Category: Academic Reportage

Source: The Conversation – USA – By Andrea Katz, Associate Professor of Law, Washington University in St. Louis

If you’re confused about what the law does and doesn’t allow the president to do with the National Guard, that’s understandable.

As National Guard troops landed in Portland, Oregon, in late September 2025, the state’s lawyers argued that the deployment was a “direct intrusion on its sovereign police power.”

Days before, President Donald Trump, calling the city “a war zone,” had invoked a federal law allowing the government to call up the Guard during national emergencies or when state authorities cannot maintain order.

The conflict throws into relief a question as old as the Constitution itself: Where does federal power end and state authority begin?

One answer seems to appear in the 10th Amendment’s straightforward language: “The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.” This text is considered to be the constitutional “hook” for federalism in our democracy.

The founders, responding to anti-Federalist anxieties about an overbearing central government, added this language to emphasize that the new government possessed only limited powers. Everything else – including the broad “police power” to regulate health, safety, morals and general welfare – remained with the states.

Yet from the beginning, the text has generated plenty of confusion. Is the 10th Amendment merely a “truism,” as Justice Harlan Fiske Stone wrote in 1941 in United States v. Darby, restating the Constitution’s structure of limited powers? Or does it describe concrete powers held by the states?

Turns out, there’s no simple answer, not even from the nation’s highest court. Over the years, the Supreme Court has treated the 10th Amendment like the proverbial magician’s hat, sometimes pulling robust state powers from its depths, other times finding it empty.

10th Amendment’s broad range

The arguments over the 10th Amendment for almost 200 years have applied not only to the National Guard but to questions about how the federal and state governments share powers over everything from taxation to government salaries, law enforcement and regulation of the economy.

For much of the 19th century, the 10th Amendment remained dormant. The federal government’s weakness and limited ambitions, especially on the slavery question, meant that boundaries were rarely tested before the courts.

The New Deal era brought this equilibrium crashing down.

The Supreme Court initially resisted the expansion of federal power, striking down laws banning child labor in Hammer v. Dagenhart in 1918, setting a federal minimum wage in 1923 in Adkins v. Children’s Hospital, and offering farmers subsidies in U.S. v. Butler in 1937. All these decisions were based on the 10th Amendment.

But this resistance wore down in the face of economic crisis and political pressure. By the time of the Darby case in 1941, which concerned the Fair Labor Standards Act and Congress’ power to regulate many aspects of employment, the court had relegated the 10th Amendment to “truism” status: The Amendment, wrote Stone, did nothing more than restate the relationship between the national and state governments as it had been established by the Constitution before the amendment.

The 1970s marked an unexpected revival. In the 1976 decision in National League of Cities v. Usery, a dispute over whether Congress could directly exercise control over minimum wage and overtime pay for state and local government employees, the court held that Congress could not use its commerce power to regulate state governments.

But that principle was abandoned nine years later, with the court doubling back on its position. Now, if the states wanted protection from federal overreach, they would have to seek it through the political process, not judicial intervention.

Yet less than a decade later, the court reversed course again. The modern federalism renaissance began in the ’90s with a pair of divided opinions stating that the federal government cannot force the states to enforce federal regulatory programs: this was the “anti-commandeering principle.”

The 10th Amendment’s meandering path

In recent decades, the court, led by Chief Justice John Roberts, has invoked the amendment to protect state power in varied, even surprising contexts: states’ entitlement to federal Medicaid spending; state authority over running elections, despite patterns of voter exclusion; even legalization of sports gambling.

On the other hand, in 2024, Colorado was barred by the court from excluding Trump from the presidential ballot as part of its power to administer elections.

That brings us back to the present, where Trump has deployed National Guard troops to Los Angeles to quell protests against immigration enforcement, and bids to send them to Portland and Chicago as well.

From the point of view of federalism, two factors lend this conflict some constitutional complexity.

One is the National Guard’s dual state-federal character. Most Guard mobilizations, including disaster relief, take place under Title 32 of the U.S. Code, which maintains state control of troops with federal funding.

By contrast, Title 10 allows the president to assert federal control over Guard units in case of “a rebellion or danger of a rebellion” against the government or where “the President is unable with the regular forces to execute the laws of the United States.”

