Mortality risk predicts global, local, and individual patterns of human reproduction.

BACKGROUND: Human reproductive dynamics in the post-industrial world are typically explained by economic, technological, and social factors including the prevalence of contraception and increasing numbers of women in higher education and the workforce. These factors have been targeted by multiple world governments as part of family policies, yet those policies have had limited success. The current work adopts a life history perspective from evolutionary biology: like most species, human populations may respond to safer environments marked by lower morbidity and mortality by slowing their reproduction and reducing their number of offspring. We test this association on three levels of analysis using global, local, and individual data from publicly available databases. RESULTS: Data from over 200 world nations, 3,000 U.S. counties and 2,800 individuals confirm an association between human reproductive outcomes and local mortality risk. Lower local mortality risk predicts "slower" reproduction in humans (lower adolescent fertility, lower total fertility rates, later age of childbearing) on all levels of analyses, even while controlling for socioeconomic variables (female employment, education, contraception). CONCLUSIONS: The association between extrinsic mortality risk and reproductive outcomes, suggested by life history theory and previously supported by both animal and human data, is now supported by novel evidence in humans. Social and health policies governing human reproduction, whether they seek to boost or constrain fertility, may benefit from incorporating a focus on mortality risk.

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.

Evolutionary Role of the Female Orgasm: Insights into Mate Choice and Beyond.

The female orgasm remains a subject of extensive debate within evolutionary sciences, primarily due to the absence of a consensus regarding its adaptive function. Some hypotheses propose that it could function as a mechanism for mate selection, possibly linked to reproductive strategies. Studies have observed that lesbian women tend to experience orgasms more frequently than straight women, suggesting a potential link to advantageous partner characteristics. We explored the connection between the female orgasm and mate selection, aiming to ascertain its role as an adaptive tool for mate choice. A total of 939 sexually active Brazilian women (Mage = 28.3 years) engaged in committed relationships participated by completing the Marital Empathy Questionnaire, the Female Sexual Function Index, and evaluations of their partners' attributes. Analysis using structural equation models revealed that higher orgasm scores were positively associated with perceptions of partner kindness, intelligence, good health, physical attractiveness, and empathy. However, the small effect sizes of these associations warrant caution in their interpretation, and no significant association was found for relationship duration, financial prospects, dominance, and masculinity/femininity. Additionally, no differences were found between women in same-sex and other-sex relationships regarding orgasm frequency and its association with partner traits. The findings partially support the mate-choice theory, encompassing both sire-choice and pair-bond hypotheses, suggesting that female orgasm is positively associated with some partner attributes related to genetic quality and the capability for emotional connection and resource investment. Therefore, female orgasm may offer information about the partner that might not be primarily accessed and contribute to relationship maintenance.

Why might animals remember? A functional framework for episodic memory research in comparative psychology.

One of Clayton's major contributions to our understanding of animal minds has been her work on episodic-like memory. A central reason for the success of this work was its focus on ecological validity: rather than looking for episodic memory for arbitrary stimuli in artificial contexts, focussing on contexts in which episodic memory would serve a biological function such as food caching. This review aims to deepen this insight by surveying the numerous functions that have been proposed for episodic memory, articulating a philosophically grounded framework for understanding what exactly functions are, and drawing on these to make suggestions for future directions in the comparative cognitive psychology of episodic memory. Our review suggests four key insights. First, episodic memory may have more than one function and may have different functions in different species. Second, cross-disciplinary work is key to developing a functional account of episodic memory. Third, there is scope for further theoretical elaboration of proposals relating episodic memory to food caching and, in particular, future-oriented cognition. Finally, learning-related functions suggested by AI (artificial intelligence)-based models are a fruitful avenue for future behavioural research.

Visual Attention to Evolutionarily Relevant Information by Heterosexual Men and Women While Viewing Mock Online Dating Profiles.

