Aphantasia challenges a centuries-old theory of abstract thought

Estonian Research Council

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Associate Professor of History of Philosophy Roomet Jakapi (left) and Associate Professor of Theoretical Philosophy Uku Tooming (right), University of Tartu. Photo: Ruth Jürjo / University of Tartu.

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Credit: Please credit: Ruth Jürjo / University of Tartu.

Aphantasia, the inability to form mental images, poses a serious challenge to an influential theory of abstract thought in the history of philosophy. The study by researchers at the University of Tartu suggests that mental imagery may play a less central role in human thought than has long been assumed and that the mind is more flexible in how it represents the world than many theories allow.

Most of us, when asked to think about triangles, dogs, or justice, spontaneously conjure up some kind of mental picture: a red triangle drawn on a blackboard, a scruffy terrier, a courtroom scene. The 18th-century Scottish philosopher David Hume believed this was not just a habit but a necessity. In his view, the mind cannot deal with pure abstractions directly and always needs a concrete mental image to work with first. To think about triangles in general, you must first picture a specific one. To think about justice, you must mentally replay some vivid scene of fairness or its violation.

But what about people who cannot form mental images at all? People with severe aphantasia draw a complete blank when asked to visualize a rainbow, picture a close friend's face, or imagine their childhood bedroom. There is simply nothing there. Yet they can reason about rainbows, recognize their friends, and reflect on their past. And they can engage with abstract concepts like geometry, morality, and mathematics just as well as anyone else.

In a paper published in Neuropsychologia, University of Tartu Associate Professor of Theoretical Philosophy Uku Tooming and Associate Professor of History of Philosophy Roomet Jakapi argue that aphantasia presents a direct challenge to Hume's theory, and to imagistic models of cognition more broadly. As Tooming puts it: “If abstract thought genuinely required mental imagery, people with aphantasia should struggle to think abstractly. They do not.”

 

How can abstract thought work without images?

The authors consider and reject several defences of the Humean account. One possibility is that aphantasics perform abstraction using imagery from non-visual modalities, for instance, by relying on auditory or tactile imagery rather than visual images. However, this is dismissed considering in light of the existence of multimodal aphantasics, who lack imagery across all sensory modalities.

Another defence appeals to involuntary imagery, suggesting that even if aphantasics cannot deliberately form images, they might still rely on imagery that arises spontaneously. This, too, is rejected on the grounds that the kind of imagery required for Humean abstraction is at least partially voluntary and that severe aphantasics lack such imagery. A further proposal invokes spatial imagery, such as a schematic sense of shape or arrangement without visual detail, for example, grasping the geometric relations of a triangle without picturing one. Yet this defence also fails because such spatial representations lack the sensory richness that Hume's account takes to be essential.

Finally, the suggestion that aphantasics could perform abstraction by means of language, for instance, by reasoning with the word “triangle” rather than an image, is rejected because the Humean framework requires imagery for understanding abstract concepts that are expressed in language.

The most compelling defence appeals to intact unconscious imagery in aphantasics. On this view, even if individuals cannot consciously visualize a rainbow or a triangle, they may still employ mental imagery unconsciously when engaging in abstract thought. The paper ultimately rejects this line of response as well, citing limited evidence for unconscious imagery in aphantasia and recent studies indicating an absence of imagery overall, both conscious and unconscious.

 

More than a philosophical exception

Finally, the paper addresses a metatheoretical response that treats aphantasia as a harmless exception. This approach suggests that Hume’s theory could still hold for most people, even if it does not apply to aphantasics. However, the authors argue that this fails because if aphantasics do not require imagery for abstract thinking, it has broader repercussions for understanding their cognitive processes generally. It would imply a radical difference between the psychology of aphantasics and non-aphantasics, which is highly implausible. Aphantasia, therefore, cannot be treated as a mere exception, but instead poses a substantive challenge to imagistic accounts of thought.

The findings have implications beyond the history of philosophy. Imagistic theories of cognition remain influential in contemporary cognitive science and philosophy of mind.

For further reading see “Aphantasia as a challenge for Humean abstraction”, Neuropsychologia.

