Understand & Improve Memory Using Science-Based Tools | Huberman Lab Podcast #72

- Welcome to the Huberman Lab Podcast,

where we discuss science, and science based tools

for everyday life.

I'm Andrew Huberman and I'm a professor

of neurobiology and ophthalmology

at Stanford School of Medicine.

Today we are discussing memory.

In particular, how to improve your memory.

Now the study of memory is one that dates back

many decades, and by now there's a pretty good understanding

of how memories are formed in the brain.

The different structures involved

and some of the neuro chemicals involved.

And we will talk about some of that today.

Often overlooked, however, is that memories

are not just about learning.

Memories are also about placing your entire life

into a context.

And that's because what's really special about the brain

and in particular the human brain,

is its ability to place events in the context

of past events, the present,

and future events.

And sometimes even combinations of the past and present.

Or present and future and so on.

So when we talk about memory what we're really talking about

is how your immediate experiences relate

to previous and future experiences.

Today I'm going to make clear how

that process occurs.

Even if you don't have a background

in biology or psychology, I promise

to put it into language that anyone

can access and understand.

And we are going to talk about

the science that points to specific tools

for enhancing learning and memory.

We're also going to talk about unlearning

and forgetting.

There are of course incidences in which

we would like to forget things.

And that too is a biological process

for which great tools exist.

To, for instance, eliminate or at least reduce

the emotional load of a previous experience

that you really did not like,

or that perhaps even was traumatic to you.

So today you're going to learn

about the systems in the brain and body

that establish memories.

You're going to learn why certain memories

are easier to form than others.

And I'm going to talk about specific tools

that are grounded in not just one,

not just a dozen, but well over 100 studies

in animals and humans that point

to specific protocols that you can use

in order to stamp down learning

of particular things more easily.

And you can also leverage that same knowledge

to better forget or unload the emotional weight

of experiences that you did not like.

We're also going to discuss topics like deja vu

and photographic memory.

And for those of you that do not

have a photographic memory,

and I should point out that I do not have

a photographic memory, either.

Well, you will learn how to use

your visual system in order to better learn

visual and auditory information.

There are protocols to do this

grounded in excellent peer reviewed research.

So while you may not have a true photographic memory,

by the end of the episode you will

have tools in hand, or I should say,

tools in mind or in eyes and mind,

to be able to encode and remember specific events

better than you would otherwise.

Before we begin I would like to emphasize

that this podcast is separate from my teaching

and research roles at Stanford.

It is, however, part of my desire and effort

to bring zero cost to consumer information about science

and science related tools to the general public.

In keeping with that theme,

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Okay, let's talk about memory.

And let's talk about how to get better

at remembering things.

Now in order to address both of those things

we need to do a little bit of brain science 101 review.

And I promise this will only take two minutes.

And I promise that even if you don't have a background

in biology, it will make sense.

We are constantly being bombarded with physical stimuli.

Patterns of touch on our skin,

light to our eyes, light to our skin, for that matter.

Smells, tastes, and sound waves.

In fact, if you can hear me saying this right now,

well, that's the consequence of sound waves

arriving into your ears through headphones,

a computer, or some other speaker device.

Each one of and all of those sensory stimuli

are converted into electricity

and chemical signals by your so-called nervous system.

Your brain, your spinal cord,

and all their connections with the organs of the body.

And all the connections of your organs of the body

back to your brain and spinal cord.

One of the primary jobs of your nervous system, in fact,

is to convert physical events in the world

that are non-negotiable, right?

Photons of light are photons of light.

Sound waves are sound waves.

There's no changing that.

But your nervous system does change that.

It converts those things into electrical signals

and chemical signals which are

the language of your nervous system.

Now just because you're being bombarded

with all this sensory information

and it's being converted into a language

that neurons and the rest of your nervous system

can understand, does not mean that you are aware of it all.

In fact, you are only going to perceive

a small amount of that sensory information.

For instance, if you can hear me speaking right now

you are perceiving my voice but you are also,

most likely, neglecting the feeling

of the contact of your skin with whichever surface

you happen to be sitting or standing on.

So it is only by perceiving a subset,

a small fraction of the sensory events

in our environment, that we can make sense

of the world around us.

Otherwise we would just be overwhelmed

with all the things that are happening

in any one given moment.

Now memory is simply a bias in which

perceptions will be replayed again in the future.

Anytime you experience something,

that is the consequence of specific chains

of neurons, that we call neural circuits, being activated.

And memory is simply a bias in the likelihood

that specific chain of neurons will be activated again.

So for instance, if you can remember your name

and I certainly hope that you can,

well, that means that there are specific chains

of neurons in your brain that represent your name

and when those neurons connect with one another

and communicate electrically with one another

in a particular sequence, you remember your name.

Were that particular chain of neurons to be disrupted,

you would not be able to remember your name.

Now this might seem immensely simple,

but it raises this really interesting question

which we've talked about before.

Which is, why do we remember certain things

and not others?

Because according to what I've just said,

as you go through life,

you're experiencing things all the time.

You're constantly being bombarded with sensory stimuli.

Some of those sensory stimuli you perceive,

and only some of those perceptions

get stamped down as memories.

Today I'm going to teach you how certain things

get stamped down as memories.

And I'm going to teach you how

to leverage that process in order

to remember the information that you want far better.

