Instruct: Given a question, retrieve relevant passages that answer the question.
Query: What is the study of sexual attraction in humans called?
Androphilia and gynephilia are terms used in behavioral science to describe sexual orientation, as an alternative to a gender binary homosexual and heterosexual conceptualization. Androphilia describes sexual attraction to men or masculinity; gynephilia describes the sexual attraction to women or femininity.[1] Ambiphilia describes the combination of both androphilia and gynephilia in a given individual, or bisexuality.[2]
Sexual orientation is an enduring pattern of romantic or sexual attraction (or a combination of these) to persons of the opposite sex or gender, the same sex or gender, or to both sexes or more than one gender. The ultimate causes and mechanisms of sexual orientation development in humans remain unclear and many theories are speculative and controversial. However, advances in neuroscience explain and illustrate characteristics linked to sexual orientation. Studies have explored structural neural-correlates, functional and/or cognitive relationships, and developmental theories relating to sexual orientation in humans.
Currin et al. (2015) carried out a study investigating the existence of the fraternal birth order effect in a variety of sexual orientation dimensions — namely, identity, attraction, fantasies, and behavior — whereas previous research studied only one such dimension (identity). Participants in the study were split into two groups: a "heterosexual group" and a "non-heterosexual" group. To determine what label participants used to identify their sexual orientation, participants were asked, "How would you classify your sexual orientation?" and selected from one of five options (heterosexual, mostly heterosexual, bisexual, mostly gay/lesbian, gay/lesbian). People who selected "heterosexual" were place in the heterosexual group, whereas people selecting "gay/lesbian" were placed in the non-heterosexual group. To assess sexual attraction, participants were asked, "How sexually attracted are you to men?" and selected from a 7-point Likert scale ranging from 1 (not at all) to 7 (very much). Participants were also asked "How sexually attracted are you to women?" and were presented with the same Likert scale. People who selected 1 (not at all) when answering the same sex sexual attraction question were placed in the heterosexual group. People who selected 2 or greater were placed in the non-heterosexual group.
Average differences in mating strategies between the sexes do not entail uniformity in mating strategies within the sexes, and in humans, such within-sex variation is substantial. Individual differences in mating strategies are commonly measured using the Sociosexual Orientation Inventory (SOI), a questionnaire that includes items assessing past sexual behavior, anticipated future sexual behavior, and openness to casual sex. Higher scores on the SOI indicate a "sexually unrestricted" mating strategy, and lower scores on the SOI indicate a "sexually restricted" mating strategy. Several studies have found that scores on the SOI are related to mate preferences, with more sexually restricted individuals preferring personal/parenting qualities in a mate (e.g. responsibility and loyalty), and with less sexual restricted individual preferring qualities related to physical attractiveness and social visibility. Other studies have shown that SOI scores are related to personality traits (i.e. extraversion, erotophilia, and low agreeableness), conspicuous consumption in men as a means to attract women, and increased allocation of visual attention to attractive opposite-sex faces.
In certain instances, physical attractiveness is distinct from sexual attraction; humans may regard the young as attractive for various reasons, for example, but without sexual attraction.
Another significant distinction can be made between what medical statisticians call incidence and prevalence. For example, even if two studies agree on a common criterion for defining a sexual orientation, one study might regard this as applying to any person who has ever met this criterion, whereas another might only regard him/her as being so if they had done so during the year of the survey. According to the American Psychological Association, sexual orientation refers to an "enduring pattern of emotional, romantic, and/or sexual attractions to men, women, or both sexes", as well as to "a person's sense of identity based on those attractions, related behaviors, and membership in a community of others who share those attractions." Therefore, a person can be celibate and still identify as being bisexual or homosexual based on romantic proclivities.
These studies suggest that men and women are different in terms of sexual arousal patterns and that this is also reflected in how their genitals react to sexual stimuli of both genders or even to non-human stimuli. Sexual orientation has many dimensions (attractions, behavior, identity), of which sexual arousal is the only product of sexual attractions which can be measured at present with some degree of physical precision. Thus, the fact that women are aroused by seeing non-human primates having sex does not mean that women's sexual orientation includes this type of sexual interest. Some researchers argue that women's sexual orientation depends less on their patterns of sexual arousal than men's and that other components of sexual orientation (like emotional attachment) must be taken into account when describing women's sexual orientations. In contrast, men's sexual orientations tend to be primarily focused on the physical component of attractions and, thus, their sexual feelings are more exclusively oriented according to sex.
