The most complex manifestation of intelligence that we know of resides between our ears.
Here are some incredible numerical facts about the human brain.
1. The typical brain comprises about 2% of the body’s total weight, but uses 20% of its total energy and oxygen intake.
2. Your brain is 73% water.
It takes only 2% dehydration to affect your attention, memory and other cognitive skills.
3. Ninety minutes of sweating can temporarily shrink the brain as much as one year of aging does.
4. Your brain weighs about three pounds.
Sixty percent of the dry weight is fat, making the brain the most fatty organ in the body.
5. Twenty-five percent of the body’s cholesterol resides within the brain.
Cholesterol is an integral part of every brain cell.
Without adequate cholesterol, brain cells die.
6. No one knows for sure, but the latest estimate is that our brains contain roughly 86 billion brain cells.
7. Each neuron can transmit 1,000 nerve impulses per second and make as many as tens of thousands of synaptic contacts with other neurons.
8. A piece of brain tissue the size of a grain of sand contains 100,000 neurons and 1 billion synapses, all communicating with each other.
9. All brain cells are not alike.
There are as many as 10,000 specific types of neurons in the brain.
10. Your brain needs a constant supply of oxygen.
As little as five minutes without oxygen can cause some brain cells to die, leading to severe brain damage.
11. Babies have big heads to hold rapidly growing brains.
A 2-year-old’s brain is 80% of adult size.
12. As any parent can attest, teenage brains are not fully formed.
It isn’t until about the age of 25 that the human brain reaches full maturity.
13. Brain information travels up to an impressive 268 miles per hour.
This is faster than Formula 1 race cars which top out at 240 mph.
14. Your brain generates about 12-25 watts of electricity.
This is enough to power a low-wattage LED light.
15. There’s a reason the brain has been called a “random thought generator.”
The average brain is believed to generate up to 50,000 thoughts per day.
16. Every minute, 750-1,000 milliliters of blood flows through the brain.
This is enough to fill a bottle of wine or liter bottle of soda.
17. Your brain can process an image that your eyes have seen for as little as 13 milliseconds — less time than it takes for you to blink.
Fun Facts About Brain Size
Size matters with some things, but with the brain, bigger doesn’t always mean better or smarter.
18. In general, men’s brains are 10% bigger than women’s, even after taking into account larger body size.
However, the hippocampus, the part of the brain most strongly linked with memory, is typically larger in women.
19. Albert Einstein’s brain weighed 2.71 pounds (1,230 grams) — 10% smaller than the average of 3 pounds (1,400 grams).
However, the neuron density of his brain was greater than average.
20. Neanderthal brains were 10% larger than our Homo sapiens brains.
21. While humans have the largest brains proportional to body weight of all animals, we don’t have the biggest brains.
That distinction belongs to sperm whales with 17-pound brains.
22. Human brains have gotten significantly smaller over the past 10-20,000 years.
The lost volume is equivalent to the size of a tennis ball.
23. The hippocampus, the part of the brain considered the “memory center,” is significantly larger in London cab drivers.
This is due to the mental workout they get while navigating the 25,000 streets of London.
The Effects of the Modern Lifestyle on the Brain
Our modern lifestyle is changing our brains.
And it’s not all for the better.
24. Chronic stress and depression are rampant in modern life.
Either can cause measurable brain shrinkage.
25. The modern diet is low in omega-3 essential fatty acids.
Low levels of omega-3s result in brain shrinkage equivalent to two years of structural brain aging.
26. Since the Victorian era, average IQs have gone down 1.6 points per decade for a total of 13.35 points.
27. Technology has forced most of us to be prodigious multitaskers.
But your brain can’t learn or concentrate on two things at once.
What it can do is quickly toggle back and forth between tasks.
But doing so decreases your attention span, ability to learn, short-term memory, and overall mental performance.
28. Unexpectedly, millennials (aged 18 to 34) are more forgetful than baby boomers.
They are more likely to forget what day it is or where they put their keys than their parents!
29. Attention spans are getting shorter.
In 2000, the average attention span was 12 seconds.
Now, it’s 8 seconds. That’s shorter than the 9-second attention span of the average goldfish.
30. Brain cells cannibalize themselves as a last ditch source of energy to ward off starvation.
So, in very real ways, dieting, especially low-fat diets, can force your brain to eat itself.
31. Over 140 proteins in the brain are negatively impacted by exposure to electromagnetic frequencies, the kind emitted by your cell phone and other electronic devices.