Now, even though I've told you

that a memory is simply a bias in the likelihood

that a particular chain of neurons

will be activated in a particular sequence

again and again, it doesn't operate on its own.

In fact, most of what we remember takes place

in a context of other events.

So for instance, you can most likely remember your name

and yet you're probably not thinking about

when it was that you first learned your name.

This generally happens when we are very,

very young children.

And yet, I'm guessing you could probably remember

a time when someone mispronounced your name,

or made fun of or name.

Or, as the case was for me,

I got to the 3rd grade and there were two Andrews.

And sadly for me, I lost the coin flip

that allowed me to keep Andrew.

And from about 3rd grade until about 12th grade

people called me Andy.

Which I really did not prefer.

So if you call me Andy in the comments,

I'll delete your comment.

Just kidding, doesn't bother me that much.

But eventually I reclaimed Andrew as my name.

Well, it was mine to begin with and throughout,

but I started going by Andrew again.

Why do I say this?

Well, there's a whole context to my name for me.

And there may or not be a whole context

to your name for you.

But presumably, if you asked your parents

why they named you your given name,

you'll get a context, etc.

That context reflects the activation

of other neural circuits that are also

related to other events in your life.

Not just your name, but probably your siblings names

and who your parents are.

And on, and on, and on.

And so, the way memory works is that each

individual thing that we remember

or that we want to remember

is linked to something by either

a close, a medium, or a very distant association.

This turns out to be immensely important.

I know many of you will read

or will encounter programs that are designed

to help you enhance your memory.

You know, you have these phenoms that can remember

50 names in a room full of people.

Or they can remember a bunch of names of novel objects

or maybe even in different languages,

and often times that's done by association.

So people will come up with little mental tricks

to either link the sound of a word

or the meaning of a word in some way

that's meaningful for them

and will enhance their memory.

That can be done and is impressive when we see it

and for those of you who can do that, congratulations.

Most of us can't do that,

or at least it requires a lot of effort and training.

However, there are things that we can do

that leverage the natural biology

of our nervous system to enhance

learning and memory of particular perceptions,

and particular information.

Let's first just talk about

the most basic ways that we learn and remember things

and how to improve learning and memory.

And the most basic one is repetition.

Now the study of memory and the role

of repetition actually dates back

to the late 1800s, early 1900s

when Ebbinghaus developed

the first so-called learning curves.

Now learning curves are simply what results

when you quantify how many repetitions

of something are required in order to remember something.

In fact, it's been said that Ebbinghaus liberated

the understanding of learning from the philosophers

by generating these learning curves.

What do we mean by that?

Well, before Ebbinghaus came along,

learning and memory were thought

to be philosophical ideas.

Ebbinghaus came along and said, well,

let's actually take some measurements.

Let's measure how well I can remember

a sequence of words or a sequence of numbers

if I just repeat them.

So what Ebbinghaus did is he would

take a sequence of numbers,

or words on a page and he would read them.

And then he would take a separate sheet of paper.

And we have to presume he didn't cheat,

and he would write down as many of them

as he could and he would try and keep

them in the same sequence.

Then he would compare to the original list

and he would see how many errors he made.

And he would do this over, and over,

and over again.

And as you would expect,

early in the training and the learning

it took a lot more repetitions

to get the sequence correct.

And over time, it took fewer sequences.

And he referred to that difference

in the initial number of repetitions

that he had to perform versus

the later number of repetitions he had

to perform as a so-called savings.

So he literally thought of the brain

as having to generate a kind of a currency of effort.

And he talked about savings as the reduction

in the amount of effort that he had

to put forward in order to learn information.

And what he got was a learning curve.

And you can imagine what that learning curve looked like.

It had a very sharp peak at the beginning

that dropped off over time.

And of course, he remembered all this

meaningless information.

But even though the information might

have been meaningless, the experiment itself

and what Ebbinghaus demonstrated was immensely meaningful.

Because what it said was that with repetition

we can activate particular sequences of neurons

and that repeated activation lays down

what we call a memory.

And that might all seem like a big duh,

but prior to Ebbinghaus, none of that was known.

Now, I should also say Ebbinghaus,

because of when he was alive,

was not aware of these things

that we called neural circuits.

It was in 1906 that Golgi and Cajal got the Nobel prize

for actually showing that neurons are independent cells

connected by synapses, these little gaps between them

where they communicate.

So he may have been aware of that,

but the whole notion of neural circuits

hadn't really come about.

Nevertheless, what the Ebbinghaus learning curves

really established was that sheer repetition,

just repeating things over and over and over again

is sufficient to learn.

Something that no doubt had been observed before

but had never been formally quantified.

Now, if we look at that result,

there's something really important that lies

a little bit cryptic, that's not so obvious to most people.

Which is, the information that he was trying to learn

wasn't any more interesting the second time

than it was the first, probably it was even less interesting

and less and less interesting with each repetition.

And yet it was sheer repetition

that allowed him to remember.

Now sometime later in the early to mid 1920s,

a psychologist in Canada named Donald Hebb

came up with what was called Hebb's postulate.

And Hebb's postulate, broadly speaking,

is this idea that if a sequence of neurons

is active at the same time, or at roughly the same time,

that would lead to a strengthening

of a connections between those neurons.

