Sexual Desire is not Partner-Specific : Evidence for a Positive Association Between Desire for One's Romantic Partner and Desire for Alternative Partners.

One longitudinal study of married couples and one experiment tested the hypothesis that the experience of sexual desire for an alternative sexual partner might heighten feelings of desire for one's long-term romantic partner, and conversely, sexual desire for one's long-term partner might heighten desire for alternative partners. A daily-diary study of newlywed couples revealed that (a) on days people reported heightened interest in alternative partners, they also reported increased desire to have sex with their partner and (b) on days people reported heightened desire to have sex with their partner, they also reported increased interest in alternative partners. An experimental study of partnered individuals revealed that people primed with sexual desire for an alternative partner reported increased sexual desire for their romantic partner (relative to a control condition). People primed with sexual desire for their romantic partner, however, did not report increased sexual desire for alternatives. Taken together, these findings support evolutionary perspectives on the function of sexual desire. Findings are consistent with the broader hypothesis that sexual desire is not partner-specific.

Kindness or Intelligence? Angry Men are Perceived as Less Intelligent by Their Female Romantic Partners.

We were interested in how people in a romantic relationship would perceive the intelligence of their partners who have high or low trait anger. Specifically, we referred to the tension between compassion (low anger) and competence (high intelligence) in mate choice. Some evolutionary theories suggest that mating might be considered a bargaining process between these two higher-order attributes. Our study involved 148 heterosexual couples in romantic relationships. We measured the relationship between relationship satisfaction, trait anger, objective intelligence, self-assessed intelligence, and subjectively assessed partners' intelligence. We found that angrier men were less satisfied in their romantic relationship than those men who were less angry, and their partners were also less satisfied in the relationship. Additionally, women perceived angrier men as less intelligent, an effect that remained after controlling for men's objective intelligence. Lastly, we found that women's perception of their partner's intelligence mediated the link between men's anger and relationship satisfaction for both sexes. Our findings suggest that both anger and intelligence play important roles in romantic relationship functioning, consistent with evolutionary theories that emphasize the value of competence (i.e., intelligence) and compassion (i.e., low anger) in romantic partners. Furthermore, our study highlights the importance of women's perception of their partner's intelligence in determining the quality of the relationship.

Exploring Attitudes Toward "Sugar Relationships" Across 87 Countries: A Global Perspective on Exchanges of Resources for Sex and Companionship.

The current study investigates attitudes toward one form of sex for resources: the so-called sugar relationships, which often involve exchanges of resources for sex and/or companionship. The present study examined associations among attitudes toward sugar relationships and relevant variables (e.g., sex, sociosexuality, gender inequality, parasitic exposure) in 69,924 participants across 87 countries. Two self-report measures of Acceptance of Sugar Relationships (ASR) developed for younger companion providers (ASR-YWMS) and older resource providers (ASR-OMWS) were translated into 37 languages. We tested cross-sex and cross-linguistic construct equivalence, cross-cultural invariance in sex differences, and the importance of the hypothetical predictors of ASR. Both measures showed adequate psychometric properties in all languages (except the Persian version of ASR-YWMS). Results partially supported our hypotheses and were consistent with previous theoretical considerations and empirical evidence on human mating. For example, at the individual level, sociosexual orientation, traditional gender roles, and pathogen prevalence were significant predictors of both ASR-YWMS and ASR-OMWS. At the country level, gender inequality and parasite stress positively predicted the ASR-YWMS. However, being a woman negatively predicted the ASR-OMWS, but positively predicted the ASR-YWMS. At country-level, ingroup favoritism and parasite stress positively predicted the ASR-OMWS. Furthermore, significant cross-subregional differences were found in the openness to sugar relationships (both ASR-YWMS and ASR-OMWS scores) across subregions. Finally, significant differences were found between ASR-YWMS and ASR-OMWS when compared in each subregion. The ASR-YWMS was significantly higher than the ASR-OMWS in all subregions, except for Northern Africa and Western Asia.

The impact of romantic relationships on deception detection: Exploring the gender differences and the mediating role of mentalizing.

In evolution, romantic relationships serve as the foundation for breeding and producing offspring. The ability to detect deception in these relationships can safeguard the investment and cultivation of descendants, leading to greater chances of survival and reproduction. However, barely any research has been carried out within this domain. The current study investigated the preliminary relationship between romantic relationships, mentalizing ability, and deception detection ability through an empirical experiment. Participants were primed by their romantic experiences and neutral experiences, and then went through a Reading the Mind in the Eyes (RTM) task and the deception detecting task for real person crime-type videos. Results showed that romantic relationships can improve participants' emotion recognition ability toward negative emotions, and females performed better in the deception detection task than males did. Most importantly, romantic relationships can improve participants' deception detection ability through the mediator of mentalizing ability. Though gender difference was not statistically significant in the RTM task, the results lay a solid foundation for further investigation into females' mentalizing ability and disclose the evolutionary meaning of romantic relationships.