32. Relying on GPS to navigate destroys your innate sense of direction, a skill that took our ancestors thousands of years to develop and hone.
When areas of the brain involved in navigation are no longer used, those neural connections fade away via a process known as synaptic pruning.
Brain Facts Update: Myths Debunked
Rapid advancements in neuroscience means that information gets outdated fast.
This is one reason that there’s a lot of misinformation and myths floating around about the brain.
New evidence has shown that these commonly accepted brain “facts” are not true.
33. The popular myth that we use only 10% of our brains is flat-out wrong.
Brain scans clearly show that we use most of our brain most of the time, even when we’re sleeping.
34. There is no such thing as a left-brain or right-brain personality/skill type.
We are not left-brained or right-brained; we are “whole-brained.” (See #33)
35. In spite of what you’ve been told, alcohol does not kill brain cells.
What excessive alcohol consumption can do is damage the connective tissue at the end of neurons.
36. The “Mozart effect” has been debunked.
While listening to certain kinds of music can improve memory and concentration, there’s nothing unique about listening to Mozart.
37. You may have heard that we have more brain cells than there are stars in the Milky Way, but this is not true.
Best-guess estimates are that we have 86 billion neurons while there are 200-400 billion stars in the Milky Way.
38. It’s often said that there are 10,000 miles of blood vessels in the brain when, actually, that number is closer to 400 miles.
Still, a substantial amount!
39. Contrary to the prevailing medical belief, having high total cholesterol is not bad for your brain. (See #5)
In fact, high cholesterol actually reduces your risk of dementia.
40. Until recently, it was a “fact” that you were born with a set level of intelligence and number of brain cells.
But it has since been discovered that your brain has the capacity to change throughout your lifetime due to a property known as brain plasticity.
The brain can continue to form new brain cells via a process known as neurogenesis.
Facts About the Brain and Memory
It was once thought that the brain recorded memories like a camera, but this is not how memory works.
Rather than being discrete recordings of experience, memory-making is more akin to the creation of improvisational jazz.
41. Memory is better thought of as an activity rather than being associated with a specific area of the brain.
Any given memory is deconstructed and distributed in different parts of the brain.
Then, for the memory to be recalled, it gets reconstructed from the individual fragments.
42. Your brain starts slowing down at the ripe old age of 24, but peaks for different cognitive skills at different ages.
In fact, at any given age, you’re likely getting better at some things and worse at others.
An extreme case is vocabulary skills which may peak as late as the early 70s!
43. If you were drinking alcohol and don’t remember what you did last night, it’s not because you forgot.
While you are drunk, your brain is incapable of forming memories.
44. It’s generally believed that people with exceptional memories are born that way, but this is rarely the case.
Most memory masters will tell you that having an outstanding memory is a skill they developed by employing the best memory techniques.
Facts About Brain Form and Function
The human brain’s design and function are uniquely amazing.
45. Human brain tissue is not dense.
It’s very fragile — soft and squishy similar to the consistency of soft tofu or gelatin.
46. The brain produces a half cup of fluid every day.
It floats in this bath of cerebrospinal fluid which acts as a shock absorber to keep the brain from being crushed by its own weight.
47. Sometimes half a brain is a good as a whole one.
When surgeons operate to stop seizures, they remove or disable half of the brain in a procedure known as a hemispherectomy.
Shockingly, patients experience no effect on personality or memory.
48. Your brain has a pattern of connectivity as unique as your fingerprints.
49. Although pain is processed in your brain, your brain has no pain receptors and feels no pain.
This explains how brain surgery can be performed while the patient is awake with no pain or discomfort.
Headache pain feels like it starts in your brain, but is caused by sensations from nearby skin, joints, sinuses, blood vessels or muscles.
50. Brain freeze sure feels like pain in the brain but is an example of referred pain emanating from the roof of the mouth.
Fortunately, brain freeze does not freeze brain cells because frozen brain cells rupture and turn to mush.
51. The brains of introverts and extroverts are measurably different.
MRIs reveal that the dopamine reward network is more active in the brains of extroverts while introverts’ brains have more gray matter.
52. According to research done at Cambridge University, the order of letters in a word doesn’t matter much to your brain.
As long as the first and last letters are in the right spot, your brain can rearrange the letters to form words as fast as you can read.
This is why you can easily make sense out of this jumble of letters:
Aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it deosn’t mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a toatl mses and you can sitll raed it wouthit porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.
