Summary. "The human eyes are continuously adjusting refractive power, vergence angle, and pupil diameter when exploring the visual environment. Adjustment errors in these visuomotor functions reduce the stimulus contrast driving ON and OFF retinal pathways, and ON retinal pathways become weaker, slower, and less sensitive in refractive disorders such as myopia. Here, we demonstrate that, in addition to these sensory deficits, myopes also have deficits in visuomotor functions driven by ON and OFF pathways during lens accommodation. We show that humans with myopia have excessive accommodative eye vergence with reduced ON pathway dominance and excessive accommodative pupil constriction. The excessive accommodative pupil constriction that we demonstrate could potentially weaken ON pathway responses and cause ON pathway deficits. This mechanism could explain why myopia increases with activities that maximize accommodative pupil constriction, such as near work, and decreases with activities/treatments that reduce it, such as outdoor activity, atropine, positive defocus, and low contrast."
Abstract. "More than 100 historically, archaeologically and ethnographically attested numerical notations have been used over the past 5,000 y; however, because most of those systems are no longer used, experimental investigation is challenging. Prior research often assumes, rather than demonstrates, the inferiority of notations like Roman numerals. Gradience is a principle whereby the length of numeral phrases correlates with the magnitude of the numbers being represented. In general, but inconsistently, larger numbers require more signs, just as larger sets of abstract dot patterns occupy more space. This study compares the gradience of 13 numerical notations varying in phylogenetic family, linguistic family, and structural properties, using two indices, inversion (how often N + 1 requires fewer signs than N) and jitter (the mean length difference between successive numbers). Place value systems are highly gradient; i.e., their length indexes numerical magnitude more accurately than other systems. The relationship between the structural properties of notations and the two indices of jitter and inversion is complex. Next, a cultural-evolutionary analysis compares the older additive Roman numerals to the eventually predominant subtractive variant (e.g., XIX = 19). Subtractive Roman numerals are more concise and have a lower jitter than additive ones, but at the cost of a significantly higher inversion ratio. This analysis permits the evaluation of cultural-evolutionary hypotheses grounded in the representational properties of attested notations, even when cognitive tests are not feasible. Several avenues for future experimental investigation using attested or constructed notations of varying properties are proposed."
Abstract. "Pluralistic ignorance—the systematic misperception of others’ attitudes—can entrench suboptimal norms, yet its dynamics remain poorly understood. We develop a mathematical model of the coevolution of actions, private attitudes, and beliefs about others, with societal tightness as a central parameter. Our framework integrates theories of spirals of silence, preference falsification, and cultural mismatch into a single dynamic system capturing the effects of material payoffs, cognitive forces, and social influence. The model shows that pluralistic ignorance can arise from lags between attitude change and belief updating, even without silence or deception. Dynamics unfold faster in loose cultures and slower in tight ones: loose societies display sharp but transient peaks of pluralistic ignorance, while tight societies sustain slower, persistent mismatches. Both can experience cultural evolutionary mismatch but through distinct pathways—internalized norm adherence in loose cultures vs. conformity pressure in tight ones. These mechanisms may help explain global patterns where private support exceeds perceived support, such as climate action, women’s rights, and abortion attitudes. Interventions must therefore be culturally tailored: accelerating attitude change through highlighting benefits is effective in loose cultures, whereas lowering expression costs (via anonymity or legal protections) empowers norm entrepreneurs in tight cultures. Our framework identifies policy levers and clarifies when apparent opinion stability conceals underlying shifts, offering insights for democratic societies navigating rapid social change."
