Primate eyes vary strikingly in pigmentation, yet the drivers of said variation are strongly debated. Recent revisions of the Cooperative Eye Hypothesis (CEH) propose that the human eye’s sclerae 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. Contrary to expectations, chimpanzee-like 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 signaling 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.

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 four 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 argument. 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 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.

Sir W. M. Flinders Petrie's lifelong beliefs in race science and eugenics underlay his significant work as an archaeologist and Egyptologist. His detection of race in ancient art provided a basis for other scholars’ construction of racial typologies. His commitment to colonialist paradigms of excavation moved numerous objects, and human remains, from Egypt and Palestine to Britain. In the 1930s, in two letters to The Times and the Palestine Post, the aging Petrie came out against Nazi understandings of race, arguing that 'foreign migration has been the making of Britain’. Petrie's claims reflected his understanding of civilisation, in antiquity and today, as a product of the 'right sort’ of racial mixing through migration of the fit, hearty, and talented. This critical reflection considers the role of archaeology in constructing race, taking Flinders Petrie’s work on migration as a case study and situating it in wider intellectual trends of the time. Understanding how Petrie’s racial logic allowed him to oppose Nazism while promoting eugenic ‘weeding’, allows us to move beyond simplistic understandings of early twentieth century race science. We can then detect the pernicious persistence of frameworks from this discipline in popular discourses about migration and culture in Britain today.

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 λ exp(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.

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.