Option to cooperate increases women's competitiveness and closes the gender gap

Option to cooperate increases women's competitiveness and closes the gender gap. Alessandra Cassar, Mary L. Rigdon. Evolution and Human Behavior, Volume 42, Issue 6, November 2021, Pages 556-572. https://doi.org/10.1016/j.evolhumbehav.2021.06.001

Highlights

• The hypothesis that women have a lower desire to compete than men is investigated through an evolutionary framework.

• Idea embraced as an explanation for why women are a minority in high-ranking economic and political positions.

• Different sexes evolved to pursue different competitive strategies, females focusing competitiveness for offspring benefit.

• Experiment (N = 438 Mturk adults) supports hypothesis that women compete as much as men with prosocial option.

• Result suggests important implications for designing policies to promote gender equality: change the system not the women.

Abstract: We advance the hypothesis that women are as competitive as men once the incentive for winning includes factors that matter to women. Allowing winners an opportunity to share some of their winnings with the low performers has gendered consequences for competitive behavior. We ground our work in an evolutionary framework in which winning competitions brings asymmetric benefits and costs to men and women. In the new environment, the potential to share some of the rewards from competition with others may afford women the benefit of reaping competitive gains without incurring some of its potential costs. An experiment (N = 438 in an online convenience sample of U.S. adults) supports our hypothesis: a 26% gender gap in performance vanishes once a sharing option is included to an otherwise identical winner-take-all incentive scheme. Besides providing a novel experiment that challenges the paradigm that women are not as motivated to compete as men, our work proposes some suggestions for policy: including socially-oriented rewards to contracts may offer a novel tool to close the persistent labor market gender gap.

Keywords: CompetitionTournamentGender differencesSocial rewardDictator game

Measured intelligence did not predict increased mate appeal in either study, whereas perceived intelligence and funniness did; intelligence is not important for initial attraction

Intelligence can be detected but is not found attractive in videos and live interactions. Julie C. Driebe et al. Evolution and Human Behavior, Volume 42, Issue 6, November 2021, Pages 507-516. https://doi.org/10.1016/j.evolhumbehav.2021.05.002

Abstract: Self-reported mate preferences suggest intelligence is valued across cultures, consistent with the idea that human intelligence evolved as a sexually selected trait. The validity of self-reports has been questioned though, so it remains unclear whether objectively assessed intelligence is indeed attractive. In Study 1, 88 target men had their intelligence measured and based on short video clips were rated on intelligence, funniness, physical attractiveness and mate appeal by 179 women. In Study 2 (N = 763), participants took part in 2 to 5 speed-dating sessions in which their intelligence was measured and they rated each other's intelligence, funniness, and mate appeal. Measured intelligence did not predict increased mate appeal in either study, whereas perceived intelligence and funniness did. More intelligent people were perceived as more intelligent, but not as funnier. Results suggest that intelligence is not important for initial attraction, which raises doubts concerning the sexual selection theory of intelligence.

Keywords: IntelligenceMate choiceSexual selection

Crushes are uncommunicated, often unilateral, attractions to an individual; research suggests that these experiences might be common among adults (as they are in the young), including among those in committed relationships

Loving you from afar: Attraction to others (“crushes”) among adults in exclusive relationships, communication, perceived outcomes, and expectations of future intimate involvement. Lucia F. O’Sullivan, Charlene F. Belu, Justin R. Garcia. Journal of Social and Personal Relationships, August 24, 2021. https://doi.org/10.1177/02654075211038612

Abstract: Crushes are uncommunicated, often unilateral, attractions to an individual, generally viewed as a state of unfulfilled longing. They are typically attributed to young people, but recent research suggests that these experiences might be common among adults as well, including among those in committed relationships. Combining findings from three studies across four datasets, this mixed-methods research explores crushes experienced by individuals in committed intimate relationships. Study 1 explored types of crushes, preferences and nature of exchanges among adults in committed relationships and compares their reports to a sample of single individuals. Study 2 examined perceived outcomes of crushes as a way to assess needs or goals served by crushes. Study 3 investigated expectations about whether and how the crush relationship might evolve into a more intimate relationship. A total of 3,585 participants (22–45 years, 53.1% women) completed anonymous online surveys addressing crush experiences and related dynamics. Those in committed relationships typically did not intend to communicate their attraction to the target, unlike single individuals. Associated outcomes were primarily positive, including excitement, increased esteem, and fantasy/escape. The vast majority reported no expectations that these crushes would evolve into more intimate relationships, replacing their current relationship. This work adds to our understanding of attraction outside of traditional human courtship processes, with implications for the study of intimate relationship development and maintenance.

Keywords: Attraction, committed, crush, intimate, romantic, sexual, single

General discussion

This series of exploratory studies on crushes was designed to provide some early insights into the nature of exchanges with attractive others for those in committed relationships, outcomes associated with having these attractions, and expectations of future involvement with the target of one’s attraction. Moving us beyond a focus on attraction to others as an indicator of poor relationship quality or a precursor to infidelity, the current series of studies established that these attractions most often seemed instrumental in gaining fairly positive psychosocial outcomes, such as diversion, fun, or excitement.

Overall, few individuals in ostensibly exclusive relationships reported plans to advance the crush relationship further. By comparison to singles, those in relationships were more inclined to keep their attraction covert and were more satisfied to simply flirt with someone for whom they experienced attraction rather than communicate their interest directly.

