Mate Attraction Research Articles

A mathematical analysis of the evolution of human mate choice traits: Implications for evolutionary psychologists

Sexually reproducing organisms often rely on various traits to judge the attractiveness of potential mates. Many mate choice preferences and traits have evolved through selection by those organisms' ancestors, with traits having been either costly (detrimental to survival) or non- costly in the environment of their evolutionary adaptation. A general mathematical analysis of the evolution of traits used in mate choice is presented. The analysis builds on a combination of Price's covariance equation and Wright's method of path analysis, and includes a set of Monte Carlo simulations. The usefulness of the mathematical analysis is demonstrated through the de- velopment of a small but important set of hypotheses and implications for the human species: (1) costly traits used in mate choice by humans should be generally less common and more attractive to the other sex than non-costly traits; (2) costly traits should be disproportionately less common in human females than in males; and (3) some harmful human mental disorders, such as schizo- phrenia, may have co-evolved as costs of attractive mental traits. It is also shown that similar analyses can be easily employed by evolutionary psychologists to theorize about the evolution of complex mate choice traits, and to test the resulting theories with modern humans through the method of path analysis.

Sexual arousal and the pursuit of attractive mating opportunities

From an evolutionary perspective, sexual arousal may function, in part, to motivate the pursuit of attractive mating opportunities. We designed a study to test three aspects of this hypothesis. Several hundred heterosexual men and women completed a short survey about sexual arousal in response to a casual sex mating opportunity. We replicated previous research documenting that men report greater sexual arousal than women in response to a short-term mating opportunity. We argue that it is unlikely that a “downplaying of alternatives” psychology evolved, whereby mated individuals rate opposite-sex targets as less attractive than do unmated individuals, but instead that men and women have a relationship-seeking psychology, motivating them to pursue attractive mating opportunities. The results supported this relationship-seeking psychology rather than a downplaying alternatives psychology. Discussion addresses directions for future research on the motivational properties of sexual arousal.

Towards the Harmonious Mating for Genetic Algorithms

Genetic algorithms (GAs) have achieved lots of success in various applications, but the problem to balance exploration and exploitation of population is still up in the air. In this paper, we propose a variant of genetic algorithm with mating operator GASF to alleviate the problem;GASFmeasures the mating attractiveness of individuals from four aspects: gender, age, similarity and fitness. Individuals are assigned gender to facilitate mimicking human reproduction, and contributions of age, similarity and fitness to the attractiveness are respectively quantified and self-adaptively adjusted. Experimental results indicate that the proposed approach can achieve competitive performance with improved convergence.

“Say it with flowers”: The effect of flowers on mating attractiveness and behavior

For millennia flowers have been used to convey romance, yet their effect on human romantic behavior has not been explicitly tested. In two experiments we show that women's perception of male attractiveness and their potential mating behavior are positively affected by simple exposure to flowers. In Study 1 women who were exposed to flowers while they watched a video of a man perceived the man to be more attractive and sexier. They also reported being more inclined to accept a date from him. In Study 2 women who were exposed to flowers responded more favorably to an explicit solicitation from a male confederate in a subsequent interaction. The results show that the simple exposure to flowers had a significant effect on women's perception of mating attractiveness and behavior.

Temperament traits and microhabitat use in bullhead, Cottus perifretum: fish associated with complex habitats are less aggressive

Temperament traits have been linked to fitness-related functional contexts such as dispersal or mating attractiveness, but few studies have linked inter-individual differences in habitat use to temperament traits. Therefore, we conducted a three-month field study with weekly tracking to define the individual microhabitat use of bullhead (Cottus perifretum). The species is known for its dependence on structured habitats. At the end of the field-survey, bullhead were recaptured and tested in the laboratory for five temperament traits: boldness, interest in novel food, novel environment activity, aggressiveness and activity. Repeated trait tests (activity, r = 0.439; novel environment activity, r = 0.422) and habitat complexity use (r = 0.568) indicated behavioural consistency. Overall, bullhead significantly preferred complex habitats, such as branch jams, while avoiding open water. Individual frequency in the use of complex habitats could not be attributed to size or sex differences, but was significantly negatively correlated to the level of aggressiveness. We hypothesize that this relationship was caused by a higher level of aggressive defence of less structured territories. Other temperament traits were not significantly linked to individual habitat use. To our knowledge, this study is the first to show a relationship between aggressiveness measured under laboratory conditions and the use of complex habitats in situ.

