Current debates concerning the use of digital technology often focus on privacy, yet privacy attitudes and behaviour are remarkably under-theorized, and relatively little empirical research has investigated privacy beyond the realm of digital communications. Building on evolutionary scholarship on information exchange, we outline a theoretical model in which cultural concepts of privacy reflect the workings of evolved psychological mechanisms that aim to regulate others’ access to fitness-relevant information towards adaptive ends. Results of two initial U.S. vignette studies distributed via Prolific (n = 425, 120) support the core predictions of this model, suggesting that people may have implicit and unstated assumptions regarding how information spreads in social environments. Specifically, participants’ privacy evaluations were predicted by whether information was intentionally acquired, the extent to which information was transmitted, and an individual’s position in an information transfer event. Importantly, how information was acquired and the nature of its transmission constituted independent but interacting influences on privacy perceptions. Additionally, results suggest the location within shared social networks of the individual to whom information is transmitted is used as a proxy for the potential costs of dissemination.

Two research branches in evolutionary psychology can make similar predictions about treatment expectations in contexts of conflict of interest, where, for those involved, costs and benefits are at stake. Recalibrational Theory of Anger suggests that evolved psychological mechanisms operate at the cognitive level and regulate human behaviour. The Dark Triad Personality posits that traits of Machiavellianism, Narcissism, and Psychopathy confer adaptive advantages, leading individuals to prioritize their interests over those of others. This study aimed to conduct a direct replication of a previously experimental study on anger in conflict-of-interest situations in a Brazilian sample (Replication Analysis) and investigated whether dark triad traits predict the magnitude of anger in conflict-of-interest situations (Extension Analysis). The Replication Analysis consistently replicated previous findings, with effect sizes from moderate to large magnitudes. The Extension Analysis revealed that only Narcissism was a significant predictor when victims were intentionally targeted by offenders. While the Recalibrational Theory of Anger predictions were largely confirmed, the dark triad personality traits, except for Narcissism, were generally poor predictors of anger magnitude. The results suggest that the universality of the information processing is robust and is little influenced by antisocial personality characteristics.

This article analyses the evolutionary genesis of the aldehyde dehydrogenase 2 mutation in East Asia through the lenses of institutional economics. While biology typically frames the absence of alcohol tolerance as a metabolic defect, this paper proposes the concept of functional redundancy. We argue that the specific social organization of rice societies – characterized by deep material interdependence – rendered alcohol consumption superfluous as an instrument for trust-building and social cohesion. The resulting genetic path dependency illustrates how historical institutional frameworks continue to shape the biological constitution of modern populations.

Most research on social media considers them as supports for information transmission, explaining online success (and pathologies) by focusing on consumers’ biases and interests. This article takes a different perspective, applying ideas from an ecological approach to culture. Success online depends both on the intrinsic appeal of content to receivers and on how well content serves producers’ strategic goals within the constraints and affordances of specific platforms. These goals include reputation management, coalition building and identity management, and coordination or participation in shared activities. Transmission is often a by-product of these motivations, and replication fidelity plays a limited role compared with transformations that adapt content to local incentives. Finally, the article suggests that platforms and communities can be understood as distinct niches, each characterised by different audience structures, affordances, metrics, and algorithmic pressures. This perspective reframes persistent debates on social media dynamics, including misinformation, radicalisation and polarisation, and the reasons behind online success.

Primate eyes vary strikingly in pigmentation, yet the drivers of said variation are strongly debated. Recent revisions of the cooperative eye hypothesis propose that the human eye’s sclera evolved to enhance gaze communication specifically under challenging conditions of visibility. We tested this idea under ecologically realistic conditions by presenting observers with a live model wearing contact lenses that simulated either a human-like or a chimpanzee-like eye. At a university lab, observers judged gaze direction at different viewing distances and lighting levels. We found no overall difference in efficacy of different eye types. Contrary to expectations, chimpanzee-like eyes outperformed human-like eyes in dim lighting and close-viewing conditions. Human-like eyes yielded the highest accuracy under bright, far-viewing conditions, consistent with a long-distance signalling advantage. Our results demonstrate that ecological visual constraints shape the potential informativeness of distinct ocular configurations. We hypothesize that species-typical eye appearances may be tuned to their species-typical visual ecology.

Humans selected hundreds of dog breeds, which show different levels of dependence on human-provided cues. While robust grouping factors, such as genetic relatedness-based ancestry and function-based cooperativeness, denote useful frameworks to analyse behavioural differences in dogs, they may lack fine enough resolution for a more detail-oriented understanding of human-oriented behaviours. Here, we focused on behaviour-based analysis of the characteristic reliance of dog breeds on human behaviour. We utilized N = 187 adult purebred dogs’ performance in a social learning task. Dogs observed a human demonstrator performing a detour around a transparent obstacle. With Principal Component Analysis, we established two behavioural dimensions: detour latency improvement and watching the demonstrator. Then, with K-means cluster analysis, we found six categories, based on different combinations of lower/higher values of the two dimensions. The clusters showed significant differences in both behavioural dimensions, highlighting attention combined with improvement types among purebred working dogs. Some extremes showed excellent improvement with only minimal attention to the human demonstrator, while others watched the human without improving their performance. We conclude that by finer analysis, it is possible to set up a dependence-based framework for the understanding of behavioural differences among dogs that go beyond functional breed-selection and ancestry.

This article examines how racialised memes circulating on X revive scientific racism, demonstrating that hybrid formats reconfigure biological essentialisation within contemporary digital culture. Using a corpus of 68 viral items and 4 case studies, our analysis applies Shifman’s content–form–stance model, informed by cognitive psychology. We show that these memes adopt common scientific conventions while relying on visual polarisation, whereby rapid perceptual contrasts stand in for arguments. Familiar templates, reinforced by selective algorithmic amplification, create a sense of perceptual legitimacy through fast categorisation and pre-attentive processing. We also trace how these cognitive shortcuts provide the basis for a regime of racialisation tailored to digitally immersed male audiences, producing gendered behavioural stereotypes and disappearance anxieties. A further pattern is the recoding of older racial hierarchies into neutral-sounding language of competence, allowing these ideas to travel across racialist, masculinist, techno-elitist, and anti-DEI (Diversity, Equity, Inclusion) communities. In this environment, memes work as micro-infrastructures of classification that align claims to objectivity with affect and platform incentives, making inequality appear natural and necessary. We conclude that effective critique must meet these images on their own terrain, with a pedagogy of the gaze that teaches publics how to recognise and challenge persuasion in meme-driven spaces.

Demographic transition, characterised by declines in fertility and mortality, is a global phenomenon associated with modernisation. While typical patterns of fertility decline have been described mainly in Western countries, their applicability to other regions and the underlying mechanisms remain unclear. Using data spanning 1800–2020 from 237 countries and territories, this study identifies two universal pathways in the change in the crude birth rate (births per 1,000 person-years, λ) and period life expectancy at birth (e0). Most countries’ demographic trajectories follow one of these two pathways or shift between them. These pathways define phases governed by different mechanisms. Phase I, conserving λe0, dominated until the mid-20th century and was characterised by high child mortality and steady population growth. By contrast, Phase II, conserving λexp(e0/17), has prevailed since 1950 and is marked by low child mortality and steady growth in GDP per capita. A theoretical model considering the trade-off between reproduction and education elucidates the transition between these phases. The transition to Phase II is accelerated by declining educational costs, rising social mobility, and cultural transmission linked to modernisation and Westernisation. This study demonstrates quantitative regularities between fertility and longevity during demographic transition and provides a theoretical lens for their underlying mechanisms.