These findings raise the obvious question of why humans might exhibit and entertain feelings of crushes in the first place, if they are expected to go unfulfilled—that is, unlike in other models of attraction, an individual does not seek out the object of the crush. On the surface, this would seem to be a poor use of an individual’s time and effort, resources meant to be adaptively leveraged in mating contexts. It is possible that these crush attractions are simply inevitable, that we cannot turn off the psychological system that helps us orient toward potential partners when we enter an established relationship. The Instrumentality Principle would indicate that these behaviors meet a motivational priority, moving an individual toward a valuable goal. However, these attractions might reassure individuals that there are other options should the primary relationship falter (i.e., mate switching; Buss et al., 2017). Similarly, many young adults report maintaining “back burner” relationships, that is, a connection with someone who they might someday connect with romantically or sexually (Dibble & Drouin, 2014; Dibble et al., 2015). Crushes might comprise a means of gauging or testing one’s commitment and interest in preserving a primary relationship.

We did not assess relationship quality of one’s primary relationship. Although participants’ self-reports suggest that crushes are relatively benign experiences, further research is needed to examine under which conditions a crush might undermine relationship quality. Intensity of one’s attraction, especially if it increases over time, mutuality of the attraction and the response of the crush target should they want to pursue a relationship are likely important moderators, as is quality of the primary relationship in terms of satisfaction and commitment. Primary relationships of lower quality are likely more vulnerable to one or both partners becoming distracted by another. We also should examine more closely the impact of the secrecy involved with crushes and indeed how much is concealed from a primary partner. Secret attraction when linked with fear of its being exposed might amplify attraction through misattribution of arousal (“excitement transfer” Marin et al., 2017; Meston & Frohlich, 2003) or frustration attraction (Fisher, 2005).

Study limitations

There are other limitations that need to be acknowledged. Our use of cross-sectional data rather than longitudinal data renders any speculation about links to relationship outcomes unwarranted. A longer trajectory, ideally using prospective methods, would allow researchers to better capture outcomes associated with attractions to others. This is a limitation of the study designs, and short of tracking individuals from the onset of their relationship, one that cannot be easily overcome. In addition, it is important to bear in mind that self-reports about sensitive topics, such as attractions to others, are often subject to issues of presentation biases. However, in every case, we ensured that participants were fully informed of the anonymous nature of their reports, which we believe offset some of the biases these concerns might introduce.

Although we were able to study gender differences to some extent, we were only able to explore differences in terms of sexual identity in the first of our three studies. Those who identified as sexual minorities (gay, lesbian, or bisexual) reported more types of crushes than did those who identified as heterosexual. This finding might reflect pressure among sexual minority individuals to keep same-sex attractions hidden. Exploring these attractions in larger and/or more diverse populations will help us determine how a mechanism that evolved to guide individuals toward a viable romantic and sexual partner with whom we intend to bond and mate (Berscheid, & Reis, 1998; Fisher, 1998; Sprecher & Hatfield, 1985) operates in contexts in which an intimate relationship is ostensibly not the goal.

Moderate heritability (30%–40%) for concern for nature, environmental movement activism, and personal conservation behavior and high genetic correlations between them (.6–.7), suggesting a partially shared genetic basis

Genetic Contribution to Concern for Nature and Proenvironmental Behavior. Chia-chen Chang, Thi Phuong Le Nghiem, Qiao Fan, Claudia L Y Tan, Rachel Rui Ying Oh, Brenda B Lin, Danielle F Shanahan, Richard A Fuller, Kevin J Gaston, L Roman Carrasco. BioScience, biab103, October 20 2021. https://doi.org/10.1093/biosci/biab103

Abstract: Earth is undergoing a devastating extinction crisis caused by human impacts on nature, but only a fraction of society is strongly concerned and acting on the crisis. Understanding what determines people's concern for nature, environmental movement activism, and personal conservation behavior is fundamental if sustainability is to be achieved. Despite its potential importance, the study of the genetic contribution to concern for nature and proenvironmental behaviors has been neglected. Using a twin data set (N = 2312), we show moderate heritability (30%–40%) for concern for nature, environmental movement activism, and personal conservation behavior and high genetic correlations between them (.6–.7), suggesting a partially shared genetic basis. Our results shed light on the individual variation in sustainable behaviors, highlighting the importance of understanding both the environmental and genetic components in the pursuit of sustainability.

Heritability of concern for nature and proenvironmental behavior

The heritability of concern for nature and proenvironmental behavior was similar to an average heritability of human personality traits (such as the big five personality traits, which have heritability of about 30%–40%; Vukasović and Bratko 2015). Concern for nature and proenvironmental behavior have also been found to be associated with several human behavioral and personality traits, such as altruism and agreeableness (Pavalache-Ilie and Cazan 2018, Gifford and Nilsson 2014, Lades et al. 2021). The genetic components of these traits (e.g., dopamine-related genes for altruism and agreeableness; Reuter et al. 2011, Kim et al. 2013) may be linked with concern for nature and proenvironmental behavior. In addition, we expect the genetic influences may be mediated through individual differences in emotional or cognitive processes, such as future discounting, social discounting, or risk aversion (Lorenzoni et al. 2007, Gifford 2011, Weber 2017), which may be also linked to personality.

The genetic influences we found might have roots in evolutionary history. Cooperation is fundamental to sustaining natural common-pool resources; all individuals must limit their short-term self-interest for the long-term collective interest, including that of future generations (Gordon 1954, Hardin 1968, Chermak and Krause 2002). Kin selection, direct reciprocity, and reputation mechanisms have been proposed to drive the evolution of cooperative behavior (Apicella and Silk 2019). For example, kin selection favors individuals with sustainable behavior because the short-term loss will benefit their offspring, provided that the offspring are likely to continue to use the resource (Lehmann 2007, Palomo-Vélez et al. 2020). It has also been shown that parents are more likely to donate for climate change mitigation when their decisions are observed by their children as a reminder of genetic relatedness with future generations (Fornwagner and Hauser 2020). The fitness consequences for cooperators may be dependent on the context. For example, proenvironmental behavior will be less beneficial or costly when many people share the same pool of resource (Suzuki and Akiyama 2005, Chang et al. 2021). Context-dependent fitness trade-offs may allow for the coexistence of different resource use behaviors.

