“When searching for possible dementia prevention tools, we thought something as prevalent as coffee may be a promising dietary intervention — and our unique access to high quality data through studies that has been going on for more than 40 years allowed us to follow through on that idea,” said senior author Daniel Wang, MD, ScD, associate scientist with the Channing Division of Network Medicine in the Mass General Brigham Department of Medicine and assistant professor at Harvard Medical School. Wang is also an assistant professor in the Department of Nutrition at Harvard Chan School and an associate member at the Broad Institute. “While our results are encouraging, it’s important to remember that the effect size is small and there are lots of important ways to protect cognitive function as we age. Our study suggests that caffeinated coffee or tea consumption can be one piece of that puzzle.”

Why Prevention Matters for Dementia

Preventing dementia early is especially important because current treatments are limited and generally provide only modest benefits after symptoms begin. As a result, scientists are increasingly focusing on lifestyle factors, including diet, that may influence the development of cognitive decline.

Coffee and tea contain compounds such as polyphenols and caffeine, which are thought to support brain health. These substances may help reduce inflammation and limit cellular damage, both of which are linked to cognitive decline. However, previous research on coffee and dementia has produced mixed results, often due to shorter study periods or limited data on long-term consumption patterns and different types of beverages.

Long-Term Data Offers Clearer Insights

The NHS and HPFS datasets helped address these gaps. Participants were tracked for up to 43 years, with repeated evaluations of diet, dementia diagnoses, subjective cognitive concerns, and objective cognitive performance. Researchers analyzed how consumption of caffeinated coffee, tea, and decaffeinated coffee related to long-term brain health outcomes.

Among the more than 130,000 participants, 11,033 developed dementia over the course of the study. Individuals who consumed higher amounts of caffeinated coffee had an 18% lower risk of developing dementia compared with those who rarely or never drank it. They also reported lower rates of subjective cognitive decline (7.8% versus 9.5%) and performed better on certain objective cognitive tests.

Caffeine May Play a Key Role

Similar patterns were observed among tea drinkers, while decaffeinated coffee did not show the same associations. This suggests that caffeine may be an important factor behind the observed brain-related benefits, although more research is needed to confirm the underlying mechanisms.

The strongest effects were seen in participants who drank 2-3 cups of caffeinated coffee or 1-2 cups of tea per day. Higher levels of caffeine intake did not appear to cause harm. Instead, they showed comparable benefits to the moderate intake range highlighted in the study.

“We also compared people with different genetic predispositions to developing dementia and saw the same results — meaning coffee or caffeine is likely equally beneficial for people with high and low genetic risk of developing dementia,” said lead author Yu Zhang, MBBS, MS, PhD student at Harvard Chan School and a research trainee at Mass General Brigham.

Study Authors and Funding

In addition to Wang and Zhang, Mass General Brigham contributors included Yuxi Liu, Yanping Li, Yuhan Li, Jae H. Kang, A. Heather Eliassen, Molin Wang, Eric B. Rimm, Frank B. Hu, and Meir J. Stampfer. Additional authors were Walter C. Willett and Xiao Gu.

The research was supported by National Institutes of Health grants UM1 CA186107, U01 HL145386, U01 CA167552, R01 HL60712, P30 DK46200, R00 DK119412, R01 AG077489, RF1 AG083764, and R01 NR019992. The funding organizations had no involvement in the study design, data collection, analysis, manuscript preparation, or the decision to publish.

For decades, these unusual rocks have puzzled researchers. Perched high on mountain ridges, they seemed out of place, raising questions about where they came from and what they might reveal about Antarctica’s past and future.

Dating Ancient Rocks From the Jurassic Period

A research team led by British Antarctic Survey (BAS) analyzed the granite by examining the radioactive decay of elements trapped inside tiny mineral crystals. This technique showed the rocks formed around 175 million years ago, during the Jurassic period.

Even with their age determined, their journey to the mountaintops remained unclear until scientists gathered new data from aircraft surveys over the region.

Airborne Surveys Reveal Buried Structure

Using highly sensitive gravity measurements collected by BAS’ Twin Otter aircraft and others, researchers detected an unusual signal beneath the glacier. The data matched what scientists would expect from a massive granite body hidden below the ice.