And many, many decades of experimentation later

we now know that postulate to be true.

Neurons themselves are not smart, they don't have knowledge.

So every memory is the consequence,

as I told you before, of the repeated activation

of a particular chain of neurons.

And what Ebbinghaus showed through repetition

and what Donald Hebb proposed and was eventually verified

through experimentation on animals and humans

was that if you encourage the co-activation of neurons.

Meaning have neurons fire at roughly the same time,

they will strengthen their connections.

It leads to a bias in the probability

that those neurons will be active again.

Now, this is vitally important because nowadays

we hear a lot about how memories are the consequence

of new neurons added into the brain.

Or that every time you learn something,

a new connection in your brain forms.

Well, sorry to break it to you,

but that's simply not the case.

Most of the time, and I want to emphasize most,

not all but most of the time when we learn something

it's because existing neurons, not new neurons,

but existing neurons strengthen their connections

through co-activation over and over and over.

Through repetition or, and this is a very important or,

or through very strong activation once and only once.

In fact, there's something called one trial learning

whereby we experience something

and we will remember that thing forever.

This is often most associated with negative events,

and I'll explain why in a few minutes.

But it can also be associated with positive events.

Like the first time you saw your romantic partner.

Or something that happened with that romantic partner.

Or the first time that you saw your child.

Or any other positive event, as well as any other

extremely negative event.

So again, both repetition, and I guess

we could label it intensity.

But what we really mean when we say intensity

is strong activation of neurons can lay down

these traces, these circuits that are far more likely

to be active again, than had there not been repetition

or not some strong activation of those circuits.

So with that in mind, let's return to the original

contrarian question that I raised before.

Which is, why do we remember anything?

Everyday you wake up, your neurons

in your brain and body are active.

Different neural circuits are active.

And yet, you only remember a small fraction

of the things that happen each day.

And yet, you retain a lot of information

from previous days and the days before those and so on.

It is only with a lot of repetition

or with extremely strong activation

of a given neural circuit that we will create new memories.

And so in a few minutes I'll explain how

to get extremely strong activation

of particular neural circuits.

Repetition is pretty obvious.

Repetition is repetition.

But in a few minutes I'll illustrate

a whole set of experiments and a whole set

of tools that point to how you can get

extra strong activation of a given neural circuit

as it relates to learning so that you will

remember that information, perhaps not just

with one trial of learning,

but certainly with far fewer repetitions

than would be required otherwise.

Before we go any further I want to preface

the discussion by saying

that there are a lot of different kinds of memory.

In fact, were you to take a voyage

into the neuroscience, and or psychology of memory

you would find an immense number

of different terms to describe

the immense number of different types

of memory that researchers focus on.

But for the sake of today's discussion,

I really just want to focus on short term memory,

medium term memory, and longterm memory.

And while there is still debate,

as is always the case with scientists, frankly,

about the exact divisions between

short term, medium, and longterm memory,

we can broadly define short term memory

and longterm memory.

And we can describe a couple different types

of those that I think you can relate to

in your everyday life.

The most common form of short term memory

that we're going to focus on is called working memory.

Working memory is your ability to keep

a chain of numbers in mind for some period of time

but the expectation really isn't

that you would remember those numbers the next day

and certainly not the next week.

So a good example would be a phone number.

If I were to tell ya a phone number,

493-2938, well you could probably remember it.

493-2938.

But if I came back tomorrow and asked you

to repeat that chain of numbers,

most likely you would not.

Unless, of course, we used a particular tool

to stamp down that memory into your mind

and commit it to longterm memory.

Now of course, in this day in age,

most people have phone numbers programmed into their phone

and they don't really have to remember the exact numbers.

It's usually done by contact identity and so forth.

So a different example that some of you

are probably more familiar with

would be those security codes.

So you try and log unto an app or a website

and it asks you for a security code

that's been sent to your text messages

and you can either plug that in directly

in some cases, or you have to remember

that short sequence of anywhere usually

from six to seven, sometimes eight numbers.

Your ability to do that, to switch back and forth

between web pages or apps and plug in that number

by remembering the sequence and plugging it in,

by texting or keying it in on your keyboard,

that's a really good example of working memory.

Longterm memory, of the sort that we're

going to be talking a lot about today

is your ability to commit certain patterns

of information, either cognitive information

or motor information.

Right, the ability to move your limbs

in a particular sequence.

Over long periods of time.

Such that you could remember it a day,

or a week, or a month, or maybe even a year

or several years later.

So we've got short term memory and longterm memory.

And we've got this working memory

which is sort of keeping something online

but then discarding okay.

Not online on a computer,

but online within your brain.

There are also two major categories of memory

that I'd like you to know about.

One is explicit memory.

So this is not necessarily explicit

of the sort that you're used to thinking about.

But rather the fact that you can declare you know something.

So you have an explicit memory of your name.

Presumably you have an explicit memory

of the house or the apartment that you grew up in.

You know something and you know you know it.

And you can declare it.

So I can ask you, what was the color

of the first car that you owned?

Or what is the color of your romantic partner's hair?

These sorts of things.

That's an explicit declarative memory.

But you also have explicit procedural memories.

Now procedural memories, as the name suggests,

involve action sequences.

The simplest one, it's almost ridiculously simple,

is walking.

