Gender differences in attitudes toward casual sex have been widely studied. It has been reported that between 44 and 75% of young adults between the ages of 18 and 25 have experienced at least one casual sexual encounter within their lives (Flack et al., 2016; Lyons et al., 2014; Maticka-Tyndale et al., 2003). Casual sex, also known as a hookup or one-night stand, can be described as engagement in sexual acts, with the absence of intimacy (Monto & Carey, 2014). Casual sex is a term that is used to describe a range of sexual behaviours, from a ‘once off’ encounter to frequent encounters of sexual intercourse in the absence of a committed relationship. It is important to note that participation in a hookup may be spontaneous and/or the result of impaired decision making, possibly due to alcohol or another external influencer (Townshend et al., 2014).
Throughout this paper, the term ‘sex’ is used to refer to intimate acts from kissing to coital intercourse and ‘gender’ is used to refer to male and female identities, either biological or social. The term ‘hookup’ is used to refer to sexual activity, from a kiss to coital intercourse, outside of a committed relationship. Sexual expression is both rich and varied, and engagement in casual sex is by no means limited to the cisgender community. For logistical reasons the current study will focus on individuals that identify as either male or female, but it draws no distinction based on either sexual orientation or non-binary gender identity. Previous research has examined variation in attitudes toward casual sex based on sexual orientation (Bothe et al., 2018; Fernandez del Rio, 2019) but has largely focused on the cisgender subset of humanity.
The prevalence of casual sex is difficult to measure, as there is typically a reliance on self-report measures; however, research suggests that casual sex is becoming increasingly socially acceptable within Western societies (Farvid & Braun, 2017). The ready availability of contraception in the 1960s led to a sexual revolution. Sexual norms were liberalised and having sex for pleasure became more acceptable. Other factors reported to have led to a sexual paradigm shift include the enhanced availability and use of pornographic material, changes in alcohol consumption and changes in perceived sexual risk—due at least in part to advances in medical technology (Heldman & Wade, 2010). Within the past decade, the development of online dating services have increased opportunities to access a sexual partner (Ranzini & Lutz, 2016; Sumter et al., 2017). The development of geo-locative smartphone applications and online dating websites has made it easier to meet a casual sexual partner, with 78.2% of participants from a sample of 395 (men and women aged between 18 and 34) claiming to have had casual sex with someone they met through a dating website (LeFebvre, 2018). However, whether or not the liberalisation of sexual norms and acceptance of sex outside of committed relationships has net positive outcomes is unclear.
Despite this, there is evidence that young adults are engaging in sexual behaviour less frequently in current times. Although COVID-19 has had the effect of reducing sexual activity (Arafat et al., 2020; Gleason et al., 2021; Lehmiller et al., 2021; Rosenberg et al., 2020), and this trend emerged prior to the COVID-19 pandemic. Ueda et al. (2020) found that from 2000 to 2018 sexual inactivity increased in the US among men aged 18–24, and among men and women aged 25–34. The authors speculate that while it is unclear what is ultimately driving this trend, there are quite possibly a number of contributing factors such as: changes in sexual norms; stress and busyness of everyday living limiting leisure opportunities (Wellings et al., 2019); and that the supply of entertainment is competing with sexual activity (Twenge et al., 2017).
Evolutionary and social psychology perspectives suggest that women experience more negative psychological consequences following casual sex than men, including regret, anxiety, and decreased overall mental wellbeing (Fisher et al., 2012; Kennair et al., 2018; Townsend & Wasserman, 2011). In addition to psychological sequelae, there are also a range of health implications of casual sex. Clearly pregnancy (and the risk of) is a potential consequence which affects women to a greater extent than men, but there are also a number of sexually transmitted diseases that disparately impact women. Due to economic, biological, and social factors, women are more susceptible to the acquisition of (and often sustain more damage from) diseases such as the human immunodeficiency virus, chlamydia, syphilis, and herpes simplex virus type 2 (Madkan et al., 2006).
It has been suggested that “the nature of motivational pursuits cannot be adequately understood in the abstract, but rather we must take into account the relational context in which one’s needs are pursued” (Cooper et al., 2011, p. 1333). However, while the weight of empirical literature supports the idea that women generally experience worse psychological outcomes following casual sex than men, some research using motivational frameworks has found no significant gender differences in emotional outcomes following casual sex (Paul et al., 2000; Vrangalova & Ong, 2014). These conflicting findings have prompted researchers to investigate what motivates people to have casual sex, what emotional outcomes follow casual sex, and whether there are gender differences among these variables.
