So, this is not true.

"The bigger the brain, the smarter the creature."

[laughing]

Size doesn't matter.

"You can't prevent a stroke."

No.

No, that's not true.

That's very not true, actually.

Hi, I'm Dr. Santoshi Billakota.

I'm a clinical assistant professor in neurology

at the NYU Grossman School of Medicine.

I'm Dr. Brad Kamitaki.

I'm a neurologist and assistant professor

at Rutgers Robert Wood Johnson Medical School.

And today we'll be debunking myths about the human brain.

"The bigger the brain, the smarter the creature."

[laughing]

Size actually does not matter when it comes to the brain,

because there are creatures out there

with bigger brains than us, but probably not as complex.

Your brain is really determined

by your body proportion, right?

So when you think of, like, a big brown bear

that's way bigger than us,

their brain is going to be bigger,

but that doesn't necessarily mean

that they are smarter than us.

We don't know that for sure

because it hasn't been fully studied,

but we've seen that in instances such as chimpanzees.

They do have smaller brains, but we do know for a fact

that chimpanzees are probably as smart as we are.

Certainly it's not the size of the brain that matters,

but probably how complex it is

and how well developed certain areas are.

Certain areas in humans are,

for example, our language centers

are just much more developed than a cow

or a bear, things like that. Billakota: Even a chimpanzee.

Yeah. That's important in determining intelligence

rather than the size itself.

And also, how do we measure intelligence?

That also becomes tricky,

because not everyone is intelligent in the same way.

Noncognitive factors also play a role.

Like, what's your social intelligence?

What's your emotional intelligence?

All of that, I think, is very complex

and really difficult to measure.

"IQ tests are always an accurate measure of intelligence."

So, this is false.

There's so much that goes into intelligence.

Normal intelligence tests might measure things

like executive function or planning,

verbal skills, reading skills, things like that,

but it's only an approximation of what you can do

and highly influenced by the conditions of the test,

how you're feeling at the time of the test,

your educational level.

It would be nice to say that there's one test or one way

that we can determine how intelligent someone is,

but there's so much that goes into intelligence

that one test or even multiple different tests

can't measure that very well.

So, the popular IQ test was developed in the early 1900s,

and it was a way to determine

which French students were cognitively delayed

so we could offer them better resources.

That got adopted in America at Stanford.

But for all the reasons Brad laid out,

it doesn't take all of those things into account.

So I think although it is nice to say,

"Hey, I am smart, I did well on an IQ test,"

I really don't think that means too much.

Neither of us were born being doctors, right?

We had to learn and develop those skills

under many years of training.

I think that education is the best way

to kind of make that happen, education very broadly.

That might not necessarily be school for everyone.

Definitely some people are savants.

Some people are prodigies.

It's really hard to say what determines that.

They might be better at certain things

but not necessarily good at others.

We're all individuals. We all have different talents

and different aptitudes for different things.

So IQ tests just kind of measure your intelligence

in that one specific area,

not how overall intelligent you are.

"We only use 10% of our brains."

So, this is not true.

We actually use all of our brain.

Not all of the time, but most of the time,

we're using some percentage of our brain.

This myth came into fruition

I think in the early 1800s

where people were trying to figure out

why injuring different parts of the brain

caused disabilities in people.

So a bunch of psychologists came up with a theory

that we only use about 10% of our brains

versus people who are smarter, who use more.

Now we simply know that that is not the case.

We know that because we have something called a PET/MRI

and a functional MRI study.

Kamitaki: We have the frontal lobe, which we use

for a lot of different purposes,

motor function, language function,

executive functioning, or planning activities.

Behind that, our parietal lobe, here,

which is our sensory cortex.

In the back of the brain, we have the occipital lobe,

which is our visual processing center.

And then here on the side,

we have the temporal lobe, which is involved

in memory, language comprehension, on the left side.

Billakota: So to give you an example,

if you are reading something, you're going to be

using your temporal lobes for comprehension.

You're going to be using your frontal lobes

for comprehension. You'll also be using

the back of your head, where your visual cortex sits,

because that's where information from your eyeballs travel

and your body kind of makes sense of it that way.

