Examining self-diagnosed synesthesia

Individuals with synesthesia experience involuntarily overlapping sensations

Tasting words or seeing colors in music results from the brain retaining extrasensory connections from infancy. While most lose these neural pathways during development, about 4% of people are synesthetes, maintaining them without realizing it's unusual.

Visualizing a synaesthetic soundscape

Artist Michal Levy has chromesthesia, a subtype of synesthesia in which sounds and music trigger involuntary associations with and sensations of color. This condition gives Levy a unique artistic perspective and ability to interact with and interpret music. In this short animation, Levy tries to capture her audiovisual experience of 'Giant Steps," considered a landmark composition in jazz history by musician John Coltrane.

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.

Brain implants can help colorblind people hear colors

Colorblind artist Neil Harbisson was born into a world of grey. In 2004, he had a chip installed connected to an external color frequency sensor. Once the sensor "reads" a color, it sends a signal to the chip and plays an associated sound both in and outside Harbisson's head.

Humans experience the world subjectively. What does that mean for scientific research?

When you close your eyes, do you see static or colorful patterns or an "intrinsic grey" known as Eigengrau in German? This variation of our internal experiences is just the tip of the iceberg, one that scientists are increasingly studying and...

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.)

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 leading expert on near-death experiences, psychiatrist Dr. Bruce Greyson, says that during his decades of research on this topic, this area of research has become far more mainstream and accepted as a rigorous area of inquiry.

Finding delight through your five senses

Digging into your immediate senses is shown to benefit your overall psychological well-being, from the happy memories evoked by familiar scents or through the transformative power of birdsong. This episode from the Science of Happiness podcast highlights insights from Gretchen Rubin, an author who has written books on the importance of engaging your senses for a happy life.

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.

Humans may be able to distinguish more than one trillion scents

That's according to one estimate published in 2014. This figure far exceeds earlier estimates of a human smelling ceiling around 10,000 odors. The newer figure is derived from experiments in which volunteers agreed to sniff varying scents. Researchers mixed odor components and had volunteers sniff the brews to detect subtle scent differences. (Some users may experience a paywall.)

Tetrachromacy allows humans to observe 10 times the normal amount of colors

Resulting from a mutation on the X chromosome, the rare genetic condition causes individuals to possess an additional type of photoreceptor cell, typically sensitive to the orange range, located between the standard red and green cones. This enables the perception of approximately 100 million colors.

If hearing is damaged, the brain may amplify remaining sounds, perhaps causing tinnitus.

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.

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.

A super-sniffer smelled her husband's Parkinson's disease years ahead of symptoms.

Accounts of near-death experiences share similarities with hallucinogens, with reports of mystical-like states of consciousness across both contexts.

Hereditary hyperosmia is the official term for being a super-smeller

Some sniffers with this rare trait may be more sensitive to pleasant smells, while others may be more attuned to unpleasant scents. Some research suggests that certain genetic mutations are associated with a heightened sense of smell.

Some people really cannot imagine. Literally.

There are many people who are astonished to discover that their complete lack of ability to picture visual imagery is different from the norm.

A stand-in 'nose' may help people with anosmia to smell certain odors

In a 2025 paper, researchers reported they'd created a proof-of-concept device that bypasses typical olfactory pathways and instead exploits an alternative—the trigeminal nerve in the nose—to detect a few strong scents. The nerve typically helps detect the temperature of inhaled air or the presence of irritants. (Some users may experience a paywall.)

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.

Wearing a 'schizophrenia simulator,' designed to build empathy for patients, CNN's Anderson Cooper finds he struggles to function

Donning headphones that play a track mimicking the auditory hallucinations common in schizophrenia, Cooper finds he is very distracted, disconcerted, and frustrated. The auditory track aims to help listeners build empathy with patient populations by understanding the challenges they face in daily life.

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.

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.

When common sounds become disturbing

Misophonia causes certain sounds to feel violating, triggering a "very visceral kind of experience" filled with extremely unpleasant emotions, including annoyance, anger, and disgust. A 2017 study found that people with misophonia have elevated activity in the brain's anterior insula—a region associated with interoception, emotional processing, and behavioral responses—when exposed to trigger sounds. Ongoing research suggests trigger sound context affects the severity and manifestation of the condition.

An ear doctor with hearing loss seeks to help those with hearing loss enjoy music

Alex Chern, an ear doctor who has hearing loss himself, dreams of restoring the ability to experience "all the richness and the beauty of the sound of music" for patients—not just functional hearing. Hearing aids amplify sound waves and aren't designed to work well with music that may have varied pitch and volume. Chern is studying how hearing loss and engaging with music may affect cognitive decline.

Meet the psychologist who reads people through the art they live with

Dimitrios Tsivrikos, an academic psychologist at University College London, says the art someone hangs in their home reveals as much about them as a bookshelf would. He advises going on a first date at a museum and asking each other about the work on the walls.

Studies of psychedelic use may help shed light on the nature of consciousness

The nature of consciousness—what it is, where it comes from, and how it manifests as moment-to-moment experience—remains under debate by scientists. Recent studies show psychedelics were found to boost low-frequency brain signals known as delta waves, a behavior also seen during dream states.