Among humans, the missionary position is the most commonly used sex position. In his seminal study "Sexual Behavior in the Human Female" (1953), which focused on American women, researcher Alfred Kinsey stated that 91% of married women surveyed reported using this position most often, whereas 9% reported using it exclusively. A "The Journal of Sexual Medicine" study entitled "What Kind of Erotic Film Clips Should We Use in Female Sex Research? An Exploratory Study" selected 18 film clips out of a sample of 90 that were found by the women studied to be particularly mentally appealing and visually arousing. 21% of the original 90 involved the missionary position, but 33% of the final 18 involved missionary. Fewer than 10% of sexually active persons rarely or never use the missionary position. According to Francoeur, the Brazilian Bororo Indians eschew missionary, finding it insulting for either partner to be above the other during sex. Balinese shun the man-on-top position in favor of what they call "the Oceanic position" due to their perception of the former as being impractical and clumsy. The Cashinahua people use the missionary position to stay stable when they have sex in a forest stream to avoid insect bites. The inhabitants of Inis Beag practice the missionary position exclusively, with very limited foreplay. In addition to humans, the missionary position has also been used by certain other species, including bonobos, gorillas, and armadillos.
The mechanics of human sexuality or mechanics of sex, or more formally the biomechanics of human sexuality, is the study of the mechanics related to human sexual activity. Examples of topics include the biomechanical study of the strength of vaginal tissues and the biomechanics of male erectile function. The mechanics of sex under limit circumstances, such as sexual activity at zero-gravity in outer space, are also being studied.
Sexual attraction is attraction on the basis of sexual desire or the quality of arousing such interest. Sexual attractiveness or sex appeal is an individual's ability to attract the sexual or erotic interest of another person, and is a factor in sexual selection or mate choice. The attraction can be to the physical or other qualities or traits of a person, or to such qualities in the context in which they appear. The attraction may be to a person's aesthetics or movements or to their voice or smell, besides other factors. The attraction may be enhanced by a person's adornments, clothing, perfume, hair length and style, and anything else which can attract the sexual interest of another person. It can also be influenced by individual genetic, psychological, or cultural factors, or to other, more amorphous qualities of the person. Sexual attraction is also a response to another person that depends on a combination of the person possessing the traits and also on the criteria of the person who is attracted.
The typology divides male-to-female transsexuals into two groups: homosexual and autogynephilic. Homosexual transsexuals are thought of as being extremely feminine gay men, while autogynephilic transsexuals are thought to be sexually attracted to the image of themselves as women. Attraction to the image of oneself as a woman is called "autogynephilia". The homosexual type corresponds to what is known as early-onset in other sources, while the autogynephilic type corresponds to what is known as late-onset in other sources. Homosexual transsexuals are proposed to be motivated by being very feminine in both behavior and appearance, and by a desire to romantically and sexually attract (ideally very masculine) men. Autogynephilic transsexuals are thought to be motivated by their sexual desire and romantic love for being women.
As mentioned in the last section, men and women, when dating, have goals and expectations. They are looking for certain qualities and characteristics. Eventually, both are looking for someone to spend the rest of their lives with. But in the meantime they are looking for different qualities and characteristics in a person that they wish to have as their immediate companion. According to the study done by Alice Eagly, a professor in Psychology at Northwestern University and Wendy Wood, also a professor in the same department, about sex differences in human behavior, they give the idea that both men and women are looking for certain attractiveness that fits their taste and style. The study states “the value of attractiveness stems from its perceived association with the ability to provide sexual pleasure.” This means that attractiveness suggests information about “sexual warmth” or sexual arousal. The study then proceeds to say that if this is true, then men will seek sexiness in a partner. In addition they will also look for characteristics such as domestic skills. However, Wood and Eagly go on to say “given that the female gender role contains sexual restraint and lacks sexual autonomy, women place less importance on sexiness in a partner.”
Williams called "The Evolution of Human Sexuality" one of the classic works on "the biology of human sexual attitudes", alongside the work of Hrdy, in "The Pony Fish's Glow" (1997). Alan F. Dixson described Symons's explanation of male homosexual promiscuity as "interesting" in "Primate Sexuality" (1998). The biologist Paul R. Ehrlich described "The Evolution of Human Sexuality" as a "classic but controversial treatise on human sexual evolution" in "Human Natures" (2000). He identified Symons's study of the development of human ovulation as a landmark. Thornhill and Palmer identified Symons as the first author to propose that rape is "a by-product of adaptations designed for attaining sexual access to consenting partners" in "A Natural History of Rape" (2000). They observed that Symons has falsely been accused of basing his arguments on the assumption that behavior is genetically determined, even though he explicitly rejects that assumption and criticizes it at length. They endorsed Symons's explanation of male homosexual promiscuity, and his arguments against the idea that rape is not sexually motivated. Gould commented in "The Structure of Evolutionary Theory" (2002) that the argument that the clitoris is not adaptive, put forward by Symons and subsequently by Gould himself, has been widely misunderstood as a denial of the adaptive value of the female orgasm in general, or even as a claim that female orgasms lack significance. The anthropologist Melvin Konner called "The Evolution of Human Sexuality" "the classic introduction to the evolutionary dimensions" of sex in "The Tangled Wing" (2002). Pinker called "The Evolution of Human Sexuality" "groundbreaking" in "The Blank Slate" (2002). He criticized what he considered personal abuse of Symons by Lewontin "et al." in their discussion of "The Evolution of Human Sexuality" in "Not in Our Genes".
