Female Preferences for Male Vocal and Facial Masculinity in Videos

Vocal and facial masculinity are cues to underlying testosterone in men and influence women’s mate preferences. Consistent with the proposal that facial and vocal masculinity signal common information about men, prior work has revealed correlated female preferences for male facial and vocal masculinity. Previous studies have assessed women’s preferences for male facial and vocal masculinity by presenting faces and voices independently and using static face stimuli. By contrast, here we presented women with short video clips in which male faces and voices were simultaneously manipulated in masculinity. We found that women who preferred masculine faces also preferred masculine voices. Furthermore, women whose faces were rated as relatively more attractive preferred both facial and vocal masculinity more than did women whose faces were rated as less attractive. These findings complement other evidence for cross‐modal masculinity preferences among women and demonstrate that preferences observed in studies using still images and/or independently presented vocal stimuli are also observed when dynamic faces and voices are displayed simultaneously in video format.     

A competitive drive? Same‐sex attentional preferences in capuchins

In primates, faces provide information about several characteristics of social significance, including age, physical health, and biological sex. However, despite a growing literature on face processing and visual attention in a number of primate species, preferences for same‐ or opposite‐sex faces have not yet been examined. In the current study, we explore the role of conspecific sex on visual attention in two groups of capuchin monkeys. Subjects were shown a series of image pairs on a Tobii Pro TX300 eye tracker, each depicting an unfamiliar male and an unfamiliar female face. Given the behavioral evidence of mate choice in both sexes, we hypothesized that capuchins would preferentially attend to images of unfamiliar conspecifics of the opposite sex. Our alternative hypothesis was that capuchins would preferentially attend to same‐sex individuals to assess potential competitors. Our results provide support for our alternative hypothesis. When comparing attention to each stimuli type across sexes, females spent significantly larger percentages of time than males looking at female photos, whereas males spent significantly larger percentages of time than females looking at male photos. Within each sex, females looked for significantly larger percentages of time to female versus male images. Males also looked for larger percentages of time to same‐sex images, though not significantly. To our knowledge, these data are the first to demonstrate significant sex‐biased attentional preferences in adult primates of any species, and suggest that, for capuchins, potential competitors garner more attention than potential mates. In addition, our findings have implications for studies of visual attention and face processing across the primate order, and suggest that researchers need to control for these demographic factors in their experimental designs.     

DEVELOPMENT OF A ‘BIPOLAR’ R‐INDEX1

A new ‘bipolar’ R‐index analysis was proposed and evaluated. Eighteen judges evaluated red color in eight wine samples by comparing each sample with the control. Judges indicated whether the sample had ‘more’, the 'same’, or ‘less’ red color than the control, and whether they were sure or unsure of their decision. Three computational methods were used to examine the results: the ‘traditional’ R‐index, the ‘bipolar’ R‐index (R_more or R_less) and the ‘weighted‐bipolar’ R‐index. While all three methods provided consistent results, the ‘bipolar’ R‐indices reflected bidirectional differences among the samples thus providing more information. A refinement to the computation (‘weighted‐bipolar’ R‐index) was an approach for eliminating the bias associated with overestimation of the sample size and accordingly changed some of the significance levels. Further research is currently underway to expand the scope and application of this method.     

Familiarity with Own Population’s Appearance Influences Facial Preferences

Previous studies have found that individuals from rural areas in Malaysia and in El Salvador prefer heavier women than individuals from urban areas. Several explanations have been proposed to explain these differences in weight preferences but no study has explored familiarity as a possible explanation. We therefore sought to investigate participants’ face preferences while also examining the facial characteristics of the actual participants. Our results showed that participants from rural areas preferred heavier-looking female faces than participants from urban areas. We also found that the female faces from the rural areas were rated as looking heavier than the female faces from the urban areas. Our findings are consistent with the hypothesis that familiarity may be contributing to the differences found in face preferences between rural and urban areas given that people from rural and urban areas are exposed to different faces.     