Psychedelic side effects, including worsening mental health for some patients, give pause

This article explores whether the therapeutic potential of psychedelic drug use is really as good as current research suggests. Scientists are exploring its applications for conditions ranging from the existential crisis that can accompany terminal diagnoses to chronic mental health conditions, including anxiety and PTSD.

Modern media exposure may impact whether people dream in color or black and white.

One theory claims the retinae of SAD patients may fail to adjust to less light in winter

Most people’s eyes become more sensitive to light in the winter months, but some do not. This failure to adjust causes ripple effects on those individuals’ biological clocks. This Ted-ED video provides a clear, brief, narrative explanation of the condition in six minutes.

Psychedelic compounds: a visual library

However psychedelic experiences manifest, they all begin with the presence of psychoactive compounds. Learn about their various chemical compositions in this structural library of psychedelic compounds. Clicking on an entry will take readers to a new page where they can learn about the chemistry and pharmacology of each compound, as well as the drug's possible applications.

Roughly 15 of every 1,000 people in the US have smell disorders

Anosmia is a lack of a sense of smell. It can be present at birth, related to diseases including Parkinson's, Alzheimer's, and COVID-19, or have unknown causes.

The research that led to sour

Scientists are trying to figure out if there are unique receptors that respond to the molecules that make up flavors we associate with calcium, blood, batteries, and other items that often escape dinner menus. Taste researcher Dr. Danielle Reed says the minimum evidence for a taste category typically involves identifying dedicated receptors and then removing them to show the taste vanishes.

Color originates from the brain processing light of varying wavelengths

Various geometric models, including Newton's color circle of hue and saturation and the horseshoe-shaped XYZ space for mixing colors via vector mathematics, have been proposed to describe colors accurately. However, these models do not encapsulate the variety of psychological effects that cause perceived colors to differ from mathematical representations.

Hear examples of what tinnitus can sound like to those suffering from it.

The psychedelic playlist inspired by a Johns Hopkins experiment

Dating back to 1967, the playlist is over seven hours long and organized in such a manner as to echo users’ experiences as their trips rise, crest, and fall. According to the initial creator of the playlist, the music is a “nonverbal support system” that keeps users from prematurely returning to normal consciousness.

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.

1 in 15 adults over age 40 experience phantom odors

This phenomenon was measured in a 2018 study that examined the prevalence and risk factors for phantom odor perception. Older adults were less likely to experience these phantom odors as they age, just as their overall sense of smell declines. Women are more likely than men to perceive phantom odors.

Blindfolded people could identify objects by touch alone a week after encountering them

These touch memories are more complex and durable than previously thought. In research published in 2018, blindfolded volunteers touched over 150 household objects for about 10 seconds each, and afterward correctly identified the objects more than 90 percent of the time when presented with the object and a similar one. Participants still knew most of the objects a week later with about 85 percent accuracy. (Some users may experience a paywall.)

How psychedelics can potentially reinvent learning

Critical periods, discovered in the early 20th century, describe a period when someone is incredibly sensitive to their environment, and any information learned can stick with them for life. Some researchers argue these states can be "reopened" via psychedelics, which put the mind into a malleable state that can potentially be used to treat conditions ranging from lazy eyes to PTSD.

How seizures (potentially) alter consciousness

Seizures occur when intense electrical activity floods the brain, prompting significant loss of self-control and a variety of sensory disruptions and hallucinations. Cultures interpret the episodes differently, with many contemporary norms viewing them as negative while others characterize them as intense spiritual occasions. Author Fyodor Dostoyevsky viewed his seizures this way, as well as cultures in Mongolia, some Shamanic indigenous religions, and others.

The main criticism of a recent neurophysiological explanation for near-death experiences is that these events are too complex to be explained as a neurochemical response to an oxygen-deprived brain.

Social media addiction, though not a clinical diagnosis, refers to the idea that infinite scroll, notifications, and algorithms override one's ability to stop using them.

50 years of research has focused on unraveling the relationship between music and frisson

One insight reveals that musical passages with surprising volume changes or unexpected harmonies and beauty are more likely to trigger frisson, perhaps because they upend listeners' expectations.

Historians theorize Vincent Van Gogh suffered from Ménière's disease or epilepsy

A century after researchers suggested he suffered from epilepsy, some researchers in the 1990s began to support an alternate diagnosis: Ménière's disease, since he had suffered from severe, repeated attacks of disabling vertigo. Still, some researchers remain skeptical of the Ménière's diagnosis. One posits that Van Gogh had temporal epilepsy complicated by his absinthe consumption.

A near-death experience is a phenomenon experienced by roughly 5% to 23% of the population, and typically occurs after a traumatic physical event or a brief clinical death.

How art helps us process our feelings

The internet is chock full of hacks and apps that supposedly help you optimize yourself into a more productive person. But Aparna Chivukula argues that spending so much mental energy on "wellness" misses a larger philosophical issue, one that can only be explored through art.

Catfish have taste buds spread across their entire skin, making their whole body function like a tongue that can taste food several feet away.

The body's response to cardiac arrest has been linked to near-death experiences.