Connecting the surface boulders to this deep underground formation solved a long-standing mystery. It also revealed that Pine Island Glacier once moved very differently, pulling rocks from its base and carrying them uphill when the ice sheet was much thicker.

Clues to Ice Sheet Behavior and Sea Level Rise

This discovery provides important insight into how the glacier behaved during the last ice age (around 20 thousand years ago). By understanding past ice thickness and movement patterns, scientists can improve computer models used to predict how Antarctica’s ice sheets may respond to future climate change.

Dr. Tom Jordan, lead author and geophysicist at BAS, analyzed the airborne data. He said:

“It’s remarkable that pink granite boulders spotted on the surface have led us to a hidden giant beneath the ice. By combining geological dating with gravity surveys, we’ve not only solved a mystery about where these rocks came from, but also uncovered new information about how the ice sheet flowed in the past and how it might change in the future.”

Why Subglacial Geology Matters Today

The findings also highlight how the geology beneath Pine Island Glacier affects present-day conditions. This region has experienced some of the fastest ice loss in Antarctica in recent decades. The type of rock below influences how easily the ice slides and how meltwater moves underneath it.

Better understanding these processes will help refine models that estimate future sea level rise.

Rocks as Records of Antarctica’s History

Dr. Joanne Johnson, a co-author and geologist at BAS, collected the boulders during fieldwork in the Hudson Mountains as part of the International Thwaites Glacier Collaboration. She says:

“Rocks provide an amazing record of how our planet has changed over time, especially how ice has eroded and altered the landscape of Antarctica. Boulders like these are a treasure-trove of information about what lies deep beneath the ice sheet, far out of reach.

“By identifying their source, we have been able to piece together how they got to where they are today, giving us clues about how the West Antarctic Ice Sheet may change in future — information that is vital for determining the impact of sea level rise on coastal populations around the world.”

This research shows how combining geology and geophysics can uncover hidden features beneath Antarctica and deepen our understanding of the forces shaping the planet.

A new study led by a researcher from the School of Zoology and the Steinhardt Museum of Natural History at Tel Aviv University analyzed rare fossils with intact feathers and found evidence that these dinosaurs were not capable of flight. This unusual discovery offers a rare look at how animals lived 160 million years ago and sheds new light on how flight evolved in both dinosaurs and modern birds. The researchers note, “This finding has broad significance, as it suggests that the development of flight throughout the evolution of dinosaurs and birds was far more complex than previously believed. In fact, certain species may have developed basic flight abilities — and then lost them later in their evolution.”

The research was led by Dr. Yosef Kiat, alongside collaborators from China and the United States, and published in the journal Communications Biology by Nature Portfolio.

How Feathers Evolved in Dinosaurs

Dr. Kiat, an ornithologist who studies feathers, explains that dinosaurs split from other reptiles about 240 million years ago. Not long after (on an evolutionary timescale), many species developed feathers, which are lightweight, protein-based structures used for flight and temperature regulation. Around 175 million years ago, a group of feathered dinosaurs known as Pennaraptora appeared. These animals are considered distant ancestors of modern birds and were the only dinosaur lineage to survive the mass extinction at the end of the Mesozoic era 66 million years ago.

Scientists believe Pennaraptora evolved feathers for flight, but environmental changes may have led some species to lose that ability over time, similar to flightless birds today such as ostriches and penguins.

Rare Fossils Preserve Feather Color and Structure

The study focused on nine fossils from eastern China belonging to Anchiornis, a feathered Pennaraptoran dinosaur. These fossils are exceptionally rare because they preserved not only the feathers but also their original coloration, thanks to unique fossilization conditions in the region. Each specimen showed wing feathers that were white with a distinct black spot at the tip.

This preserved coloration allowed researchers to closely examine the structure and growth of the feathers in ways that are usually impossible with fossils.

Molting Patterns Reveal Flight Ability

Dr. Kiat explains that feathers grow over two to three weeks before detaching from the blood supply and becoming nonliving material. Over time, they wear out and are replaced in a process known as molting. This process can reveal whether an animal could fly.

“Feathers grow for two to three weeks. Reaching their final size, they detach from the blood vessels that fed them during growth and become dead material. Worn over time, they are shed and replaced by new feathers — in a process called molting, which tells an important story: birds that depend on flight, and thus on the feathers enabling them to fly, molt in an orderly, gradual process that maintains symmetry between the wings and allows them to keep flying during molting. In birds without flight ability, on the other hand, molting is more random and irregular. Consequently, the molting pattern tells us whether a certain winged creature was capable of flight.”