The other factor is political.

Since World War II, the National Guard has been deployed only 10 times by presidents, mostly in support of racial desegregation and the protection of civil rights. All but one of these mobilizations came at the governor’s request – the lone exception, pre-Trump, being President Dwight Eisenhower’s 1957 mobilization of the Arkansas National Guard to desegregate schools in Little Rock over the wishes of Gov. Orval Faubus.

In sharp contrast, Trump has now attempted three times to send troops to large cities over the explicit objection of Democratic governors. Such is the case in Portland.

National Guard deployments and constitutional stakes

Oregon’s lawsuit argues that there is no national emergency in the city, and that deploying Guard troops to the state without Gov. Tina Kotek’s consent – indeed, over her explicit objection – and absent the extraordinary circumstances that might justify Title 10 federalization, is illegal. The National Guard, asserts the lawsuit, remains a state institution that federal authorities cannot commandeer.

The two deployments, in Oregon and Illinois, are making their way through the federal courts, and the Trump administration has asked the Supreme Court to intervene to authorize the deployments. What the court will do, if the cases reach it, is uncertain. Roberts has proved willing to invoke state sovereignty in some contexts while rejecting it in others.

For now, the court has upheld several Trump administration actions while constraining others, suggesting a jurisprudence driven more by specific contexts than categorical rules.

Whether Oregon’s challenge succeeds may depend less on the long and changing history of 10th Amendment doctrine than on how the court views immigration enforcement, presidential authority and the consequences of Trump’s frequent invocations of emergency power for American democracy.

Andrea Katz does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Trump’s National Guard deployments reignite 200-year-old legal debate over state vs. federal power – https://theconversation.com/trumps-national-guard-deployments-reignite-200-year-old-legal-debate-over-state-vs-federal-power-267259

Source: The Conversation – USA – By David W. Lawson, Professor of Anthropology, University of California, Santa Barbara

In July 2025, Uganda’s courts swiftly dismissed a petition challenging the legality of polygamy, citing the protection of religious and cultural freedom. For most social scientists and policymakers who have long declared polygamy a “harmful cultural practice,” the decision was a frustrating but predictable setback in efforts to build healthier and more equal societies.

In the vast majority of cases, polygamy takes the form of one husband and multiple wives – more precisely referred to as polygyny, originating from the Greek words “poly” (“many”) and “gynē” (“woman or wife”). The opposite arrangement of one wife and multiple husbands is referred to as polyandry (from “anēr” meaning “man” or “husband”) and is exceedingly rare worldwide.

Critics of polygyny present two main arguments. First, they contend it squeezes low-status men out of the marriage market, fostering social unrest, crime and violence against women by frustrated unwed men. Second, it harms women and children by dividing limited resources among more dependents.

This logic has led leading political scientist Rose McDermott to describe polygyny as evil. Other researchers, such as anthropologist Joseph Henrich, even go as far as to credit Christianity’s derision of polygyny as a driving force of Western prosperity.

However, a trio of new studies, all relying on the highest standards of data analysis, contend that these arguments are misguided.

I have spent my career working at the intersection of anthropology and global health, researching how and why family structure varies – and what this diversity means for human well-being. Much of this work has been carried out with colleagues in Tanzania where, like Uganda, polygyny is relatively common. This new wave of work underscores the value of our research, effectively demonstrating that good intentions and intuition are no substitute for cultural sensitivity and evidence.

Does polygyny lock men out of marriage?

A new study published in October 2025 in the Proceedings of the National Academy of Sciences presents the first comprehensive, large-scale analysis of polygyny and men’s marriage prospects. The project is a collaboration between demographer Hampton Gaddy and evolutionary anthropologists Rebecca Sear and Laura Fortunato.

The researchers drew on demographic modeling and an extraordinary trove of census data – over 84 million records from 30 countries in Africa, Asia and Oceania, plus the entire U.S. census from 1880, when polygyny was practiced in some American communities. They demonstrate that polygyny does not lock large numbers of men out of marriage. In fact, in many contexts, men are actually more likely to marry where polygyny is common than where it is rare.