Lordosis in Humans.

Despite progress in attractiveness research, we have yet to identify many fitness-relevant cues in the human phenotype or humans' psychology for responding to them. Here, we test hypotheses about psychological systems that may have evolved to process distinct cues in the female lumbar region. The Fetal Load Hypothesis proposes a male preference for a morphological cue: lumbar curvature. The Lordosis Detection Hypothesis posits context-dependent male attraction to a movement: lordosis behavior. In two studies (Study 1 N: 102, Study 2 N: 231), we presented men with animated female characters that varied in their lumbar curvature and back arching (i.e., lordosis behavior). Irrespective of mating context, men's attraction increased as lumbar curvature approached the hypothesized optimum. By contrast, men experienced greater attraction to lordosis behavior in short-term than long-term mating contexts. These findings support both the Lordosis Detection and Fetal Load Hypotheses. Discussion focuses on the meaning of human lordosis and the importance of dynamic stimuli in attractiveness research.

The Effect of Female Orgasm Frequency on Female Mate Selection: A Test of Two Hypotheses.

Female orgasm has been a mystery that psychologists have been attempting to understand for decades. Many have contended that female orgasm is a functionless by-product of male orgasm, while others have argued that female orgasm may be an adaptation in its own right, offering several adaptationist accounts of female orgasm. In the current research, we tested predictions derived from two hypotheses regarding adaptive functions of female orgasm: female orgasm indicates partner mate value or female orgasm promotes long-term, pair bonding. 199 female undergraduates participated in an experiment where they imagined themselves as a member of a romantic relationship provided in a scenario. Within these scenarios, the relationships varied between either short- or long-term and the frequency that the female experienced orgasm during intercourse varied between never, occasionally, and almost always. Participants answered questions regarding relationship satisfaction and perceptions of the fictional relationship. A series of analysis of variance (ANOVAs) indicated that females assigned to conditions of experiencing more frequent orgasms reported greater relationship satisfaction, across both short- and long-term relationships. The relationship between female orgasm frequency and relationship satisfaction was fully mediated by the female's perceived love for her hypothetical partner but not by perceptions of her hypothetical partner's commitment. Taken together, this study provides preliminary support for the hypothesis that female orgasm evolved as a mate-selection tool for females and promotes long-term, pair bonding but does not provide support for the hypothesis that female orgasm evolved as an indicator of male value.

Does scent attractiveness reveal women's ovulatory timing? Evidence from signal detection analyses and endocrine predictors of odour attractiveness.

Odour cues associated with shifts in ovarian hormones indicate ovulatory timing in females of many nonhuman species. Although prior evidence supports women's body odours smelling more attractive on days when conception is possible, that research has left ambiguous how diagnostic of ovulatory timing odour cues are, as well as whether shifts in odour attractiveness are correlated with shifts in ovarian hormones. Here, 46 women each provided six overnight scent and corresponding day saliva samples spaced five days apart, and completed luteinizing hormone tests to determine ovulatory timing. Scent samples collected near ovulation were rated more attractive, on average, relative to samples from the same women collected on other days. Importantly, however, signal detection analyses showed that rater discrimination of fertile window timing from odour attractiveness ratings was very poor. Within-women shifts in salivary oestradiol and progesterone were not significantly associated with within-women shifts in odour attractiveness. Between-women, mean oestradiol was positively associated with mean odour attractiveness. Our findings suggest that raters cannot reliably detect women's ovulatory timing from their scent attractiveness. The between-women effect of oestradiol raises the possibility that women's scents provide information about overall cycle fecundity, though further research is necessary to rigorously investigate this possibility.

Assessment of the Mate Retention Inventory-Short Form Using Item Response Theory.