Heritability captures how much individual variation in a phenotype can be explained by individual differences in genes and describes the existing variations in a specific study population with its environment. The heritability estimated in this study can therefore not be directly transferred to other study populations. In addition, heritability may change with age (Visscher et al. 2008). In our age moderation analyses (supplemental note 1), genetic influences for concern for nature and personal conservation behavior slightly increased with age. This could be because people may actively choose their environments on the basis of their genetic predisposition (e.g., actively learn about climate change or spend time with people with similar interests), reinforcing their concern for nature and personal conservation behavior as they age (Rutter and Silberg 2002, Plomin and Deary 2015). As unique environmental influences also increased with age, heritability was stable across age groups.

High heritability does not suggest the insignificance of environments. Suitable educational policies have been found to mitigate the health problems arising from genetic background (e.g., obesity; Barcellos et al. 2018). Environmental interventions, such as policies, may influence heritability. For instance, a high-quality teaching environment, which reduces the variance associated with environmental factors, improves students’ educational achievements and increases the heritability of educational achievement (Taylor et al. 2010). In countries with higher social class mobility, heritability of educational attainment is higher because of lower environmental variance (Engzell and Tropf 2019). Future studies with access to twin data sets from other populations could expand the understanding of genetic and environmental influences in other cultural or demographic contexts. We hypothesize that, all other things being equal, heritability of proenvironmental behavior will increase if the environmental barriers are lower for most people in a population.

Limitations and future research

There are several limitations in our study. First, twin analysis assumes that MZ twins do not have stronger environmental similarity than DZ twins for shared environmental factors (Horwitz et al. 2003). However, this assumption may be violated if, for example, MZ twins are more likely to have the same school activities or be treated more similarly by their parents than DZ twins. If this assumption is violated, heritability may be overestimated. Second, the scale used to measure one's concern for nature only shows a marginally acceptable level of internal consistency (DeVellis 2012). Future studies could use other scales with higher internal consistency. Similarly, unique environmental influences also include measurement error, and future studies could conduct repeated measures to address this issue (Ge et al. 2017). Third, our study population is biased toward females. Although we adjusted for this in our analyses, future studies using a more gender-balanced population would be beneficial and could test whether there is a sex difference in the genetic and environmental influences of these phenotypes. Fourth, our population is predominantly older individuals. How genetic and environmental influences change across age should be further investigated. With long-term repeated measurements (e.g., from child to adult stage) in the future, understanding of the development of a person's concern for nature and proenvironmental behavior could be improved.

Rolf Degen summarizing... People like copartisan political-perspective seekers, who attempt to hear from the other side, but less so if they venture too far into enemy ideological territory

Seek and Ye Shall Be Fine: Attitudes Toward Political-Perspective Seekers. Gordon Heltzel, Kristin Laurin. Psychological Science, October 22, 2021. https://doi.org/10.1177/09567976211011969

Abstract: Six preregistered studies (N = 2,421) examined how people respond to copartisan political-perspective seekers: political allies who attempt to hear from shared opponents and better understand their views. We found that North American adults and students generally like copartisan seekers (meta-analytic Cohen’s d = 0.83 across 4,231 participants, representing all available data points). People like copartisan perspective seekers because they seem tolerant, cooperative, and rational, but this liking is diminished because seekers seem to validate—and may even adopt—opponents’ illegitimate views. Participants liked copartisan seekers across a range of different motivations guiding these seekers’ actions but, consistent with our theorizing, their liking decreased (though rarely disappeared entirely) when seekers lacked partisan commitments or when they sought especially illegitimate beliefs. Despite evidence of rising political intolerance in recent decades, these findings suggest that people nonetheless celebrate political allies who tolerate and seriously consider their opponents’ views.

Keywords: political intolerance, intergroup relations, ideology, polarization, perspective seeking, open data, open materials, preregistered

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People like co-partisan seekers because they seem tolerant, cooperative, and rational, but this liking is diminished because seekers seem to validate—and may even adopt—opponents’ illegitimate views

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General Discussion

People generally like political allies who seek to understand, rather than avoid, shared opponents’ beliefs. These findings suggest that Sarah Silverman’s show might have been canceled despite her willingness to hear opposing views, not because of it. More importantly, they align with recent evidence that people prefer copartisans who tolerate and respect their opponents (Druckman et al., 2019; Frimer & Skitka, 2018; see Heltzel & Laurin, 2020). Yet they clash with other work suggesting that people do not tolerate their political opponents (Haidt et al., 2003), dislike copartisan politicians who compromise with opponents (Ryan, 2017), and reject people who empathize with proponents of illegitimate views (Wang & Todd, 2020).

Our findings reframe this contradiction, suggesting that both tendencies coexist: Seekers are both admirable and alarming but to different degrees. People like them because they seem tolerant, cooperative, and rational, yet they simultaneously (and to a lesser degree) dislike them for validating illegitimate beliefs and potentially changing their minds. Accordingly, people like seekers less when they lack partisan commitments and seek especially illegitimate viewpoints.

Theoretical implications

Our findings contribute to a new literature extending political intolerance from its intergroup origins to intragroup contexts. In so doing, we highlight a paradox: People refuse to tolerate political out-groups (Finkel et al., 2020; Haidt et al., 2003; Kalmoe & Mason, 2019), yet value tolerance and praise tolerant in-group members (W. Brown, 2009; Druckman et al., 2019; Frimer & Skitka, 2018), even those willing to compromise with the enemy (Study 2). However, people do not praise in-group leaders who could actually enact compromise (Ryan, 2017). More research is needed to understand these contours of people’s political tolerances (and intolerances) and how people reconcile their paradoxical reactions in their own minds (Guan et al., in press).