Evolutionary psychologists refer to casual sex as short-term mating and claim that gender differences in sexual motivations and behaviour are innate and universal (Buss & Schmitt, 1993). Sexual motivation is a psychological construct that describes the reasons why people pursue sex (Stark et al., 2015). According to Sexual Strategies Theory (SST), men and women have evolved different underlying motivations for engaging in sex (Buss & Schmitt, 1993). This evolutionary theory on human mating was established with findings from a large-scale study, consisting of 10,047 participants across 37 different cultures (Buss, 1989). Participants were asked to rank desirability of characteristics in short-term and long-term partners, and results indicated gender differences that were consistent cross-culturally. Men regarded a higher quantity of short-term partners as highly desirable, whereas women desired the ability for a partner to provide immediate resources and the potential for him to become a long-term partner (Buss & Schmitt, 1993).
Buss and Schmitt (1993) claim that the differences in reproductive benefits can explain why men report a greater desire to engage in short-term mating and report more positive emotional outcomes than women (Pillsworth et al., 2004; Trivers, 1972). Compared to female sex cells sperm are small, motile, and inexpensive to manufacture, thus men can impregnate multiple partners in a short period of time. In contrast, women have a higher obligate investment in the gestation process, and a typically higher investment in the direct child-rearing process, therefore a long-term partner providing support throughout this process enhances the fitness (and survival prospects) of the woman and her offspring (Pillsworth et al., 2004; Trivers, 1972).
Evolutionary psychologists recognise that both men and women can benefit from short-term sexual encounters, however, short-term relationships are considered less advantageous for women because of the risk of conceiving a child without the support of a long-term mate, which can be detrimental to fitness and survival (Trivers, 1972). Negative emotions have been described as an evolved adaptation to deter decision-making that is not beneficial for reproductive success (Dawson & McIntosh, 2006). Regret following short-term mating is an evolved emotional–cognitive response experienced predominantly by women because it is less reproductively advantageous to engage in short-term mating (Dawson & McIntosh, 2006). Kennair et al. (2018) found that in both Norwegian (N = 547) and US samples (N = 216), more women than men regretted engaging in their most recent casual sex encounter (41% and 50% vs. 26% and 35% respectively). Worry and physical gratification were measured using single items, compromising the internal validity of the scale used to measure these variables. Results indicated worry, disgust, and pressure were predictive of regret, but sexual gratification and self-initiation of sex was associated with less regret. In support of these findings, a large-scale study (N = 24,230), found that 46% of women experienced regret after casual sex compared to 23% of men (Galperin et al., 2013). There was also a substantial gender difference, in the opposite direction, for regret experienced for not pursuing an opportunity for sex (43% men, 16% women). Findings support the general idea that men desire short-term mating more than women, and are consistent with an evolutionary perspective. The authors ultimately suggest that women experience more negative emotions following casual sex because of the higher obligatory costs of sexual reproduction they have paid throughout history, and to avoid future decision-making that are not beneficial for reproduction. However, missed sexual opportunities have historically been associated with higher reproductive fitness costs for men than for women, thus regret following sexual inaction is higher for them.
The evolutionary perspective focuses on gender differences as a result of evolved strategies to enhance reproductive success (Galperin et al., 2013), however, this perspective does not adequately explain motivations to engage in sexual acts that are not concerned with reproducing such as same-sex relations and non-penetrative sexual intercourse. Furthermore, the ease of access to contraception in Western societies supports the notion that people are having sex for other reasons (Emmerink et al., 2016). Although environmental conditions are considered to influence the expression of evolved adaptations, the evolutionary perspective alone does not explain individual, social, and cultural variation.
Eagly and Wood (1999) claim that gender differences in sexual motives and behaviour originate from social structure. According to Social Structural Theory, gender differences develop from the contrasting roles men and women accommodate in society. Typically, men occupy dominant roles with greater authority and autonomy, in comparison to women who spend less time in paid occupations and perform more domestic duties (Eagly & Wood, 1999). These contrasting roles have led to a gender hierarchy of power and the development of traditional gendered social scripts. Social scripts are less distinct in gender egalitarian societies, whereby rights, responsibilities and opportunities are less limited by defined gender roles, stereotypes, or discrimination (Darmstadt et al., 2019). This has led to liberalised gendered sexual norms in Western societies.
To determine whether levels of gender equality influenced sexual motives, Eagly and Wood (1999) conducted a reanalysis of the data collected by Buss (1989) using the Gender Empowerment Measure (GEM) to determine levels of gender equality among the 37 different regions sampled. The GEM calculates the difference in men’s and women’s income and representation in political and senior economic positions. Equal representations depict greater levels of gender equality (Klasen & Schüler, 2011). Findings indicated that gender differences were attenuated as rates of gender empowerment increased, supporting the contention that societal factors influence sexual motives.