CONSUMERS REPORT PREFERENCES WHEN THEY SHOULD NOT: A CROSS-CULTURAL STUDY

If a chi‐squared analysis were to be performed to determine whether preferences were significant in a paired preference test, the appropriate expected frequencies in the analysis would represent those that would occur should the consumers have no preference. One way of determining these ‘no preference’frequencies, for a particular test situation, would be to note the preference responses obtained when the stimuli were putatively identical. Over 2000 consumers were given paired preference tests in which the stimuli were putatively identical. Response conditions and consumer groups were varied and the proportions of preference and no preference responses were noted. In a preliminary experiment, further research was seen to be justified when for putatively identical stimuli, judges did not exclusively express lack of preference; many expressed a preference for one or other of the stimuli. Further experiments were conducted using a written response condition and putatively identical potato chips (potato crisps) as stimuli. Using a single ‘no preference’option, variation in the placement of this option at either first, second or third place on the response sheet had no significant effect on the response frequencies. The proportion of ‘no preference’responses was approximately 30% in all cases. A previously reported 40‐20‐40 distribution was not always confirmed. The experiment was repeated with Korean consumers; these had fewer ‘no preference’responses. Deriving preferences from hedonic scales, rather than having judges respond to preference options, increased the proportion of ‘no preference’responses, with American judges still having more than Korean judges. Yet there are logical objections to extracting preference data from hedonic scales. Increasing the number of ‘no preference’options to two or three, had the effect of increasing the number of ‘no preference’responses up to as much as approximately 60%. Extending the results to Koreans, using two ‘no preference’options, it was seen that only the judges in an anonymous response condition had significantly fewer ‘no preference’responses than Americans. The use of these response frequencies as expected frequencies in chi squared analyses was illustrated, after adjustments for counterbalancing.     

Mass spectrometry‐compatible silver staining of histones resolved on acetic acid‐urea‐Triton PAGE

Acetic acid‐Urea‐Triton (AUT) PAGE is commonly used method to separate histone variants and their post‐translationally modified forms. Coomassie staining is the preferred method for protein visualization; however, its sensitivity is less than that of silver staining. Though silver staining of histones in AUT‐PAGE has been reported, the method is time‐consuming, dependent on prior staining by Amido black and has not been reported suitable for mass spectrometry. Here, we propose ‘SDS‐Silver’ method for rapid, sensitive and mass spectrometry‐compatible staining of histones resolved on AUT‐PAGE.     

Does Early Psychosocial Stress Affect Mate Choice?

Early psychosocial stress (e.g., parental divorce, abuse) is conjectured to place individuals on a developmental trajectory leading to earlier initiation of sexual activity, earlier reproduction, and having more sex partners than those with less early psychosocial stress. But does it also affect an individual’s mate choice? The present study examined whether early psychosocial stress affects preferences and dislikes for opposite-sex faces varying in masculinity/femininity, a putative indicator of mate quality, in premenopausal women (58 with a natural cycle, 53 pill-users) and 196 men. No significant three-way interactions were found when women selected the most or least preferred face with participant group (natural cycle, pill), conception risk (low, high), and early psychosocial stress (low, high) as between-subjects factors. Early psychosocial stress did not affect men’s face preferences when selecting the most preferred face. However, men with high early psychosocial stress disliked masculine faces significantly more so than men with low early psychosocial stress. Overall it was concluded that early psychosocial stress does not affect mate choice with the exception that men with high early psychosocial stress were more likely to dislike masculine female faces. It was suggested that men with high early psychosocial stress may dislike masculine female faces because they have nothing to gain from associating with women with such faces.     

Visual adaptation to masculine and feminine faces influences generalized preferences and perceptions of trustworthiness

Although previous studies of individual differences in preferences for masculinity in male faces have typically emphasized the importance of factors such as changes in levels of sex hormones during the menstrual cycle, other research has demonstrated that recent visual experience with faces also influences preferences for sexual dimorphism in faces. Adaptation to either masculine or feminine faces increases preferences for novel faces that are similar to those that were recently seen. Here, we replicate this effect and demonstrate that adaptation to masculine or feminine faces also influences the extent to which masculine faces are perceived as trustworthy. These adaptation effects may reflect a proximate mechanism that contributes to the development of face preferences within individuals, underpins phenomena such as imprinting-like effects and condition-dependent face preferences, and shapes personality attributions to faces that play an important role in romantic partner and associate choices. Furthermore, our findings also support the proposal that visual exposure alone cannot explain the context specificity of attitudes to self-resemblance in faces.     

Evidence against perceptual bias views for symmetry preferences in human faces

Symmetrical human faces are attractive. Two explanations have been proposed to account for symmetry preferences: (i) the evolutionary advantage view, which posits that symmetry advertises mate quality and (ii) the perceptual bias view, which posits that symmetry preferences are a consequence of greater ease of processing symmetrical images in the visual system. Here, we show that symmetry preferences are greater when face images are upright than when inverted. This is evidence against a simple perceptual bias view, which suggests symmetry preference should be constant across orientation about a vertical axis. We also show that symmetry is preferred even in familiar faces, a finding that is unexpected by perceptual bias views positing that symmetry is only attractive because it represents a familiar prototype of that particular class of stimuli.     

