How Much of Our Brain Do We Use? — And Other Questions Answered

Medically reviewed by Deborah Weatherspoon, PhD, RN, CRNA, COI on January 10, 2017Written by Ann Pietrangelo

Overview

You can thank your brain for everything you feel and understand about yourself and the world. But how much do you truly know about the complex organ in your head?

If you’re like most people, some of the things you think about your brain may not be true at all. Let’s explore some common beliefs about the brain to find out if they’re true.

1: Do you really use only 10 percent of your brain?

The idea that we only use 10 percent of our brain is deeply entrenched in popular culture and often stated as fact in books and movies. A 2013 study found that 65 percent of Americans believe this to be true.

It’s not entirely clear how it all started, but it’s more science fiction that fact.

Sure, some parts of your brain are working harder than others at any given time. But 90 percent of your brain isn’t useless filler. Magnetic resonance imaging shows that most of the human brain is active most of the time. In the course of a day, you use just about every part of your brain.

This doesn’t mean that you can’t improve your brain health. Your whole body is depending on your brain. Here’s how to give your brain the TLC it deserves:

Eat well

A well-balanced diet improves overall health as well as brain health. Eating right reduces the risk of developing health conditions that can lead to dementia.

Foods that promote brain health include:

  • olive oil
  • fruits and vegetables high in vitamin E, such as blueberries, broccoli, and spinach
  • fruits and vegetables high in beta carotene, such as spinach, red peppers, and sweet potatoes
  • foods rich in antioxidants, such as walnuts and pecans
  • omega-3 fatty acids that can be found in fish, such as salmon, mackerel, and albacore tuna

Exercise your body

Regular physical activity helps reduce the risk of health problems that can cause dementia.

Challenge your brain

Research indicates that activities like crossword puzzles, chess, and deep reading can lower your risk of memory problems. Even better is a mentally stimulating hobby that involves a social component, such as a book club.

2: Is it true that you get new brain “wrinkles” when you learn something?

Not all brains are wrinkled. In fact, most animals have fairly smooth brains. Some exceptions are primates, dolphins, elephants, and pigs, which also happen to be some of the more intelligent animals.

The human brain is exceptionally wrinkled. That’s probably why people conclude that we gain more wrinkles as we learn new things. But that’s not how we acquire brain wrinkles.

Your brain starts developing wrinkles before you’re even born. The wrinkling continues as your brain grows, until you’re about 18 months old.

Think of the wrinkles as folds. The crevices are called sulci and the raised areas are called gyri. The folds allow room for more gray matter inside your skull. It also decreases wiring length and improves overall cognitive functioning.

Human brains vary quite a bit, but there’s still a typical pattern to brain folds. Research shows that not having the major folds in the right places could cause some dysfunction.

3: Can you really learn through subliminal messages?

Various studies suggest that subliminal messages might be able to:

Learning entirely new things is far more complicated.

Say you’ve been studying a foreign language. There’s only a small chance that listening to vocabulary words in your sleep can help you remember them a bit better. A 2015 study found that this is true only under the best of circumstances. The researchers noted that you can’t learn new things during your sleep.

On the other hand, sleep is crucial to brain function. Getting adequate sleep can help improve learning, memory, and problem-solving skills.

Perhaps the boost to intellectual performance from sleep is the reason this myth endures. If you want to learn something new, your best bet is to tackle it head on rather than subliminally.

4: Is there such a thing as being left-brained or right-brained?

Well, your brain definitely has a left side (left brain) and a right side (right brain). Each hemisphere controls certain functions and movement on the opposite side of your body.

Beyond that, the left brain is more verbal. It’s analytical and orderly. It takes in the small details, and then puts them together to understand the whole picture. The left brain handles reading, writing, and calculations. Some call it the logical side of the brain.

The right brain is more visual and deals in images more than words. It processes information in an intuitive and simultaneous manner. It takes in the big picture, and then looks at the details. Some say it’s the creative, artsy side of the brain.

There’s a popular theory that people can be divided into left-brained or right-brained personalities based on one side being dominant. Left-brained people are said to be more logical, and right-brained people are said to be more creative.

After a two-year analysis, a team of neuroscientists found no evidence to prove this theory. Brain scans showed that humans don’t favor one hemisphere over the other. It’s not likely that the network on one side of your brain is substantially stronger than the opposite side.

As with most things relating to the human brain, it’s complicated. While each hemisphere has its strengths, they don’t work in isolation. Both sides contribute something to logical and creative thinking.

5: Does alcohol really kill your brain cells?

There’s no question that alcohol affects the brain in negative ways. It can impair brain function even in the short term. In the longer term, it can lead to serious brain damage. It doesn’t actually kill brain cells, though.

Long-term heavy drinking can cause shrinking of the brain and result in deficiencies in white matter. This can lead to:

  • slurred speech
  • blurred vision
  • balance and coordination problems
  • slowed reaction times
  • memory impairment, including blackouts

Exactly how alcohol affects an individual’s brain depends on many factors, including:

  • age
  • gender
  • how much and how often you drink, and how long you’ve been drinking
  • general health status
  • family history of substance abuse

Alcoholics are prone to developing a brain disorder called Wernicke-Korsakoff syndrome. Symptoms include:

  • mental confusion
  • paralysis of nerves that control eye movement
  • muscle coordination problems and difficulty walking
  • chronic learning and memory problems

Drinking during pregnancy can affect your baby’s developing brain, a condition known as fetal alcohol syndrome. Children with fetal alcohol syndrome tend to have smaller brain volume (microcephaly). They can also have fewer brain cells or normally functioning neurons. This can cause long-term behavioral and learning problems.

Alcohol may interfere with the brain’s ability to grow new brain cells, which is another reason this myth may persist.

The bottom line

Why is it so easy to believe these myths about the brain? There’s a grain of truth running through some of them. Others seep into our own brains through repetition, and we fail to question their validity.

If you previously bought into some of these brain myths, take heart. You weren’t alone.

As much as scientists know about the human brain, there’s a long way to go before we come close to fully understanding the mysterious organ that makes us human.

Keep reading: 7 health myths, debunked »

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