This study investigates how adolescents from two culturally distinct Central African communities—the Aka hunter-gatherers and Ngandu farmers—perceive health, attractiveness, and marriageability, focusing on how local socio-ecological contexts shape perceptions of health, attraction, and mate preferences. The research examines how body mass index and parasite load relate to perceived health and attractiveness. Seventy-five adolescents (39 Aka and 36 Ngandu) evaluated photographs of peers for health, attractiveness, and marriagability, while physical health was objectively measured using anthropometric and parasitological data. Regression analyses revealed that BMI was a consistent and significant predictor of both perceived health and attractiveness, whereas total parasite load did not significantly influence either outcome. Notably, perceptions of health strongly predicted attractiveness and marriageability, but not vice versa. Ethnic and gender differences in perception were also found: Aka adolescents prioritized social traits like kindness and cooperation, while Ngandu participants emphasized physical cleanliness and robustness. Male raters showed more variability and stricter standards, particularly when evaluating females. These findings underscore the role of robust phenotypic features, such as BMI, in determining how health, beauty, and reproductive value are interpreted. This research contributes to understanding how evolutionarily evolved preferences and cultural contexts shape perceptions of health, attraction, and marriageability.

The human microbiota —the collection of microorganisms living on and inside the body—plays a fundamental role in human health. While diet, genetics, and environment strongly shape microbiota composition, social interactions may also influence the microbial communities associated with the human body. Intimate kissing is a widespread human behaviour that involves close contact and exchange of saliva, providing an opportunity for direct microbial transmission between individuals. This article explores the hypothesis that intimate kissing can induce a reinforcing cycle – a positive feedback loop - that shapes and stabilizes the oral microbiota of partners over time. Neurobiological pathways, including the gut microbiota–brain axis, might reinforce this feedback loop. Current evidence is synthesized and a study design outlined to explore how kissing may lead to sustained microbial sharing and potential systemic effects.

Men overestimate women's sexual interest and women underestimate men's. Error Management Theory conceptualizes these sexual over- and underperception biases as adaptations. While the presence of these biases is well documented in adults, no previous research has explored their emergence and development during adolescence. We examined whether sexual over- and underperception biases were already present at age 16, whether they emerged later, and how they developed from ages 16 to 19. Given that adolescents face similar reproductive challenges as adults, we predicted these adaptations would already be activated by age 16. Following Haselton's (2003) procedure, a high-school community sample (males = 551, females = 739) from the Norwegian Health, Sexual Harassment, and Experiences Study (2013) reported if they had experienced being sexually over- and underperception during the previous 12 months. Unexpectedly, females were first 17 years of age when they reported that males had an overperception bias, and it was not until age 19 that females were more frequently overperceived than males. This pattern resulted from females becoming increasingly overperceived from age 16 (7 %) to 19 (25 %). More males (13 %) than females (3 %) were underperceived at all ages. Since the proportion of overperceived males dropped to 3 % at age 19, 19-year-old males consequently reported that females had an underperception bias. Sociosexuality increased the risk of being overperceived for both sexes and additionally increased males' risk of being underperceived. Singlehood and sexual debut did not influence risk of being misperceived. Mate value strongly increased males' likelihood of being overperceived. Developmentally, reports of sexual overperception undergo sex differentiation from mid- to late adolescence, while reports of sexual underperception are already sex-differentiated by age 16. Thus, males' overperception bias appears to emerge in middle adolescence, whereas females' greater tendency to underperceive males is likely present before mid-adolescence. Limitations regarding the timing of these biases and future directions for studying their developmental trajectories are discussed.