How science explains déjà vu

What exactly is déjà vu?

While people have wondered about déjà vu for a long time, only recently have scientists started experimentally investigating what might trigger it. Read this deep dive into the latest science.

Déjà vu is a memory illusion involving brain regions correcting inaccurate memories

Neuroscientists suggest the phenomenon is your brain recognizing that this feeling of familiarity is incorrect, showing off the brain's internal fact-checking system. Younger people experience déjà vu more often because their brains have higher excitatory activity and stronger memory monitoring systems.

The science of optical illusions

The human brain has developed cognitive shortcuts to help us navigate in a world where our visual senses are constantly bombarded of information. But these shortcuts can also be exploited, tricking the brain into telling us something is happening when it really isn't. This short video unpacks the neuroscience behind some of the most common (but perplexing) optical illusions.

The science behind ghosts, explored

Every culture has them—restless spirits, haunted houses, things that go bump in the night. But why do we believe in ghosts? Psychologist and skeptic Dr. Chris French joins host Sony Kassam to explore the science behind the supernatural, from sleep paralysis and hallucinations to the brain’s pattern-making instincts.

What’s with the teen brain, anyway

In this video NIDA explores the intriguing similarities between the processes of brain development and computer programming. This analogy helps us understand why toxic environmental factors like drugs, bullying, or lack of sleep strongly affect a teenager’s life The information provided by this video can empower your children or students with information they need make better decisions.

The evolution of dream science—from interpretation to advanced brain imaging

In the mid-1900s, dream scientists would tape study participants' eyes open, wait for them to fall asleep, and attempt to influence their dreams by shaking, tickling, and more. Now, advanced techniques like MRIs have shed new light on what’s happening in the brain as we sleep.

Visualize the difference between a healthy brain and one with Alzheimer's

The brain has three main parts—the cerebrum, brain stem, and cerebellum—each combining to control the entirety of the body's operations. Alzheimer's progressively deteriorates the circuitry in these structures, resulting in what we see as the symptoms of the disease.

What happens in a dying brain?

Near-death experiences usually happen during death or on the border of life and death when a person isn't understood to be conscious. This article details the science of what's going on with the brain during NDEs.

The brains of people who experience frisson have unique neural pathways

A small 2016 study aimed to investigate the behavioral and neural differences between 10 individuals who experience goose bumps when listening to music and 10 who typically don’t. Scientists reported that individuals experiencing musical chills had greater white matter connectivity in specific auditory, emotional, and social processing areas of the brain.

A brain scientist's experience with a stroke

What happens when a leading brain scientist has a stroke of her own? Dr. Jill Bolte Taylor recounts moment by moment watching her brain function slow and then cease, followed by a prolonged recovery. Through this experience, she details what she learned about the phenomenon of stroke and how it has impacted her research ever since.

How burnout alters your brain

Stress is a normal part of everyday life, and it’s not necessarily all bad. But chronic stress—the kind that leads to burnout—can change the size and functioning of parts of your brain. It can alter the ability to make new brain cells and memories and even potentially modify your DNA.

Explaining the physical connection between the gut and brain

This video overview from Duke University helps visualize the gut-brain axis—a physical connection of nerves running from the brain to digestive tract that acts as a physical and chemical link.

Neural replays in mice help explain food aversions

Princeton University scientists published research in 2025 analyzing how mice learn to associate certain foods or flavors with feeling ill—even when there’s a time gap between eating something and feeling sick. The work, performed with grape Kool-Aid and injections of a substance that made mice sick, traced the literal “gut reaction” of how gut distress signals are linked to neural replays of what the mouse ate.

How to think yourself into health

Can the right thoughts lead to a stronger immune system? Neuroimmunologists like Hai Qi study how drugs targeting the brain, as well as thought exercises, can prompt stronger immune responses to infection. This six-minute video investigates the radical claims.

The science of spring fever

Researchers have confirmed what people have sensed for ages: Our emotions during the springtime can go a little wild. This piece breaks down the impact of the seasonal transition on our bodies and prescribes a few ways to mitigate the effects.

There’s a psychological explanation for ‘FOMO,’ or the fear of missing out

This video breaks down FOMO—what it is, how it works, and why it happens—showing how social comparison and uncertainty trigger anxiety that pushes people toward risk-taking and constant checking behaviors.

What is the brain up to when the mind wanders?

As you stare into the distance while washing your home's seemingly never-ending pile of dishes, the brain activates its default mode network. This collection of "task-negative" brain regions associated with memory, reward, action consideration, and prediction alight with activity when humans mentally turn inward, possibly giving rise to the brain's ability to wander and humans' ability to construct internal narratives about the world.