Abstract: "We present the first representative international data on firm-level AI use. We survey almost 6000 CFOs, CEOs and executives from stratified firm samples across the US, UK, Germany and Australia. We find four key facts. First, around 70% of firms actively use AI, particularly younger, more productive firms. Second, while over two thirds of top executives regularly use AI, their average use is only 1.5 hours a week, with one quarter reporting no AI use. Third, firms report little impact of AI over the last 3 years, with over 80% of firms reporting no impact on either employment or productivity. Fourth, firms predict sizable impacts over the next 3 years, forecasting AI will boost productivity by 1.4%, increase output by 0.8% and cut employment by 0.7%. We also survey individual employees who predict a 0.5% increase in employment in the next 3 years as a result of AI. This contrast implies a sizable gap in expectations, with senior executives predicting reductions in employment from AI and employees predicting net job creation."
Abstract: "Constraining the long-term evolution of geoid anomalies is essential for unraveling Earth’s internal dynamics. While most studies focus on present-day geoid snapshots, we reconstruct the time-dependent evolution of Earth’s strongest geoid depression, the Antarctic Geoid Low (AGL), over the Cenozoic. Unlike geodetic reference frames that place the deepest geoid low in the Indian Ocean, a geodynamic perspective – relative to a hydrostatic ellipsoid – reveals the strongest nonhydrostatic geoid depression resides over Antarctica. Using a back-and-forth nudging technique for time-reversed mantle convection modeling, we leverage 3-D mantle density structures derived from seismic tomography and geodynamic constraints. Our results show that the AGL has persisted for at least ~70 Myr, undergoing a major transition in amplitude and position between 50 and 30 Ma. This transition coincides with an abrupt lateral shift in Earth’s rotation axis at ~50 Ma, independently validated through paleomagnetic constraints on True Polar Wander. Initially, the AGL was supported by stable lower mantle density anomalies, but over the past ~40 Myr, an increasing contribution from upper-mantle buoyancy – particularly above ~1300 km depth – amplified the AGL magnitude. This shift reflects the interplay between long-term deep subduction beneath the Northwest Antarctic margin and a broad, thermally driven upwelling of buoyant material sourced from the lowermost mantle. These results contrast with earlier interpretations by demonstrating the crucial role of time-dependent coupling between both positive and negative mantle buoyancy in shaping global geoid anomalies. By integrating seismic, geodynamic, and mineral-physics data, our reconstructions provide a dynamically consistent view of mantle flow beneath Antarctica and offer new insights into the coupling between deep and shallow mantle processes that govern Earth’s long-wavelength geoid evolution."
"Abstract. In the search for extraterrestrial intelligence (SETI), the highly incomplete sampling of the technosignature search space is often considered as a plausible explanation for the persistent lack of detections over six decades of searches. If correct, this would imply that technosignatures may already have reached Earth without being detected or correctly identified. Here, we explore this possibility using a Bayesian inference framework to estimate present-day detectability given n ≥ 1 undetected contacts over the past 65 yr—the period since the first SETI experiment. We show that achieving high detectability of technosignatures emitted within a few hundred light-years of Earth would require implausibly large n values, even exceeding the population of habitable planets within that range. More conservative estimates can be obtained only assuming that emitters are tightly clustered near Earth or that their population in the Milky Way has undergone a very recent and sudden boost. This tension is further exacerbated for short-lived technosignatures and persists whether they are omnidirectional, as in Dysonian megastructures, or directional, as in intentional communication attempts. These findings suggest that, if undetected past contacts from the Milky Way have indeed occurred, the best prospects of detection may lie in searches extending over several thousand light years, though only a few detectable technoemissions would be expected."
