The science of optical illusions

Visualizing 11 cognitive biases that influence how you think

Humans are hardwired to make mental mistakes called cognitive biases, affecting the way we view our world. Among the most common are confirmation bias (seeking only evidence that affirms your views), authority bias (overweighting things said by authority figures), groupthink (assimilating ideas to avoid conflict), and more. This quick chart gives an overview of some of the most notable ways we mislead ourselves.

Optical illusions were a key component in animating the Muppets

Despite being fairly typical puppets, Jim Henson's Muppets often ventured out into the real world without any apparent humans controlling them. That's thanks to several ingenious optical illusions devised by Henson and his partners, including well-placed mirrors, platformed sets, and remote-controlled puppeting.

Behind the fascinating disguising mechanism of camouflage

Camouflage—nature's master game of hide-and-seek—is more complex than simply how things look. The disguising process required millions of years of evolution that have programmed how our brains take shortcuts. Watch this video to see examples of camouflage and understand how we process it.

How science explains déjà vu

Take a fun look at the science explaining the odd experience of déjà vu, which some theories suggest is actually a sign of a healthy brain.

Why patterns in art are so pleasing

Repeated visual cues like shapes or lines derive from the brain's innate compulsion to identify faces, places, bodies, and more. With repeated shapes, the brain seeks out resolution to the subtle variations between them. See examples in art and music.

Our brains trick us into seeing an enlarged Moon when on the horizon

Humans perceive the sky as a flattened bowl and judge the size of an object by accounting for its perceived distance away from us. Combined, studies have found that the Moon on the horizon is perceived to be larger because the terrain makes it seem like it is farther away, similar to the Ponzo illusion.

Using brain implants to restore vision

Several companies are attempting to create brain-computer interfaces that skip over retinas and optic nerves to allow visual input to go straight to the brain, potentially restoring some sight to the blind. Clinical trial findings suggest restored sight is sparse and manifests differently than a sighted person might expect, appearing as specks of "light" clusters called phosphenes to help differentiate one's surroundings.

The dreaming brain, as understood by scientists

Technology has advanced to where the seemingly separate fields of psychology and neuroscience are asking the same questions about dreams, such as whether they're more closely related to perception or visualization. Some field-intersecting findings include research that shows people with impaired face perception don't dream of faces, those with brain legion-related cognition difficulties deal with similar issues in dreams, and children's dreams change in parallel to their cognitive development.

When processing light, the brain can perceive colors with no natural wavelength

While some animals are sensitive to many forms of light, humans possess receptors that are sensitive to red, green, and blue wavelengths. These receptors send signals to the brain, which are processed and mixed to produce the array of colors we observe, including magenta, pink, and "supercolors" that lack a corresponding natural wavelength in the visible spectrum.

How the brain processes a calendar year

When most of us picture a calendar year, we have a foggy image in our minds of the months, in rough, calendar-like grids. But for some folks, that picture is a whole lot more clear. Around 1 percent of the population has a strange ability known as "calendar synaesthesia," which means they're able to visualize in crisp detail an elaborate calendar of the months of the year. Learn how it works here.

Explore an optical table to create quantum physics experiments

This interactive teaches users to create quantum experiments through lessons resembling video game levels. Users can also use the virtual lab to visualize landmark quantum experiments like entanglement, teleportation, cryptography, and quantum computing, or create their own experiments with drag-and-drop elements.

The doorway effect is when people forget their task when entering a new space

The "why did I come in here?" feeling after walking into a room comes from the brain creating event boundaries to organize memories. Mentally revisiting a previous room can help recall tasks and reverse memory loss. (Some readers may experience a paywall.)

The science of fear

The Hidden Brain podcast team explores the science of fear by traveling to a haunted house curated by a scientist to investigate what scares us, and why some people enjoy this sensation more than others.

How do brain scans work?

There’s only one thing in our solar system sophisticated enough to study itself: the human brain. But this self-investigation is challenging because a living brain is shielded by skull, swaddled in tissue, and made up of billions of tiny cells. How do we study living brains without harming their owners? Two experts explain how the various techniques like EEGs, fMRIs, and PETs work in this TedEd talk.

Engineer explains VR at five levels of complexity

While its possible to grab a virtual reality headset and hop into an immersive world with little effort, a significant amount of technical and biological science has gone into creating the effect of a 3D world. This video breaks down the technology in five layers of increasing complexity.

