure of well-being. We are currently investigating whether face health judgement is sensitive to laboratory manipulations of mood.     

Facial symmetry and judgements of apparent health: Support for a “good genes” explanation of the attractiveness–symmetry relationship

The “good genes” explanation of attractiveness posits that mate preferences favour healthy individuals due to direct and indirect benefits associated with the selection of a healthy mate. Consequently, attractiveness judgements are likely to reflect judgements of apparent health. One physical characteristic that may inform health judgements is fluctuating asymmetry as it may act as a visual marker for genetic quality and developmental stability. Consistent with these suggestions, a number of studies have found relationships between facial symmetry and facial attractiveness. In Study 1, the interplay between facial symmetry, attractiveness, and judgements of apparent health was explored within a partial correlation design. Findings suggest that the attractiveness–symmetry relationship is mediated by a link between judgements of apparent health and facial symmetry. In Study 2, an opposite-sex bias in sensitivity to facial symmetry was observed when judging health. Thus, perceptual analysis of symmetry may be an adaptation facilitating discrimination between potential mates on the basis of apparent health. The findings of both studies are consistent with a “good genes” explanation of the attractiveness–symmetry relationship and problematic for the claim that symmetry is attractive as a by-product of the ease with which the visual recognition system processes symmetric stimuli.     

Perception of facial attractiveness requires some attentional resources: implications for the “automaticity” of psychological adaptations

Traditional criteria for modularity assert that perceptual adaptations for processing evolutionarily important stimuli should operate “automatically” in the sense of requiring no central attentional resources. Here, we test the validity of this automaticity criterion by assessing the attentional demands of a well-studied perceptual adaptation: judgment of facial attractiveness. We used locus-of-slack logic in a dual-task psychological refractory period paradigm, where Task 1 was a speeded judgment of tone pitch (low vs. high), and Task 2 was a speeded judgment of whether a face was attractive or unattractive, with the Task-2 judgment manipulated to have a low or a high difficulty level. In two studies (N=36 and N=73 female participants; 384 trials each), the Task 2 difficulty effects were additive with stimulus-onset asynchronies (100, 300, 500 or 900 ms) on Task 2 response times. According to the locus-of-slack logic, this result implies that participants could not discriminate facial attractiveness level, while their central attentional resources were still occupied by Task 1. If the human capacity for perceiving facial attractiveness—a premier example of an adaptation—does not show automaticity in this sense, automaticity may not be a useful criterion for identifying psychological adaptations.     

Physical Attractiveness of an Animal Species as a Decision Factor for its Preservation

ABSTRACT

This experimental study examines how framing an animal species as endangered affects its perceived attractiveness and how an animal's perceived attractiveness affects support for its conservation. Undergraduate students were shown a flyer from a fictitious environmental organization pleading for the protection of either a bat or an ape. The flyer contained either no picture, a picture of an attractive member of its species, or a picture of an unattractive member of its species. For both species, an animal's attractiveness substantially increased support for its protection. There was also more support for saving the species that was larger in size and more resembled humans. In a second experiment, participants rated an unattractive animal as more attractive if it was framed as endangered. There was no such effect for an animal originally perceived as attractive. The implications of the results for environmental policy and conservation support are discussed.     

Color 3D bodies and judgements of human female attractiveness

For a set of color video clips that depict a 360° view of the bodies of 43 young Caucasian women who are within the normal range of percentage of body fat, we show that their attractiveness to both male and female observers depends strongly on their percentage of body fat and their level of skin tanning, but is not significantly related to their cardiovascular fitness (a key health measure). Although evolutionary psychology suggests that physical health should play a role in determining attractiveness judgements, it appears that cardiovascular fitness may be a weak cue, at least in bodies not undergoing cardiovascular exercise. Instead, it seems that more salient cues, such as body mass and skin tanning, are the primary determinants of attractiveness judgements.     

The effect of male sandfly pheromone and host factors as attractants for female Lutzomyia longipalpis (Diptera: Psychodidae)

Abstract Male Lutzomyia longipalpis (Lutz & Neiva) pheromone extracted from tergal glands combined with heat, carbon dioxide gas and hamster urine was found to be attractive to virgin female sandflies. The host factors if offered in the absence of pheromone or a heat source were, however, unattractive to female flies. Pheromone stored for 6 days and then combined with the same host components remained attractive to female flies but storage failed to enhance its attractiveness. The effects of carbon dioxide gas, hamster urine, chicken uropygial gland extract and octenol plus acetone on the responses of females were inconsistent. A ceramic battery powered heat source was tested with pheromone and host attractants and showed potential for field application in developing a pheromone trap.