Some scientists think consciousness comes from an ancient part of the brain ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏
May 28, 2026—What if consciousness doesn't arise in the cerebral cortex? Plus, scientists find the oldest evidence for plate tectonics, and the physics of "Wemby's" basketball skills.
—Andrea Gawrylewski
Chief Newsletter Editor
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VICTOR de SCHWANBERG/SCIENCE PHOTO LIBRARY
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- Between April 2024 and January 2025 gravitational wave detectors captured a record-breaking 161 events. The era of gravitational wave astronomy has truly begun. | 2 min read
- Homing pigeon livers are packed with magnetic immune cells containing a specific form of iron, according to a new study. It may be involved in how the birds navigate. | 4 min read
- A near-miss incident at a chemical plant and a deadly chemical accident this week have affected thousands and drawn scrutiny to federal rules around risk management at chemical plants. Such incidents might become more common. | 4 min read
- The Trump administration’s plan to offer plutonium from dismantled Cold War–era nuclear weapons to private energy companies makes little economic sense, experts say. | 3 min read
- San Antonio Spurs star Victor “Wemby” Wembanyama is rocking the NBA playoffs. Here's the science of how he does what he does. | 4 min read
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A statement can be true or false. But as logician Kurt Gödel demonstrated, there will always be mathematical assumptions that can neither be proven nor disproven. | 3 min read
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Where Does Consciousness Come From?
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Most neuroscientists and theorists have long assumed that consciousness arises from the cerebral cortex, the wrinkly outer layer of the brain that’s responsible for sophisticated cognitive functions like language, self-reflection and abstract thought. But a growing number of consciousness researchers are seriously considering the possibility that consciousness could originate deep within the brain’s most evolutionarily ancient realm: the subcortex.
Why this is interesting: The cortex and the subcortex are tightly interconnected and virtually all neuroscientists agree that consciousness depends on this continuous dialogue between cortex and subcortex. The question is whether the subcortex is merely a power supply keeping the cortex online, as corticalists hold, or whether it can sustain basic consciousness by itself.
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A cross section shows the brain's cortex (yellow), subcortex (blue) and cerebellum (gray). The brain stem, thalamus, basal ganglia, amygdala and hippocampus are all key subcortical structures and are important for learning, memory, emotion and wakefulness. Amanda Montañez
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Evidence for the subcortex: Children with a rare developmental disorder called hydranencephaly are born without a cortex. And yet, their behavior shows responsiveness to their environment and reactions to nearby events. Some animals, too, display behaviors that imply consciousness beyond simply acting on instinct. Are we defining consciousness too narrowly as a purely cortex phenomenon?
What the experts say: “I don’t think we’ve got enough evidence to support either of those versions fully,” says Anil Seth, a neuroscientist at the University of Sussex in England. “There’s a wealth of evidence” tying cortical processing to consciousness, yet the precise brain activity that corresponds with experience—the so-called "neural correlates of consciousness"—have remained elusive.
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Outcrop of a 3.5-billion-year-old “pillow basalt” lava flow. Alec Brenner/Harvard University/Yale University
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Earliest Plate Tectonics
Earthquakes, volcanic activity, and the movement of the continents all stem from one of Earth’s most powerful forces: plate tectonics. But the Earth’s crust wasn’t always shifting around like it does today. Scientists recently found the earliest evidence of the relative motion of the Earth’s plates, dating to 3.48 billion years ago. The early date has implications for understanding the beginnings of life on Earth and how the planet’s tectonic activity began.
How they did it: The researchers analyzed rock samples from remote parts of Western Australia and South Africa. These regions contain some of the planet’s oldest cratons—chunks of crust that have survived billions of years of grinding and melting and form the building blocks of continents. The rock layers’ magnetic record shows the shifting of a chunk of the craton in Australia while part of the craton in South Africa stayed still. Evidence of plates moving toward or away from one another, called relative motion, is an essential part of geologists’ investigation into how Earth’s crust has changed over the eons.
What the experts say: Multiple researchers agreed that this study’s findings likely represent the earliest possible evidence, as so few rocks remain intact from Earth’s first billion years. “It’s like having a 1,000-piece jigsaw, but you have only 35 pieces,” Brown says. The relative motion doesn’t tell us exactly what was going on in this period, he adds, but it can put new limits on the mathematical models that researchers use to re-create ancient Earth. Why did life begin to flourish when it did? Plate tectonics might help us find out. —Emma Gometz, newsletter editor
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TRAVEL WITH SCIENTIFIC AMERICAN
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Space Now Open for Icelandic Eclipse Adventure
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New availability! Grab your spot while they last and experience the 2026 solar eclipse in the Land of Ice and Fire on this trip of a lifetime led by Senior News Editor Andrea Thomspon.
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In this photo, epigeneticist Andrew Pask is checking his team’s store of stem cells of the fat-tailed dunnart (Sminthopsis crassicaudata), a mouse-like marsupial that is the closest living relative of the thylacine, or Tasmanian tiger (Thylacinus cynocephalus). “Our main project is to bring back the thylacine,” says Pask. To achieve it, the team is trying to produce a complete genome for the species and developing cloning and in vitro fertilization for marsupials. “People say we are playing God with our work. But we played God when we wiped out the thylacine. My research is looking at ways to heal lost biodiversity.” Nature | 3 min read
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Consciousness may be the most intimate thing we experience—and also the hardest to define. Our understanding of it is rooted so deeply in human experience that it can be difficult to imagine what consciousness might look like outside ourselves: in another species, in another kind of brain, perhaps even in entirely different forms of life. But if consciousness gives us imagination, I hope we use it to expand our thinking.
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—Andrea Gawrylewski, Chief Newsletter Editor
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