The limbic system has primacy over our brain.

It can hijack neural activity instantly.

And that's why when you smell smoke

or somebody gets too close

or if you hear a loud noise, our limbic system kicks in.

It's one of those beautiful things that has evolved with us.

My name is Joe Navarro

and I am a nonverbal communications expert.

We are a species that is always communicating.

But we're also communicating with gestures.

In fact, we have been primarily communicating

with gestures for millions of years.

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Think about 2.5 million years ago,

we were all still in Africa.

We were surrounded by predators at all times.

Lions, tigers, wild dogs, all these things were after us.

So we evolved to communicate silently but effectively.

We had to move through the jungle.

We had to move between trees.

We had to move in all sorts of environments, very quietly,

and still be able to communicate that which mattered

the most, which was what are my needs wants and desires,

and what are my fears.

If one of us saw a tiger or a lion

we evolved the capacity to freeze in place

so that by freezing the predator would move on

and not notice us.

This has been with us for millions of years.

All our earlier ancestors, all our hominids had to adapt

to this one behavior, which was to freeze

and it allowed to survive another day.

Those that ran initiated the chase, trip, bite sequence.

It was that movement that was so perilous to our species.

And so we have behaviors that are hardwired in us.

It's part of our paleo circuits.

These very ancient circuits that

have allowed us to survive.

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Deep within the brain is an area called the limbic system.

And the limbic system is both exquisite

and elegant in that it merely responds to the world.

It doesn't have to really think about the world.

The limbic system is often also referred to

as the mammalian brain.

And it can be activated in a variety of ways.

For instance, if the room suddenly gets too hot

your limbic system can be activated.

Or if it gets too cold.

If you smell smoke,

the limbic system is immediately activated.

It is on while we sleep.

It is on while we think we are in charge.

When we're writing something

the limbic system is running in the background.

It's like software.

It's looking at, it's listening for, it's sensing.

Are there things out there that could hurt me?

I'll give you an example.

If you take two gas stations and they're identical,

but you dim the lights of one versus the other,

people will go to the better lit gas station

without realizing why they're doing it.

And they're doing it because light represents visual clarity

and you naturally feel safer.

So even though they may charge you a little bit more

you'll still go there because there's something

about being able to see everything with greater clarity.

Those of you who have children

probably remember whenever the baby was startled

the baby would immediately bring up its hands

and its fingers would be spread out.

This is called the moro reflex.

And this reflex we share with all primates,

which allows us to immediately grab onto the hair

of those hairy individuals

which we used to be and allows us to hang on.

This was essential for survival.

Remember even before we were Australopithecines

dependent on our ability to be able to hang

on to hair so that a very mobiles and very agile mother

could move about while we assisted in hanging on.

The babinski reflex is very similar.

It has to do with the feet.

If you stroke the foot of a child at a very young age

before they're two, their toes immediately spread out.

Again, so that they can grab on to hair and hang on.

Or maybe you've never noticed for instance,

when you lay a young baby down,

as you put them on their back,

their hand and arm goes into what's called

the fencing posture.

And that is as they lay down, their head will turn

to one side and their arm will immediately come up

as though they're fencing.

We think we go into the fencing posture

at this early age to protect us from rolling over.

If our arms were at our side,

then we become a more perfect object to roll.

One of the other vestigial behaviors

is we have a reflex that orients us,

referred to as the orientation reflex.

And it's very ancient.

In fact, it's most likely pre reptilian.

It probably goes back to our amphibian past.

And that is that anytime there's any movement,

any change in pattern, we orient on that.

And so our eyes turn to it. We react to it.

And then if it's coming at us, we will raise a hand

to block it.

Fishermen'll tell you that fish will actually notice them.

They'll notice the movement on the surface.

So they move away.

Fish are aware that they will be hunted down by birds.

And so their orientation reflex is what usually saves them.

But for humans, we have never lost this

because this is key to survival.

We could not have survived as a species

if we could not respond to changes in imagery

or changes in pattern.

You know, oftentimes when you're sitting,

talking to somebody and somebody walks by

and your attention turns to them.

Or the screen on a nearby television is on.

And then all of a sudden there's a change in color

or a change in pattern.

The orientation reflex makes us take notice.

And a lot of guys use that an excuse to look

at the football game when they should be paying attention

to their friends.

But in fact, it is anchored in our biology

and our physiology.

We have passed this on to react to anything that's different

because it goes directly to our survival mode.

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Because the limbic system is responsible for our survival,

it can hijack neural activity instantly.

And that's why you can not run to the edge of a building

and just look down.

Your brain says slow down, inch your way

to the edge of that building and then look down.

One of the other things the limbic system does

is it orients us away from anything that we perceive

as hurtful or that we don't particularly care for.

It says, I will not permit you to expose your ventral side

to that person which you perceive as nasty

or dangerous or whatever.

And so we have a lot of collateral behaviors

that are associated with a startling situation.

For instance, with primates,

we know that when they're scared or they're angry

they open up their mouths and they show their large canines.

Well, we've lost our large canines.

But in displaying our teeth,

this was supposed to scare others.

You'll see people react by tucking in their thumbs.

And this is very much part of

what we do in our species, which is when we're scared

we tend to bring our fingers together

and tuck our thumbs in.

It's not just when somebody frightens us.

You can see it sometimes at the poker table.

You'll have poker players that have a lousy hand

and you'll see their fingers come together

and their thumbs disappear,

indicating just how weak they are.

We're not sure why we tend to tuck our thumbs in.

It may be in part something that we evolved

as we moved through areas where there's a lot

of vegetation so that our opposable thumbs

don't catch on different objects.

I remember an FBI agent friend of mine during an operation.

We were taking down some drug dealers

and we were jumping from one house to the other

over a fence and his thumb caught,

it was just completely ripped off.

So it's not far-fetched that this is a behavior

that we use so that we don't have any appendages

sort of loose that could get caught.

And the other one that we most often see is bringing a hand

to the neck and bring this little area here

called the suprasternal notch.

And if you look at the photographs that are out there

of predators, this area of the body is primarily

where they go to suffocate their prey.

And so our paleo circuits, when we're struggling

with something, or we hear even something that's terrible,

we instinctively develop this set of procedures

where we cover the neck, cover the mouth,

or tuck the chin in, in an effort to protect ourselves.

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Most of our behaviors that are universal

come from the limbic system.

And so when I see a limbic response

in Madison, Wisconsin of somebody touching their neck

I will also see in Botswana.

There's no difference.

Because they're universal they're also very reliable.

And so we can use it to assess others

to determine what are they thinking?

What are they feeling or what might they be fearing.