The way people create social connections and access information has been altered greatly by technology in recent decades. Online browsing of visual profiles has become a common means for seeking potential partners for both short- and long-term relationships. Little is known, however, about how people prioritize mate quality information while viewing online profiles. Using eye-tracking methods and self-report, this study investigated how people evaluated profile-based facial attractiveness and text-based financial resources information, represented by income and occupation. Heterosexual male and female participants, aged between 18 and 27 years, viewed opposite-sex profiles while their eye-movements were recorded using a remote eye-tracking camera. In line with current theory, resources information had little effect on men's overall attention to women's faces, whereas women's overall attention to men's faces varied depending on the level of income and occupation. Women evaluated men's faces more when income and occupation were low, regardless of attractiveness. Unexpectedly, however, men marginally increased their attention toward unattractive women who showed a high-level of income and more esteemed occupation. Men self-reported a higher interest in women for a short-term relationship and women self-reported a higher interest in men for a long-term relationship. This work provides a foundation to further examine how people browse profile-based information and to investigate the mate selection process, with real-world implications for online dating app users, profile design, and content.

The motivations and reputational consequences of spreading conspiracy theories.

Some people deliberately spread conspiracy theories. What are the reputational benefits and costs of doing so? The Adaptive-Conspiracism hypothesis proposes that it pays to be vigilant against possible conspiracies, especially in case of intergroup threat. Those who spread conspiracy theories may therefore be seen as valuable group members. Few studies have focused on the reputational impact of spreading a conspiracy theory. We conducted five studies (NPilot = 303; NStudy1 = 388; NStudy2 = 560; NStudy3 = 391; NStudy4 = 373) where participants rated a conspiracy spreader (vs. a neutral person) on a range of personality traits in different intergroup contexts. The results indicated that conspiracy spreaders were consistently perceived as more dominant and less warm than people making non-conspiratorial claims about certain events. Moreover, intergroup conflict attenuated the negative effects of spreading conspiracy theories on competence and warmth. These findings support the notion that besides drawbacks, spreading conspiracy theories can have benefits for the spreader's reputation, particularly during an intergroup conflict.

Parents' Reproductive Concerns and Negativity Toward Their Child Disclosing a Minoritized Sexual Orientation.

Parents often respond negatively when a child discloses their minoritized sexual orientation. We propose that parents' negativity in this context may be shaped by evolutionary concerns regarding their children's reproductive outcomes. We tested relevant hypotheses in a correlational study (Study 1) and two randomized experiments (Studies 2 and 3) that recruited parents with children under age 6 as participants. Study 1 (N = 386; 192 mothers and 194 fathers; 84.68% non-Hispanic White) revealed associations between parents' concerns regarding their children's reproductive outcomes and views toward a child disclosing a lesbian, gay, or bisexual (LGB) orientation in the future. The most negative views were reported by parents with elevated reproductive concerns and pessimistic beliefs about the possibility of reproduction for LGB individuals. Studies 2 (N = 327 mothers; 84.10% non-Hispanic White) and 3 (N = 279 fathers; 81.00% non-Hispanic White) tested whether information about reproductive assistance available to same-gender couples might promote more favorable views toward a child's hypothetical LGB orientation disclosure relative to control information. Parents who received reproductive versus control information reported more positive attitudes toward having an LGB child and toward the LGB community. These effects were statistically mediated by their more optimistic beliefs about the possibility of LGB reproduction. Taken together, this work suggests that reproductive concerns may influence parents' views toward their children's sexual orientation disclosures, and alleviating these concerns may be one way to improve parents' relationships with their sexually diverse children.

Temperaments as Basic Bias.

In this work, we argue that the lack of a solid theoretical basis and the absence of an integrative movement in psychological science within evolutionary perspectives has meant that the various attempts to explain and define the phenomenon of "temperaments" offer notions that are either too broad or simply imprecise and, as a result, they failed to reach a high level of consensus among researchers in this science. In this regard, we understand that the evolutionary theory proposed by Osmo (Integrative Psychological and Behavioral Science 57:205-234, 2023) is promising for reaching such a consensus. Thus, the objective of this article is, from this theory, to offer a better understanding of the phenomenon of "temperaments", and, based on it, to develop a precise and parsimonious definition of this term.