By examining the fossilized feathers, researchers identified a continuous line of black spots along the wing edges. They also spotted developing feathers whose black spots were out of alignment, showing they were still growing. A detailed analysis revealed that the molting pattern was irregular rather than orderly.

Evidence That Anchiornis Could Not Fly

Dr. Kiat concluded, “Based on my familiarity with modern birds, I identified a molting pattern indicating that these dinosaurs were probably flightless. This is a rare and especially exciting finding: the preserved coloration of the feathers gave us a unique opportunity to identify a functional trait of these ancient creatures — not only the body structure preserved in fossils of skeletons and bones.”

He adds, “Feather molting seems like a small technical detail — but when examined in fossils, it can change everything we thought about the origins of flight. Anchiornis now joins the list of dinosaurs that were covered in feathers but not capable of flight, highlighting how complex and diverse wing evolution truly was.”

In total, the team evaluated more than 700 hypotheses and asked the same question 10 times for each one to measure consistency.

Accuracy Results and Limits of AI Performance

When the experiment was first conducted in 2024, ChatGPT answered correctly 76.5% of the time. In a follow-up test in 2025, accuracy rose slightly to 80%. However, once the researchers adjusted for random guessing, the results looked far less impressive. The AI performed only about 60% better than chance, a level closer to a low D than to strong reliability.

The system had the most difficulty identifying false statements, correctly labeling them only 16.4% of the time. It also showed notable inconsistency. Even when given the exact same prompt 10 times, ChatGPT produced consistent answers only about 73% of the time.

Inconsistent Answers Raise Concerns

“We’re not just talking about accuracy, we’re talking about inconsistency, because if you ask the same question again and again, you come up with different answers,” said Cicek, an associate professor in the Department of Marketing and International Business in WSU’s Carson College of Business and lead author of the new publication.

“We used 10 prompts with the same exact question. Everything was identical. It would answer true. Next, it says it’s false. It’s true, it’s false, false, true. There were several cases where there were five true, five false.”

AI Fluency vs. Real Understanding

The findings, published in the Rutgers Business Review, highlight the importance of using caution when relying on AI for important decisions, especially those that require nuanced or complex reasoning. While generative AI can produce smooth, convincing language, it does not yet demonstrate the same level of conceptual understanding.

According to Cicek, these results suggest that artificial general intelligence capable of truly “thinking” may still be further away than many expect.

“Current AI tools don’t understand the world the way we do — they don’t have a ‘brain,'” Cicek said. “They just memorize, and they can give you some insight, but they don’t understand what they’re talking about.”

Study Design and Methods

Cicek worked with co-authors Sevincgul Ulu of Southern Illinois University, Can Uslay of Rutgers University, and Kate Karniouchina of Northeastern University.

The team used 719 hypotheses from scientific studies published in business journals since 2021. These types of questions often involve nuance, with multiple factors influencing whether a hypothesis is supported. Reducing such complexity to a simple true or false judgment requires careful reasoning.

The researchers tested the free version of ChatGPT-3.5 in 2024 and the updated ChatGPT-5 mini in 2025. Overall, performance remained similar across both versions. After adjusting for random chance, which gives a 50% probability of a correct answer, the AI’s effectiveness was only about 60% above chance in both years.

Key Weakness in AI Reasoning

The results point to a fundamental limitation of large language model AI systems. Although they can generate fluent and persuasive responses, they often struggle to reason through complicated questions. This can lead to answers that sound convincing but are actually incorrect, Cicek said.

Why Experts Urge Caution With AI

Based on these findings, the researchers recommend that business leaders verify AI-generated information and approach it with skepticism. They also emphasize the need for training to better understand what AI systems can and cannot do effectively.

Although this study focused specifically on ChatGPT, Cicek noted that similar experiments with other AI tools have produced comparable outcomes. The work also builds on earlier research pointing to caution around AI hype. A 2024 national survey found that consumers were less likely to purchase products when they were marketed with a focus on AI.

“Always be skeptical,” he said. “I’m not against AI. I’m using it. But you need to be very careful.”