If I say, how is it that you walk

from one room to the other?

You'd probably say, well, I go that direction

and then I turn left.

I say, no, no, no.

How is it exactly that you do it?

You say, well, I move my left foot,

then my right foot, then my left foot.

And you could describe that.

So it's an explicit procedural memory.

So much so that if you were going

to teach a young toddler how to walk,

you would probably say okay, good, good, try.

Okay, then you know, probably that's going to be pre-language

for the toddler.

But you're going to encourage them

to move one leg then the other.

And you're going to encourage and reward them

for moving one leg then the other.

Because you have an explicit

procedural memory of how to walk.

Okay, almost ridiculously simple.

Maybe even truly ridiculously simple,

but nonetheless, when you think about it

in the context of neural circuits and neural firing,

pretty amazing.

Even more amazing is the fact that all

explicit memories, both declarative

and procedural explicit memories

can be moved from explicit to implicit.

What do I mean by that?

Well, in the example of walking

you might have chuckled a little bit

or kind of shook your head and said,

this is a ridiculous thing to ask.

How do I walk from one room to the next?

I just walk.

I just do it.

Ah, well, what is just do it?

What it is, is that you have an implicit understanding.

Meaning your nervous system knows how to walk

without you actually having to think about

what you know about how to walk.

You just get up out of your chair

or you get up out of bed and you walk.

In the brain you have a structure.

In fact, you have one on each side of your brain.

It's called the hippocampus.

The hippocampus literally means seahorse.

Anatomists like to name brain structures after things

that they think those brain structures resemble.

When I look at the hippocampus,

frankly, it doesn't look like a seahorse.

Which either reflects my lack of understanding

of what a seahorse really looks like, a visual deficit,

or I think it's fair to say

that those anatomists were using a little bit

of creative elaboration when thinking about

what the hippocampus looks like.

Nonetheless, it is a curved structure.

It has many layers.

It's been described by my colleague Robert Sapolsky

and by others as looking more like a jelly roll

or a cinnamon roll, is what it looks like to me.

And if you were to take one cinnamon roll,

chop it down the middle.

So now you've got two half cinnamon rolls

and rather than put them back together

in the configuration they were before,

you just slide one down so that you've got

essentially two C's.

Two C-shaped halves of this cinnamon roll

and you push them together, right,

slightly off set from one another.

Well, that's what the hippocampus looks like to me.

And I think that's a far better description

of its actual physical structure.

But I guess if you were to use that physical structure

as the name, well then you'd have to open up

a brain atlas and it would be called

two half-C cinnamon rolls stuffed halfway together.

So that's not very good.

So I guess, seahorse will work.

Hippocampus is the name of this structure

and it is the site in your brain,

and again, you have one on each side of your brain,

in which explicit declarative memories are formed.

It is not where those memories are stored and maintained.

It is where they are established in the first place.

In contrast, implicit memories,

the subconscious memories, are formed and stored

elsewhere in the brain.

Mainly by areas like the cerebellum,

but also the neocortex,

the kind of outer shell of your brain.

The cerebellum literally means mini-brain.

And it does in fact look like a mini-brain.

And is in the back of the brain.

And the neocortex is the outer part of the brain

that covers all the other stuff.

So, the hippocampus is vitally important

for establishing these new, declarative memories

of what you know and what you know how to do.

Now, in order to really understand the role

of the hippocampus in memory, in particular

explicit declarative, and explicit procedural memory

and to really understand how that's distinct

from implicit declarative and implicit procedural memories

we have to look to a clinical case.

And the clinical case that I'm referring to

is a patient who went by the name HM.

Patient's go by their initials in order

to maintain confidentiality of their real identity.

HM had what's called intractable epilepsy.

So he would have these really dramatic,

so-called grand mal seizures, or drop seizures.

For those of you that know somebody with epilepsy,

or that have epilepsy, you might be familiar with this.

You can have petite mal seizures, which are minor seizures.

You can have tonic clonic seizures,

which are sometimes not even detectable.

You can have absent seizures where people

will just stop, it's almost as if their brain

kind of goes on pause and they'll just stop there.

It was reported actually that Einstein had absent seizures.

Although I don't know that's ever

really been confirmed neurologically.

Grand mal seizures are extremely severe

and that's what HM had.

So he could just be going about his day

and maybe even cooking, or doing something, driving,

operating any kind of machinery,

and then all of a sudden he would just have

a drop seizure.

So he would just physically drop

and go into a grand mal seizure.

So convulsing of the whole body,

loss of consciousness, etc.

Or he would feel it coming on.

Often times people with epilepsy

can feel the epileptic seizure coming on.

Kind of like a wave from the back of the brain.

And sometimes they can get

to a safe circumstance, but not always.

And so the frequency and the intensity of his seizures

were so robust that the neurosurgeons

and neurologists decided that they needed to locate

the origin, what they call the foci

of those seizures, and remove that brain tissue.

Because the way seizures work

is they spread out from that focus,

or that foci of brain tissue.

And unfortunately for HM,

the focus of his seizures was the hippocampus.

So after a lot of deliberation,

a neurosurgeon, in fact one of the most famous

neurosurgeons in the world at that time,

made what are called electrolytic lesions,

actually burned out the hippocampus in the brain of HM.