Our findings also speak to ongoing debates about whether conservatives, extremists, or moralizers are most guilty of political intolerance (Crawford, 2014; Ganzach & Schul, 2021; Skitka, 2010). Our findings best support the intolerant-extremist view, while also highlighting commonalities across levels of ideology and moralization.

When might people prefer avoiders?

Despite focusing on contentious, morally laden issues (e.g., abortion, gun control, immigration; Koleva et al., 2012), we never observed a case in which participants preferred avoiders over seekers. Our mechanisms nonetheless allow for such cases. For example, our participants were North Americans, but other societies value tolerance and rationality less and therefore might like seekers less. Additionally, there should be a point at which beliefs seem so illegitimate that people prefer others who avoid rather than seek them. Perhaps the beliefs featured in our studies never reached this point: Even the extreme views from Study 4 were rated far from maximally illegitimate (5.29 on a 7-point scale).

That said, many people expect their political opponents to hold precisely these sorts of abhorrent views (Ahler & Sood, 2018). When perspective seekers aim to understand their opponents in general, their allies’ minds may naturally conjure the worst of these opponents’ views and take great offense. For instance, liberals may interpret copartisans’ seeking to understand conservatives as trying to understand White supremacists, and conservatives may interpret copartisans’ seeking to understand liberals as trying to understand flag-burning Communists. For this reason, seekers might be most liked when seeking opponents’ views on specific policy debates. Indeed, Studies 1b and S7 revealed a remarkably weaker preference for targets who sought to understand their ideological opponents generally rather than their specific policy beliefs (see Table 1).

Intuitions about perspective seeking’s social desirability

For many—ourselves included—these findings may seem counterintuitive. Outrage pervades political discourse on social media and in the news (Brady et al., 2020; Pew Research Center, 2019), fueling intuitions that people’s hate for opponents would extend to allies seeking those opponents’ views. Our results suggest that this intuition is incorrect, but even incorrect intuitions can powerfully shape behavior (Prentice & Miller, 1993). For instance, if people mistakenly believe that others discourage political-perspective seeking, they may abstain from it out of fear of social punishment, thereby perpetuating polarization.

Conservatives (vs. liberals) are more satisfied with the products & services they consume; they are more likely to believe in free will (i.e., that people have agency over their decisions) & therefore to trust their decisions

How Political Identity Shapes Customer Satisfaction. Daniel Fernandes et al. Journal of Marketing, October 19, 2021. https://doi.org/10.1177/00222429211057508

Abstract: This article examines the effect of political identity on customers’ satisfaction with the products and services they consume. Recent work suggests that conservatives are less likely to complain than liberals. Building on that work, the present research examines how political identity shapes customer satisfaction which has broad implications for customers and firms. Nine studies combine different methodologies, primary and secondary data, real and hypothetical behavior, different product categories, and diverse participant populations to show that conservatives (vs. liberals) are more satisfied with the products and services they consume. This happens because conservatives (vs. liberals) are more likely to believe in free will (i.e., that people have agency over their decisions) and therefore to trust their decisions. We document the broad and tangible downstream consequences of this effect for customers’ repurchase and recommendation intentions and firms’ sales. The association of political identity and customer satisfaction is attenuated when belief in free will is externally weakened, choice is limited, or the consumption experience is overwhelmingly positive.

Keywords: political identity, belief in free will, customer satisfaction, repurchase intention, sales, political ideology

Considering how often people gossip about each other, they also underestimate how often others gossip about them—and probably don't even want to know; a recording of all the gossip about us would be dreadful

Cooney, G., Boothby, E. J., & Lee, M. (2021). The thought gap after conversation: Underestimating the frequency of others’ thoughts about us. Journal of Experimental Psychology: General, . https://doi.org/10.1037/xge0001134

Abstract: After conversations, people continue to think about their conversation partners. They remember their stories, revisit their advice, and replay their criticisms. But do people realize that their conversation partners are doing the same? In eight studies, we explored the possibility that people would systematically underestimate how much their conversation partners think about them following interactions. We found evidence for this thought gap in a variety of contexts, including field conversations in a dining hall (Study 1), “getting acquainted” conversations in the lab (Study 2), intimate conversations among friends (Study 3), and arguments between romantic partners (Study 4). Several additional studies investigated a possible explanation for the thought gap: the asymmetric availability of one’s own thoughts compared with others' thoughts. Accordingly, the thought gap increased when conversations became more salient (Study 4) and as people’s thoughts had more time to accumulate after a conversation (Study 6); conversely, the thought gap decreased when people were prompted to reflect on their conversation partners’ thoughts (Study 5). Consistent with our proposed mechanism, we also found that the thought gap was moderated by trait rumination, or the extent to which people’s thoughts come easily and repetitively to mind (Study 7). In a final study, we explored the consequences of the thought gap by comparing the effects of thought frequency to thought valence on the likelihood of reconciliation after an argument (Study 8). Collectively, these studies demonstrate that people remain on their conversation partners’ minds more than they know.

Members of rival ideological camps in Israel perceived the Israeli attorney general & the Israeli police to be biased against their side; both Democrats and Republicans perceived the social network Facebook to be biased against their side

The Hostile Mediator Phenomenon: When Threatened, Rival Partisans Perceive Various Mediators as Biased Against Their Group. Omer Yair. Public Opinion Quarterly, nfab035, October 18 2021. https://doi.org/10.1093/poq/nfab035

Abstract: Rival partisans tend to perceive ostensibly balanced news coverage as biased against their respective sides; this is known as the “hostile media phenomenon” (HMP). Yet complaints of hostile bias are common in contexts besides the media (e.g., law enforcement and academia). Does a process similar to the HMP occur outside the context of news coverage? And do perceptions of political bias in different contexts share certain similarities? This paper proposes that the HMP is a specific case of a more general hostile mediator phenomenon, where rival partisans perceive various public institutions and organizations that are expected to be neutral as biased against their respective sides. The paper starts by presenting a theoretical framework according to which partisans’ bias perceptions are affected by the threat to the power and status of their ingroup posed by a mediator’s actions. Evidence from three studies (total N = 4,164) shows that members of rival ideological camps in Israel perceived the Israeli attorney general and the Israeli police to be biased against their respective camps. An additional study (N = 2,172) shows that both Democrats and Republicans perceived the social network Facebook to be biased against their side. Moreover, an embedded, pre-registered survey experiment buttresses the causal claim that ingroup-threatening information increases perceptions of hostile bias. The implications of these findings for our understanding of people’s bias perceptions, as well as for citizens’ trust in public institutions and democratic stability more generally, are discussed.