The narrative that polygyny leads to lonely bachelors is intuitive. In a community with equal numbers of men and women, if one man marries two wives, then another man must remain unmarried. Expand that across a whole society, and polygyny looks like a recipe for an army of resentful, single men.

Parallel arguments have been made about the rise of incel – a portmanteau of “involuntary” and “celibate” – subcultures within monogamous nations, including the U.S. Here, the argument is that high-status men leave low-status men sexless and frustrated, ultimately leading to violence.

The trouble is that real demography is not so simple. Women typically live longer than men, men frequently marry younger women, and populations in many parts of the world are growing, ensuring younger spouses are available for older cohorts. These factors, which are characteristic of many contemporary African nations, tilt the marriage market toward a surplus of women. Under many realistic conditions, a sizable proportion of men can have multiple wives without leaving their peers out in the cold.

In fact, in nearly half of the countries examined, higher rates of polygyny were associated with fewer, not more, unmarried men. Only a handful of countries showed the expected positive relationship, and even then inconsistently over time.

The case of historical Mormon communities in North America is equally revealing. When the researchers compared counties with documented Mormon polygyny to others in the 1880 census, they found lower rates of unmarried men in polygynous areas. Gaddy and his colleagues contend that this is explained by the tendency for cultural norms that favor polygyny to also be relatively pronatalist, driving marriage rates upward for all.

Do women and children get a smaller share?

What about the argument that polygyny harms women and children by dividing male-owned wealth among more mouths to feed? There certainly are studies that have demonstrated associations between polygyny and poor health. But another line of thinking argues that correlation should not be equated with causation.

Ten years ago, my colleages and I documented that polygyny is associated with higher food insecurity and poor child health when comparing outcomes across over 50 Tanzanian villages. However, this pattern was an artifact of polygyny being most common in marginalized Maasai communities, which tend to live in drought-prone areas with inadequate health care. Moreover, when comparing families within communities, polygynous households were typically wealthier, a key factor in making polygyny attractive to women, and children were not disadvantaged.

Echoing these results, anthropologist Riana Minocher and her colleagues recently published a study that uses a detailed, longitudinal dataset from a 20-year prospective study in another region of Tanzania. Analyzing survival, growth and education for thousands of children, they found no evidence that monogamous marriage is advantageous.

Together, these results support a theory known as the polygyny threshold model. Simply put, provided women have choice in marriage, sharing a husband is unlikely to be economically detrimental, since they will prioritize marrying men with sufficient wealth to offset any cost. This scenario may not fit all contexts, but these studies clearly undercut claims that polygyny is unequivocally harmful.

Hidden advantages of polygyny

Another recent study, published in August 2025 by economist Sylvain Dessy and his colleagues, goes further, suggesting that polygyny has unrecognized advantages when times are tough.

Drawing on crop yield data from over 4,000 farm households across Mali, census data on marriage patterns and detailed meteorological records, they found that in villages where polygyny is rare, droughts cut harvests dramatically. But in villages where polygyny is common, that blow is softened.

The researchers argue that polygynous marriage, by increasing the number of in-laws, creates stronger networks of social support. Furthermore, with wives often coming from different villages and regions, extended kin are well positioned to send food, money or labor when local crops fail. Such support helps to explain both the resilience of polygynous communities during drought and the continued endurance of the marriage practice from one generation to the next.

So, is polygyny harmless?

These studies don’t mean that polygyny is harmless. Indeed, allowing men but not women to have multiple spouses is clearly unequal and entwined with patriarchal ideology that positions women as subordinate or inferior to men. Recent studies, for example, have suggested that polygynous marriages are more prone to intimate partner violence.

In short, there remain multiple ways polygyny can be harmful.

Nevertheless, the best evidence suggests that polygyny is unlikely to be a root cause of social unrest. Moreover, within wider patriarchal systems that afford few women, regardless of marital status, economic and social security, polygyny may not just be a tolerable choice but in some contexts a preferred arrangement with tangible benefits for both genders.

Simplistic stories about the dangers of polygyny can be compelling and intuitive, but they risk misleading the public, reinforcing stubborn notions of Western cultural superiority and disrupting effective global health policy by sidelining more pertinent initiatives. Building healthier societies necessitates paying attention to the evidence and remaining open to the possibility that all family structures have capacity to cause harm.

