Table Of Contents Page, PNAS Volume 122, Number 25
Special Feature
Collective Artificial Intelligence and Evolutionary Dynamics
Cooperation at scale is critical for achieving a sustainable future for humanity.
However, achieving collective, cooperative behavior—in which intelligent actors in
complex environments jointly improve their well-being—remains poorly understood. Complex
...
Evolutionary game theory (EGT) has been pivotal in the study of cooperation, offering
formal models that account for how cooperation may arise in groups of selfish, but
simple agents. This is done by inspecting the complex dynamics arising from simple
...
Human society is coordinated by mechanisms that control how prices are agreed, taxes
are set, and electoral votes are tallied. The design of robust and effective mechanisms
for human benefit is a core problem in the social, economic, and political ...
Inspired by the challenges at the intersection of Evolutionary Game Theory and Machine
Learning, we investigate a class of discrete-time multiagent reinforcement learning
(MARL) dynamics in population/nonatomic congestion games, where agents have diverse
...
Choosing social partners is a potentially demanding task which involves paying attention
to the right information while disregarding salient but possibly irrelevant features.
The resultant trade-off between cost of evaluation and quality of decisions can ...
Theories on group-bias often posit an internal preparedness to bias one’s cognition
to favor the in-group (often envisioned as a product of evolution). In contrast, other
theories suggest that group-biases can emerge from nonspecialized cognitive ...
Theories of the evolution of cooperation through reciprocity explain how unrelated
self-interested individuals can accomplish more together than they can on their own.
The most prominent theories of reciprocity, such as tit-for-tat or win-stay-lose-shift,
...
Multiagent learning is challenging when agents face mixed-motivation interactions,
where conflicts of interest arise as agents independently try to optimize their respective
outcomes. Recent advancements in evolutionary game theory have identified a class
...
In an era increasingly influenced by autonomous machines, it is only a matter of time
before strategic individual decisions that impact collective goods will also be made
virtually through the use of artificial delegates. Through a series of behavioral
...
This Week in PNAS
Inner Workings
QnAs
Retrospective
Ralph Holloway pioneered and developed the field of hominin paleoneurology. Although
Holloway’s undergraduate degrees were in metallurgical engineering and geology, at
graduate school his interests switched to the brain. Holloway and his graduate students
...
Commentaries
Letters
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Brief Report
We use crowd-sourced assessments from X’s Community Notes program to examine whether
there are partisan differences in the sharing of misleading information. Unlike previous
studies, misleadingness here is determined by agreement across a diverse ...
Physical Sciences
Applied Physical Sciences
Microscopic robots exhibit efficient locomotion in liquids by leveraging fluid dynamics
and chemical reactions to generate force asymmetry, thereby enabling critical applications
in photonics and biomedicine. However, achieving controllable locomotion of ...
Using machine learning (ML) to construct interatomic interactions and thus potential
energy surface (PES) has become a common strategy for materials design and simulations.
However, those current models of machine-learning interatomic potential (MLIP) ...
Despite over a century of studies, fundamental questions remain about the processes
governing crystal nucleation from melts or solutions. Research over the past three
decades has presented mounting evidence for kinetic pathways of crystal nucleation
that ...
Water molecules at the solid–liquid interface display intricate behaviors sensitive
to small changes. The presence of different interfacial components, such as cations
or functional groups, shapes the physical and chemical properties of the hydrogen-bond
...
Biophysics and Computational Biology
Circulating monocytes are recruited to the tumor microenvironment, where they can
differentiate into macrophages that mediate tumor progression. To reach the tumor
microenvironment, monocytes must first extravasate and migrate through the type-1
collagen ...
The surface layer or “S-layer” is a two-dimensional lattice of proteins that coats
a wide range of archaea and bacteria in place of a cell wall or capsular polysaccharides.
S-layers are thought to play an important role in chemically and physically ...
Chemistry
Protein–protein interactions (PPIs) are crucial for comprehending the molecular mechanisms
and signaling pathways underlying diverse biological processes and disease progression.
However, investigating PPIs involving membrane proteins is challenging due ...