No evidence was found to support the hypothesis that beards are honest (or dishonest) signals of the beard owners’ testosterone levels and dominance

Are Beards Honest Signals of Male Dominance and Testosterone? Marta Kowal, Piotr Sorokowski, Agnieszka Żelaźniewicz, Judyta Nowak, Sylwester Orzechowski, Grzegorz Żurek, Alina Żurek & Magdalena Nawrat. Archives of Sexual Behavior, Oct 21 2021. https://link.springer.com/article/10.1007/s10508-021-02012-w

Abstract: The male beard is one of the most visually salient and sexually dimorphic traits and a hypothesized potential marker of other traits, such as dominance, masculinity, social status, and self-confidence. However, as men can easily alter their facial hair, beards may provide unreliable information about the beard owner’s characteristics. Here, we examined whether beards are honest signals of biological (testosterone levels) and psychological (self-reported dominance) traits. Young (M = 21.29, SD = 1.54) and healthy men (N = 97) participated in the study. Their beards were measured directly (using digital calipers) and by self-report. Participants provided saliva samples before and after acute exercise (to assess their testosterone and cortisol levels) and reported their dominance on a 5-item scale. The results showed that beard length (directly measured and self-reported) was not related to testosterone levels or dominance; thus, no evidence was found to support the hypothesis that beards are honest (or dishonest) signals of the beard owners’ testosterone levels and dominance.

On women, we found a positive effect of hormonal contraceptives on frequency of vaginal intercourse and a negative effect of hormonal contraceptives on masturbation frequency

Hormonal Contraception and Sexuality: Causal Effects, Unobserved Selection, or Reverse Causality?Laura J. Botzet, Tanja M. Gerlach, Julie C. Driebe, Lars Penke, Ruben C. Arslan. Collabra: Psychology (2021) 7 (1): 29039. Oct 21 2021. https://doi.org/10.1525/collabra.29039

Many of the women who take hormonal contraceptives discontinue because of unwanted side effects, including negative psychological effects. Yet scientific evidence of psychological effects is mixed, partly because causal claims are often based on correlational data. In correlational studies, possible causal effects can be difficult to separate from selection effects, attrition effects, and reverse causality. Contraceptive use and, according to the congruency hypothesis, congruent contraceptive use (whether a woman’s current use/non-use of a hormonal contraceptive is congruent with her use/non-use at the time of meeting her partner) have both been thought to influence relationship quality and sexual functioning. In order to address potential issues of observed and unobserved selection effects in correlational data, we studied a sample of up to 1,179 women to investigate potential effects of contraceptive use and congruent contraceptive use on several measures of relationship quality and sexual functioning: perceived partner attractiveness, relationship satisfaction, sexual satisfaction, and diary measurements including libido, frequency of vaginal intercourse, and frequency of masturbation. No evidence for substantial effects was found except for a positive effect of hormonal contraceptives on frequency of vaginal intercourse and a negative effect of hormonal contraceptives on frequency of masturbation. These effects were robust to the inclusion of observed confounders, and their sensitivity to unobserved confounders was estimated. No support for the congruency hypothesis was found. Our correlational study was able to disentangle, to some extent, causal effects of hormonal contraceptives from selection effects by estimating the sensitivity of reported effects. To reconcile experimental and observational evidence on hormonal contraceptives, future research should scrutinize the role of unobserved selection effects, attrition effects, and reverse causality.

Keywords: sexual frequency, sexuality, relationship quality, sex hormones, contraception

Discussion

Our study aimed to disentangle selection effects from causal effects of contraceptive use. It showed that additional selection effects (including information about demography and personality) did not describe the choice of contraceptive method and congruent contraceptive use substantially better than did selection effects of age, income, and relationship duration. Furthermore, there was no evidence for substantial effects of contraceptive method, congruent contraceptive use, and their interaction on perceived partner attractiveness, relationship satisfaction, sexual satisfaction, and libido. While congruent contraceptive use and its interaction with contraceptive use had no substantial effects on frequency of vaginal intercourse and frequency of masturbation, we found a positive effect of current use of hormonal contraceptives on frequency of vaginal intercourse and a negative effect of current use of hormonal contraceptives on frequency of masturbation. These links were robust to the inclusion of observed confounders and sensitivity analyses suggested that unobserved confounders would need to strongly influence outcomes (about as strong as all observed confounders taken together) in order to substantially alter conclusions.

Selection Effects

Including additional selection variables pertaining to demography (education) and personality (openness, conscientiousness, extraversion, agreeableness, neuroticism, and religiosity) did not substantially improve models predicting contraceptive method or congruent contraceptive use compared to models based only on age, relationship duration, and income. Therefore, Hypothesis 1—that the complex model explains more variance compared to the simple model in (1) the choice of contraception and (2) congruent contraceptive use—was rejected.