Cross-Cultural Agreement in Facial Attractiveness Preferences: The Role of Ethnicity and Gender

Previous work showed high agreement in facial attractiveness preferences within and across cultures. The aims of the current study were twofold. First, we tested cross-cultural agreement in the attractiveness judgements of White Scottish and Black South African students for own- and other-ethnicity faces. Results showed significant agreement between White Scottish and Black South African observers'' attractiveness judgements, providing further evidence of strong cross-cultural agreement in facial attractiveness preferences. Second, we tested whether cross-cultural agreement is influenced by the ethnicity and/or the gender of the target group. White Scottish and Black South African observers showed significantly higher agreement for Scottish than for African faces, presumably because both groups are familiar with White European facial features, but the Scottish group are less familiar with Black African facial features. Further work investigating this discordance in cross-cultural attractiveness preferences for African faces show that Black South African observers rely more heavily on colour cues when judging African female faces for attractiveness, while White Scottish observers rely more heavily on shape cues. Results also show higher cross-cultural agreement for female, compared to male faces, albeit not significantly higher. The findings shed new light on the factors that influence cross-cultural agreement in attractiveness preferences.     

Head Tilt and Fertility Contribute to Different Aspects of Female Facial Attractiveness

Subjective attractiveness ratings of facial portraits of women taken at the fertile phase of the menstrual cycle are higher than those of portraits of the same women taken during non‐fertile periods. As female faces tilted downward are rated as more attractive and female courtship behaviours change across the menstrual cycle, we investigated whether systematic downward tilt of women's faces during the fertile phase might be responsible for increased attractiveness ratings. In the original study (Proc. R. Soc. Lond. B, 271, 2004, S272), the fertile‐phase portrait of each woman was deemed more attractive in 56–62% of cases. When the portraits were reclassified by head pitch, the more downward‐tilted portrait was preferred in 64–73% of cases. The fertile‐phase portrait was no more likely to be the downward‐tilted one, however, suggesting that effects of fertility on attractiveness are not simply due to changes in head position. We also had these portraits rated (N = 130) for physical attractiveness and behavioural allure. Fertile‐phase portraits were rated as more physically attractive than non‐fertile portraits, while more downward‐tilted portraits were rated as more behaviourally alluring than less downward‐tilted ones. These data not only confirm reported effects of head tilt and fertility on perceived female attractiveness, but also suggest that these factors influence different components of the attractiveness percept.     

Beauty in the eyes of the beholders: colour vision is tuned to mate preference in the Trinidadian guppy (Poecilia reticulata)

A broad range of animals use visual signals to assess potential mates, and the theory of sensory exploitation suggests variation in visual systems drives mate preference variation due to sensory bias. Trinidadian guppies (Poecilia reticulata), a classic system for studies of the evolution of female mate choice, provide a unique opportunity to test this theory by looking for covariation in visual tuning, light environment and mate preferences. Female preference co‐evolves with male coloration, such that guppy females from ‘low‐predation’ environments have stronger preferences for males with more orange/red coloration than do females from ‘high‐predation’ environments. Here, we show that colour vision also varies across populations, with ‘low’‐predation guppies investing more of their colour vision to detect red/orange coloration. In independently colonized watersheds, guppies expressed higher levels of both LWS‐1 and LWS‐3 (the most abundant LWS opsins) in ‘low‐predation’ populations than ‘high‐predation’ populations at a time that corresponds to differences in cone cell abundance. We also observed that the frequency of a coding polymorphism differed between high‐ and low‐predation populations. Together, this shows that the variation underlying preference could be explained by simple changes in expression and coding of opsins, providing important candidate genes to investigate the genetic basis of female preference variation in this model system.     