Computer Sciences
In Shannon’s seminal paper, the entropy of printed English, treated as a stationary
stochastic process, was estimated to be roughly 1 bit per character. However, considered
as a means of communication, language differs considerably from its printed form:
...
As large language models (LLMs) become more widely used, people increasingly rely
on them to make or advise on moral decisions. Some researchers even propose using
LLMs as participants in psychology experiments. It is, therefore, important to understand
...
Earth, Atmospheric, and Planetary Sciences
The physics of the heat-trapping properties of CO were established in the mid-19th century, as fossil fuel burning rapidly increased
atmospheric CO levels. To date, however, research has not probed when climate change could have
been detected if ...
State-of-the-art ice sheet model simulations used in the Ice Sheet Model Intercomparison
Project (ISMIP) that informs the Intergovernmental Panel on Climate Change tend to
underestimate observed mass loss from the Greenland Ice Sheet, leading to the ...
Pure siderite [FeIICO3] was recently discovered in abundant quantities (4.8 to 10.5 wt.%) by the Curiosity
rover at Gale crater, Mars. Diagenetic alteration of siderite likely caused the carbonate-sequestered
CO2 to be released back into the atmosphere ...
Removing CO2 from the atmosphere is emerging as a viable strategy to mitigate global warming,
yet the responses of the climate system to CO2 reduction remain uncertain. One of the most uncertain aspects of El Niño behavior
is the change in periodicity in ...
Unraveling the origin(s) of carbon on Earth has remained challenging, not only because
of the multiple isotopic fractionation episodes that may have occurred during planet
formation processes but also because the end point of these processes, the current
...
We demonstrate a tripling in the frequency of planetary wave resonance events over
the past halfcentury, coinciding with the rise in persistent boreal summer weather
extremes. This increase aligns with changes in the underlying climate conditions favoring
...
Engineering
The vertical transport of solid material in a stratified medium is fundamental to
a number of environmental applications, with implications for the carbon cycle and
nutrient transport in marine ecosystems. In this work, we study the diffusion-limited
...
Physics
The thymus is one of the most important organs of the immune system. It is responsible
for both the production of T cells and the prevention of their autoimmunity. It comprises
two types of tissue: The cortex, where nascent T cells (thymocytes) are ...
The freezing of droplets on surfaces is closely relevant with various industrial processes
such as aviation, navigation, and transportation. Previous studies mainly focus on
physiochemically heterogeneous but electrically homogeneous surfaces, on which ...
A charge density wave (CDW) is a phase of matter characterized by a periodic modulation
of valence electron density coupled with lattice distortion. Its formation is closely
tied to the dynamical charge susceptibility, , which reflects the collective ...
Statistics
It is increasingly recognized that participation bias can pose problems for genetic
studies. Recently, to overcome the challenge that genetic information of nonparticipants
is unavailable, it is shown that by comparing the IBD (identity by descent) shared
...
Social Sciences
Anthropology
Determining how people behave in contexts governed by social norms can clarify both
how norms influence human behavior and how norms evolve. We examined cooperative farming
harvest division among the Derung, a Tibeto-Burman-speaking horticultural society
...
Political Sciences
Assessing model uncertainty is crucial to quantitative political science. Yet, most
available sensitivity analyses focus only on a few modeling choices, most notably
the covariate space, while neglecting to jointly consider several equally important
...
Psychological and Cognitive Sciences
As large language models (LLMs) become more widely used, people increasingly rely
on them to make or advise on moral decisions. Some researchers even propose using
LLMs as participants in psychology experiments. It is, therefore, important to understand
...
Regional collectivism has been observed to contribute to better coping with public
crises such as the COVID-19 pandemic. This study poses a reverse question: Does the
eruption of public crises increase people’s conformity to the collective? To answer
this ...
We investigate the hypothesis that family resemblance on school performance can be
fully explained by additive genetic effects and assortative mating. Our sample consists
of all schoolchildren who took Norwegian national standardized tests between 2007
...
