The human brain is an impossibly complex organ. It is so complex, in fact, that scientists still do not fully understand all of its functions—or even recognize what all of its functions are.

After all, the brain is responsible for everything we do and experience and even differs from person to person. This complexity makes it one of the most interesting areas of science, and it provides some truly mind-blowing facts.

Brains Are Both Fast and Slow

Our brains send out and receive a remarkable number of signals to react to the world around us. However, the speeds of these signals vary.

The fastest transmission in the human body involves sending a signal along an alpha motor neuron in the spinal cord, which reaches 268 miles per hour. Meanwhile, the slowest involve the sensory receptors in the skin, which travel at a single mile per hour.

light rail train going fast


Brains Have the Best Storage Devices

Many people think of the brain as a computer. While modern scientists have backed away from this analogy, it is not entirely wrong. Among the brain’s many computer-like functions is the ability to store information.

However, unlike a standard storage device that can only hold a limited amount of data, the brain's space is virtually unlimited. Research indicates that brains consist of over 86 billion neurons, which interconnect to form up to 1 quadrillion connections. As we age, these neurons connect to create even more storage space.

person inserting usb into head


Brains Produce Tons of Thoughts

Researchers have long attempted to determine how many thoughts people have throughout the day. However, it is difficult to quantify what a “thought” is and it is even more difficult to actually measure it.

A 2020 study suggests that the average person has over 6,000 thoughts each day. Older, less reliable research has suggested amounts ranging between 15,000 and 70,000 daily thoughts.

woman looking thoughtful


Brain Freezes Have a Medical Name

When eating something cold, the temperature in the back of the throat at the meeting place of two key arteries drops dramatically. These arteries are responsible for feeding blood to the brain and meet in the outer layers of the brain, the meninges.

In response to the cold, the arteries in the meninges dilate and contract, triggering the signature headache known as brain freeze. The medical term for this is sphenopalatine ganglioneuralgia.

little boy having brain freeze from ice cream


The Brain Does Not Multitask

Many people take pride in their ability to multitask, but studies show that people who feel they are the best multitaskers are typically among the worst. Modern research points to the prefrontal cortex being able to balance two complex tasks, such as talking on the phone and cooking. However, the more tasks we try to add, the worse the brain performs.

Experts believe this is because the brain does not actually multitask, but bounces between goals at an incredibly fast pace. With each new responsibility, the time the brain can spend processing and performing each one diminishes. Additionally, streams of information from one goal can easily interfere with information from another, resulting in worse processing.

woman at desk multitasking with multiple arms


Brain Size Does Not Affect Intelligence

From the modern term “galaxy brain” to 19th-century remarks like “lowbrow,” some of the most common phrases for intelligence involve the size of the brain.

There is a small amount of truth to this, but not for the reasons most people think. The number of synapses and folds matter, not the general circumference of the brain. Essentially, the more complex a brain, the higher the intelligence, and the more wrinkles it has.

two model brains on a seesaw equal weight


Most of the Brain’s Growth Occurs Early

Human babies have large heads in comparison to their body size. One reason for this is to provide space for the rapidly growing brain. In the first year, a baby’s brain will triple in size.

A two-year-old's brain is typically 80% of the size of an adult’s brain. The spinal cord stops growing at about four years old.

little girl drawing a brain on the chalkboard


It Takes a Long Time for the Brain to Finish Forming

Throughout the history of medical science, researchers have continually discovered more about how the brain forms. By the age of nine, all of the major brain structures are in place. However, it takes another 15 or 16 years to fully develop in most cases.

Some people’s brains develop even slower and will not become fully mature until their early thirties.

teenagers taking apart a brain model


Brain Hemisphere Does Not Correlate to Personality

One of the longest-standing brain myths is that creative people use more of the right side of their brain, while analytical and methodical individuals use the left side of their brain.

While it is true that sections of the brain are responsible for different functions, there is no real connection to someone’s personality.

young man below drawing of brain with hemisphere characteristics


The Brain Needs Lots of Blood

Human brains need a lot of oxygen and nutrients to operate. One of the main ways that the body transfers fuel to the brain is through blood.

To provide ample nutrition, an incredible amount of blood constantly travels through. Every minute, between 750 and 1000 milliliters of blood flows through the brain — enough to fill a wine bottle.

digital illustration of a brain with nerve and blood vessels


Brains Are Very Wet

While the actual amount of water and fluid in the brain can vary, the brain is a very wet organ. Even a minor amount of dehydration can impact cognitive skills, memory, and attention. Plus, 90 minutes of sweating without adequate replenishment can shrink the brain by up to 3%.

model of a brain in a jar


Each Brain Has A Fingerprint

Occasionally, the phrase “our brains are wired differently” will pop up in conversation. This is truer than people might realize. With billions of neurons to link together, each brain can have wildly different patterns of connectivity.