The mate retention inventory (MRI) has been a valuable tool in the field of evolutionary psychology for the past 30 years. The goal of the current research is to subject the MRI to rigorous psychometric analysis using item response theory to answer three broad questions. Do the individual items of the MRI fit the scale well? Does the overall function of the MRI match what is predicted? Finally, do men and women respond similarly to the MRI? Using a graded response model, it was found that all but two of the items fit acceptable model patterns. Test information function analysis found that the scale acceptably captures individual differences for participants with a high degree of mate retention but the scale is lacking in capturing information from participants with a low degree of mate retention. Finally, discriminate item function analysis reveals that the MRI is better at assessing male than female participants, indicating that the scale may not be the best indicator of female behavior in a relationship. Overall, we conclude that the MRI is a good scale, especially for assessing male behavior, but it could be improved for assessing female behavior and individuals lower on overall mate retention behavior. It is suggested that this paper be used as a framework for how the newest psychometrics techniques can be applied in order to create more robust and valid measures in the field of evolutionary psychology.

Corrigendum: Proximate and Ultimate Perspectives on Romantic Love.

[This corrects the article DOI: 10.3389/fpsyg.2021.573123.].

Proximate and Ultimate Perspectives on Romantic Love.

Romantic love is a phenomenon of immense interest to the general public as well as to scholars in several disciplines. It is known to be present in almost all human societies and has been studied from a number of perspectives. In this integrative review, we bring together what is known about romantic love using Tinbergen's "four questions" framework originating from evolutionary biology. Under the first question, related to mechanisms, we show that it is caused by social, psychological mate choice, genetic, neural, and endocrine mechanisms. The mechanisms regulating psychopathology, cognitive biases, and animal models provide further insights into the mechanisms that regulate romantic love. Under the second question, related to development, we show that romantic love exists across the human lifespan in both sexes. We summarize what is known about its development and the internal and external factors that influence it. We consider cross-cultural perspectives and raise the issue of evolutionary mismatch. Under the third question, related to function, we discuss the fitness-relevant benefits and costs of romantic love with reference to mate choice, courtship, sex, and pair-bonding. We outline three possible selective pressures and contend that romantic love is a suite of adaptions and by-products. Under the fourth question, related to phylogeny, we summarize theories of romantic love's evolutionary history and show that romantic love probably evolved in concert with pair-bonds in our recent ancestors. We describe the mammalian antecedents to romantic love and the contribution of genes and culture to the expression of modern romantic love. We advance four potential scenarios for the evolution of romantic love. We conclude by summarizing what Tinbergen's four questions tell us, highlighting outstanding questions as avenues of potential future research, and suggesting a novel ethologically informed working definition to accommodate the multi-faceted understanding of romantic love advanced in this review.

Couple Simulation: A Novel Approach for Evaluating Models of Human Mate Choice.

Choosing a mate is perhaps the most important decision a sexually reproducing organism makes in its lifetime. And yet, psychologists lack a precise description of human mate choice, despite sustained attention from several theoretical perspectives. Here, I argue this limited progress owes to the complexity of mate choice and describe a new modeling approach, called "couple simulation," designed to compare models of mate choice by challenging them to reproduce real couples within simulated mating markets. I present proof-of-concept simulations that demonstrate couple simulation can identify a population's true model of mate choice. Furthermore, I apply couple simulation to two samples of real couples and find that the method (a) successfully reconstructs real-world couples, (b) discriminates between models of mate choice, and (c) predicts a wide range of dimensions of relationship quality. Collectively, these results provide evidence that couple simulation offers a framework useful for evaluating theories of human mate choice.

The Development and Psychometric Evaluation of a New Mating Effort Questionnaire.

In this study, we review the psychometric literature on mating effort and find that extant instruments (1) have not been adequately evaluated in terms of internal structure and measurement invariance, and (2) disproportionately focus on mate retention and intrasexual competition tactics designed to repel competitors, relative to attraction and investment effort. To address these gaps in the literature, we carried out two studies to develop and validate a new Mating Effort Questionnaire (MEQ). In Study 1, we report a pilot study in which participants' responses to an item pool were submitted to exploratory factor analysis. In Study 2, we replicated the structure found in Study 1 using confirmatory factor analysis in an independent sample. A three-factor solution yielded the best fit. The three factors reflected respondents' allocation of energy to attracting high mate value partners when already mated, seeking out romantic partners when single, and investing in their current romantic partner and relationships. Strong partial measurement invariance held across the sexes, implying that observed scores may be used to compare them. We also found evidence of concurrent validity via associations between the MEQ and constructs such as sociosexual orientation, K-factor, mate retention behaviors, and respondents' sexual behavior. These findings suggest that the MEQ is a valid and novel measure of individual differences in mating effort which is well suited to complement existing mating effort measures.

Individual differences in preference for risky behaviors during courtship.