Havelock Ellis was an English physician and writer born in the eighteen hundreds who studied human sexuality, and is referred to as one of the earliest sexologists. Ellis's work was geared towards human sexual behavior. His major work was a seven-volume publication called "Studies in the Psychology of Sex", which related sex to society. Published in 1921, "Studies in the Psychology of Sex" covered the evolution of modesty, sexual periodicity, auto-erotism, sexual inversion, sexual impulse, sexual selection, and erotic symbolism. Ellis also conceived the term eonism, which references a man dressing as a woman. He elaborated on this term in his publication of "Eonism and Other Supplementary Studies." He wrote "Sexual Inversion" as well in hopes to address any ignorance people have on the topic.
Sexual behavior and intimate relationships are strongly influenced by a person's sexual orientation. Sexual orientation is an enduring pattern of romantic or sexual attraction (or a combination of these) to persons of the opposite sex, same sex, or both sexes. Heterosexual people are romantically/sexually attracted to the members of the opposite sex, gay and lesbian people are romantically/sexually attracted to people of the same sex, and those who are bisexual are romantically/sexually attracted to both sexes.
Alternative approaches to the concept of bisexuality have been developed that expand the definition of sexual identity outward from a "this "or" that" mentality to a "this "and" that" mentality. Jenée Wilde presents the idea of what she calls "dimensional sexuality" in an article for "Sexual and Relationship Therapy", a theoretical framework in which gender is not the primary factor in sexual attraction, rather it is one of many axes. These other axes of attraction can include the desire for either monogamy or polyamory, and the fluidity of desire for the various gender(s) in a partner over time. Wilde uses her framework to broaden the scale of sexual identity from a simple binary spectrum from "mono-sexual" to "bisexual", and to establish relationships between these identities; these relationships would not alienate individuals without a single "fixed object" of attraction.
Attraction within these friendships can cause challenges. Sexual attraction can arise for a variety of reasons in cross-sex friendships. In a study by Halatsis and Christakis (2009), participants cited social pressures and emotional vulnerability as reasons for sexual attraction arising in a cross-sex friendship. A social pressure that may prompt sexual attraction between cross-sex friends is the perceptions other friends have of their relationship and emotional vulnerability coupled with closeness may provoke sexual attraction between cross-sex friends. When sexual attraction develops in a friendship, it can corrupt the friendship and individuals state that behavior often changes. Sexual attraction in cross-sex friendships is often dealt with in one of three ways: management of this attraction through communication or an internal decision not to pursue the attraction in order to preserve the friendship, a sexual relationship forms then dissipates, or sex becomes a part of the friendship. When participants in the study by Halatsis and Christakis (2009) were asked about their experience with sexual attraction in cross-sex friendships, over 50% had experienced attraction, and over 50% of that group had expressed or acted on their sexual attraction. However, men had a tendency to be more attracted to their cross-sex friends, and a higher tendency to act on that attraction. Only 16% of individuals who had acted on their sexual attraction claimed that their friendship ended as a result, otherwise the friendship remained intact or transformed into a romantic relationship. 
Reeder (2000) found that there are four types of attraction within cross-sex friendships: subjective physical/sexual attraction, objective physical/sexual attraction, romantic attraction, and friendship attraction. Subjective physical/sexual attraction occurs when one of the individuals in the friendship is physically attracted to the other. Objective physical/sexual attraction happens when one individual thinks that the other is attractive in general, yet they are not attracted to the person. Romantic attraction within the cross-sex friendship occurs when one of the individuals within the friendship desires to turn the friendship into a romantic relationship because they believe he or she would make a good girlfriend or boyfriend. Friendship attraction is simply when an individual feels very platonically connected to his or her friend. The four types can coexist together within a friendship or can occur separately. Furthermore, the type of attraction that an individual feels within a cross-sex friendship can change over time. Within Reeder’s (2000) sample, friendship attraction is the most prevalent type of attraction within cross-sex friendships. Even when participants felt other types of attraction within their cross-sex friendships, they prioritized their friendship attraction so that they relationship would not be ruined.