How The Human Brain Compares to a Computer
The human brain is usually compared to the most advanced technology of the day.
It’s been compared to a clock, a switchboard, a computer, and, most recently, to the internet.
You might be surprised to learn that, in every way it’s been tested, the brain is still far superior to the most powerful computers in existence.
53. Your brain’s storage capacity is considered virtually unlimited.
It doesn’t get “used up” like RAM in your computer.
54. The latest research shows that the brain’s memory capacity is a quadrillion, or 1015, bytes.
Astoundingly, this is about the same amount needed to store the entire internet!
55. The human brain is capable of 1,016 processes per second, which makes it far more powerful than any existing computer.
56. Researchers involved in the AI Impacts project have developed a way to compare supercomputers to brains — by measuring how fast a computer can move information around within its own system.
By this standard, the human brain is 30 times more powerful than the IBM Sequoia, one of the world’s fastest supercomputers.
57. Japan’s K computer is one of the most powerful computers in the world.
When programmed to simulate human brain activity, it took 40 minutes to crunch the data equivalent to just one second of brain activity.
Evidence Our Brains “Could Be Better”
You’ve seen plenty of evidence so far that our brains are truly amazing!
But the brain can also work in ways that are illogical, fallible, and counterproductive.
58. There are almost 200 known cognitive biases and distortions that cause us to think and act irrationally.
59. Memories are shockingly unreliable and change over time.
Emotions, motivation, cues, context and frequency of use can all affect how accurately you remember something.
This includes “flash bulb memories” which occur during traumatic events.
60. Of the thousands of thoughts a person has every day, it’s estimated that 70% of this mental chatter is negative — self-critical, pessimistic, and fearful.
61. Think you’re in control of your life? Don’t be so sure.
Ninety-five percent of your decisions take place in your subconscious mind.
62. A blood-brain barrier protects your brain by preventing many foreign substances in your vascular system from reaching the brain.
But the barrier doesn’t work perfectly and many substances sneak through.
Nicotine rushes into the brain in a mere 7 seconds.
Alcohol, on the other hand, takes 6 minutes.
63. Our brains crave mental stimulation, sometimes to a fault.
Men especially would rather give themselves electric shocks than sit quietly in a room and think!
64. Synesthesia is a condition where stimulation of one sense automatically evokes a perception of another sense.
People with synesthesia might “taste” words, “smell” sounds, or see numbers as colors.
While it’s not known exactly why this occurs, the prevailing theory is that these brains have hyper-connectivity between sensory areas in the brain.
65. The human brain is extraordinarily complex and consequently can go awry in some spectacular ways.
Some of the strangest disorders include exploding head syndrome disorder (hearing phantom explosions in your head), Capgras syndrome (thinking loved ones have been substituted by impostors, robots or aliens), and Cotard’s syndrome (believing you are dead).
66. Savant syndrome is a condition where those with serious mental disabilities have an “island of genius.”
The most common areas of genius fall into one of these categories: music, art, mathematics, mechanical, or spatial skills.
67. Most savants are born that way, but a brain trauma can cause acquired savant syndrome where ordinary people suddenly develop genius-level abilities they didn’t have before.
68. Brain cells need a constant supply of fuel to stay alive, yet they lack the ability to store energy.
Fortunately, there’s a backup system.
Your liver breaks down stored fat to produce ketone bodies that can be used as a substitute fuel when commonly-used blood glucose is not available.
Brain Facts That Are Just Plain Weird
And there are some facts that may just make you smile at the seemingly miraculous wonder that is our brain.
69. The brain in your head isn’t your only brain.
There’s a “second brain” in your intestines that contains 100 million neurons.
Gut bacteria are responsible for making over 30 neurotransmitters including the “happy molecule” serotonin.
70. Some scientists believe zombies could actually be created.
They think it’s possible that a mutated virus or parasites could attack the brain and rapidly spread throughout large populations, essentially causing a “zombie apocalypse.”
71. Users of Apple devices really are different than those who use Android products. (It’s not your imagination.)
MRIs reveal that Apple products stimulate the “god spot” in their users’ brains — the same part of the brain activated by religious imagery in people of faith.
72. Few facts about the brain are as strange as the posthumous story of Albert Einstein’s brain.
The pathologist who performed Einstein’s autopsy kept the brain in a jar in his basement for 40 years.
Eventually, he made a cross-country trip with the brain in a Tupperware container to deliver it to Einstein’s granddaughter.