Computational theories of reinforcement learning suggest that two families of algorithm—model-based
and model-free—tightly map onto the classic distinction between automatic and deliberate
systems of control: Deliberate evaluative responses are thought to ...
AI is increasingly replacing human decision-makers across domains. AI-based tools
have become particularly common in assessment decisions, such as when recruiting employees
or admitting students. Calls for transparency and new legislation require ...
Emerging theories in cognitive neuroscience propose a third brain pathway dedicated
to processing biological motion, alongside the established ventral and dorsal pathways.
However, its role in computing dynamic social signals for behavior remains ...
Biological Sciences
Biochemistry
Protein–protein interactions (PPIs) are crucial for comprehending the molecular mechanisms
and signaling pathways underlying diverse biological processes and disease progression.
However, investigating PPIs involving membrane proteins is challenging due ...
The nucleobase queuine (q) and its nucleoside queuosine (Q) are micronutrients derived
from bacteria that are acquired from the gut microbiome and/or diet in humans. Following
cellular uptake, Q is incorporated at the wobble base (position 34) of tRNAs ...
The host–microbiome interface is rich in metabolite exchanges and exquisitely sensitive
to diet. Hydrogen sulfide (H2S) is present at high concentrations at this interface and is a product of both microbial
and host metabolism. The mitochondrial enzyme, ...
Cellular senescence, an irreversible cell cycle arrest, plays a pivotal role in development,
aging, and tumor suppression. However, the fundamental pathway coordinating senescence
and neoplastic transformation remains unclear. Here, we describe the ...
Biophysics and Computational Biology
Mutations that impact splicing play a significant role in disease etiology but are
not fully understood. To characterize the impact of exonic variants on splicing in
71 clinically actionable disease genes in asymptomatic people, we analyzed 32,112
exonic ...
Cell Biology
Circulating monocytes are recruited to the tumor microenvironment, where they can
differentiate into macrophages that mediate tumor progression. To reach the tumor
microenvironment, monocytes must first extravasate and migrate through the type-1
collagen ...
The surface layer or “S-layer” is a two-dimensional lattice of proteins that coats
a wide range of archaea and bacteria in place of a cell wall or capsular polysaccharides.
S-layers are thought to play an important role in chemically and physically ...
Gonadotropin-releasing hormone receptor (GnRHR) is critical for reproductive health
and a key therapeutic target for endocrine disorders and hormone-responsive cancers.
Using high-resolution cryoelectron microscopy, we determined the structures of Sus ...
Neuroblastoma (NB) is a heterogeneous childhood cancer, characterized by the amplification
of the MYCN oncogene in 40% of the high-risk cases. Our previous work demonstrated that MYCN
drives metabolic reprogramming in NB, including upregulation of ...
Developmental Biology
During vertebrate development, the heart primarily arises from mesoderm, with crucial
contributions from cardiac neural crest (CdNC) cells that migrate to the heart and
form a variety of cardiovascular derivatives. Here, by integrating bulk and single
...
Ecology
Vertebrate scavengers play a critical role in ecosystem functioning worldwide. Through
the cascading effects of their ecological role, scavengers can also alleviate the
burden of zoonotic diseases on people. This importance to human health fuels a growing
...
Symbioses with microorganisms expand the genetic and metabolic repertoire of many
insects. The lac insect Kerria lacca (Hemiptera: Sternorrhyncha) is a phloem-feeding scale insect that is brightly colored
due to the presence of natural polyhydroxy-...
On shallow rocky and coral reefs, cultural and recreational values, like aesthetics,
are critical aspects of Nature’s Contributions to People (NCP) that support human
well-being and provide billions of dollars in tourism revenue. Quantifying the aesthetic
...
Evolution
A brief global warming event known as the Pre-Onset Excursion (POE) occurred just
before the Paleocene–Eocene Thermal Maximum (PETM, 56 Mya). The deconvolution of the
evolutionary consequences of these two hyperthermal events is puzzling because of
their ...
Isolated populations of postglacial relicts are known from many regions and are typically
found on mountains for terrestrial species and in lakes for aquatic species. Among
the few aquatic mammalian relicts, the Saimaa ringed seal (Pusa hispida saimensis) ...