Cognitive Bias Toward Female Facial Attractiveness in Males: Evidences from An ERP Study

Facial attractiveness is of high importance for human interaction and communication (Joshua, Henderson, Jeremy, Anglin, 2003). Neuroimaging studies found several brain areas to be differentially responsive to attractive as opposed to unattractive female faces (Aharon et al., 2001; Cloutier, Heatherton, Whalen, Kelley, 2008; Iaria, Fox, Waite, Aharon, Barton, 2008; Ishai, 2007; Kranz Ishai, 2006; Penton-voak, Jacobson, Tribers, 2004; Senior, 2003). The brain areas responsive to facial attractiveness of potential mates include the superior temporal sulcus (O’ Doherty et al., 2003), basal ganglia (Aharon et al., 2001) and medial orbitofrontal cortex (Kranz et al., 2006). However, little is known about the time course of brain responses related to this process. The present study aimed to compare event-related potentials (ERPs) in response to attractive and unattractive female faces in order to determine which time periods were sensitive during judgment and recognition of female facial attractiveness for males. ERPs were used to explore temporal changes of judgment and recognition toward attractive female faces based on a study-recognition experiment paradigm. Data from 13 heterosexual males participants (mean age 22.35 years) were included in the analysis. There are 490 unfamiliar Chinese female pictures from Google. First, 80 college students rated the female pictures as attractive, unattractive and average. In the judgment task, after practice with 10 face pictures participants evaluated 84 attractive faces pictures and 84 unattractive faces pictures presented on computer. In the recognition task, they were asked to identify previously viewed faces from the initial judgment task among attractive, unattractive, and average face pictures. The results showed that attractive and unattractive faces elicited significant differences in early and late ERP components in judgment and recognition tasks. The most enhanced activity was produced in the prefrontal-central cortex. Attractive faces elicited more enhanced ERP effects than unattractive faces on N300 component and P350~550ms during the judgment task. N300 and P350~550ms are thought to reflect different cognitive functions, including perceptual closure, stimulus evaluation, decision-making and working memory during judgment tasks (Polich, 2003). As well, attractive faces elicited more enhanced ERP effects than unattractive female faces on the P160 component, N300~500ms, and P500~700ms time windows during the recognition task. Early ERP effects such as P160 in recognition tasks may reflect not only perception-related processing of attractive facial stimulus features but also the detection of perceptual features or facial configurations, which is associated with stimulus-driven frontal attention mechanisms (Chen et al., 2007). On the other hand, attractive female faces may have higher intrinsic reward values for males (Senior, 2003). It is suggested that facial attractiveness processing may start prior to the LPC time window (Werheid, Schacht, Sommer, 2007), thus in time periods that are related to stimulus-driven rather than evaluative processes. Behavior research evidence has shown that people have longer reaction times and higher accuracy rates in identifying attractive faces. Therefore, the results of this study indicated that there were female facial attractiveness bias in processing of judgment and recognition for males. It may be that attractive female faces represent reproductive fitness and mating value for males from the evolutional perspective.