And as a consequence, he lost all explicit memory.

Now the consequence of this

was that he couldn't exist in normal,

everyday life, like most people.

So he had to live mostly, not entirely,

but mostly in a kind of hospital setting.

And I've talked to several people, who have

I should say, who met HM directly,

because he's no longer alive.

But an interaction with him might look like the following.

He would walk up to you just fine.

You wouldn't know that he had any kind of brain damage.

He could walk fine, he could speak fine.

And you'd say, hi, I'm Andrew.

And he'd say, hi, I'm whatever his name happened to be.

He wouldn't say HM, but he'd probably say his real name.

And then perhaps someone new would walk into the room.

He might turn around, look at that person,

as any of us might do.

Then turn around back to me and say, hi, what's your name?

And if I were to say, well, I just told you my name.

And you just told me your name, do you remember that?

And he'd say, I'm sorry, I don't remember any of that.

What's your name?

So you'd go through this over and over again.

So a complete lack of explicit declarative memory.

Now he did have some memory for

previous events in his life that dated way back, okay.

Again, hinting at the idea that memories

are not necessarily stored in the hippocampus,

they're just formed in the hippocampus.

So once they've moved out of the hippocampus

to other brain areas, he could still keep those memories.

They're in a different database, if you will.

They're in a different pattern of firing

of other neural circuits.

But he couldn't form new memories.

Now there's some very important

and interesting twists on what HM could

and could not do in terms of learning and memory

that teach us a lot about the brain.

In fact, I think most neuroscientists would agree

that this unfortunate case of HM's epilepsy

and the subsequent neuro surgery that he had

taught us much of what we know,

or at least think about,

in terms of human learning and memory.

For instance, as I mentioned before,

he still had implicit knowledge.

He knew how to walk.

He knew how to do certain things like

make a cup of coffee.

He knew the names of people

that he had met much earlier in his life, and so on.

And yet he couldn't form new memories.

Now, in violation to that last statement,

there were some elements of HM's emotionality

that suggests that there was some sort

of residual capacity to learn new information

but it wasn't what we normally think of

as explicit declarative or procedural memory.

For instance, it's been reported

or it's been said, I should say,

because I don't know that the studies

were ever done with intense physiological measurements,

that if you were to tell HM a joke,

and he thought it was funny, he would laugh really hard.

He liked jokes, so you'd say hey, HM,

I want to tell you a joke.

You tell him a joke and he'd laugh really hard.

Then you could leave the room, come back,

and tell him the same joke again.

Now keep in mind, he did not remember

that you told him the joke previously.

And the second time he would laugh a little bit less.

And then you'd leave the room, come back again.

Say hi, I'm Andrew.

And he'd say, oh, nice to meet you.

Because as you know, as you recall,

because you can recall things.

But he couldn't recall things.

He didn't know that he just met you.

Or at least he couldn't remember it.

You tell him the joke a third time, or a fourth time,

and with each subsequent telling of the joke

he found it a little less funny.

Just as, keep this in mind, folks,

if you tell a joke and you get a big laugh,

don't tell it again.

At least not immediately.

Not to the same person or the same crowd

because the second time it's a little less funny

and the third time it's a little less funny.

And that actually has to do with a whole element

of dopamine and it's relationship to surprise.

And that's the topic of a future podcast

where we talk all about humor and novelty in the brain.

But the point being that certain forms of memory

seem to exist in a kind of phantom like way

within HM's brain.

What do I mean by that?

Well, this underscores that he had

an implicit memory of having heard the joke before.

And it suggests that humor, or at least what we find funny,

is somehow more related to procedures.

Similar to walking or a motor ability

than it is to this precise content of that joke.

All right, that's a little bit of an abstract concept,

but the point is that HM lacked explicit declarative memory.

He couldn't tell you what he had just heard.

He could not learn new information.

And he couldn't tell you how to do something

unless he had learned how to do that something

many years prior.

Now, there have been a lot of other patients besides HM

that have had brain lesions due to epilepsy,

or I should say due to surgeries to treat epilepsy,

due to strokes, due to sadly gunshot wounds

and other forms of what we call infarcts, infarct.

I-N-F-A-R-C-T, infarct is the word we use

to describe damage to a particular brain region.

And many different patients with many different patterns

of infarct have taught us a lot about how memory

and other aspects of the brain work.

HM really teaches us that what we know

and what we are able to do is the consequence

of things that we are aware of

and learnings that have been passed off

into subconscious knowledge, that our body knows.

Our brain knows, but we don't know exactly

how we know that thing.

And I tell you the story about HM's ability

to understand a joke, but that with repeated telling

of the joke it has less and less and less

of an impact in creating a sense of laughter,

of humor in HM.

Not as just an anecdote to flesh out his story,

but because emotion itself turns out

to be the way in which we can enhance memories

even if those are memories for things

that are not funny, are not intensely sad,

are not immensely happy or don't evoke

a really strong emotional response,

or even any emotional response.

And the reason for that is that emotions,

just like perception, just like sensation,

are the consequence of particular neuro chemicals

being present in our brain and body.

And as I'm going to tell you next,

there are particular neuro chemicals

that you can leverage in order to learn

specific information faster and to remember it

for a much longer period of time,

maybe even forever.