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Journal

Neuropsychologia

DOI

10.1016/j.neuropsychologia.2026.109465 

Method of Research

Content analysis

Subject of Research

People

Article Title

Aphantasia as a challenge for Humean abstraction

Article Publication Date

3-Jul-2026

 

Rethinking the governance of human embryo model research

Insights from comparing Japan’s new guidelines with international standards

Institute for the Advanced Study of Human Biology (ASHBi), Kyoto University

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Background

Human embryo models can help researchers study early human development and infertility without relying solely on human embryos. As the technology advances, these models are becoming more complex and can be maintained in culture for longer periods. These developments have raised new questions about how such research should be regulated.

In 2025, the ISSCR revised its guidelines for human embryo model research. Japan followed with revisions to the “Guidelines on the Utilization of Human Embryonic Stem (ES) Cells” and the “Guidelines on Research on Producing Germ Cells from Human-Induced Pluripotent Stem (iPS) Cells or Human Tissue Stem Cells”, which came into effect in April 2026. The study examines why these changes were introduced, how the Japanese and ISSCR guidelines differ, and what challenges those differences may create for researchers and institutions.

Methods and Findings

Japan’s revised regulations brought all human embryo model research under a single oversight system. This included certain iPS cell-derived embryo model studies that had previously fallen into a regulatory gray area. As a result, all such research now requires ethics review and notification to the national government. The regulations also prohibit transfer into a human or animal uterus and organismal development, require researchers to define the minimum culture period needed for the research in advance, and call for research findings to be made publicly available.

The authors found that the Japanese and ISSCR guidelines are broadly aligned on many key issues. Both require specialized ethical and scientific review, prohibit uterine transfer and organismal development, and emphasize limiting culture periods to what is necessary for the research. However, they differ in how they define human embryo models and what types of research are covered. One notable difference concerns organoid research. The ISSCR guidelines classify some organoid models of human somitogenesis and body-axis formation as human embryo model research, while Japan’s guidelines continue to treat organoids and human embryo models as separate categories.

These differences may have practical consequences. Research that is not considered human embryo model research under Japan’s regulations may nevertheless be treated as such by international journals and scientific meetings. The authors discuss how researchers, ethics review committees, regulatory authorities, academic societies, and journals can help navigate these differences as expectations and regulations continue to evolve.

Outlook

Advances in human embryo model research are prompting changes in how the field is regulated. As countries revise their regulatory systems at different times and according to different policy approaches, new challenges are likely to emerge for researchers and institutions working across international contexts. Continued dialogue and sharing of experiences across countries will be important to support both scientific progress and public trust.

Researcher’s Comment

The idea for this study grew out of conversations with researchers working on human embryo models and our involvement in national discussions on how this research should be regulated. Differences between international and domestic rules can create practical challenges for researchers, ethics review committees, journals, and regulatory authorities. We hope this study helps bring those challenges into focus and encourages discussion among the people responsible for addressing them. Establishing new rules is only part of the challenge. Going forward, the focus will shift to how these rules are interpreted and applied in practice.

Glossary

Human embryo models (stem cell-based embryo models)

Research models created from human embryonic stem (ES) cells or human-induced pluripotent stem (iPS) cells that mimic some or all aspects of human embryonic development. Although distinct from embryos created through fertilization, they are used to investigate early developmental processes and the causes of infertility and miscarriage. They may also provide an alternative to the use of human embryos in research, which can be difficult because of ethical considerations.

Organoids

Three-dimensional cellular structures created from stem cells that replicate certain features of organs such as the brain, intestine, and liver in vitro. Unlike embryo models, which are designed to mimic early developmental processes, organoids are intended to model specific organs or tissues.

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Journal

Cell Stem Cell

Article Title

Human stem cell-based embryo model governance: Insights from Japan.

Article Publication Date

2-Jul-2026

 

Urbanicity, neighborhood conditions, and dementia mortality

JAMA Network Open

About The Study: 

In this cohort study, dementia mortality risk was greatest in mid-urbanicity and lower in dense urban cores and rural areas, and this gradient was largely attenuated by neighborhood conditions. These findings suggest that targeted improvements in modifiable neighborhood conditions may substantially reduce dementia mortality and advance equity, particularly in vulnerable communities.