The definition of sexual selection and its implications for dinosaurian biology

We are delighted by the constructive and thoughtful comments of Knell & Sampson (2010) on our original article (Padian H whereas, to Knell and Sampson, sexual selection does not require sexual dimorphism, and mate recognition is a more closely related concept to sexual selection. In our view, Charles Darwin understood organismal biology better than anyone of his time, partly because he thought through problems so thoroughly. In devising his theory of natural selection, he realized that certain living animals bore some salient phenotypic characteristics, such as horns and antlers, that could not be readily explained through the agency of natural selection. He knew that these sorts of features (and their associated behaviors) would pose a threat to the acceptance of his theory of natural selection (because they would be seen as fatal exceptions), and he also understood that these features were not, in most cases, directly relevant to an individual’s survival (i.e. ecologically adaptive). Rather, they helped an individual attract mates or repel rivals for mates. The opposite sex lacked these features (or did not use them in mating). To this phenomenon he gave the name sexual selection, and he explicitly defined it (1859, pp. 89–90 and nearly the same words in 1871, p. 243) by stating that these features were present in one sex and not the other, and that they either attracted mates or repelled rivals. This was the genesis of the term sexual selection. Darwin needed this concept as a contrast to natural selection, in order to defuse a false argument of his detractors; he knew exactly what he was doing. Darwin cannot be ‘wrong’ about the definition of this concept, despite the protests or confusion of later authors, because he invented it, and his empirical basis for it is entirely valid; he was not ‘imprecise’ (pace Carranza, 2009). Myriad examples prove the presence of distinct, monosexual characters in species that are used to attract mates and repel rivals (Darwin, 1871; Andersson, 1994). Thus, the only possible definition of sexual selection requires sexual dimorphism (and not simply allometric sexual differences: Padian & Horner, 2010). To say this does not deny that many factors are involved in the attraction of mates, the repulsion of rivals, success in mating and the differential production of offspring. But sexual selection is only a small part of this, and Darwin was not trying to explain all aspects of mate recognition, attraction, competition and reproductive success. The notion that sexual selection involves more or different aspects than those defined by Darwin is an historical error of misinterpretation in the scholarly literature that has sadly become entrenched. But one cannot change the definition of a term at will. This only creates confusion and fosters misinterpretation [consider the later misuses of Van Valen’s (1973) original concept of the ‘Red Queen,’ which denoted the control of energy in an ecosystem by individual species]. We acknowledge that Darwin’s term is widely misused in the recent literature, and unfortunately, this has brought confusion to an extremely interesting and productive field. Futuyma (2009), whose textbooks have been the ne plus ultra of the field for many years, views sexual selection as a subtype of natural selection, and many biologists agree. There is an historical context for this misunderstanding. In the early 20th century, mathematical modelers of the Modern Synthesis needed to examine whether natural selection could be a viable force in populations (Mayr & Provine, Journal of Zoology

Can buy me love: Mate attraction goals lead to perceptual readiness for status products

Exposure to mating cues activates the goal to signal one's mate value to members of the opposite sex. This mate attraction goal may render men perceptually ready for products that signal their mate value to women. As men's mate value is partly determined by their financial prospects, men may be more likely to notice products that would signal their financial resources to women. The current study demonstrates that exposure to a sexily dressed woman increases single men's likelihood of noticing status products in a visual display. Not only do these findings further support the link between conspicuous consumption and male mating strategies, they are the first to demonstrate perceptual readiness for indirect (i.e., products) rather than direct (i.e., opposite sex individuals) means for reproduction.

Relative Effects of Juvenile and Adult Environmental Factors on Mate Attraction and Recognition in the Cricket,Allonemobius socius

Finding a mate is a fundamental aspect of sexual reproduction. To this end, specific-mate recognition systems (SMRS) have evolved that facilitate copulation between producers of the mating signal and their opposite-sex responders. Environmental variation, however, may compromise the efficiency with which SMRS operate. In this study, the degree to which seasonal climate experienced during juvenile and adult life-cycle stages affects the SMRS of a cricket, Allonemobius socius (Scudder) (Orthoptera: Gryllidae) was assessed. Results from two-choice behavioral trials suggest that adult ambient temperature, along with population and family origins, mediate variation in male mating call, and to a lesser extent directional response of females for those calls. Restricted maximum-likelihood estimates of heritability for male mating call components and for female response to mating call appeared statistically nonsignificant. However, appreciable “maternal genetic effects” suggest that maternal egg provisioning and other indirect maternal determinants of the embryonic environment significantly contributed to variation in male mating call and female response to mating calls. Thus, environmental factors can generate substantial variation in A. socius mating call, and, more importantly, their marginal effect on female responses to either fast-chirp or long-chirp mating calls suggest negative fitness consequences to males producing alternative types of calls. Future studies of sexual selection and SMRS evolution, particularly those focused on hybrid zone dynamics, should take explicit account of the loose concordance between signal producers and responders suggested by the current findings.