And you can do that by leveraging

the relationship in your nervous system

between your brain and your body.

And your body back to your brain.

So let's talk about tools for enhancing memory.

Now there's one tool that it's absolutely clear works.

And it's always worked, it works now,

and it will work forever.

And that's repetition.

The more often that you perform something

or that you recite something,

the more likely you are to remember it in the future.

And while that might seem obvious,

it's worth thinking about what's happening

when you repeat something.

But when I say what's happening,

I mean at the neural level.

What's happening is that you're encouraging

the firing of particular chains of neurons

that reside in a particular circuit, right.

So a particular sequence of neurons playing

neuron A, B, C, D played in that particular sequence

over and over and over again.

And with more repetitions, you get more strengthening

of those nerve connections.

Now, repetition works but the problem for most people

is they either don't have the patience,

they don't have the time,

and sometimes they literally don't have the time

because they've got a deadline

on something that they're trying to remember and learn.

Or they simply would like to be able

to remember things better in general

and remember them more quickly.

This process of accelerating repetition based learning

so that your learning curve doesn't go

from having to perform something 1,000 times

and then gradually over time it's 1,000, 750 times a day,

500 times a day, 300 times a day,

and down to no repetitions, right?

You can just perform that thing the first time

and every time.

Well, there is a way to shift that curve

so that you can essentially establish stronger connections

between the neurons that are involved

in generating that memory or behavior more quickly.

How do you do that?

Well, in order to answer that we have

to look at the beautiful work of James McGaugh

and Larry Cahill.

James McGaugh and Larry Cahill did

a number experiments over several decades really

based on a lot of animal literature,

but mainly focused on humans

that really established what's required

to get better at remembering things

and to do so very quickly.

I want to talk about one experiment that they did

that was particularly important.

And we will provide a link to this paper,

it's some years old now,

but the results still hold up.

In fact, the results established

an entire field of memory and neuroscience and psychology.

What they did is they had human subjects

come into the laboratory and to read

a short paragraph of about 12 sentences.

And the key thing is that some subjects read

a paragraph that was pretty mundane.

The content, the information within the paragraph

was all related to the content of the previous sentence.

So it was a cogent paragraph.

Right, it just wasn't a meaningless scramble of words.

But it described a kind of mundane set of circumstances.

Maybe it would be a story about someone

who walked into a room, sat down at a desk,

wrote for a little bit, then got up

and had lunch.

You know, just kind of mundane information.

Not very interesting.

Another group of subjects read also

a 12 sentence paragraph.

But that paragraph included a subset

of sentences that had a lot of emotionally intense language.

Or that had language that could evoke

an emotionally intense response

in the person reading it.

So it might have talked about a car accident

or a very intense surgery.

But it also could be positive stuff.

Things like a birthday party,

or a celebration of some other kind.

Or a big sports win.

So in other words, you have two conditions of this study.

People either read a boring paragraph,

or they read a really emotionally laden paragraph.

And again, the emotions could either be

positive or negative emotions.

Subjects left the laboratory and sometime later

they were called back to the laboratory

and I should say, at no point in the experiment

did they know they were part of a memory experiment.

Okay, they don't even know why

they were reading this paragraph.

They came in either for class credit or to get paid.

That's typically how these things are done

on college campuses or elsewhere.

They come back into the lab

and they would get a pop quiz.

They would be asked to recall the content

of the paragraph that they had read previously.

Now as is probably expected, perhaps even obvious to you,

the subjects that read the emotionally intense paragraph

remembered far more of the content of that paragraph

and were far more accurate

in their remembering of that information.

Now, that particular finding wasn't very novel.

Many people had previously described

how emotionally intense events

are better remembered than non-emotionally intense events.

In fact, way back in the 1600s

Francis Bacon, who's largely credited

with developing the scientific method,

said, quote, memory is assisted by anything

that makes an impression on a powerful passion.

Inspiring fear, for example,

or wonder, shame, or joy.

Francis Bacon said that in 1620.

So Jim McGaugh and Larry Cahill

were certainly not the first

to demonstrate or to conceive of the idea

that emotionally laden experiences

are more easily remembered than other experiences.

However, what they did next

was immensely important for our understanding of memory

and for our building of tools

to enhance learning and memory.

What they did was they evaluated

the capacity for stress and for particular

neuro chemicals associated with stress

to improve our ability to learn information.

Not just information that is emotional,

but information of all kinds.

So I'm going to describe some experiments done

in animal models just very briefly,

and then experiments done on humans subjects.

Because McGaugh worked mainly on animals,

also human subjects.

Larry Cahill, almost exclusively on human subjects.

If you take a rat or a mouse

and put it in an arena where at one location

the animal receives an electrical shock

and then you come back the next day,

you remove the shock evoking device

and you let the animal move around that arena,

that animal will, quite understandably,

avoid the location where it was shocked.

So called conditioned place aversion.

That affect of avoiding that particular location

occurs in one trial.

That's a good example of one trial learning.

So somehow the animal knows

that it was shocked at that location,

it remembers that.

It is a hippocampal dependent learning.

So animals that lack a hippocampus

or who have their hippocampus pharmacologically

or otherwise incapacitated, will not learn

that new bit of information.

But for animals that do, they remember it

after the first time and every time.