Corresponding Author: To contact the corresponding author, Shujuan Chen, MS, email sc2343@cam.ac.uk.

To access the embargoed study: Visit our For The Media website at this link https://media.jamanetwork.com/

(doi:10.1001/jamanetworkopen.2026.21153)

Editor’s Note: Please see the article for additional information, including other authors, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.

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About JAMA Network Open: JAMA Network Open is an online-only open access general medical journal from the JAMA Network. On weekdays, the journal publishes peer-reviewed clinical research and commentary in more than 40 medical and health subject areas. Every article is free online from the day of publication.

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JAMA Network Open

 

The real effect of digital media on thinking and learning

Estonian Research Council

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The effort recalibration framework illustrates a choice between low-effort social media and a more demanding task, such as studying. Each option's subjective utility is based on expected reward minus effort cost, weighted by effort sensitivity. Because social media offers immediate rewards with little effort, it is chosen more often. Repeated selection increases effort sensitivity over time, making demanding tasks feel harder and further reinforcing preference for low-effort activities such as digital media consumption.

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Credit: Wisnu Wiradhany, Kristjan-Julius Laak

Imagine opening a difficult book in a quiet room. The first page is dense. You read one paragraph, then reread it. Nothing “clicks” yet. Your brain is doing what learning often requires: spending effort before the reward arrives. Then your phone lights up. One thumb movement, and the situation changes completely. A joke, a message, a clip, a tiny social reward: all available instantly, all requiring almost no effort. The book has not become harder and, definitely, your intelligence has not disappeared. But the book now feels more expensive, because another activity nearby offers a much better bargain: reward now, effort almost zero.

That is the central idea of the paper An Effort Recalibration Framework for Digital Media Use and Cognition that just appeared in Nature Human Behavior. It argues that the most important effect of social media might be that repeated exposure to effortless digital rewards changes how we value effort itself. Over time, the authors suggest, digital media may recalibrate our internal sense of what effort is worth. Difficult work then begins to feel less attractive, not because we can no longer do it, but because our everyday decision system has learned to expect faster returns.

This matters because public debate about smartphones and social media often swings between extremes. One side warns that screens are destroying attention, learning, and childhood. The other points out that the evidence is mixed, effect sizes are often small, and digital media can also support connection, creativity, learning, and political participation. The result is a frustrating argument: are phones harmful or not? Are teenagers addicted or just living in the world adults built for them? Are we distracted, multitasking, or morally panicking?

The paper proposes a way out of that debate. Instead of asking whether digital media simply reduce cognitive capacity, it asks how they may reshape the choices people make about where to invest their limited mental energy. 

Our brains are constantly weighing costs and benefits: Is this worth concentrating on? Should I persist? Should I switch? Should I keep reading, or check something easier? Digital platforms enter this weighing process with an attractive offer. Infinite scroll, notifications, algorithmic feeds, likes, and short videos reduce friction and deliver rapid, personalized rewards. They make exploration cheap.

The authors build their framework around the distinction between exploration and exploitation. Exploration means sampling the world: looking around, browsing, trying new sources, seeing what is out there. Exploitation means staying with something long enough to use it deeply: studying a chapter, practicing an instrument, solving a hard problem, writing a careful argument. Both are necessary. Exploration helps us discover possibilities; exploitation builds mastery. But learning often requires a painful transition: you must stop sampling and stay with one demanding thing before its rewards become visible.

The authors argue that digital media may tilt this balance. Digital media make exploration extraordinarily easy and frequently rewarding. A swipe brings novelty. A tap brings social feedback. A recommendation system anticipates what might hold you. The danger is that repeated low-effort reward loops may train the mind to abandon effortful tasks before their delayed benefits arrive.

One of the paper’s novel contributions is that it treats users as active agents. A smartphone can be used to read a long essay, write to a friend, learn a language, or organize collective action. The relevant issue is the effort-and-reward structure of the activity. Is the platform encouraging deliberate engagement or rapid sampling? Is it helping people pursue goals, or making goal-free switching feel constantly worthwhile?