David W. Lawson does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Rethinking polygamy – new research upends conventional thinking about the advantages of monogamous marriage – https://theconversation.com/rethinking-polygamy-new-research-upends-conventional-thinking-about-the-advantages-of-monogamous-marriage-267201

Source: The Conversation – USA – By Taylor Lonner, Ph.D. Candidate in Aerospace Engineering, University of Colorado Boulder

When learning about the effects of spaceflight on human health, you typically will hear about the dangers of radiation, bone density loss and changes in eyesight. While these long-term risks are important, a less frequently discussed concern is motion sickness.

As a child, one of us (Taylor) was highly prone to motion sickness – whether in the backseat of a car, sitting on a train or riding a bus. At the time, she considered it a cruel twist of fate, but as an adult – and a scientist to boot – Taylor can tell you with confidence that it was entirely her fault.

You see, like most children during long car rides, Taylor would get bored. So, to combat this boredom, she would either read a book or play on her Gameboy. She would stare down at whatever form of entertainment was in her lap that day until the familiar creeping sensation of nausea developed.

Sometimes, looking out the side window would help, but more often than not, Taylor’s dad would have to pull over at the next gas station for a short break, or else they’d all suffer the consequences.

Now, she understands what was happening on a more fundamental level. As children, you are taught about the five senses: sight, hearing, smell, taste and touch. However, there is a hidden sixth sense that helps your body understand how you are moving – the vestibular system. The brain takes information from all these senses and compares it to what it might expect when moving, based on past experiences.

Optimally, any disagreement between your vestibular senses and your brain’s expectations would be small. But when there are large, sustained conflicts, you get sick.

While reading in the car, Taylor was staring at nonmoving words on a page while her vestibular system told her brain she was traveling down a road. This discrepancy confused her brain since usually, when Taylor felt movement, she should see the world shifting around her in the same way – hence her motion sickness. Had she been looking out the window and watching the world pass by, she would have been fine. Even better, had she been in the front seat, she would have been able to see the road ahead and predict how she would move in the future.

The sensory conflict between what you experience and what your brain expects doesn’t cause only carsickness. It is also the leading suspect behind cybersickness from using virtual reality headsets, seasickness on ships and spaceflight-driven motion sickness. Our team of aerospace engineers is particularly interested in the latter.

Motion sickness during spaceflight

To date, all astronauts have grown up on Earth. So, their brains expect any motion cues to include the presence of Earth’s gravity. But when they get to orbit in space, that is no longer the case.

When in orbit around Earth in microgravity, the vestibular system does not have any gravitational input. The conflict between the brain’s expectation of Earth’s gravity and the reality of no gravity causes space motion sickness.

Thankfully, the brain’s expectations can change over time, after enough exposure to a new environment. Often referred to as “getting your sea legs” in the nautical community, astronauts also eventually overcome space motion sickness while in space. However, overcoming it introduces another problem when they return.

If an astronaut’s brain expects microgravity, what happens when they come back to Earth? As you might expect, the process starts again, and astronauts are now prone to terrestrial readaptation motion sickness. To make matters worse, since the retirement of the space shuttle, crew vehicles frequently land in the water, which means astronauts may deal with choppy waves until their capsule is recovered. Seasickness can potentially exacerbate terrestrial readaptation motion sickness.

These conditions are not rare. Over half of all astronauts experience some symptoms of space motion sickness when they first get to space, and terrestrial readaptation motion sickness occurs at a similar incidence rate when they come back down.

Dangers to astronauts

If you have ever experienced motion sickness, you know how hard it is to do anything other than close your eyes and take deep breaths to expel the creeping urge to vomit. As a passenger in a car, that may be OK, since you aren’t expected to jump into action at a moment’s notice. But while isolated on the water in a return capsule, astronauts need to remain focused and clearheaded. In case of an emergency, they’ll need to respond rapidly.

If the astronauts need to get out of the capsule prior to pickup up by the recovery team, any motion sickness they have could delay their response time and impede evacuation attempts.