Local above‐ground persistence of vascular plants: Life‐history trade‐offs and environmental constraints

Questions: 1. Which plant traits and habitat characteristics best explain local above‐ground persistence of vascular plant species and 2. Is there a trade‐off between local above‐ground persistence and the ability for seed dispersal and below‐ground persistence in the soil seed bank? Locations: 845 long‐term permanent plots in terrestrial habitats across the Netherlands. Methods: We analysed the local above‐ground persistence of vascular plants in permanent plots (monitored once a year for ca. 16 year) with respect to functional traits and habitat preferences using survival statistics (Kaplan‐Meier analysis and Cox’ regression). These methods account for censored data and are rarely used in vegetation ecology. Results: Local above‐ground persistence is determined by both functional traits (especially the ability to form long‐lived clonal connections) and habitat preferences (especially nutrient requirements). Above‐ground persistence is negatively related to the ability for dispersal by wind and to the ability to accumulate a long‐term persistent soil seed bank (‘dispersal through time’) and is positively related to the ability for dispersal by water. Conclusions: Most species have a half‐life expectation over 15 years, which may contribute to time lags after changes in habitat quality or ‐configuration (‘extinction debt’). There is evidence for a trade‐off relationship between local above‐ground persistence and below‐ground seed persistence, while the relationship with dispersal in space is vector specific. The rate of species turnover increases with productivity.     

‘Prudent habitat choice’: a novel mechanism of size‐assortative mating

Assortative mating, an ubiquitous form of nonrandom mating, strongly impacts Darwinian fitness and can drive biological diversification. Despite its ecological and evolutionary importance, the behavioural processes underlying assortative mating are often unknown, and in particular, mechanisms not involving mate choice have been largely ignored so far. Here, we propose that assortative mating can arise from ‘prudent habitat choice’, a general mechanism that acts under natural selection, and that it can occur despite a complete mixing of phenotypes. We show that in the cichlid Eretmodus cyanostictus size‐assortative mating ensues, because individuals of weaker competitive ability ignore high‐quality but strongly competed habitat patches. Previous studies showed that in E. cyanostictus, size‐based mate preferences are absent. By field and laboratory experiments, here we showed that (i) habitat quality and body size are correlated in this species; (ii) territories with more stone cover are preferred by both sexes in the absence of competition; and (iii) smaller fish prudently occupy vacant territories of worse quality than do larger fish. Prudent habitat choice is likely to be a widespread mechanism of assortative mating, as both preferences for and dominance‐based access to high‐quality habitats are generic phenomena in animals.     

Environment contingent preferences: Exposure to visual cues of direct male–male competition and wealth increase women's preferences for masculinity in male faces

Previous studies show that parasite prevalence and mortality/health are related to cultural variation in women's preferences for attractive and masculine traits in men. Other studies have suggested that both male–male competition and wealth may also be important correlates of cross-cultural variation in women's masculinity preferences. Here we examined whether exposure to cues of direct male–male competition, violence, or wealth influenced women's face preferences. We showed women slideshows of images with cues of low and high direct male–male competition/violence or wealth and measured their visual preferences for masculine face traits. Recent visual experience changed women's preferences for facial masculinity, with women preferring more masculine male faces after exposure to images of men engaged in direct physical competition, images of weapons, or images depicting items of high monetary value. Recent visual experience had no significant effects on preferences for masculinity in same-sex faces. Given that high levels of direct physical competition and violence among males may increase the importance of direct intra-sexual competition, it may be adaptive for women to shift visual preferences in favor of males with face cues indicating physical strength and dominance over investment in such environments. Similarly, in wealthy environments investment may be less important than other aspects of quality and so it may be adaptive for women to shift visual preferences in favor of males with face cues indicating other aspects of quality over investment. Overall, our data demonstrate that preferences can be strategically flexible according to recent visual experience and support the notion of environment contingent preferences.     

The ‘sparkle’ in fake eyes – the protective effect of mimic eyespots in lepidoptera

Many species of lepidoptera bear conspicuous circular patterns on their wings, known as eyespots, that are hypothesised to protect their bearers against predatory birds. In this study, we focus on a small but ubiquitous feature occurring naturally in lepidopteran eyespots, namely the so‐called ‘sparkle’. The ‘pupil’ in an eyespot is often highlighted by a ‘sparkle’, which is hypothesised to mimic a natural corneal total light reflection evident as a highlight, twinkle, or sparkle in the vertebrate eye. In a study exploring the presence of such sparkles, we found that 53% of lepidopteran eyespots exceeding 1 mm in diameter have a central, pinpoint‐like ‘sparkle’, 12% have a marginal, crescent‐shaped ‘sparkle’, 13% have a semi‐circular ‘sparkle’, and 22% have an intermediate semi‐circular to crescent‐shaped ‘sparkle’. In the lepidopterans’ natural resting position, the marginal ‘sparkles’ are positioned in the upper part of the eyespots’‘pupil’ and thus may create the illusion of a spherical eyeball. The ‘sparkles’ in lepidopteran eyespots do not only appear white to humans, but also reflect ultraviolet light. White and UV‐reflecting ‘sparkles’ also appear ‘white’ for UV‐sensitive viewers such as birds, and thus may effectively mimic the natural highlight in vertebrate eyes as an area of total light reflection. In field experiments using lepidopteran dummies baited with a mealworm, we show that the ‘sparkle’ is one of several components of eyespots eliciting a deterrent effect and that eyespots with a ‘sparkle’ in a natural position have a stronger deterrent effect than those with a ‘sparkle’ in an unnatural position. These findings support the eye mimicry hypothesis that better vertebrate eye mimicry improves the deterrent effect of eyespots.     