Although gender differences are attenuated in higher gender egalitarian societies, research suggests that men and women are perceived differently for engaging in the same sexual behaviour (Farvid et al., 2017). Most research indicates that heterosexual men report more previous sexual partners than heterosexual women (Fisher et al., 2012; LeFebvre, 2018; Maticka‐Tyndale et al., 2003). It is important to acknowledge that, assuming a 1:1 sex ratio, the reports of heterosexual partners should be roughly the same for men and women, as each new sex partner for a man must also be a new sex partner for a woman. There is an implicit understanding that while it is socially acceptable for a man to be sexually autonomous, a woman’s sexual agency is discouraged (Farvid et al., 2017). This polarised standard can be socially damaging for women, leading to social stigma and condemnation of women who exercise sexual autonomy outside of a committed relationship (Pickel & Gentry, 2017). ‘Slut shaming’ refers to the pejorative action of degrading women presumed to have engaged in sexual behaviour outside of a committed relationship. Internalisation of this sexual inequality has been associated with negative emotional outcomes for women (Armstrong et al., 2014).
Uecker and Martinez (2017) collected data via an online survey over a six-year period from 2005 to 2011. The large sample consisted of 21,549 college students and indicated that more women (77%) than men (53%) experienced regret after having sexual intercourse outside of a committed relationship. A mediation analysis revealed that 34% of the total effect was attributable to lack of sexual enjoyment, 29% due to perceived loss of respect, and 12% to a loss of self-respect. The large sample size provides support for gender differences with results indicating that women experience more negative consequences following sexual intercourse than men. In this study participants were not provided with a definition for what constitutes a hookup, asking participants to use whatever definition is used among friends (Uecker & Martinez, 2017).
Sexual Motivations and Outcomes
Research using motivational frameworks has reported minimal and non-significant gender differences in emotional outcomes following sex and argues that outcomes are different depending on the individual’s sexual motivation. Motivational theories posit that sex is used strategically to pursue different goals, and that different motivations explain differences in psychological outcome following sex (Vrangalova, 2015).
In contrast to research documenting gender differences, Vrangalova and Ong (2014) found that gender did not moderate wellbeing following casual sex. Levels of sociosexuality (willingness to engage in casual sex) were measured via a nine-item survey and participants responded to items measuring previous casual sex behaviour, and attitudes and desire for casual sex. In a sample of 371 participants, those that scored highly on sociosexuality reported lower levels of anxiety and depression, and higher levels of self-esteem and life satisfaction, suggesting that casual sex can have positive emotional outcomes. The study concluded that there were no long-term negative consequences on psychological wellbeing following casual sex. Additionally, Vrangalova (2015) investigated the influence of gender and motivation on emotional outcome. Using Self-Determination Theory (Deci & Ryan, 2012), it was hypothesised that people engaging in the same behaviour would have different psychological outcomes depending on whether the motivation was autonomous (self-directed), controlled (other-directed) or amotivated (no intention for behaviour). The longitudinal study consisted of a sample of North American college students (N = 528) below the age of 24. Participants were asked to complete surveys at two different time intervals, nine months apart. Depression, anxiety, self-esteem and physical symptoms were measured as outcome variables. Results suggest that engagement in casual sex did not have a long-term impact on psychological wellbeing. Motives that were non-autonomous, such as adhering to peer pressure, were associated with poorer self-esteem and increased depression and anxiety in male participants only. Participants that engaged in casual sex for autonomous self-directed reasons, such as to achieve sexual gratification or personal satisfaction, reported significantly greater levels of self-esteem than participants that had no hookups. Vrangalova concluded that casual sex may increase self-esteem and subsequently enhance positive psychological growth, but that non-autonomously motivated ‘genital’ hook-ups were associated with outcomes of poor self-esteem, anxiety, and depression. The study found no significant differences between men and women, supporting the argument that other factors predict emotional outcomes following casual sex. It is important to realize that while findings suggesting no gender differences are noteworthy, they are somewhat anomalous and stand in contrast to an overwhelming weight of empirical evidence. There are indications that portions of Vrangalova’s work may be methodologically problematic. For example, Vrangalova and Ong (2014) statistically equalized the gender differences they found with transformations (centering) leading to null effects.
The Current Study
Given the inconsistencies in the literature the following hypotheses were generated:
It was hypothesised that there would be gender differences in the motivations for engaging in casual sex (1a), and in the outcomes of casual sex (1b).
While a number of studies have looked at the various motivations behind engaging in casual sex (Grubbs et al., 2019; McMahan & Olmstead, 2021; Sevi et al., 2018; Vrangalova, 2015), and separately, the outcomes (emotional and otherwise) following casual sex (see Wesche et al., 2020 for a systematic review), far fewer have examined the relationship between these variables.
Exploratory principal component analyses were conducted separately for (a) motivations for engaging in casual sex, and (b) outcomes of casual sex. It was furthermore hypothesised that the outcomes of casual sex will be able to be predicted by the motivations for casual sex (2).