Unless, you are to block the release

of certain chemicals in the brain and body

and the chemicals I'm referring to are epinephrine,

adrenaline, and to some extent the corticosterones.

Things like cortisol.

Now we know that the effect of getting one trial learning

somehow involves epinephrine,

at least in this particular experimental scenario.

Because if researchers do the exact same experiment,

and they have done the exact same experiment,

but they introduce a pharmacological blocker

of epinephrine, so that epinephrine is released

in response to the shock,

but it cannot actually bind to its receptors

and have all its biological effects,

well then the animal is perfectly happy

to tread back into the area where it received the shock.

It's almost as if it didn't know,

or we have to assume, it didn't remember

that it received the shock at that location.

So it all seems pretty obvious when you hear it.

Something bad happens in a location,

you don't go back to that location.

So that's condition place avoidance.

But it turns out that the opposite is also true.

Meaning for something called condition place preference

you can take an animal, put it into an arena,

feed it or reward it some how at one location

in that arena.

So you can give a hungry rat or mouse food

at one particular location,

take the animal out, come back the next day.

No food is introduced, but it will go back

to the location where it received the food.

Or you can do any variant of this.

You can make the arena a little bit chilly

and provide warmth at that location.

Or you can take a male animal.

And it turns out male rats and mice

will mate at any point.

Or a female animal that's at the particular

so called receptive phase of her mating cycle

and give them an opportunity to mate

at a give location, they'll go back to that location

and wait away.

This is perhaps why people go back

to the same bar, or the seat at the bar,

or the same restaurant and wait

because of the one time they, you know,

things worked out for them.

Whatever the context was.

Condition place preference.

Condition place preference as with condition place avoidance

depends on the release of adrenaline, right.

It's not just about stress.

It's about a heightened emotional state

in the brain and body.

Okay, this is really important.

It's not just about stress.

You can get one trial learning

for positive events, condition place preference.

And you can get one trial learning for negative events.

Here I say positive and negative,

I'm putting what's called valence on it.

Making a value judgment about whether not

the animal liked it or didn't like it.

And we have to presume what the animal liked

or didn't like and how it felt.

But this turns out all to be true for humans as well.

We know that because McGaugh and Cahill

did experiments where they gave people

a boring paragraph to read

and only a boring paragraph to read.

But one group of subjects was asked

to read the paragraph and then to place their arm

into very, very cold water.

In fact, it was ice water.

We know that placing one's arm into ice water,

especially if it's up to the shoulder or near to it,

evokes the release of adrenaline in the body.

It's not an enormous release,

but it's a significant increase.

And yes, they measured adrenaline release.

In some cases they also measured for things like

cortisol, etc.

And what they found is that if one evokes

the release of adrenaline through

this arm into ice water approach,

the information that they read previously,

just a few minutes before,

was remembered, it was retained as well

as emotionally intense information.

But keep in mind the information that they read

was not interesting at all.

Or at least, it wasn't emotionally laden.

This had to be the effect of adrenaline released

into the brain and body, because if they blocked the release

or the function of adrenaline in the brain

and or body, they could block this effect.

Now the biology of epinephrine and cortisol

are a little bit complex,

but there's some nuance there that's actually interesting

and important to us.

First of all, adrenaline is released

in the body and in the brain.

It's released in the body from the adrenals.

Remember, epinephrine and adrenaline are the same thing.

Cortisol is also released from the adrenal glands.

These two little glands that ride atop our kidneys.

But it can't cross into the brain.

It only has what we call peripheral effects.

Quickening of the heart rate, right?

Changes the patterns of blood flow.

Changes our patterns of breathing.

In general, makes our breathing more shallow and faster.

In general makes our heart beat more quickly, etc.

Within our brain we have a little brain area

called locus coeruleus, which is in the back of the brain.

Which has the opportunity to sprinkler

the rest of the brain with

the neuromodulator epinephrine, adrenaline,

as well as norepinephrine, a related neuromodulator.

And to essentially wake up or create a state of alertness

throughout the brain.

So it's a very general effect.

The reason we have two sites of release

is because these neuro chemicals do not cross

the blood-brain barrier.

And so waking up the body with adrenaline

and waking up the brain are two separate,

so-called parallel phenomena.

Cortisol can cross the blood-brain barrier

because it's lipophilic.

Meaning it can move through fatty tissue.

And we'll get into the biology of that

in another episode.

But cortisol in general is released

and has much longer term effects.

And as I just told you, can permeate

throughout the brain and body.

Adrenaline has more local effects.

Or at least is segregated between the brain and the body.

This will turn out to be important later.

The important thing to keep in mind

is that it is the emotionality evoked

by an experience, or to be more precise,

it is the emotional state that you are in

after you experience something

that dictates whether or not you will learn it

quickly or not.

This is absolutely important

in terms of thinking about tools

to improve your memory.

And no, I am not going to suggest

that every time you want to learn something

you plunge your arm into ice water.

Why won't I suggest that?

Well, it will induce the release of adrenaline,

but there are better ways to get that adrenaline release.

Before I explain exactly what those tools are,

I want to tamp down on the biology

of how all this works.

Because in that understanding you will have access

to the best possible tools to improve your memory.

First of all, McGaugh and Cahill

were excellent experimentalists.