Ambient light alters temporal-updating behaviour during mate choice in a Neotropical frog

It is well known that animal decision-making can be influenced by environmental variables, such as the risk of predation. During the breeding season, nocturnal amphibians encounter a range of environmental conditions at breeding aggregations, including variable ambient light conditions. For nocturnal frogs, illumination is expected to minimize conspicuous movement that might increase predator detection. Previous work has shown that female Physalaemus pustulosus (Cope, 1864) (= Engystomops pustulosus (Cope, 1864)) are sensitive to variation in light levels during mate choice. Here we use an acoustic playback design in which stimuli are adjusted for intensity and complexity during female phonotaxis to show that choosiness is influenced by light level. Frogs were more likely to commit to an initial mate choice despite a dynamic reduction in mate attractiveness under dim light conditions compared with darkness. These results suggest that females are trading off the attractiveness of potential mates with the perceived costs of executing mate choice by committing to an initial decision and thereby reducing assessment time and movement. The dynamic playback design used here provides an approach that could be applied in other systems in which context-dependent decision-making is thought to be important.

Competing for last place: Mating behaviour in a pill-box crab, Halicarcinus cookii (Brachyura: Hymenosomatidae)

The mating strategy of Halicarcinus cookii was investigated to ascertain how males maximised their fitness through mate choice. An intertidal population at Kaikoura, New Zealand, was dominated by mature crabs of both sexes in summer and by immature crabs in the colder months. More than 95% of mature females were ovigerous with early stage and late stage broods found in almost every month, indicating that egg production and larval release is continuous. The operational sex ratio was less than 1 male/female in summer, but often more than 1.0 in the colder months. The gonosomatic index increased along with brood development so that as soon as zoeae were released, the next clutch of eggs was ready to be fertilised. Males searched for receptive females and began pre-copulatory mate guarding without any courtship display. They mated preferentially with late stage or non-ovigerous females: copulation duration was longest for stage 5 females as was post-copulatory guarding (mean 18.3 h). Late stage females were up to 14% of the female population. Mate attraction seems to be the result of an ovarian signal rather than from the developing brood. Manipulation of the sex ratio had effects upon copulation duration and post-copulatory guarding: presence of a rival male increased duration of guarding. Females showed precocious mating in the penultimate instar and were able to lay fertilised eggs after their pubertal moult in the absence of males. H. cookii females have many mates, but males attempt to ensure paternity by preferentially pursuing mature females close to egg laying and by guarding these females after copulation. These behaviours are all elements of a competitive strategy to ensure that a male loses (not wins) the race to copulate because females have a ventral seminal receptacle, giving sperm precedence to the last male to mate. Male mating behaviour is a consequence and evolutionary response to female morphology.

Sex-biased parental investment is correlated with mate ornamentation in eastern bluebirds

Males typically have greater variance in reproductive success than females, so mothers should benefit by producing sons under favorable conditions. Being paired with a better-than-average mate is one such favorable circumstance. High-quality fathers can improve conditions for their offspring by providing good genes, good resources, or both, so females paired to such males should invest preferentially in sons. Ornamentation has been linked to male quality in many birds and, in support of differential allocation theory, females of several avian species invest more in entire broods when paired to attractive mates. Additionally, the females of some bird species apparently manipulate the primary sex-ratio of their broods in relation to the attractiveness of their mates. However, empirical support for a link between mate ornamentation and preferential feeding of sons (another form of biased investment) is lacking. We tested for correlations between sex-biased parental investment and mate plumage colour in the eastern bluebird (Sialia sialis), a species in which juveniles have sexually dichromatic UV-blue plumage. We found that the proportion of maternal feeding attempts to fledgling sons (versus fledgling daughters) was positively correlated with structurally coloured plumage ornamentation of fathers. Additionally, paternal feeding attempts to sons were correlated with plumage ornamentation of mothers and increased in fathers exhibiting breast plumage characteristics typical of older males. These results provide further support for the idea that parental strategies are influenced by mate attractiveness and provide the first evidence that mate ornamentation can influence parental behavior even after offspring have left the nest.