A second contribution is that the framework explains why research findings can look inconsistent. In laboratory studies, people may perform perfectly well when asked to focus, especially if the task is structured and the stakes are clear. That does not mean nothing has changed in daily life. It may mean people can still summon effort when the context demands it. The problem may appear less as a measurable collapse in cognitive ability and more as a real-world change in when people choose to deploy that ability. In other words, the engine still works, but the driver increasingly takes the easier road.

A third contribution is the paper’s formal model. The authors describe effort recalibration as a value-based choice process: people compare the expected reward of an activity with its expected effort cost. Digital media often increase expected reward and lower effort cost. With repetition, the subjective weight of effort may increase, making demanding tasks feel less worthwhile in future choices. This model gives researchers something testable. It moves the discussion toward precise questions: Does repeated low-effort digital reward reduce persistence on later demanding tasks? Does it lower the threshold for switching? Who is most vulnerable? Can design changes reverse the pattern?

This paper provides a more humane and scientifically useful story about technology and the mind. It shows how environments teach us what to value. If our tools repeatedly teach us that reward should be immediate and effort should be minimal, we may gradually become less willing to endure the slow, awkward, effortful beginnings of understanding. The framework gives researchers, educators, designers, and policymakers a shared language for studying that possibility. Its central warning is simple: the future of cognition may depend not only on what information we consume, but on whether our daily environments still train us to find effort worthwhile.

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Journal

Nature Human Behaviour

DOI

10.1038/s41562-026-02500-w 

Method of Research

Literature review

Subject of Research

People

Article Title

An effort recalibration framework for digital media use and cognition

Article Publication Date

1-Jul-2026

New book examines how community coalitions work to alleviate digital inequality

University of Illinois School of Information Sciences

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Colin Rhinesmith, associate professor of information sciences at the University of Illinois, has authored a new book examining how community coalitions address digital inequality and strengthen democracy. Digital Equity Ecosystems: How Community Coalitions Reduce Inequality and Strengthen Democracy, published by University of California Press, introduces the concept of "digital equity ecosystems" to describe how community coalitions work to alleviate technological inequity and social injustice. 

The book is the first in-depth look at how cross-sector coalitions—led by local governments, philanthropic organizations, and community members—address information needs and opportunities. The coalitions' work includes environmental sustainability, featuring examples of technology refurbishers, who provide low-cost computers to individuals and families while keeping e-waste out of landfills. 

"This book is really about the groundswell of human activity, in the form of community coalitions, focused on helping people to meet their information and technology needs and to achieve their goals and aspirations using technology," Rhinesmith said. "It's a hopeful book filled with stories of everyday people doing impactful things with others in their community, particularly after realizing they could do more when working in coalitions."

Drawing on theories and concepts from information, communication, technology, and public health studies, Rhinesmith argues that understanding digital equity ecosystems—environments in which digital inclusion practices occur—is essential to addressing urgent digital inequalities. 

"The COVID-19 pandemic exposed the depth of the digital divide, which many people did not know existed until they saw individuals and families in their communities relying on internet access outside of closed schools and libraries," he said. "In response, there was a significant increase in the number of cross-sector coalitions working to help people gain access. I wrote this book to describe how these coalitions do this work not only to provide information access, but also to combat digital inequity and social injustice."

The book presents five case studies of digital equity ecosystems in Chicago, Illinois; Baltimore, Maryland; San Antonio, Texas; Essex County, Massachusetts; and Los Angeles County, California. Through these examples, Rhinesmith examines coalition development, community contexts, ecosystem threats, and ecosystem health, providing a framework for understanding how communities work together to advance digital equity.

Rhinesmith is an associate professor and director of the Digital Equity Action Research (DEAR) Lab in the School of Information Sciences at the University of Illinois Urbana-Champaign. His research contributes to the fields of community informatics, engaged scholarship, and information policy. Rhinesmith earned his PhD in library and information science from Illinois.