Potential solutions

Presently, most astronauts rely on medication that interrupts the brain’s ability to use hormones to trigger motion sickness. However, as with many commercial products, these drugs can cause side effects such as drowsiness and can lose efficacy over time.

Our research team completed two experiments to investigate how we might be able to manipulate visual information to mitigate motion sickness in astronauts, without relying on pharmaceuticals.

Our participants were exposed to motions meant to simulate transitions between gravity environments and then ocean wavelike motion. During the hour of wavelike motion, we investigated whether a “virtual window” could reduce the incidence of motion sickness.

When in a capsule on the ocean, astronauts are strapped into their seats and likely cannot see out of the small windows built into the capsule. In place of windows, we used virtual reality headsets to create a full-view virtual window.

In our control group, the subjects received no visual cues of motion – akin to Taylor’s poorly advised backseat reading. Meanwhile, one countermeasure group got to see a visual scene that moved naturally with their motion, like looking out the side window of the car at the surrounding world. The other countermeasure group saw a scene that moved appropriately and was provided an overlay showing future motion, like looking out the front window and seeing the road ahead.

As expected, the group with no cues of motion got the sickest. Two-thirds of the subjects needed to stop prior to finishing an hour of wavelike motion, due to excessive nausea. Only about one-fifth of the group that was given the side window view needed to stop early. Only one-tenth of the front window group that received present and future visual cues dropped out.

These results mean that by tracking the capsule motion and projecting it on a headset for the astronauts inside, our team may be able to reduce debilitating motion sickness by roughly half. If we could figure out how to predict how the capsule would move, we could give them that front window experience and improve the landing even more. In case of emergency, they could always take off the headsets.

This work shows promise for motion sickness interventions that do not rely on pharmaceuticals, which are currently used to combat these effects. Our solutions don’t have the same concerns around shelf life, stability or side effects. In addition to the benefits for astronauts, such approaches could help those prone to motion sickness here on Earth, particularly in scenarios where looking out the front window at the road isn’t feasible, such as on planes, trains, buses or high-speed transportation.

This work was supported by the National Aeronautics and Space Administration Human Research Program under Grant No. 80NSSC21K0257.

Torin Clark receives funding from NASA, the Office of Naval Research and the National Institutes for Health, and he receives fellowships from the Charles Stark Draper Laboratory and the National Science Foundation.

– ref. Astronauts can get motion sick while splashing back down to Earth – virtual reality headsets could help them stay sharp – https://theconversation.com/astronauts-can-get-motion-sick-while-splashing-back-down-to-earth-virtual-reality-headsets-could-help-them-stay-sharp-263706

Source: The Conversation – USA – By James Higgins, Professor of Aviation, University of North Dakota

Approximately 185,000 people have died in civilian aviation accidents since the advent of powered flight over a century ago. However, over the past five years among the U.S. airlines, the risk of dying was almost zero. In fact, you have a much better chance of winning most lotteries than you do of dying as a passenger on a U.S. air carrier.

How did flying get so safe? And can we apply the hard-earned safety lessons from aviation to artificial intelligence?

When humanity introduces a new paradigm-shifting technology and that technology is rapidly adopted globally, the future consequences are unknown and often collectively feared. The introduction of powered flight in 1903 by the Wright brothers was no exception. There were many objections to this new technology, including religious, political and technical concerns.

It wasn’t long after powered flight was introduced that the first airplane accident occurred – and by not long I mean the same day. It happened on the Wright brothers’ fourth flight. The first person to die in an aircraft accident was killed five years later in 1908. Since then, there have been over 89,000 airplane accidents globally.

I’m a researcher who studies air travel safety, and I see how today’s AI industry resembles the early – and decidedly less safe – years of the aviation industry.

From studying accidents to predicting them

Although tragic, each accident and each fatality represented a moment for reflection and learning. Accident investigators attempted to recreate every accident and identify accident precursors and root causes. Once investigators identified what led up to each crash, aircraft makers and operators put safety measures into effect in hopes of preventing additional accidents.

For example, if a pilot in the earlier era of flight forgot to lower the landing gear prior to landing, a landing accident was the likely result. So the industry figured out to install warning systems that would alert pilots about the unsafe state of the landing gear – a lesson learned only after accidents. This reactive process, while necessary, is a heavy price to pay to learn how to improve safety.