Exploring Within-Gender Differences in Friendships Using an Online Social Network.

People tend to befriend others similar to themselves, generating a pattern called homophily. However, existing studies on friendship patterns often rely on surveys that assess the perspective of relatively few participants on their friendships but do not measure actualized friendship patterns. Here, we used data from a large Slovakian online social network to assess the role of gender, age, and body mass index (BMI) in same-gender online connections among more than 400,000 users. We found that age and BMI homophily occurred in both men's and women's same-gender connections, but somewhat more strongly among men's. Yet, as women diverged in BMI, their connections were less likely to be reciprocated. We discuss how the evolutionary legacy of men's coalitional competition (e.g., warfare) and women's mating competition or recruitment of allocare providers might contribute to these patterns in modern same-gender relationships. For example, men's engagement in physical activities may lead to similar formidability levels among their same-gender peers. Altogether, our findings highlight the importance of trait similarity to same-gender friendship patterns.

Psychometric Characteristics of the Italian Version of the Revised Sociosexual Orientation Inventory.

Sociosexuality refers to the tendency to engage in uncommitted sexual behavior and has been dissected into three domains: sociosexual behavior, attitudes, and desire (Penke & Asendorpf, 2008), which led to the revised Sociosexual Orientation Inventory (SOI-R), which was validated on a German sample. The current research aimed at translating and validating an Italian version (I-SOI-R), administered to three distinct Italian participant groups. In the first sample (N = 710, females = 521, age = 18-59 years), we found evidence for a bifactor model, articulated in a general sociosexuality factor and three specific factors (behavior, attitudes, desire). High internal consistency was established for total and subscale scores, alongside favorable test-retest reliability. A connection was found between relationship status and sociosexual desire, though not gender dependent. We found evidence for test-retest reliability in a second sample (N = 55, females = 37, age 20-58 years). In a third study (N = 305, females = 147, age = 19-60 years), the earlier findings were replicated, further confirming the I-SOI-R's construct, criterion, and nomological validity on an online sample. Combining data from the three studies revealed full configural, metric, and scalar invariance regarding gender. This allowed us to meaningfully compare the observed scores of women and men and replicated the finding that men display higher levels of unrestricted sociosexuality. In conclusion, the I-SOI-R may serve as a valuable tool to assess and enhance sexual health, albeit warranting future research on construct and criterion validity.

The interactive effect between economic uncertainty and life history strategy on corrupt intentions: a life history theory approach.

Introduction: Why do some people show more corruption when facing uncertain environment? The present study aimed to give a plausible answer from an evolutionary perspective: this might be rooted in people's different life history strategies (slow vs. fast). Methods: The present study measured the participants' corrupt intentions by a hypothetical scenario and primed the feeling of economic environmental uncertainty by requiring the participants to read economic uncertainty (vs. neutral) materials. Results: It is revealed that the participants with fast life history strategies had stronger corrupt intentions after reading materials about economic uncertainty than reading neutral materials. In addition, the desire for power mediated the interactive effect between life history strategy and economic uncertainty on corrupt intentions for fast life history strategists. Discussion: This finding was discussed for its theoretical and practical implications from the perspective of life history theory.

An Evolutionary Psychological Approach Toward BDSM Interest and Behavior.