Abstract: "The fate of carbon stored in Arctic peatlands remains uncertain because of the complex nature of the effects of climate change on permafrost and peatland carbon cycling. Expansion and/or shrinkage of Arctic peatlands under climate change also remain unknown due to lack of ground data and difficulties detecting changes in the extent of these ecosystems, meaning that land surface model predictions currently inadequately quantify Arctic terrestrial carbon storage changes. Pan-Arctic shifts in peatland extent would profoundly change the fate of carbon in the terrestrial Arctic. Here, we tackle this knowledge gap by answering three main questions: (a) has lateral expansion occurred in Arctic peatlands as a response to recent warming? (b) if so, how fast has this occurred? (c) how does the response vary regionally? To answer these, we collected a dataset (12 peatland sites, 91 peat cores) combining peat cores collected across two latitudinal (north–south) transects: one in the European Arctic and one in the Canadian Arctic. In each region, we selected three peatland sites, with cores collected from transects spanning the peat-edge to the peat-centre. Our large-scale dataset shows that peatlands have expanded, often rapidly, with some rates exceeding ~1 m per year since 1950 AD. This rapid expansion has occurred during a period of widespread Arctic warming and is still ongoing: two thirds (8/12) of our peatland sites evidence new peat formation after ~1990 AD based on age-depth models constrained by 14C and 210Pb dating. Given that our sites comprise a broad range of Arctic conditions, we expect peatland expansion to be a pan-Arctic phenomenon. Within specific regions, there are constraints on peat expansion including topographical limits, but we present the basis for future work to estimate pan-Arctic peatland expansion, plus the associated carbon cycle implications under future climate change."
"Abstract. Understanding ocean freshwater variability is key to assessing the global water cycle and climate change, but changes in freshwater storage and transport remain unclear. Here we show that the South Indian Ocean—a vital conduit for interocean exchange—has experienced the strongest freshening in the Southern Hemisphere since the 1960s. This freshening drives a southward expansion of the Indo-Pacific freshwater pool into the South Indian Ocean, where freshwater has increased by 6.5 ± 0.5% per decade, as indicated by the shrinking 35.3 psu isohaline. Strengthened Indonesian Throughflow and intensified Subtropical Gyre inflow are the primary causes. In the upper ~200 m, freshening follows a new subtropical pathway rather than the usual tropical route. These changes arise from wind shifts linked to the Hadley cell’s poleward expansion and a stronger Indonesian Throughflow, both driven by warm-pool warming. Ongoing warming will further expand the freshwater pool and broaden the subtropical pathway, affecting climate, interocean exchange and marine ecosystems."
"Abstract. Utilizing a quasi-natural experiment design, we identify an exogenous cut in local taxes accompanied by an equivalent reduction in local government spending, and we estimate the impact of these exogenous changes on income. We exploit a unique regional dataset that combines local income data with local voting outcomes on current expense tax levies. Taxes and the associated spending change abruptly at the 50 percent vote share cutoff below which a tax levy fails to pass. This cutoff determines which observations serve as controls and which receive treatment: a reduction in local taxes and government spending. Voting percentages around the cutoff are a source of exogenous variation, with observations around this quasi-randomly assigned and very similar across characteristics. We find that balanced budget reductions in taxes and spending cause a large drop in local incomes in the first two years after the vote, suggesting that government expenditure effects on income are larger than fiscal revenue effects. The cumulative government spending multiplier of a balanced-budget change in spending for our baseline is a sizable 1.5. This effect of local tax-financed government spending is prominent in low-income and high-poverty areas, suggestive of mechanisms related to the share of liquidity-constrained agents."
Summary. "The human eyes are continuously adjusting refractive power, vergence angle, and pupil diameter when exploring the visual environment. Adjustment errors in these visuomotor functions reduce the stimulus contrast driving ON and OFF retinal pathways, and ON retinal pathways become weaker, slower, and less sensitive in refractive disorders such as myopia. Here, we demonstrate that, in addition to these sensory deficits, myopes also have deficits in visuomotor functions driven by ON and OFF pathways during lens accommodation. We show that humans with myopia have excessive accommodative eye vergence with reduced ON pathway dominance and excessive accommodative pupil constriction. The excessive accommodative pupil constriction that we demonstrate could potentially weaken ON pathway responses and cause ON pathway deficits. This mechanism could explain why myopia increases with activities that maximize accommodative pupil constriction, such as near work, and decreases with activities/treatments that reduce it, such as outdoor activity, atropine, positive defocus, and low contrast."
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