Over the course of the 20th century, the aviation world organized and standardized its operations, procedures and processes. In 1938, President Franklin Roosevelt signed the Civil Aeronautics Act, which established the Civil Aeronautics Authority. This precursor to the Federal Aviation Administration included an Air Safety Board.

The fully reactive safety paradigm shifted over time to proactive and eventually predictive. In 1997, a group of industry, labor and government aviation organizations formed a group called the Commercial Aviation Safety Team. They started to look at the data and attempted to find trends and analyze user reports to identify risks and hazards before they became full-blown accidents.

The group, which includes the FAA and NASA, decided early on that there would be no competition among airlines when it came to safety. The industry would openly share safety data. When was the last time you saw an airline advertising campaign claiming “our airline is safer than theirs”?

It’s down to data

The Commercial Aviation Safety Team helped the industry transition from reactive to predictive by adopting a data-driven, systemic approach to tackling safety issues. It generated this data using reports from people and data from aircraft.

Every day, millions of flights occur worldwide, and on every single one of those flights, thousands of data points are recorded. Aviation safety professionals now use Flight Data Recorders – long used to investigate accidents after the fact – to analyze data from every flight. By closely examining all this data, safety analysts can spot emerging and troublesome events and trends. For example, by analyzing the data, a trained safety scientist can spot if certain aircraft approaches to runways are becoming riskier due to factors like excessive airspeed and poor alignment – before a landing accident occurs.

To further increase proactive and predictive capabilities, anyone who operates within the aviation system can submit anonymous and nonpunitive safety reports. Without guarantees of anonymity, people might hesitate to report issues, and the aviation industry would miss crucial safety-related information.

All of this data is stored, aggregated and analyzed by safety scientists, who look at the overall system and try to find accident precursors before they lead to accidents. The risk of dying as a passenger onboard a U.S. airline is now less than 1 in 98 million. You are more likely to die on your drive to the airport than in an aircraft accident. Now, more than 100 years since the advent of powered flight, the aviation industry – after learning hard lessons – has become extremely safe.

A model for AI

AI is rapidly permeating many facets of life, from self-driving cars to criminal justice actions and hiring and loan decisions. The technology is far from foolproof, however, and errors attributable to AI have had life-altering – and in some cases even life-and-death – consequences.

Nearly all AI companies are trying to implement some safety measures. But they appear to be making these efforts individually, just like the early players in the aviation field did. And these efforts are largely reactive, waiting for AI to make a mistake and then acting.

What if there was a group like the Commercial Aviation Safety Team where all AI companies, regulators, academia and other interested parties convened to start the proactive and predictive processes of ensuring AI doesn’t lead to calamities?

From a reporting perspective, imagine if every AI interface had a report button that a user could click to not only report potentially hallucinated and unsafe results to each company, but also report the same to an AI organization modeled on the Commercial Aviation Safety Team. In addition, data generated by AI systems, much like we see in aviation, could also be collected, aggregated and analyzed for safety threats.

Although this approach may not be the ultimate solution to preventing harm from AI, if Big Tech adopts lessons learned from other high-consequence industries like aviation, it just might learn to regulate, control and, yes, make AI safer for all to use.

James Higgins receives funding from the FAA to conduct research regarding flight safety topics. He is also the co-founder of two companies, one is HubEdge, which is a company that helps airlines optimize their ground operations. The other is Thread, which helps utilities operate drones to collect information about their assets.

– ref. Flying is safe thanks to data and cooperation – here’s what the AI industry could learn from airlines on safety – https://theconversation.com/flying-is-safe-thanks-to-data-and-cooperation-heres-what-the-ai-industry-could-learn-from-airlines-on-safety-265960

Source: The Conversation – USA (2) – By Shannon Pruden, Professor of psychology, Florida International University

What do puzzles, gymnastics, writing and using maps all have in common?

They all rely on people’s ability to visualize objects as they spin, flip or turn in space, without physically moving them. This is a spatial skill that developmental psychologists call mental rotation.

Whether a person is navigating a new city or doing a cartwheel, they must use mental rotation skills to move shapes or objects in their mind and make sense of where their bodies are going and what surrounds them.