Adaptation to novel environments requires genetic variation, but whether adaptation
typically acts upon preexisting genetic variation or must wait for new mutations remains
a fundamental question in evolutionary biology. Selection during domestication has
...
The evolutionary histories of many polyploid plant species are difficult to resolve
due to a complex interplay of hybridization, incomplete lineage sorting, and missing
diploid progenitors. In the case of octoploid strawberry with four subgenomes ...
Genetics
It is increasingly recognized that participation bias can pose problems for genetic
studies. Recently, to overcome the challenge that genetic information of nonparticipants
is unavailable, it is shown that by comparing the IBD (identity by descent) shared
...
Evolutionary adaptation to new environments likely results from a combination of selective
sweeps and polygenic shifts, depending on the genetic architecture of traits under
selection. While selective sweeps have been widely studied, polygenic responses ...
Protein structure–function relationships are critical for understanding molecular
mechanisms and the impacts of genetic variation. Mutational scanning approaches can
deliver scalable analysis, usually through the study of loss-of-function variants.
Rarer ...
Immunology and Inflammation
The thymus is one of the most important organs of the immune system. It is responsible
for both the production of T cells and the prevention of their autoimmunity. It comprises
two types of tissue: The cortex, where nascent T cells (thymocytes) are ...
Medical Sciences
The utility of a pure population of highly regenerative satellite stem cells (SSCs)
is a prerequisite for successful cell-based muscle therapies. Previous works have
reported several methods for the SSC isolation. However, the majority of cells isolated
...
Microbiology
Herpesviruses, including Epstein–Barr virus (EBV) – a human oncogenic virus and essential
trigger of multiple sclerosis – must bypass host DNA-sensing mechanisms to establish
lifelong, latent infection. Therefore, herpesviruses encode viral proteins to ...
How tick-borne pathogens interact with their hosts has been primarily studied in vertebrates
where disease is observed. Comparatively less is known about pathogen interactions
within the tick. Here, we report that Ixodes scapularis ticks infected with ...
Neisseria meningitidis is a human commensal bacterium that can opportunistically invade the bloodstream
and cross the blood–brain barrier, where it can cause septicemia and meningitis. These
diseases, if left untreated, can be lethal within hours. ...
Neuroscience
Emerging theories in cognitive neuroscience propose a third brain pathway dedicated
to processing biological motion, alongside the established ventral and dorsal pathways.
However, its role in computing dynamic social signals for behavior remains ...
Refinement of thalamic circuits is crucial for the proper maturation of sensory circuits.
In the visual system, this process is regulated by corticothalamic feedback during
the experience-dependent phase of development. Yet the cortical circuits ...
In multiple sclerosis (MS), cerebellar gray matter atrophy, white matter demyelination,
and Purkinje cell (PC) loss have been linked to tremors, impaired motor control, and
loss of coordination. Similar pathologies have been observed in the mouse model of
...
Pregnancy- and birth-related factors affect offspring brain development, emphasizing
the importance of early life exposures. While most previous studies have focused on
a few variables in isolation, here we investigated associations between a broad range
...
The gut microbiome has emerged as a key factor influencing a wide range of host physiological
processes and behaviors, though the mechanisms behind these effects remain only partially
understood. In this study, we explored the role of the gut microbiome ...
Physiology
Negative feedback of the cochlear efferent system plays a critical role in control
of hearing sensitivity and protection from noise trauma. Type II auditory nerves (ANs)
innervate outer hair cells (OHCs) in the cochlea and provide an input to the cochlear
...
Plant Biology
Iron (Fe) availability limits photosynthesis at a global scale where Fe-rich photosystem
(PS) I abundance is drastically reduced in Fe-poor environments. We used single-particle
cryoelectron microscopy to reveal a unique Fe starvation-dependent ...
Sustainability Science
Antarctic krill is a keystone species in the Antarctic marine ecosystem and the target
of a growing fishery. Given the ecological importance of krill, concerns have been
raised about potential negative impacts of fishing on the Southern Ocean ecosystem.
...
Corrections
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