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

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.

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.

Examining self-diagnosed synesthesia

A growing number of people on social media claim to have a perceptual condition that lets them smell colors, see music, or taste sounds. But do they really?

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.

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.

Science is rarely a linear progression of understanding

Particularly at the frontiers, investigations conducted based on established knowledge can provide unexpected results. This opens the door to revising existing models, inspiring new lines of research, and ultimately leading to better future comprehension. For instance, experiments on the speed of light and the expansion of the universe yielded then-confusing data that led to revolutionary insights.

Some scientists argue NDEs are constructed by the brain, not actually experienced

Despite the powerful memories associated with NDEs, scientists question the idea that the experiences prove consciousness endures after death, opting instead to find physiological explanations for common reports of out-of-body experiences, euphoric and lucid thinking, and more.

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.

By separating light with tools such as prisms, scientists can reveal the presence and composition of celestial matter by identifying color fingerprints unique to specific elements and molecules.

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.

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.

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.

Sleep is no longer considered a binary state—scientists are seeking to map a variety of liminal states between sleep and waking, including the hypnagogic state associated with boosts of creativity.

Psychiatrist Bruce Greyson created a scale to identify and rate NDEs

Researcher Bruce Greyson is one of the world’s leading experts on near-death experiences. This article explores what the field of NDE research has learned over the last five decades, discusses the difficulties of studying such a controversial topic, and outlines what we’ve ruled out as the cause of these events.

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.

Psychedelics set off a flurry of brain activity that may permanently alter it

The brain seems to experience a sharp increase in communication between areas that generally don't interact. New research suggests a thin, sheet-like gray matter structure tucked deep within the brain, between the insular cortex and striatum, may be the key to this change. The area is centrally located and home to many of the receptors that psychedelics target, potentially rewiring the brain and rewriting thought patterns.

How the buildings you occupy may affect your brain health

Beautiful spaces filled with light and natural motifs aren't just aesthetic, but likely key to your health. Researchers had study participants view photographs of two distinct buildings, one designed with more natural elements while the other featured more abstract shapes and lines. Using electroencephalograph readings of each participant, they discovered participants had less brain inflammation while viewing the "biophilic," or natural, architecture. Learn more about the interdisciplinary framework of so-called neuroarchitecture here.

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

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

The perception of haunted places is influenced by psychology, setting and suggestion

Gothic architecture and tragic histories contribute to the perception of hauntings. Infrasound and black mold can cause experiences reminiscent of paranormal phenomena. Although paranormal investigators use technology to seek natural explanations, many paranormal experiences remain non-falsifiable.

The neurobiology of meaningfulness: the benefits of psychedelics

Psychedelics produce powerful emotions in its users, including a profound sense of meaningfulness. The philosopher William James called this sense "noetic" in the late 19th century, but for decades researchers avoided studying the effects of such drugs on the brain. However, the recent resurgence in psychedelic research has heightened interest in the relationship between this noetic sense resulting from the therapeutic use of drugs. Learn what researchers have found out here.

Wave-particle duality—a simple overview

Our notion of reality is built on everyday experiences. But wave-particle duality is so strange that we are forced to re-examine our common conceptions. Wave-particle duality refers to the fundamental…

Experimenting with space-time

Einstein's theory of general relativity—that mass literally bends space and time—can be difficult for the human brain to imagine. This interactive resource lets you create celestial objects, imagine their effect on space-time, and see how they interact with each other (best viewed on desktop).

The study of dreams, formally called oneirology, has evolved over the centuries, from anecdotal interpretations to advanced brain imaging.

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.

New ways of seeing the cosmos have redrawn the map of human identity

From Galileo’s crude spyglass to the James Webb Space Telescope, each technological leap has expanded our observational reach and redefined philosophical and moral conceptions of our place in the universe. Identifying signs of life through the study of exoplanet atmospheres would represent the next great revolution.

Physiological changes to the brain on LSD can be captured via MRI

Psychedelics like LSD often take users on novel experiences that can result in lasting shifts in perspective and behavior. See how LSD affects brain activity in this video that details how scientists visually captured the psychedelic's effect for the first time.

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.

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.

Colorizers convert Hubble's gray scale images into color composites of different wavelengths

The near-infrared and ultraviolet light captured by the space telescope is not visible to human eyes, but observational data of these types of light can be filtered and modified into visible colors. Many detailed images of astronomical objects are the result of combining these artificially colored images into layers.

The 'overview effect' heightens one's sense of unity and connectedness

Coined by space philosopher Frank White in 1987, the term refers to the paradigm-shifting experience a person undergoes upon viewing Earth from space. Commercial spaceflights aim to bring this perspective to a broader audience, inspiring changes in behavior and worldview among participants.

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.

The overview effect is a cognitive shift experienced when viewing Earth from space

Astronauts regularly report profound realizations after seeing Earth from space for the first time, sometimes prompting significant philosophical changes, including a greater awareness of the interconnectedness and fragility of life.

Scientists are studying dying patients' brain activity in the final moments of life

In the final moments of life there are distinctive bursts of coordinated neural activity. Researchers are interested in parsing that data to better understand the dying process and also exploring how this data relates to our understanding of consciousness.

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.

Light has been modeled as a wave and a stream of particles throughout history

Isaac Newton first identified white light as composed of a spectrum of colors, which he believed consisted of particles of different hues. Various light phenomena, including refraction, led Christiaan Huygens to develop an alternative wave model. Quantum mechanics validated both models through the concept of wave-particle duality.

Apophenia, the cognitive bias that leads people to find meaning in randomness, helps explain why humans look for meaning in their dreams and even in their tea leaves.

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.

Scientists create contact lenses that give you infrared vision

Scientists have created lenses that use nanoparticles to convert infrared light into visible light, allowing human eyes to observe previously invisible parts of the electromagnetic spectrum. This technology may help colorblind individuals by converting colors they cannot see into wavelengths they can.

A 'paranormal activity' unit at the University of Virginia studies challenges to mainstream scientific ideas about human consciousness.

'1440 Explores' Episode 3: Why We See Ghosts and What Isn't There

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. Together, they uncover why our minds see meaning—and sometimes ghosts—where none exist, and what that reveals about fear, memory, and our need to believe in something beyond the grave.

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.

How can octopuses and MDMA help scientists understand the human brain?

Research shows that psychedelics may induce something called "critical periods" in the adult brain, which can make our brains more open to learning and changing, like they once were back in early childhood. Psychedelics similarly change how social creatures like octopuses behave, which demonstrates that these animals could help us better understand our own neurobiology.

Visualizing Einstein's special relativity

Before Einstein developed his theory of general relativity, he worked out what is known as special relativity—or why time is experienced different for different observers. The breakthrough rests on his theory that light travels at a constant...

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.

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.

Friedrich's perspective draws in viewers

Friedrich produced several works, including "Wanderer," portraying figures with their back to the viewer. The effect—called Rückenfigur, or ”figure from the back”—can create complex emotions of longing, immersion, or awe.

Scientific progress works toward absolute truth, but can never reach it

Through the acquisition of scientific knowledge, scientists construct explanations of the world, which are rigorously tested and verified until they narrow down to a leading theory of the natural world. However, because of how science works, these ideas will never become factual, as they must always remain open to be iteratively revision based on new data.

The debate on why humans are conscious—and what that means

Understanding what consciousness is, and why and how it evolved, is perhaps the greatest mystery known to science. Watch interviews with the world's leading experts on what it is and whether we'll ever know.

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.