Of the predictors included in the simpler models, age and relationship duration had a significant effect on choice of contraceptive method and congruent contraceptive use; income was no significant predictor. Overall, age had a negative effect on the use of hormonal contraceptives, i.e. the percentage of women using hormonal contraceptives decreased with increasing age. In addition, age had a negative effect on congruency in women who were using hormonal contraceptives when they met their partner (i.e., older women were more likely to switch to no/nonhormonal contraceptives) but a positive effect on congruency in women who were using no/nonhormonal contraceptives when they met their partner (i.e., younger women were more likely to switch to hormonal contraceptives). Overall, women in a romantic relationship were more likely to use hormonal contraceptives. Relationship length played no significant role in choice of contraceptive use, but partnered women who were in longer relationships were more likely to switch contraceptive methods, independent of whether they had been using hormonal contraceptives or no/nonhormonal contraceptives when they met their partner. Even though the complex models showed no improvement in model fit over the simple models, three predictors in the complex models stood out: First, conscientiousness had a positive effect on hormonal contraceptive use and a positive effect on congruent contraceptive use in women who had been using hormonal contraceptives when they met their partner (i.e., they were more likely to continue using hormonal contraceptives). Second, openness had a negative effect on hormonal contraceptive use and a negative effect on congruent contraceptive use in women who had been using hormonal contraceptives when they met their partner (i.e., they were more likely to switch to no/nonhormonal contraceptives). Third, agreeableness had a positive effect on congruent contraceptive use in women who had been using hormonal contraceptives when they met their partner (i.e., they were more likely to continue using hormonal contraceptives) and a negative effect on congruent contraceptive use in women who had been using no/nonhormonal contraceptives when they met their partner (i.e., they were more likely to switch to hormonal contraceptives). Future research concerning selection effects on contraceptive use and congruent contraceptive use could consider excluding measures of income (where appropriate⁶) and including measures of conscientiousness, openness, and agreeableness in addition to age and relationship duration.

Table 3. Unstandardized Effect Size Estimates of Hormonal Contraceptives on Outcomes

Effects of Hormonal Contraceptives

The evidence for effects of hormonal contraceptives is inconclusive on perceived partner attractiveness, relationship satisfaction, sexual satisfaction, and libido, therefore neither accepting nor rejecting Hypothesis 2.1(1–4)—hormonal contraceptives lead to decreased (1) perceived partner attractiveness, (2) relationship satisfaction, (3) sexual satisfaction, and (4) libido—and Hypothesis 2.2(1–4)—after controlling for all selection variables, hormonal contraceptives lead to decreased (1) perceived partner attractiveness, (2) relationship satisfaction, (3) sexual satisfaction, and (4) libido. The estimates were insufficiently precise; future research with even larger samples is needed to reach a conclusion. Nevertheless, given the rather small effect sizes, it appears unlikely that use of hormonal contraceptives has a strong association with these outcomes.

Hormonal contraceptives had a positive effect on frequency of vaginal intercourse, even after controlling for observed confounders—thereby rejecting Hypotheses 2.1(5) and 2.2(5). Contrary to the RCTs by Graham et al. (1995) and Zethraeus et al. (2016) that provided evidence for negative effects of hormonal contraceptives on sexual desire, sexual arousal, and sexual pleasure, the results of our study are in line with studies based on correlational data that found a positive relationship between hormonal contraceptives and sexual frequency (Alexander et al., 1990; Caruso et al., 2005; McCoy & Matyas, 1996).

Hormonal contraceptives had a negative effect on frequency of masturbation, even after controlling for observed confounders—thereby accepting Hypotheses 2.1(6) and 2.2(6). Most studies show no difference in frequency of masturbation between HC users and non-HC users (Alexander et al., 1990; Bancroft et al., 1991), but a recent study by Mark et al. (2016) provided evidence of a positive association between hormonal contraceptives and women’s dyadic libido and a negative association between hormonal contraceptives and women’s solitary libido. The libido item in our study included dyadic and solitary libido (“I experienced increased libido [desire to have sexual intercourse/to masturbate/to be sexually active].”) and did not distinguish between them as proposed by Spector et al. (1996). Thus, it seems possible that the divergent relationships described by Mark et al. (2016) resulted in the overall null relationship between hormonal contraceptives and libido that we observed. Our study could therefore provide evidence for behavioral consequences (measured as frequency of vaginal intercourse and frequency of masturbation) of the divergent relationships between hormonal contraceptives and dyadic and solitary libido described by Mark et al. (2016).

Effects of Congruent Contraceptive Use

Evidence was inconclusive on effects of congruent contraceptive use on perceived partner attractiveness, relationship satisfaction, sexual satisfaction, libido, frequency of vaginal intercourse, and frequency of masturbation after considering observed confounders. We could therefore neither accept nor reject Hypotheses 3.1—congruent contraceptive use leads to increased (1) perceived partner attractiveness, (2) relationship satisfaction, (3) sexual satisfaction, (4) libido, (5) frequency of vaginal intercourse, and (6) frequency of masturbation—and 3.2—after controlling for all selection variables, congruent contraceptive use leads to increased (1) perceived partner attractiveness, (2) relationship satisfaction, (3) sexual satisfaction, (4) libido, (5) frequency of vaginal intercourse, and (6) frequency of masturbation.

While these findings do not support most of the literature based on the congruency hypothesis (Birnbaum et al., 2019; Cobey et al., 2013; French & Meltzer, 2020; Roberts, Cobey, et al., 2014; Roberts et al., 2012; Roberts, Little, et al., 2014; Russell et al., 2014), they are in line with a recent large-scale replication attempt by Jern et al. (2018). Marcinkowska et al. (2019) provided additional evidence that questions the congruency hypothesis: In a large-scale study (n = 6,482), they found no evidence that women using the pill had weaker preferences for male facial masculinity than did women not using the pill. Differences in partner preferences have been suggested to be the driving mechanism behind the congruency hypothesis: Incongruent contraceptive methods are thought to lead to a shift in partner preferences, resulting in less satisfaction with the current romantic partner.