Engaging in risky behaviors is a sexual signalling strategy that men use to procure mates. The present study investigates men's preferences for engaging in risky behaviors (along with women's preferences for their male partner's risky behavior) within dating couples. We investigated associations between relationship length, self-perceived attractiveness, sociosexuality orientation, and preference for risky behaviors in a sample of 256 couples. Results indicated that men had stronger preferences for risky behaviors than their partner's ideal preference. Furthermore, relationship length was associated with a decline in women's preference for their partner's risk-taking, but not men's preference for their own risk-taking. Self-perceived attractiveness was negatively associated with risk preference, and sociosexuality orientation was not directly related to risk preference. Female preferences for less intense male risky behaviors could reflect the need of paternal investment which is required for offspring care. Decreased male sexual signalling could account for lower preferences of risky behaviors in females who are involved in longer lasting romantic relationships.

Hormones in speed-dating: The role of testosterone and cortisol in attraction.

There is evidence that testosterone and cortisol levels are related to the attraction of a romantic partner; testosterone levels relate to a wide range of sexual behaviors and cortisol is a crucial component in the response to stress. To investigate this, we conducted a speed-dating study among heterosexual singles. We measured salivary testosterone and cortisol changes in men and women (n = 79) when they participated in a romantic condition (meeting opposite-sex others, i.e., potential romantic partners), as well as a control condition (meeting same-sex others, i.e., potential friends). Over the course of the romantic speed-dating event, results showed that women's but not men's testosterone levels increased and cortisol levels decreased for both men and women. These findings indicate that men's testosterone and cortisol levels were elevated in anticipation of the event, whereas for women, this appears to only be the case for cortisol. Concerning the relationship between attraction and hormonal change, four important findings can be distinguished. First, men were more popular when they arrived at the romantic speed-dating event with elevated cortisol levels. Second, in both men and women, a larger change in cortisol levels during romantic speed-dating was related to more selectivity. Third, testosterone alone was unrelated to any romantic speed-dating outcome (selectivity or popularity). However, fourth, women who arrived at the romantic speed-dating event with higher testosterone levels were more selective when their anticipatory cortisol response was low. Overall, our findings suggest that changes in the hormone cortisol may be stronger associated with the attraction of a romantic partner than testosterone.

Mate Preferences and Their Behavioral Manifestations.

Evolved mate preferences comprise a central causal process in Darwin's theory of sexual selection. Their powerful influences have been documented in all sexually reproducing species, including in sexual strategies in humans. This article reviews the science of human mate preferences and their myriad behavioral manifestations. We discuss sex differences and sex similarities in human sexual psychology, which vary according to short-term and long-term mating contexts. We review context-specific shifts in mating strategy depending on individual, social, and ecological qualities such as mate value, life history strategy, sex ratio, gender economic inequality, and cultural norms. We review the empirical evidence for the impact of mate preferences on actual mating decisions. Mate preferences also dramatically influence tactics of mate attraction, tactics of mate retention, patterns of deception, causes of sexual regret, attraction to cues to sexual exploitability, attraction to cues to fertility, attraction to cues to resources and protection, derogation of competitors, causes of breakups, and patterns of remarriage. We conclude by articulating unresolved issues and offer a future agenda for the science of human mating, including how humans invent novel cultural technologies to better implement ancient sexual strategies and how cultural evolution may be dramatically influencing our evolved mating psychology.

Best Practices for Testing the Predictive Validity of Ideal Partner Preference-Matching.

Many psychological hypotheses require testing whether the similarity between two variables predicts important outcomes. For example, the ideal standards model posits that the match between (A) a participant's ideal partner preferences, and (B) the traits of a current/potential partner, predicts (C) evaluative outcomes (e.g., the decision to date someone, relationship satisfaction, breakup); tests of the predictive validity of ideal-matching require A × B → C analytic strategies. However, recent articles have incorrectly suggested that documenting a positive samplewide correlation between a participant's ideals and a current partner's traits (an A-B correlation) implies that participants pursued, selected, or desired partners with traits that matched their ideals. There are at least six alternative explanations for the emergence of a samplewide A-B correlation; A-B correlations do not provide evidence that ideals guide the selection/evaluation of specific partners. We review appropriately rigorous A × B → C tests that can aid scholars in identifying the circumstances in which ideal-matching exhibits predictive validity.

Human Mating Theory, Migration, and Marital Dissolution.