When children play with puzzles, building blocks or pattern games, they are also practicing mental rotation.

Over time, these skills support learning in math, science and reading. This can look like visualizing pulley systems in physics or seeing the differences between similar-looking letters such as b and d, which young children often confuse.

Strong mental rotation skills also lay the foundation for doing well in school and developing interest in careers in science, technology, engineering and math.

Most preschool-age children are not yet learning to read – but it turns out they are still using some of these same spatial reasoning skills as they think about the world around them.

We are scholars of, developmental science and were curious to find out how children as young as 3 years old mentally rotate objects.

While there is research on the age at which children can mentally rotate objects, less is understood about how children are solving mental rotation problems. We found in our research, conducted from 2022 to 2023, that young children are using the same problem-solving strategies as adults when they solve a mental rotation task.

Children think visually, just like adults

We used eye-tracking technology to understand how a sample of 148 children, all between 3 and 7 years old, solved different mental rotation problems. Eye-trackers use harmless infrared light to capture eye movements. This technology lets us observe how children solve these problems in real time.

As part of our study, we showed each child a large picture of items such as a fire truck, as well as two smaller pictures of the same truck, one placed above the other and positioned slightly differently.

Children were asked to say which small picture on the right matched the large one on the left. In this example, the correct answer is the top picture, because that top fire truck can be rotated to match the large fire truck. The bottom fire truck was a mirrored image, and no matter how much you rotate it, it will never match the large fire truck.

While the children thought about their response, the eye-tracker, mounted right below the computer screen, recorded their eye movements.

By looking at where and for how long children looked at each image, we figured out what kind of strategy they were using.

Some children focused on fewer parts of the object and spent less time studying its details. This suggests they used a holistic strategy, meaning they took in the whole image at once, instead of breaking it into pieces. These children mentally rotated the entire object to solve the task.

Other children focused on parts of the object and spent more time studying its details. This suggests they broke the image down into pieces instead of visualizing the image as a whole, known as a piecemeal strategy. Our findings support prior work showing that children generally use these two visual approaches to solve mental rotation problems.

This study helped us learn where children look while solving puzzles and identify how they solve these problems – without ever having to ask the child, who might be too young to explain, about their process.

Children were more likely to turn the whole image instead of breaking it down into pieces, a pattern of problem solving adults typically also use. This means that even very young children are already thinking about how objects move and turn in space in ways that are more advanced than expected.

Supporting children’s visual skills

Knowing how young children mentally rotate objects may help researchers, teachers and parents understand why some children struggle with learning to read.

Children who break an image down into pieces, instead of visualizing it as a whole, to solve mental rotation problems may be the very same children who struggle with discriminating similar-looking letters such as p and q and may later be diagnosed with dyslexia.

Parents can play an important role in building their child’s mental rotation skills. Parents can help children by offering them opportunities to practice rotating real objects with toys such as three-dimensional puzzles or building blocks. Tangrams – flat, colorful puzzles that come in different shapes – can be used to practice breaking down shapes of animals into pieces. Parents can encourage their child to look for shapes that match parts of the animal or object they are building.

Nov. 8 is International STEM Day, a celebration of all things science, technology, engineering and mathematics.

Research like ours provides valuable guidance for designing early STEM activities and educational tools. By directly observing children’s problem solving in real time, we can develop better ways for educators and toy makers to support strong spatial thinking from an early age. To celebrate, we encourage people to engage in activities that test their spatial skills, such as ditching the GPS for the day or playing a game of Tetris.

Mental rotation is a powerful skill that helps us understand and interact with the surrounding physical world. From solving puzzles to reading maps, mental rotation plays a role in many everyday activities. Building mental rotation abilities can improve children’s performance in subjects such as reading, math and science and may inspire future careers in STEM fields.

Shannon Pruden receives funding from National Institutes of Child Health and Human Development and National Science Foundation.

Karinna Rodriguez does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

– ref. Even before they can read, young children are visualizing letters and other objects with the same strategies adults use – https://theconversation.com/even-before-they-can-read-young-children-are-visualizing-letters-and-other-objects-with-the-same-strategies-adults-use-264532