Geertz wrote that "virtually none" of Symons's claims are based on research Symons conducted himself, and that Symons "made no direct inquiries into human sexuality", instead basing himself on anthropological reports and other material, resulting in a book that is "a pastiche more than a study". He accused Symons of supporting his views through selective use of evidence, such as an "extremely brief and fragmentary" review of the effects of hormones on human sexuality. He considered Symons's characterizations of male and female homosexuals to be on the level of national or ethnic stereotypes, and found it questionable whether Symons's observations support his claims about differences between male and female sexuality. He questioned whether Symons was correct to believe it possible to determine what natures and dispositions men and women have prior to the influence of human culture, and criticized Symons for viewing human sexuality as a biological fact with cultural implications rather than a cultural activity sustaining a biological process. He disagreed with the favorable views of "The Evolution of Human Sexuality" expressed by the biologists E. O. Wilson and George C. Williams, and the then president of the American Anthropological Association, calling the work impoverished. He wrote that if the book was the most important work on human sociobiology to date, this was unfortunate.
Augustine, Hincmar and Psellos thought that lust was what led demons to have sexual relationships with humans. William of Auvergne conceived the idea that demons felt a particular and morbid attraction by long and beautiful female hair, and thus women had to follow the Christian use of covering it to avoid exciting desire in them. Tauler had the opinion that demons were lascivious and thus they wanted to have sexual intercourse with humans to satisfy their lewdness. Sinistrari supported the idea that demons felt sexual desire, but satisfaction and pleasure were not the only motivation to have sexual relationships with humans, another reason being that of fecundating women.
Further empirical data about an asexual demographic appeared in 1994, when a research team in the United Kingdom carried out a comprehensive survey of 18,876 British residents, spurred by the need for sexual information in the wake of the AIDS pandemic. The survey included a question on sexual attraction, to which 1.05% of the respondents replied that they had "never felt sexually attracted to anyone at all". The study of this phenomenon was continued by Canadian sexuality researcher Anthony Bogaert in 2004, who explored the asexual demographic in a series of studies. Bogaert's research indicated that 1% of the British population does not experience sexual attraction, but he believed that the 1% figure was not an accurate reflection of the likely much larger percentage of the population that could be identified as asexual, noting that 30% of people contacted for the initial survey chose not to participate in the survey. Since less sexually experienced people are more likely to refuse to participate in studies about sexuality, and asexuals tend to be less sexually experienced than sexuals, it is likely that asexuals were under-represented in the responding participants. The same study found the number of homosexuals and bisexuals combined to be about 1.1% of the population, which is much smaller than other studies indicate.
According to "Sexual Behavior in the Human Male" by Alfred Kinsey and several other modern studies, the majority of humans have had both heterosexual and homosexual experiences or sensations and are bisexual. Kinsey himself, along with current sex therapists, focused on the historicity and fluidity of sexual orientation. Kinsey's studies consistently found sexual orientation to be something that evolves in many directions over a person's lifetime; rarely, but not necessarily, including forming attractions to a new sex. Rarely do individuals radically reorient their sexualities rapidly—and still less do they do so volitionally—but often sexualities expand, shift, and absorb new elements over decades. For example, socially normative "age-appropriate" sexuality requires a shifting object of attraction (especially in the passage through adolescence). Contemporary queer theory, incorporating many ideas from social constructionism, tends to look at sexuality as something that has meaning only within a given historical framework. Sexuality, then, is seen as a participation in a larger social discourse and, though in some sense fluid, not as something strictly determinable by the individual.
Although reported frequently as anecdote in the field of psychology, there are no studies showing that people are sexually attracted to those genetically similar to them. Studies of MHC genes show that unrelated people are less attracted to those genetically similar to them. However, in mice, this lack of attraction can be reversed by adoption. Whilst it has been documented that sexual attraction can occur between related individuals in some cases, it is not clear that calling this attraction GSA is appropriate.
There is a relationship between various aspects of human biology and genetics with sexual attraction. This includes the role of the major histocompatibility complex (MHC), the human leukocyte antigen (HLA) and their different heterozygotic variations. Such genetic factors may play a role in sexual selection. Signalling odours in reproduction are called attractants; their function is to bring about successful mating.
Odour is sensory stimulation of the olfactory membrane of the nose by a group of molecules. Certain body odours are connected to human sexual attraction. Humans can make use of body odour subconsciously to identify whether a potential mate will pass on favourable traits to their offspring. Body odour may provide significant cues about the genetic quality, health and reproductive success of a potential mate. Body odour affects sexual attraction in a number of ways including through human biology, the menstrual cycle and fluctuating asymmetry. It also affects the sexual attraction of insects and mammals.
MHC similarity in humans has been studied in three broad ways: odor, facial attractiveness, and actual mate choice. Studies of odor find MHC-dissimilarity preferences but vary in details, while facial attractiveness favors MHC-similarity and actual mating studies are varied.