Jern et al. (2018) pointed out an important difference between their study and earlier studies on the congruency hypothesis: Earlier studies often had unequal distributions of congruent and incongruent users such that one group was almost entirely based on HC users or non-HC users. For instance, in the study by Cobey et al. (2013) the group of incongruent current HC users consisted of only four participants (3% of the final sample), while the group of congruent HC users consisted of 71 participants (59% of the final sample). This is especially problematic because most studies featured relatively small incongruent HC user groups and relatively large congruent HC user groups. Considering the small expected effect sizes based on the congruency hypothesis, main effects of current contraceptive use could have led to a spurious effect of congruency based on unequal distributions. Although the sample sizes of congruent and incongruent use differed in our study, the subgroups were relatively balanced (congruent non-HC users: 32%; congruent HC users: 31%; incongruent non-HC users: 19%; incongruent HC users: 17%) and the models always accounted for current contraceptive use and its interaction with contraceptive congruency.

Table 4. Unstandardized Effect Size Estimates of Hormonal Contraceptives, Congruent Contraceptive Use, and Their Interaction on Outcomes

Another possibility is that the reported effects based on the congruency hypothesis were false positives (Simmons et al., 2011). None of the earlier studies used preregistered hypotheses, and sample sizes were relatively small (ranging between n = 48 and n = 365), apart from the study by Roberts et al. (2012), which found a positive effect of congruent use on perceived partner attractiveness and sexual satisfaction (n = 993). Indeed, two failed large-scale replication attempts (Jern et al., 2018 and the current study) and a range of recent evidence question the theory underlying the congruency hypothesis (Arslan et al., 2018; C. R. Harris et al., 2013; Jones, Hahn, & DeBruine, 2018; Jünger, Kordsmeyer, et al., 2018; Jünger, Motta-Mena, et al., 2018; Stern et al., 2020; Stern & Penke, in press; Wood et al., 2014; for a current discussion on evidence for psychological cycle shifts see Gangestad et al., 2019a, 2019b; Higham, 2019; Jones, Hahn, & DeBruine, 2018; Roney, 2019; Stern et al., 2019).

Overall, recent work has cast doubt on the evidence for both the assumed mechanism and the interaction effect underlying the congruency hypothesis. Our study could not accept the null hypotheses that there are no effects of congruent contraceptive use on perceived partner attractiveness, relationship satisfaction, sexual satisfaction, libido, frequency of vaginal intercourse, and frequency of masturbation because the sample size was too small and because we applied rigorous decision criteria for accepting the null hypotheses. Future research on congruent contraceptive use should be preregistered, be adequately powered to detect small effects, and appropriately account for current and past contraceptive use.

Sensitivity to Unobserved Confounders

We estimated the robustness of the effects of hormonal contraceptives and congruent contraceptive use in light of potential unobserved confounders. Sensitivity analysis suggested that the influence of unobserved confounders would need to be nearly 1.5 times as strong as the influence of observed confounders to fully account for the effect of hormonal contraceptives on frequency of vaginal intercourse, and nearly as strong as the influence of observed confounders to fully account for the effect of hormonal contraceptives on frequency of masturbation. Even when taking into account the broad range of included observed confounders (demography, personality, and romantic relationship information) it seems plausible that unobserved confounders might exist that would fully explain the reported effects of hormonal contraceptives on frequency of vaginal intercourse and frequency of masturbation. Besides potential unobserved selection effects, we now consider three additional possible challenges: reverse causality, attrition effects, and further unobserved confounders.

Selection Effects and Reverse Causality

There was a positive effect of hormonal contraceptive use on frequency of vaginal intercourse. Although frequency of vaginal intercourse was measured after contraception in the diary, it is somewhat habitual and thus stable. Reverse causality might therefore be at play, even after excluding women who were not sexually active and therefore not using hormonal contraception. Women who have sex more frequently might place a larger premium on safeness and convenience for contraception. Higher frequency of vaginal intercourse is associated with a higher risk of (unwanted) pregnancy, and therefore safe contraception is even more important, especially if a woman does not want to forego sexual intercourse or use additional contraceptive methods. In addition, higher frequency of vaginal intercourse affects economic considerations: At higher sexual frequencies, the pill can be cheaper than condoms. Reverse causation would explain why there are effects on behavior (frequency of vaginal intercourse) but not on the psychological outcomes that might be expected to precede the behavior in the causal chain (libido and sexual satisfaction). A similar, if slightly more speculative, explanation could be plausible for frequency of masturbation. If women who have sexual intercourse only infrequently eschew the pill and its cost and side effects, they might instead opt to use condoms. If these women have the same level of libido as women who have sex more frequently, they might masturbate more. Because the stable component of some of these outcomes could be quite large, these are plausible unobserved confounders, and repeated longitudinal data would be needed to adjust for them.