Kamitaki: And then also, if we take the brain apart

a little bit, we have our brain stem over here,

which is kind of our lizard brain.

It's our primitive brain that controls things

like level of arousal, breathing, respirations,

heart rate, blood pressure.

We have some deep motor functions here in the brain as well.

Another part of the brain that we have

is our cerebellum, kind of on the bottom,

which is also involved in motor control and motor planning.

In doing one task,

you could be using multiple parts of your brain,

but you're not using everything at the same time.

"Video games rot your brain."

So, this is a myth.

Video games in and of themselves

don't actually rot your brain.

That's something that I definitely heard a lot

when I was younger from my grandma and my mom.

Billakota: A lot of our literature

has shown that video games,

especially the ones that focus on team building,

on solving riddles, solving puzzles,

building strategy, are actually pretty good for you.

They actually do build up those centers of your brain,

especially when you're a child.

You know, games can be used for other purposes.

For example, our colleagues in surgery,

when they do scopes, they practice those skills

with things like video-game simulators.

Looking at the trials,

no one has actually defined what too much video games is.

Every literature study that I've looked at

quotes between 12 hours to 90 hours a week is OK.

I feel like 90 hours might be a little excessive.

But I think in reality, the bigger signs

of someone withdrawing from social activities

and wanting to just stay at home and play video games

and they'd prefer to do that than do other things,

that's more of a red flag.

I always say, everything in moderation.

Like, if it's affecting your social life,

if you're just stuck in front of the TV all day,

that's not good psychologically.

"Memory gets worse as you age."

So, this is false.

In fact, there are some types of memory

that improve as you get older.

For example, things like semantic memory:

your vocabulary, reading.

Procedural memory. For example, people that are very good

at musical instruments, like, can play the piano,

often will retain those skills.

Some people will notice some change in memory.

That's often things like episodic memory,

which is kind of our memory of recent events.

Episodic memory is basically the who, what, where, and when,

so, "Where did I put my keys?

Where did I park my car?"

Those kind of things do tend to decline,

and I think a lot of it is because

we just aren't as focused on things.

It's not necessarily something that's pathological

or suggests dementia.

Kamitaki: Not everyone will get dementia,

but that risk does increase as you get older.

Right now, we don't have any medications

or treatments that can prevent someone

from getting Alzheimer's disease,

but there are some environmental risk factors

that if you address can prevent you from getting dementia

or at least prevent your memory from getting worse.

So some of those things include just general health,

eating healthy foods, taking care of your heart,

moderate exercise, making sure

that you stay healthy cardiovascularly,

which is also going to help your brain.

"Left-brained people are logical,

and right-brained people are creative."

I think the myth came from the 1800s

when, as neurologists were trying

to figure out different functions of the brain,

they discovered that the left side of our brain

in most people is dominant for language, verbal memory,

whereas the right brain was much more

of our visual-spatial functions.

But there's no structural brain difference in people

who are more logical versus more creative.

Rather, it's more their environment,

the way that they were raised.

In neurology, when we talk about

brain hemispheric dominance, we typically are talking

about language and verbal memory dominance.

Where does that live? And for most people,

that's on the left side of the brain.

Billakota: So if you're right-handed,

about 90% of the time,

you're going to be left-hemisphere-dominant,

which means a lot of your memory and speech production

and understanding, comprehension,

that kind of stuff's going to sit

on the left side of your brain,

whereas if you're left-handed,

it can kind of go both ways.

So I think the reality is,

we say that someone is left-brain-dominant

or right-brain-dominant, and it doesn't really mean

that one person is more creative

and the other one is more logical.

These are just talents and sort of skills

that people develop, whether inherently

or through their personalities,

but it really has nothing to do

with the side of their brain that they use more.

"You can't prevent a stroke." No.

That's not true.

That's very not true, actually.

You can definitely prevent a stroke.

How to do that is by really addressing

all of the factors that could result in a stroke.

We know very clearly that things

like high blood pressure, smoking, high cholesterol,

diabetes unfortunately increase your risk for a stroke,

which is basically when there's not enough blood flow

going to your brain because of a blood clot

or bleeding in the brain.

There's no quick and easy fix.