Marriage dissolution has been extensively analyzed in the last few decades, looking for the determinants of this well-known phenomenon, but so far the relationship between female migration and marriage dissolution does not seem to have been thoroughly investigated. This work aimed to analyze the correlation between marriage dissolution and migration, which might bias the sex ratio within a given society, introducing new social and cultural values. Considering the Regions of Italy between 2002 and 2007 (i.e., 120 observations), several multiple regression models (OLS) were presented to test the proposed hypothesis, applying the robust option. The dependent variable of our empirical investigation was a marriage dissolution index, while the key explanatory variables were a sex ratio and several female rates. Based on the results, the hypothesis of a statistically significant positive relation between the influx of female immigrants and household dissolution could be supported (i.e., p < .01). However, not all migrating women are the same and a different impact is foreseeable according to the nature of this influx. Indeed, given a 1% influx of unmarried foreign females, increasing the sex ratio within society, marital dissolutions grow by 5381 for every 100,000 marriages. In the case of a 1% influx of Italian unmarried females, marital dissolutions grew by 3173 for every 100,000 marriages. Therefore, females could have specific sexual, social and cultural characteristics, which might be able to increase (or decrease) the probability of men being driven to sexual infidelity, thus leading to a higher frequency of marriage dissolutions.

Passion, Relational Mobility, and Proof of Commitment: A Comparative Socio-Ecological Analysis of an Adaptive Emotion in a Sexual Market.

Although monogamy, the exclusive bonding with a specific partner, is one characteristic of modern human mating, long-term romantic relationships inherently possess the commitment problem, which is the conflict between maintaining a relationship with a certain partner and seeking attractive alternatives. Frank has argued that love and passion help solve this problem because they make individuals commit voluntarily to the relationship, leading the other party to also be committed with less concern over being cheated on or rejected. Combining this idea with the comparative socio-ecological approach, we hypothesize that passion will be more pronounced in social environments in which people have greater freedom to choose and replace their partners (i.e., high relational mobility) than in societies in which relationships tend to be more stable and hard to change (i.e., low relational mobility). To test this hypothesis, we compared Americans (living in a society with high relational mobility) and Japanese (living in a society with low relational mobility). As predicted, Americans were more passionate toward their romantic partners than Japanese, and this cultural difference was partially explained by the levels of perceived relational mobility in participants' local ecology. Moreover, more intense passion was found to lead to greater commitment behaviors in both societies. The importance of taking socioecological factors into consideration for the theory of the adaptive function of interpersonal emotions is also discussed.

Preference Versus Choice in Online Dating.

This study explores factors that influence matches of online dating participants' stated preference for particular characteristics in a potential partner and compares these with the characteristics of the online daters actually contacted. The nature of online dating facilitates exploration of the differences between stated preference and actual choice by participants, as online daters willingly provide a range of demographics on their ideal partner. Using data from the Australian dating website RSVP, we analyze 219,013 contact decisions. We conduct a multivariate analysis using the number of matched variables between the participants' stated preference and the characteristics of the individuals contacted. We find that factors such as a person's age, their education level, and a more social personality all increase the number of factors they choose in a potential partner that match their original stated preference. Males (relative to females) appear to match fewer characteristics when contacting potential love interests. Conversely, age interaction effects demonstrate that males in their late 60's are increasingly more selective (than females) regarding who they contact. An understanding of how technology (the Internet) is impacting human mating patterns and the psychology behind the participants informs the wider social science of human behavior in large-scale decision settings.

Why (and When) Straight Women Trust Gay Men: Ulterior Mating Motives and Female Competition.

Previous findings indicate that heterosexual women experience a greater sense of comfort and trust in their friendships with gay men than in their friendships with heterosexual individuals. In the present studies, we tested a hypothesis that not only explains why women exhibit increased trust in gay men but also yields novel predictions about when (i.e., in what contexts) this phenomenon is likely to occur. Specifically, we propose that gay men's lack of motives to mate with women or to compete with them for mates enhances women's trust in gay men and openness to befriend them. Study 1 demonstrated that women placed greater trust in a gay man's mating-but not non-mating (e.g., career) advice-than in the same advice given by heterosexual individuals. Study 2 showed that women perceived a gay man to be more sincere in scenarios relevant to sexual and competitive mating deception. In Study 3, exposing women to a visualization of increased mating competition enhanced their trust in gay men; when mating competition was salient, women's trust in mating information from a gay man was amplified. Study 4 showed that women who perceived higher levels of mating competition were more open to befriending gay men. Together, these converging findings support our central hypothesis, which not only provides a distal explanation for the trust that straight women place in gay men, but also provides novel insights into previously unidentified contexts that facilitate the formation and strengthening of this unique bond.