Psychedelic drugs are having a scientific renaissance

After decades of repression, psychedelic research is making a resurgence. Hear from a host of experts in this 20-minute video on what that could mean for the future of mental health. The current science on psychedelics believes LSD can cause a particular brain network to quiet or deactivate.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

Researchers believe the brain consolidates memories, processes emotions, and plans for the future during dream states

Synesthesia: when sensation in one sense triggers an unrelated sense in the brain

The first reported clinical case of synesthesia dates back to the early 1800s, though the perceptual phenomenon may be much older than surviving records imply. This article by researcher Richard Cytowic details the scientific history of synesthesia, a neurological trait that causes some senses to overlap, giving color to numbers and flavors to names.

Some founders of quantum mechanics thought consciousness could influence phenomena

Since quantum systems exist as a superposition of states before producing a definitive outcome, some quantum pioneers wondered if the act of conscious observation was what collapsed the wave function of possibilities into one state.

Everything scientists could learn by looking at your skull

Our skulls are all unique, but they also share characteristics across groups of people. In the absence of fingerprints, forensic scientists can learn a lot about you just from your skull.

A scientific analysis of famous time travel stories

This 8-minute video explores how time travel influences the narrative arc of several movies, books and video games, from Harry Potter to A Christmas Carol. (Warning: it contains spoilers!) J.K. Rowling and Charles Dickens set myriad parameters as they’re worldbuilding to avoid paradoxes and create quasi-logical timelines. By drawing diagrams as he’s speaking, the video breaks down how time works in some of popular culture’s most beloved fictional universes.

Misfired motor signals may explain why many people with schizophrenia hear voices

Up to 80% of schizophrenia patients may have auditory hallucinations. Recent research concluded that this symptom may be from misfired motor signals that feed into each other, essentially failing to suppress certain sensory neural activities and that resulting overexcitment fuels hallucinations. The finding suggests that, one day, magnetic pulses might be used to stimulate specific nerves to better regulate the errant signals and reduce or stop hallucinations. (Some users may encounter a paywall.)

See this first-person virtual reality view of vertigo

This video shows a virtual reality environment view of what benign paroxysmal positional vertigo will look like, from a first-person view. It includes a virtual rendering of eye spinning associated with the condition. (Warning: Watching this may make some users feel a bit nauseous.)

Recent research found that the brain doesn't seem to massively rewire following amputation—upending earlier beliefs about the cause of phantom limb pain.

Learn how your body is, scientifically, like a firework with its own slow, controlled burn.

Why your favorite color is probably blue

From a young age, we are primed to choose a favorite color, but strangely as we grow up, our preference often changes—and it’s largely due to influences outside our control.

After 25 people used virtual reality headsets to practice flying with virtual wings—flapping their arms—their visual cortex responded to the wings almost as if they were real arms, treating them as body parts.

Crows are believed to have intelligence on par with a seven-year-old child and demonstrate complex behaviors, from problem-solving with tools to recognizing human faces.

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

Watch how viruses like Ebola can spill over from animals to humans—and vice-versa.

Salvador Dalí believed he was his own dead brother, who had died nine months before he was born

Chaos theory—informally known as the butterfly effect—is the reason why weather forecasts are presented with probabilities rather than certainties.

Explore our favorite visualization of the immense scale of space, from an astronaut to the size of the observable universe

Fear or disgust related to clusters of holes and cracks, called trypophobia, may stem from evolutionary processes to help us avoid pathogens.

Listen to an in-depth conversation on the links between Parkinson's disease and herbicide exposure and the challenging pace of scientific investigation.

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

The Dracula character, now seen as the vampire archetype, was inspired by a seafood-induced nightmare its creator experienced.

Clever Hans was a 1900s horse that was believed to be able to solve math equations, tell time, and read and comprehend German, until a psychology student discovered how he got his answers.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

Netflix profits when you're not watching, and its movies are designed that way—read a detail-rich critical essay exposing lesser-known Netflix takes

The name 'Silicon Valley' arose from the founding of Shockley Semiconductor Laboratory in Fairchild Semiconductor in 1956-57, founded near Stanford University in Palo Alto

The Mona Lisa's celebrity status and repeated restorations have obscured what made the painting so revolutionary for its time

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.

Bone marrow (soft tissue found inside certain bones) generates roughly 500 billion new blood cells each day

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

The first steps to rebuilding your credit score include getting to know exactly what's on your credit report and figuring out how far you are from the '700 club,' or 'good score' range.

Hear 50 years of iconic hip-hop samples, the genre's foundational looped tracks