Persistent inequities in maternal and neonatal care and regional disparities are major factorsTexas A&M UniversityMessageWhatsAppEmailOver the decade from 2014 to 2023, Mexico’s infant death rate barely budged, suggesting the country hit a wall in saving babies’ lives—even as official paperwork claimed that almost all babies had a medical professional present when they died.That’s among the findings of a new study co-led by Genny Carrillo, MD, a children’s health expert with the Texas A&M University School of Public Health. She worked closely with colleagues from a Mexican hospital, university and national government agency to track what caused these deaths, where they happened and whether the families had access to medical care.“A child’s survival during the critical first year is a structural issue as well as a medical issue—it’s a direct reflection of how a healthcare system treats mothers and newborns,” Carrillo said. “We found that Mexico’s disorganized and disconnected healthcare system from 2014 to 2023 made improvements difficult.”

Study: Mexico’s infant mortality rates did not improve from 2014 to 2023

Persistent inequities in maternal and neonatal care and regional disparities are major factors

Texas A&M University

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Over the decade from 2014 to 2023, Mexico’s infant death rate barely budged, suggesting the country hit a wall in saving babies’ lives—even as official paperwork claimed that almost all babies had a medical professional present when they died.

That’s among the findings of a new study co-led by Genny Carrillo, MD, a children’s health expert with the Texas A&M University School of Public Health. She worked closely with colleagues from a Mexican hospital, university and national government agency to track what caused these deaths, where they happened and whether the families had access to medical care.

“A child’s survival during the critical first year is a structural issue as well as a medical issue—it’s a direct reflection of how a healthcare system treats mothers and newborns,” Carrillo said. “We found that Mexico’s disorganized and disconnected healthcare system from 2014 to 2023 made improvements difficult.”

A deep-rooted issue

The issues behind infant mortality in Mexico are complex and deep-rooted. For example, while the team found that the infant death rates overall were higher in rural areas, the rates in some cities were just as bad as, or even worse than, those in rural areas.

“This is largely because of ‘medical deserts’—poor, crowded or isolated neighborhoods that lack real access to care, even if there are large hospitals elsewhere in the city,” Carrillo said. “These neighborhood-level issues are not apparent when looking only at national averages or hospital counts.”

Digging into the data

For their retrospective study, the team analyzed the 224,212 deaths of infants under one year old in Mexico as recorded in a national database.

They compared the total number of infant deaths against the official number of live births each year to see how the death rate changed over time. They also looked at the medical codes listed on death certificates to identify the cause of each death and organized these causes into medical categories to help determine geographical patterns and which deaths might have been prevented with better, faster healthcare.

They included demographic factors, city of residence and social security insurance coverage (IMSS, Mexico’s main public health insurance, which is funded by workers, employers and the government to provide free medical care and typically has crowded facilities and long wait times).

In the case of infant deaths, they added whether a healthcare professional was present at the time of death, whether the infant died in a healthcare or other facility and whether an autopsy was performed.

“It’s important to remember that having a medical worker present at the time of death does not mean that the care provided was timely, of high quality or complete,” Carrillo said. “In some cases, the infant might be declared dead shortly after arrival, for example.”

Uncovering the gaps

To determine the yearly infant death rate, the team counted how many babies out of every 1,000 born alive died before their first birthday across the country and for each of Mexico’s 32 states from 2014 to 2023.

Their analysis revealed several key findings:

• Male infants accounted for a higher proportion of deaths than female infants. This pattern persisted after accounting for differences in the number of live births by sex and was steady consistently across years and across most causes of death.
• Most baby deaths occurred during the first month of life (the neonatal period) or right around birth (the perinatal period) and were caused by premature births, blood infections and other conditions affecting newborns. This suggests that many deaths could have been prevented with more medical attention during pregnancy, the delivery or right after birth.
• Babies in rural areas fared worse. Infants in smaller, rural towns had less access to medical care at the time of death and were far less likely to receive an autopsy. On the other hand, several smaller states did a better job of providing medical care at the time of death and performing autopsies than Mexico City.
• Autopsies in rural areas were less accurate. In smaller towns, infant deaths were more likely to be attributed to vague “external causes,” which suggests dangerous environments as well as inconsistent medical investigations.
• Health insurance does not guarantee quality care. More pregnant women had health insurance, but poor and vulnerable populations, such as Indigenous women, still face major structural barriers and discrimination that results in inferior medical treatment.
• Better reporting. Doctors or medical staff reported attending to 99.5% of infant deaths by 2023—a major statistical increase from earlier years—but because the overall infant death rate did not go down, this likely resulted from changes in government modifications in paperwork and administrative processes.