Parental investment amplifies effects of genetic complementarity on growth rates in song sparrows, Melospiza melodia

Life history theory predicts that individuals paired with attractive mates may invest more in offspring. Such differential investment may amplify the effects of genetic quality on fitness. Attractiveness can include ‘good gene’ and ‘complementary gene’ components, but how the latter affects parental investment remains unknown. We found that nestling song sparrows with genetically dissimilar parents grew faster than did nestlings whose parents were genetically more similar to one another. A cross-fostering experiment revealed complementary gene effects on growth; nestlings produced by genetically dissimilar parents grew faster than their adoptive ‘siblings’ reared in the same nest but produced by parents that were more genetically similar. To explore whether parental investment exaggerates these complementary gene effects on growth, we monitored parental nest visits. Maternal visits were negatively related to genetic similarity between mates. The novel finding that females adjust levels of care according to the genetic diversity of their offspring suggests that parental investment can amplify complementary gene effects on fitness.

Meeting Your Match: How Attractiveness Similarity Affects Approach Behavior in Mixed-Sex Dyads

This experimental study investigated approach behavior toward opposite-sex others of similar versus dissimilar physical attractiveness. Furthermore, it tested the moderating effects of sex. Single participants interacted with confederates of high and low attractiveness. Observers rated their behavior in terms of relational investment (i.e., behavioral efforts related to the improvement of interaction fluency, communication of positive interpersonal affect, and positive self-presentation). As expected, men displayed more relational investment behavior if their own physical attractiveness was similar to that of the confederate. For women, no effects of attractiveness similarity on relational investment behavior were found. Results are discussed in the light of positive assortative mating, preferences for physically attractive mates, and sex differences in attraction-related interpersonal behaviors.

Genes, Legitimacy and Hypergamy: Another Look at the Economics of Marriage

In order to credibly sell legitimate children to their spouse, women must forego more attractive mating opportunities. This paper derives the implications of this observation for the pattern of matching in marriage markets, the dynamics of human capital accumulation, and the evolution of the gene pool. A key consequence of the trade-off faced by women is that marriage markets will naturally tend to be hypergamous – that is, a marriage is more likely to be beneficial to both parties relative to remaining single, the greater the man's human capital, and the lower the woman's human capital. As a consequence, it is shown that the equilibrium can only be of two types. In the type, all agents marry somebody of the same rank in the distribution of income. In the Sex and the City (SATC) type, women marry men who are better ranked than themselves. There is a mass of unmarried men at the bottom of the distribution of human capital, and a mass of single women at the top of that distribution. It is shown that the economy switches from a Victorian to an SATC equilibrium as inequality goes up. The model sheds light on how marriage affects the returns to human capital for men and women. Absent marriage, these returns are larger for women than for men but the opposite may occur if marriage prevails. Finally, it is shown that the institution of marriage may or may not favour human capital accumulation depending on how genes affect one's productivity at accumulating human capital.

Testing Miller's theory of alleles preventing androgenization as an evolutionary explanation for the genetic predisposition for male homosexuality

The genetic background of male homosexuality presents an evolutionary paradox, since homosexuality could be considered a reproductive disadvantage. We tested E.M. Miller's (2000) balanced polymorphism explanation, which states that alleles partially preventing androgenization in male fetuses during pregnancy would be associated with a homosexual orientation. Having all the alleles produces homosexuality, while heterosexual carriers with only a few of these alleles instead have a reproductive advantage; that is, they have more traits, which, by controlling for excessive aggressiveness and psychopathy, make them more attractive mates. Pairs of brothers were used to test these assumptions. If homosexuality is due to having all the androgenization-preventing alleles, then heterosexual men with homosexual brothers are more likely to also have some of the these alleles compared to heterosexual men with heterosexual brothers. These two categories were compared on variables related both directly and indirectly to reproductive success, with heterosexual men with a homosexual brother hypothesized to have an advantage on the variables. However, no statistically significant findings in support of the theory were detected. The results were discussed together with alternative explanations.