Bondage/discipline, Dominance/submission, and Sadism/Masochism (BDSM) have gained increased attention and discussion in recent years. This prevalence is accompanied by a shift in perceptions of BDSM, including the declassification of sadomasochism as a paraphilic disorder. Evolutionary psychology offers a unique perspective of why some individuals are interested in BDSM and why some prefer certain elements of BDSM over others (e.g., dominance versus submission). In this paper, we examine BDSM from an evolutionary standpoint, examining biopsychosocial factors that underlie the BDSM interests and practice. We articulate this perspective via an exploration of: proximate processes, such as the role of childhood experiences, sexual conditioning, and physiological factors; as well as ultimate explanations for power play and pain play dimensions of BDSM, highlighting the potential adaptive advantages of each. While BDSM may not be adaptive in itself, we examine the literature of sex differences in BDSM role preferences and argue that these preferences may stem from the extreme forms of behaviors which enhance reproductive success. In the realm of pain play, we explore the intersection of pain and pleasure from both physiological and psychological perspectives, highlighting the crucial role of psychological and play partner factors in modulating the experience of pain. Finally, we encourage future research in social sciences to utilize evolutionary frameworks to further explore the subject and help alleviate the mystification surrounding BDSM. This multifaceted exploration of BDSM provides valuable insights for clinicians, kink-identified individuals, and scholars seeking to understand the evolutionary perspectives of human sexual behavior and preferences.

The reliability and validity of the brief measures of perceived childhood harshness and unpredictability: A revised Chinese version for emerging adults.

BACKGROUND: Childhood harshness and unpredictability significantly shape life history strategies, as well as downstream psychological and behavioral patterns. However, prior research involving Chinese populations has suffered from inconsistent metrics and limited measurement items. OBJECTIVE: We adapted the English version of Maranges et al.'s (2022) Harshness and Unpredictability Scale in Childhood, translating it into Chinese and assessing its reliability and validity. PARTICIPANTS AND SETTING: Six groups of different college student samples have been collected and the Chinese version of the Harshness and Unpredictability scales has been revised in two separate studies. METHODS: We evaluated the factor structure using both exploratory and confirmatory factor analyses, determined internal consistency, item discrimination, concurrent validity, and assessed gender measurement invariance through multiple CFAs. The test-retest reliability was subsequently established by assessing participants after a designated interval. RESULTS: Both scales passed psychometric tests, including exploratory and confirmatory factor analyses, and exhibited strong internal consistency and item discrimination. Gender invariance in the measurements was also confirmed. CONCLUSIONS: The Chinese version of the Childhood Harshness and Unpredictability Scale demonstrates high reliability and validity, making it suitable for deeper examinations into the relationship between early environments and life history strategies in Chinese contexts.

Visual Preference for Socially Relevant Spatial Relations in Humans and Monkeys.

As a powerful social signal, a body, face, or gaze facing toward oneself holds an individual's attention. We asked whether, going beyond an egocentric stance, facingness between others has a similar effect and why. In a preferential-looking time paradigm, human adults showed spontaneous preference to look at two bodies facing toward (vs. away from) each other (Experiment 1a, N = 24). Moreover, facing dyads were rated higher on social semantic dimensions, showing that facingness adds social value to stimuli (Experiment 1b, N = 138). The same visual preference was found in juvenile macaque monkeys (Experiment 2, N = 21). Finally, on the human development timescale, this preference emerged by 5 years, although young infants by 7 months of age already discriminate visual scenes on the basis of body positioning (Experiment 3, N = 120). We discuss how the preference for facing dyads-shared by human adults, young children, and macaques-can signal a new milestone in social cognition development, supporting processing and learning from third-party social interactions.

CyberStatus: Responses to status manipulation and fears of positive and negative evaluations.

Fear of positive evaluation (FPE) and fear of negative evaluation (FNE), which play distinct and central roles in social anxiety (SA), are postulated to reflect conflicting forces in hierarchal group contexts. Yet, experimental studies testing these assumptions are scarce. We examined the impact of status positions on FPE, FNE, and SA using a novel manipulation, CyberStatus. Participants (N = 557) provided self-descriptive statements before being randomly assigned to high, intermediate, or low-status conditions. Next, they reported their emotions, status, and belongingness-related cognitions and adjusted their self-presentation. FPE was more strongly linked to self-presentation modifications in the high- compared to intermediate-status conditions and positively associated with perceived status in the low vs. intermediate conditions. Furthermore, FPE and SA were more linked to belongingness in low vs. intermediate status conditions while FNE demonstrated the reversed pattern. These findings support and expand the evolutionary perspective on evaluation fears and emphasize the importance of assessing the linkage between status and belongingness systems in SA.