What pupils can reveal about a person’s thoughts and feelings

Eyes have long been said to be the window to the soul. In this article, a psychologist and pupillometrist explores research demonstrating pupils as a window into the mind. Pupils tell us how intensely someone is exerting mental effort, or even reveal what a person is imagining. Read this article for insight into the field of pupillometry and how it can offer insights into our psyches.

Why do some people always get lost?

Using GPS, anthropological data, and VR, scientists have learned that one's sense of direction is largely influenced by upbringing. A person's wayfinding ability can be measured by how accurately they point toward an out-of-sight location, a challenge further complicated by imagining they're somewhere else and pointing toward a third location. Anxiety, safety concerns, and dislike of wandering can negatively impact one's sense of direction, which can improve with practice.

How the five senses share information with each other

The human body depends on information from the five sensory organs—the eyes, ears, nose, tongue, and skin—to react to the world around it. Each of these organs, in its own way, relies on complex circuitry to send signals back to the central nervous system.

The science behind the movie 'Interstellar'

Christopher Nolan's 2014 sci-fi action film "Interstellar" relies on real science for its wild space-time travel. This infographic dives into the physics basis of the fictionalized Gargantua black hole, the relativity effect, and more.

The myth of multitasking's prestige

In this article, renowned neurologist Richard Cytowic seeks to expose multitasking as a fool’s errand. Cytowic explains how the brain, like a computer, switches between tasks rather than handling multiple tasks at once. He shares that attempting to focus on multiple activities at the same time consequentially decreases the brain's ability to ignore distractions, maintain focus, and organize information. Instead, he suggests, try to focus on completing one thing at a time.

Vertigo is a mismatch of information between the eyes and the ears

Both vertigo and motion sickness can be caused by mismatches between visual and auditory inputs.The brain relies on inputs from the eyes, inner ear, and receptors in muscles and joints to orient the body. When the eyes suggest movement but other signals suggest the body is stationary dizziness and nausea can occur.

The art of 'undiscovering' phantom islands

Centuries of maps include islands and isles that appear to only exist on atlases. This article explores the discovery and "undiscovery" of such landscapes, which still persist despite modern technology. As recently as 2012, Google Maps showed an...

When you complete a CAPTCHA on a website to prove you are human, you may be unknowingly training algorithms for self-driving cars, whose systems require training data to help identify crosswalks, bicycles, and other outdoor objects.

Surreal backgrounds, asymmetry, and indecipherable text can help identify deepfakes

Differences in the backgrounds of training data with the same subject introduce variability, resulting in background textures and text that lack realistic detail. Difficulties with managing long-distance dependencies, the complexity of hair, and other real-world phenomena introduce errors that can be used to flag AI-generated content.

The impact of gravitational force on our bodies surprised early coaster riders and engineers

There is only a certain amount of gravitational force that the body can handle before dealing with consequences like short-term vision loss or unconsciousness. Increased scientific understanding has largely reduced these impacts, with engineers combining periods of intense pressure with periods of relief.

What is psychology? An overview

What is psychology and why should we study it? This short video from Macat explains how the subject has developed over the years and introduces some of the key thinkers and ideas.

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.

According to the physics of black holes, our 4D reality may be a hologram—a projection of information coded on a 2D surface on the edge of the universe.

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.

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

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.

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

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

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.

All rainbows are 'raincircles' caused by water droplets separating white sunlight into a spectrum of colors, but Earth's surface blocks the bottom half of the circle from our line of sight.

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

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

The first horror movie is believed to be George Méliès' 1986 short 'The Haunted Castle,' which pioneered the use of special effects

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

Explore the animals that populate the depths of the ocean, from fish and coral in the first few hundred feet, all the way down to the bottom of the Mariana Trench.

After NASA's Voyager 1 captured Earth as a single pixel as it left the solar system in 1990, astronomer Carl Sagan used the image to reflect on humanity's fragility and the responsibility to protect 'the only world we've ever known.'

Browse a detailed visual analysis of over 200,000 similes—comparisons that often use 'like' or 'as'—from popular fiction to see how frequently writers the same idiomatic expressions.

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

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

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.

Discover the catastrophic consequences of a failure of the US electrical grid—something that is more likely than many Americans think.

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

Legendary architect Frank Lloyd Wright designed the SC Johnson headquarters in Wisconsin, aiming to make a cathedral-like workplace