In fact, a person’s neuron network is like a fingerprint—completely unique. Even twins’ brains are only 12% similar.

digital illustration showing half a brain and half a fingerprint


Brains Have a Lot of Fat

Most people tend to think of fats negatively, but the body needs fats and fatty acids to operate effectively. In fact, the brain is almost 60 percent fat, making it the fattiest organ in the human body.

Because the brain needs so many fat-related nutrients to perform even basic tasks, many clinical studies have found links between poor diets and loss of brain performance.

healthy fatty foods on a table


Alcohol Does Not Kill Brain Cells

Despite decades of people saying otherwise, moderate alcohol use does not damage brain cells.

However, binge drinking or regular heavy drinking can harm the ends of neurons, called dendrites. Damaging the dendrites can prevent the neurons from transmitting and receiving messages, which can harm cognitive ability.

brain model on a table with a glass of scotch and beer bottle


The Brain Produces Electricity

Each neuron in the brain communicates using rapid electrical impulses. Scientists have measured this electrical activity and discovered that the organ produces about 23 watts of electrical power.

Modern household LED light bulbs typically draw between five and 10 watts, meaning the brain could power several lights.

brain scan showing electrical impulses on screen


Brains See Faces Everywhere

The brain is constantly assembling a jigsaw of memories to help interpret what we experience. However, it also looks for things that we expect to see. One example of this is pareidolia —the phenomenon of seeing faces in common objects. A bowling ball might look excited while a tree could seem like it is scowling.

This occurs because faces have a general pattern of features that the brain responds to. Some experts also feel that the human brain evolved to encourage social interaction, resulting in being better at detecting faces.

view of a metal box that looks like a face


Brain Surgery Is Ancient

Humanity has always had an interest in the brain, but we tend to think of surgery itself as a relatively new practice. However, archaeologists have discovered hundreds of Stone Age skulls that show evidence of trepanation, a form of brain surgery.

Trepanation was the practice of creating a hole through the skull into the brain. While it is not clear what the goal of the Stone Age surgery was, some experts suggest that it could have been to relieve pressure or was part of a spiritual practice.

ancient skull with a hole from brain surgery trepanation


The Brain Cannot Feel Pain

Though it might seem otherwise when experiencing a splitting headache, the brain cannot actually feel any pain because it lacks pain receptors. Headache pain actually originates in the various nerves, muscles, and tissues surrounding the brain and neck.

Because it cannot feel pain, surgeons can perform brain surgery while the patient is completely awake. Doing so actually helps ensure doctors that they are treating the correct area, lowering the risk of damage.

doctor's gloved hands holding a model of a brain


The Brain is Soft

For various reasons, many people think of the brain as being firmer than it really is. The few people who have touched brains typically do so in lab environments, meaning the brains are full of chemicals for preservation that make the brain quite firm.

A fresh, untreated brain is very soft, with the consistency of tofu or gelatin.

fingers poking a brain model


We Use the Entire Brain...

One of the most prevailing brain myths is that humans only use about 10% of the brain’s full potential. This is completely false and the brain never “turns off.” Even while sleeping, the brain remains very active.

Some research has even found that 15% of coma patients still show brain activity comparable to healthy individuals.

person holding a key unlock brain concept


But We Don't Need the Entire Brain

Though rare, some people have medical conditions that require them to undergo a hemispherectomy. In this surgery, doctors remove half of the brain or disconnect it from the other half. Usually, this is to stop seizures that are not responding to medication.

While the healing process involves significant rehabilitation, the procedure is effective and does not affect memory, personality, or humor. Cognitive changes are typically minor, if present at all.

doctors performing surgery with brain scans in background


Scientists Keep Finding New Brain Cells

Despite all the advances in medical science, experts are still far away from understanding everything about the brain. They have not even identified all of the types of cells in the brain.

As recently as 2018, scientists discovered new inhibitory neurons called rosehip neurons. Their functions are still not well understood.

digital illustration of a brain through a magnifying glass


The Brain Has a Lot of Neurons

Even knowing the brain contains over 86 billion neurons, it is difficult to grasp just how large that number is. A piece of brain the size of a grain of sand would still contain roughly 100,000 neurons and about 1 billion synapses.

Because of this, brain damage can result in the loss of millions of neurons, even if the damage is minimal.

digital illustration of the synapses and neurons in the brain


The Brain Is Light But Hungry

For most people, the brain comprises a mere 2% of their body weight, about three pounds or the weight of a half-gallon of milk.

Despite its small size, the brain has an incredibly high-energy budget. It uses 20% of the calories and oxygen that the body consumes.

model of brain on a scale


Scientists Still Do Not Know Why We Yawn

One of the persisting mysteries of the brain is why we yawn. Experts have eliminated common theories like the brain lacking oxygen or needing to exchange gasses.

The strangest thing about yawning is that it is contagious. This has led researchers to suggest that yawning involves the brain's social functions and empathy.

researcher in lab yawning


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