The world, called L 98-59 d (an exoplanet, meaning it orbits a star outside our Solar System), circles a small red star about 35 light-years from Earth. Data from the James Webb Space Telescope (JWST) and ground based observatories revealed something unusual. For a planet about 1.6 times the size of Earth, it has a surprisingly low density and an atmosphere rich in hydrogen sulfide.

A Planet That Defies Classification

Until now, scientists would have grouped a planet like L 98-59 d into one of two categories. It could be a rocky “gas-dwarf” with a hydrogen dominated atmosphere, or a water rich world covered by deep oceans and ice.

New evidence shows it fits neither category. Instead, L 98-59 d appears to belong to a completely different class of planet dominated by heavy sulfur compounds.

A Global Magma Ocean Beneath the Surface

To understand this unusual world, researchers from the University of Oxford, the University of Groningen, the University of Leeds and ETH Zurich used advanced computer simulations to trace its evolution from shortly after formation to today, spanning nearly five billion years. By combining telescope observations with detailed models of planetary interiors and atmospheres, they were able to infer what is happening deep inside the planet.

Their findings suggest that L 98-59 d has a mantle made of molten silicate, similar to lava on Earth. Beneath its surface lies a vast magma ocean extending thousands of kilometers deep. This enormous reservoir allows the planet to trap large amounts of sulfur within its interior over long periods of time.

The magma ocean also helps maintain a thick hydrogen rich atmosphere that contains sulfur bearing gases such as hydrogen sulfide (H2S). Normally, radiation from the host star would gradually strip these gases away into space through X-ray driven processes.

Sulfur Cycling Between Interior and Atmosphere

Over billions of years, ongoing chemical exchanges between the molten interior and the atmosphere have shaped the planet’s current appearance. These interactions explain the unusual signals detected by telescopes.

Researchers suggest that L 98-59 d may be the first identified example of a broader population of gas rich sulfur dominated planets that sustain long lived magma oceans. If that is the case, it points to a much wider variety of planetary types across the galaxy than previously recognized.

Lead author Dr. Harrison Nicholls (Department of Physics, University of Oxford) said: “This discovery suggests that the categories astronomers currently use to describe small planets may be too simple. While this molten planet is unlikely to support life, it reflects the wide diversity of the worlds which exist beyond the Solar System. We may then ask: what other types of planet are waiting to be uncovered?”

How Sulfur Shapes the Atmosphere

JWST observations from 2024 detected sulfur dioxide along with other sulfur gases high in the upper atmosphere of L 98-59 d. According to the team’s models, these gases form when ultraviolet radiation from the host star, the red dwarf L 98-59, drives chemical reactions.

At the same time, the magma ocean below acts as a massive storage system for volatile materials, absorbing and releasing gases over billions of years after the planet formed. This combination of deep interior storage and ultraviolet driven chemistry explains the planet’s distinctive properties.

Simulations indicate that L 98-59 d likely formed with a large supply of volatile material and may once have resembled a larger sub-Neptune type planet. Over time, it cooled, lost part of its atmosphere, and became smaller.

Scientists note that magma oceans are thought to be the initial state of all rocky planets (including the Earth and Mars). Studying these environments on distant worlds can provide insight into the earliest stages of our own planet’s history.

Reconstructing Alien Worlds With Models

Co-author Professor Raymond Pierrehumbert (Department of Physics, University of Oxford) said: “What’s exciting is that we can use computer models to uncover the hidden interior of a planet we will never visit. Although astronomers can only measure a planet’s size, mass and atmospheric composition from afar, this research shows that it is possible to reconstruct the deep past of these alien worlds — and discover types of planets with no equivalent in our own Solar System.”

JWST is already delivering a growing stream of data, and future missions such as Ariel and PLATO are expected to expand that dataset even further. The research team plans to apply their models to these observations using machine learning to map the diversity of planets beyond our Solar System and link them to their early development.

By doing so, scientists hope to better understand how planets form and evolve, and to identify which types of worlds might be capable of supporting life.

Dr. Richard Chatterjee (University of Leeds/ University of Oxford) said: “Our computer models simulate various planetary processes, effectively enabling us to turn back the clock and understand how this unusual rocky exoplanet, L 98-59 d, evolved. Hydrogen sulfide gas, responsible for the smell of rotten eggs, appears to play a starring role there. But, as always, more observations are needed to understand this planet and others like it. Further investigation may yet show that rather pungent planets are surprisingly common.”