Attrition Effects

Unlike our study, RCTs reported negative effects of hormonal contraceptives on libido, sexual arousal, and sexual pleasure (Graham et al., 1995; Zethraeus et al., 2016) as well as on general well-being (Zethraeus et al., 2017). One potential reason for the positive effect of hormonal contraceptives on frequency of vaginal intercourse reported in our study and in earlier correlational studies (Alexander et al., 1990; Caruso et al., 2005; McCoy & Matyas, 1996) are attrition effects. As Graham (2019) noted, there is great variability in women’s experiences with hormonal contraceptives, with reports of negative, positive, and no effects. Women with negative experiences were more likely to stop using hormonal contraceptives (Bancroft & Sartorius, 1990; Sanders et al., 2001), and discontinuation rates are high. For instance, 11.6% of Swedish women who took hormonal contraceptives for the first time stopped using them within six months (Josefsson et al., 2013). Predictors of discontinuation include emotional side effects, worsening of the premenstrual syndrome, decreased frequency of sexual thoughts, and decreased psychosexual arousability (Sanders et al., 2001). Women with depressive and premenstrual complaints tend to discontinue hormonal contraceptive use, leaving the remaining users with greater reported well-being (Bancroft & Sartorius, 1990). Therefore, it is likely that empirical, correlative evidence suggesting positive effects of hormonal contraceptives on sexual functioning stems at least in part from the fact that women with negative experiences of hormonal contraceptives switch to other contraceptive methods. Much of the current evidence on positive effects of hormonal contraceptives might thus rest on samples skewed toward women who have already tailored their contraception regimen to their experiences with hormonal contraceptives; reported correlations could even be the reverse of the average causal effect. This may also be the case in our study: The estimated effect of hormonal contraceptives may not equal their average effect because women with negative experiences of hormonal contraceptives had already stopped taking them. Women who continued using hormonal contraceptives would be more likely to have had positive experiences with them, which would result in an overall positive relationship between hormonal contraceptive use and frequency of vaginal intercourse based on correlational data masking negative causal effects on average. Analyses on the congruency of contraceptive use at the time of meeting the current partner can only partly address this, as participants were generally old enough to have been able to try out different methods of contraception before meeting their current partner. This limitation implies that estimated effects should not be expected to generalize to the experiences of women using hormonal contraceptives for the first time. Attrition effects could be studied using longitudinal data. In addition, research on women using hormonal contraceptives for the first time could provide more information on how preferences for contraceptives form.

Further Unobserved Confounders

Besides the already included selection and outcome variables, frequency of vaginal intercourse has been found to relate to less restricted sociosexuality (Grøntvedt et al., 2020), increased satisfaction with own body image (Ackard et al., 2000), and increased satisfaction with life (Muise et al., 2016) in women. Frequency of masturbation has been found to be positively associated with less restricted sociosexuality (Velten & Margraf, 2017), body acceptance and orgasm frequency (Burri & Carvalheira, 2019), and greater importance of sex and higher levels of general anxiety and depression (Rowland et al., 2020) in women. Regnerus et al. (2017) reported a negative relationship between frequency of masturbation and contentment with sexual frequency.

While some of these potential unobserved confounders were not measured in the available dataset (in particular orgasm frequency, importance of sex, anxiety, depression, and contentment with sexual frequency), others would have been available (in particular sociosexuality, general life satisfaction, and satisfaction with own body image) but we decided not to include them in the current study to prevent controlling for potential colliders or mediators (Rohrer, 2018). Nevertheless, they could be strong unobserved confounders that could explain the observed links between hormonal contraceptive use and frequency of vaginal intercourse and frequency of masturbation. For example, higher desire for penetrative intercourse could lead to higher frequency of vaginal intercourse. At the same time, it could lead to the decision to use hormonal contraceptives because they are among the safest contraceptive methods available. Body acceptance could lead to higher frequency of masturbation and, at the same time, to the decision to use no/nonhormonal contraceptives in order to avoid artificial hormones. Therefore, even though our study quantitatively estimated the needed strength of unobserved confounders, it is unable to definitively rule out the possibility that the observed relationships are due to the influence of potential unobserved confounders. In future research on larger samples, more pointed comparisons of contraceptives with similar Pearl indices indicating the effectiveness of this birth control (e.g., the pill and intrauterine devices) might answer some of these questions, and again, examining within-subject changes in sexuality in longitudinal data would reduce some of the concerns about potential unobserved confounders.

Causal Effects of Hormonal Contraceptives on Frequency of Vaginal Intercourse and Frequency of Masturbation?

Our study provides evidence for a positive effect of hormonal contraceptives on frequency of vaginal intercourse and a negative effect of hormonal contraceptives on frequency of masturbation. Both effects were somewhat attenuated when adjusting for observed confounders. Fairly strong unobserved confounders would be necessary to nullify or reverse the remaining effects but some plausible candidates exist. The questions of reverse causality, selection effects, and attrition effects regarding the reported effects persist.

Limitations and Strengths

Our study was not without limitations: First, while the total sample size of our study was relatively large, the sample sizes used for the analyses—especially those investigating effects of congruent contraceptive use—were too small to reach a definite conclusion about potential effects. Second, even though our study provides valuable insights into the links between contraceptive use, relationship quality, and sexual functioning, the conclusions based on correlational data remain inconclusive about any putative causal effect of hormonal contraceptives.

Nevertheless, our study had several key strengths: First, even though conclusions remain cautious because of the available sample size, the size of the sample still exceeds domain standards. Second, measures for libido, frequency of vaginal intercourse, and frequency of masturbation were based on diary reports, which have been shown to be more reliable than retrospective behavior measurements (McAuliffe et al., 2007) and described as the gold standard for measuring sexual frequency by Graham et al. (2003). Third, by providing a directed acyclic graph, controlling for observed confounding, and estimating the sensitivity to unobserved confounding, this study is better positioned than previous correlational work to disentangle selection effects from causal effects.

Constraints on Generality

Following the guidelines on constraints on generality (Simons et al., 2017) the following four factors reduce the broad generalizability of the current results: First, the sample studied consisted of heterosexual WEIRD (Henrich et al., 2010) women with a high proportion of undergraduate psychology students. Although our main explanation assumes a universal biological mechanism for the results, different absolute hormone levels in less prosperous and well-nourished populations (Vitzthum, 2009) might affect the frequency of ovulation and hence the observable effect size. Moreover, some of our alternative explanations (such as reverse causality) may be much more dependent on circumstances. Second, even though the gold standard for measuring sexual frequency and masturbation frequency by using diary reports was applied, all results are purely based on self-reports and generalizability to other measures might be limited. Third, from a temporal perspective the composition of hormonal contraceptives (e.g., the dosage of estrogen and progestin) has changed over the decades and will change further in the future. If the reported effects are due to certain estrogen or progestin dosages, results might not be replicable based on samples from different times.

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