“Infant death rates did not change based on the season or weather, indicating that babies were not dying simply because of short-term seasonal temperature spikes or flu outbreaks,” Carrillo said. “The main culprits are structural problems like poverty and broken healthcare systems.”

She added that real progress requires deep investments to improve the quality of care, better coordination between different clinics and honest investigations into why babies die.

The research team suggested that Mexico should follow the lead of several countries in South Asia and sub-Saharan Africa in lowering infant death rates through a chain of medical care that starts with early pregnancy checkups, moves through safe delivery and continues with support for the newborn.

Their study was published in Sage Open Pediatrics and was supported by IMSS-BIENESTAR, the Mexican Social Security Institute for Well-being.

Others involved in the study were Nina Mendez-Dominguez, MD, PhD, with the Regional Specialty Hospital of the Yucatan Peninsula; Hugo Azcorra, PhD, with Modelo University; and Amonario Olivera-Mar, PhD, and Adrian Perez-Navarrete, MD, with Mexico’s General Directorate of Health Education.

By Ann Kellett, Texas A&M University School of Public Health

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Journal

Sage Open Pediatrics

DOI

10.1177/30502225261451592 

Article Title

Mapping Infant Mortality Inequities in Mexico: Ten Years (2014-2023) of Individual and Population Level Challenges

 

Prize winner’s research reveals microbiota’s hidden role in in mosquito-borne disease

Summary author: Walter Beckwith

American Association for the Advancement of Science (AAAS)

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For his work in revealing the hidden role of the microbiota in mosquito-borne disease, Yibin Zhu is the winner of the 2026 Noster NOSTER & Science Microbiome Prize. The work shows how microbiota from both the hosts and vectors can either promote or suppress virus transmission, depending on where they act in the transmission cycle. “Pathogens have taught us many of the foundational principles of infectious disease. Yet my work has convinced me that some of the most powerful regulators of transmission are neither pathogens nor hosts but the microbial communities that inhabit them,” writes the author. Mosquito-borne diseases, such as malaria and dengue, arise through interactions among viruses, hosts, mosquitoes, and their environments. While microbiota are known to affect host immunity and physiology, research has traditionally focused on viruses or mosquito vectors, overlooking the microbes that connect them. Zhu’s work aims to fill this gap by investigating how microbes influence multiple stages of the disease transmission cycle, including mosquito attraction to infected hosts and viral infection within mosquitoes.

 

Zhu and his colleagues’ research has found that in infected hosts, viral infection altered the skin immune environment, suppressing the antimicrobial peptide RELMα and allowing acetophenone-producing skin bacteria to expand. Increased acetophenone production made infected hosts more attractive to mosquitoes, potentially enhancing virus transmission. In mosquitoes, a naturally occurring bacterial symbiont, Rosenbergiella_YN46, strongly reduced dengue and Zika virus infection in both disease-carrying Aedes aegypti and Aedes albopictus mosquito species. After blood feeding, the bacterium secreted an enzyme that acidified the mosquito gut, prematurely triggering irreversible changes in viral envelope proteins and rendering the viruses noninfectious. The symbiote microbe imposed no detectable fitness cost on mosquitoes and was more abundant in regions with lower dengue incidence. “Understanding this invisible hand of the microbiota may help us rethink how vector-borne diseases emerge and how they might finally be controlled,” Zhu writes.

 

Finalists for the prize were Erik Bakkeren for his essay “Ecology of the gut microbiome: microbial competition can be harnessed to prevent and cure deadly diseases,” and Taichi Suzuki for his essay “The missing thriftiness: host-microbial coevolution and its influence on human health.”

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Journal

Science

DOI

10.1126/science.aej2364 

Article Title

The invisible hand

Article Publication Date

2-Jul-2026