Evolutionary perspectives on substance and behavioural addictions: Distinct and shared pathways to understanding, prediction and prevention.

Addiction poses significant social, health, and criminal issues. Its moderate heritability and early-life impact, affecting reproductive success, poses an evolutionary paradox: why are humans predisposed to addictive behaviours? This paper reviews biological and psychological mechanisms of substance and behavioural addictions, exploring evolutionary explanations for the origin and function of relevant systems. Ancestrally, addiction-related systems promoted fitness through reward-seeking, and possibly self-medication. Today, psychoactive substances disrupt these systems, leading individuals to neglect essential life goals for immediate satisfaction. Behavioural addictions (e.g. video games, social media) often emulate ancestrally beneficial behaviours, making them appealing yet often irrelevant to contemporary success. Evolutionary insights have implications for how addiction is criminalised and stigmatised, propose novel avenues for interventions, anticipate new sources of addiction from emerging technologies such as AI. The emerging potential of glucagon-like peptide 1 (GLP-1) agonists targeting obesity suggest the satiation system may be a natural counter to overactivation of the reward system.

Fertility Fails to Predict Voter Preference for the 2020 Election: A Pre-Registered Replication of Navarrete et al. (2010).

As part of the Systematizing Confidence in Open Research and Evidence (SCORE) program, the present study reassesses the claim made in Navarrete et al. (2010) Study 1, that women's voter preference for male candidates who demonstrate cues of strong genetic fitness increases across the reproductive cycle as a function of conception risk. We report an attempt to conceptually replicate these findings, modifying the outcome variables for voter preference to reflect the 2020 election rather than the 2008 election, while maintaining fidelity to the original study by including Barack Obama as a candidate. Contrary to the original findings, conception risk did not predict greater voter support for Obama as a younger, more attractive alternative to Donald J. Trump, nor was conception risk a significant factor in other matchups we presented to participants. Candidate intelligence and participant psychopathy scores on the Dark Triad were found to be factors in preference for Obama/Biden or Trump, respectively. We discuss these results in the context of evolutionary and political psychology, suggesting the need for further research that takes political factors into account.

The Desirable Dad Hypothesis: Male Same-Sex Attraction as the Product of Selection for Paternal Care via Antagonistic Pleiotropy.

Same-sex attraction, a heritable trait with a reproductive cost, lacks a comprehensive evolutionary explanation. Here we build on a hypothesis invoking antagonistic pleiotropy, which suggests that genes linked to male same-sex attraction remain in the gene pool because they have conferred some fitness advantage to heterosexual men possessing them. We posit the "desirable dad hypothesis," which proposes that alleles linked to male non-heterosexual orientations increase traits conducive to childcare; heterosexual men possessing same-sex attracted alleles are more desirable mating partners as a function of possessing superior paternal qualities. We conducted three studies to test predictions from this hypothesis. Results were consistent with all three predictions. Study 1 (N = 1632) showed that heterosexual men with same-sex attracted relatives were more feminine than men without, as indicated by self-report measures of femininity (η2 = .007), warmth (η2 = .002), and nurturance (η2 = .004 - .006). In Study 2 (N = 152), women rated feminine male profiles as more romantically appealing than masculine ones (d = 0.83)-but less so than profiles possessing a combination of feminine and masculine traits. In Study 3 (N = 153), women perceived feminine male profiles as depicting the best fathers and masculine profiles the worst (d = 1.56): consistent with the idea that femininity is attractive for childcare reasons. Together, these findings are consistent with the idea that sexual selection for male parental care may be involved in the evolution of male same-sex attraction.