Similar preferences for ornamentation in opposite‐ and same‐sex choice experiments

Selection due to social interactions comprises competition over matings (sexual selection stricto sensu) plus other forms of social competition and cooperation. Sexual selection explains sex differences in ornamentation and in various other phenotypes, but does not easily explain cases where those phenotypes are similar in males and females. Understanding such similarities requires knowing how phenotypes influence nonsexual social interactions as well, which can be very important in gregarious animals, but whose role for phenotypic evolution has been overlooked. For example, ‘mate choice’ experiments often found preferences for ornamentation, but have not assessed whether those are strictly sexual or are general social preferences. Using choice experiments with a gregarious and mutually ornamented finch, the common waxbill (Estrilda astrild), we show that preferences for ornamentation in the opposite‐sex also extend to same‐sex interactions. Waxbills discriminated between opposite‐ and same‐sex individuals, but most preferences for colour traits were similar when interacting with either sex. Similar preferences in sexual and nonsexual associations may be widespread in nature, either as social adaptations or as by‐product of mate preferences. In either case, such preferences may set the stage for the evolution of mutual ornamentation and of various other similarities between the sexes.     

Restoration and management for cliff‐nesting birds in Mediterranean mining sites: the Sand Martin case study

Habitat enhancement for birds is frequently implemented during mine site restoration. Cliff‐nesting birds often colonize anthropogenic environments such as mining areas (aggregate sites and quarries for aggregate and cement production). Mining activity can compromise breeding success, causing cliff‐nesting birds to depend on the management and restoration of mining areas. The objective of our study is to assess the importance of mine site habitats for Sand Martin conservation and reconcile mining activity with breeding success in Mediterranean environments. We studied Sand Martin breeding habitat preferences in mining areas at three spatial scales. At the mining site scale, we compared 10 mining sites with Sand Martin burrows with 19 mining sites without burrows. At the colony scale (vertical structures with colonies), we evaluated the relationships between the number of breeding pairs, number of burrows, and colony characteristics within 30 distinct Sand Martin colonies. At the burrow scale, we compared the characteristics of the available vertical structure with the areas used by Sand Martins. At the mining site scale, Sand Martins preferred more surface of water bodies, shorter distances to flowing water, older sites, and mining sites which produce aggregates instead of cement. At the colony scale, Sand Martins preferred southwest orientations and stockpiles to vertical extraction faces. At the burrow scale, birds preferred the most vertical areas of the face. Our results support the need for effective habitat restoration and improved management for more effective Sand Martin conservation within mining areas. Simple interventions can enhance habitat quality and conservation of cliff‐nesting birds.     

Exposure to visual cues of pathogen contagion changes preferences for masculinity and symmetry in opposite-sex faces

Evolutionary approaches to human attractiveness have documented several traits that are proposed to be attractive across individuals and cultures, although both cross-individual and cross-cultural variations are also often found. Previous studies show that parasite prevalence and mortality/health are related to cultural variation in preferences for attractive traits. Visual experience of pathogen cues may mediate such variable preferences. Here we showed individuals slideshows of images with cues to low and high pathogen prevalence and measured their visual preferences for face traits. We found that both men and women moderated their preferences for facial masculinity and symmetry according to recent experience of visual cues to environmental pathogens. Change in preferences was seen mainly for opposite-sex faces, with women preferring more masculine and more symmetric male faces and men preferring more feminine and more symmetric female faces after exposure to pathogen cues than when not exposed to such cues. Cues to environmental pathogens had no significant effects on preferences for same-sex faces. These data complement studies of cross-cultural differences in preferences by suggesting a mechanism for variation in mate preferences. Similar visual experience could lead to within-cultural agreement and differing visual experience could lead to cross-cultural variation. Overall, our data demonstrate that preferences can be strategically flexible according to recent visual experience with pathogen cues. Given that cues to pathogens may signal an increase in contagion/mortality risk, it may be adaptive to shift visual preferences in favour of proposed good-gene markers in environments where such cues are more evident.