Mate attraction by females in a sexually cannibalistic praying mantis

We studied mate attraction by females of the praying mantid, Tenodera aridifolia sinensis, testing honest signaling of mate availability versus deceptive signaling to attract males for sexual cannibalism. We experimentally varied female diet and mating history and measured the rate of attraction of a wild population of males to caged females. Honest signaling theory predicts that virgin females will attract males at the greatest rate whereas deceptive signaling predicts that hungry females (which are more likely to cannibalize males) will attract more males, particularly among non-virgin females. Our results show that hungry females did not attract more males than well-fed females. Indeed, the opposite was true: hungry females attracted significantly fewer males. Moreover, hungry females were no more likely than well-fed females to attract males subsequent to mating, and mated females attracted males at a lower rate than did virgin females. We also observed female T. aridifolia sinensis and male Mantis religiosa arriving at the caged females and we discuss the significance of these observations. The results refute the hypothesis of deceptive signaling and show that mate attraction signals of female T. aridifolia sinensis are honest indicators of female mate availability and a lower risk of sexual cannibalism.

Female preferences for long tails constrained by species recognition in short-tailed red bishops

Sexual selection and species recognition both play important roles in mate choice. Typically, females use the relative expression of male sexual traits to select high-quality or attractive mates (sexual selection) of the same species (species recognition). However, when the variation in male trait expression of both conspecifics and heterospecifics overlaps, females potentially face a conflict between sexual selection and mate recognition. Among the highly polygynous and closely related African Euplectes species (widowbirds and bishops), females show a general and open-ended mate preference for extreme male tail length (even in relatively short-tailed species). To evaluate the relative strength and interaction of directional versus stabilizing selection pressures on tail length, we experimentally examined female mating preferences in the red bishop (Euplectes orix), a short-tailed (4 cm) species sympatric with longer tailed widowbirds (tails 7–50 cm). In standardized mate-choice experiments, females preferred naturally long-tailed males (5 cm), were indifferent to controls (4 cm), but discriminated against short-tailed (3 cm) and supernormal-tailed (8 cm) males. Although the naturally small variation in tail length (5%) is unlikely to function as a primary mate-choice cue, these results suggest a generalized female bias for longer tails (within the natural range). However, directional preferences for longer tails may be constrained by selection pressures to avoid heterospecific mating with the closely related and sympatric longer tailed widowbirds.

Listening in Pheromone Plumes: Disruption of Olfactory-Guided Mate Attraction in a Moth by a Bat-Like Ultrasound

Nocturnal moths often use sex pheromones to find mates and ultrasonic hearing to evade echolocating bat predators. Male moths, when confronted with both pheromones and sound, thus have to trade off reproduction and predator avoidance depending on the relative strengths of the perceived conflicting stimuli. The ultrasonic hearing of Plodia interpunctella was investigated. A threshold curve for evasive reaction to ultrasound of tethered moths was established, and the frequency of best hearing was found to be between 40 and 70 kHz. Flight tunnel experiments were performed where males orienting in a sex pheromone plume were stimulated with 50 kHz pulses of different intensities. Pheromone-stimulated males showed increased defensive response with increased intensity of the sound stimulus, and the acoustic cue had long-lasting effects on their pheromone-mediated flight, revealing a cost associated with vital evasive behaviours.

Male sexual attractiveness affects the investment of maternal resources into the eggs in peafowl (Pavo cristatus)

According to the differential investment hypothesis, females paired with attractive mates are expected to invest more in the current reproduction relative to females paired with unattractive males. We experimentally tested this hypothesis in the peafowl (Pavo cristatus) by providing females with males that differed in sexual attractiveness. In agreement with the differential allocation hypothesis, females paired with more ornamented males laid larger eggs, and deposited higher amounts of testosterone into the egg yolk, independently of the sex of the embryo. These results show that the association between paternal phenotype and offspring quality could arise via a differential maternal investment. They also suggest that, if ornamented males do transmit good genes to the progeny, the maternal differential investment can amplify the effect of such good genes on the offspring fitness.