They did not just establish that you could

quicken the formation of a memory

by accessing material that was very emotionally laden

or creating an emotional, high adrenaline state

after interacting with some thing.

Some word, some person, some information.

They also tested whether or not that whole effect

could be blocked by blocking the emotional state

or by blocking adrenaline.

So what they did is they had people read paragraphs

that either had a lot of emotional content

or they had people read paragraphs

that were pretty boring, but then had them

put their arm into ice water.

And I should say they did other experiments too

to increase adrenaline.

There were even some shock experiments

that were done by other groups.

Any number of things to evoke

the release of adrenaline.

Even people taking drugs that increase adrenaline.

But then they also did what are called blocking experiments.

They did experiments where they had people

get into a highly emotional state

from reading highly emotional material,

or they got people to get into a highly emotional

neuro chemical state by reading boring material

and then taking a drug to increase adrenaline,

or an ice bath, or a shock.

And then they also administered a drug called a beta blocker

to block the affect of adrenaline

and related chemicals in the brain and body.

And what they found is that even

if people were exposed to something really emotional

or had a lot of adrenaline in their system

because they received a drug to increase

the amount of adrenaline.

Two manipulations that normally would increase memory,

keep that in mind.

If they gave them a beta blocker,

which reduced the response to that adrenaline, right?

So no quickening of the heart rate.

No quickening of the breathing.

No increase in the activity of locus coeruleus

and these kind of wake up signals to the rest of the brain.

Well then, the material wasn't remembered better at all.

What this tells us is that, yes,

Francis Bacon was right.

McGaugh and Cahill were right.

Hundreds, if not thousands of philosophers,

and psychologists, and neuroscientists were right.

In stating and in thinking that

high emotional states help you learn things.

But what McGaugh and Cahill really showed,

and what's most important to know,

is that it is the presence of high adrenaline,

high amounts of norepinephrine and epinephrine

and perhaps cortisol as well, as you'll soon see,

that allows a memory to be stamped down quickly.

It is not the emotion.

It is the neuro chemical state that you go into

as a consequence of the emotion.

And it's very important to understand

that while those two things are related,

they are not one and the same thing.

Because what that means is that were you to evoke

the release of epinephrine, norepinephrine, and cortisol

or even just one or two of those chemicals

after experiencing something,

you are stamping down the experience

that you just previously had.

Now this is fundamentally important

and far and away different than the idea

that we remember things because they're important to us,

or because they evoke emotion.

That's true, but the real reason,

the neuro chemical reason, the mechanism behind all that

is these neuro chemicals have the ability

to strengthen neural connections

by making them active just once.

There's something truly magic about

that neuro chemical cocktail that removes

the need for repetition.

Okay, so let's apply this knowledge.

Let's establish a scientifically grounded set of tools.

Meaning tools that take into account

the identity of the neuro chemicals

that are important for enhancing learning

and the timing of the release of those chemicals

in order to enhance learning.

When I first learned about the results

of McGaugh and Cahill, I was just blown away.

I was also pretty upset, but not with them,

I was upset with myself.

Because I realized that the way that I had

been approaching learning and memory was not optimal.

In fact, it was probably in the opposite direction

to the enhanced protocol for learning and memory

that I'm going to teach you today.

My typical mode of trying to learn something

while I was in college, or while I was in graduate school,

or as a junior professor, or a tenured professor

was to sit down to whatever it is I was going

to try and learn, and perhaps even memorize.

Or if it was a physical skill, move to whatever

environment I was going to learn that physical skill in,

and prior to that, to make sure that I was

hydrated, because that's important to me.

And certainly can contribute to your brain's

ability to function and your body's ability to function.

And general patterns of alertness.

But also, to caffeinate.

I would have a nice, strong cup of coffee or espresso.

I would have a nice strong cup of yerba mate.

And I still drink coffee or yerba mate very regularly.

I drink them in moderation, I think.

Certainly for me.

But typically I would drink those things

before I would engage in any kind of attempt

to learn or memorize.

Or to acquire a new skill.

Now caffeine in the form of coffee or yerba mate

or any other form of caffeine does create

a sense of alertness in our brain and body

and it does that through two major mechanisms.

The first mechanism is by blocking the effects of adenosine.

Adenosine is a molecule that builds up

in the brain and body the longer that we are awake.

And it's largely what's responsible

for our feelings of sleepiness and fatigue

when we've been awake for a very long time.

Caffeine essentially acts to block

the effects of adenosine.

It's a competing agonist, not to get technical,

but it binds to the receptor for adenosine

for some period of time and prevents adenosine

from having its normal pattern of action.

And thereby reduces our feelings of fatigue.

But it also increases state of alertness.

So while it's reducing fatigue,

it's also pushing on neuro chemical systems

in order to directly increase our alertness.

And it does that in large part by increasing

the transmission of epinephrine, adrenaline,

in the brain and body.

It also has this interesting effect of up regulating

the number and or efficiency, or we say the efficacy,

of dopamine receptors.

Such that when dopamine is present,

and is a molecule that increases motivation,

and craving, and pursuit, that dopamine

can have a more potent effect than it would otherwise.

So caffeine really hits these three systems.

It hits other systems too, but it mainly reduces fatigue

by reducing adenosine, increases alertness

by increasing epinephrine release,

or adrenaline release I should say,

both from the adrenals in your body

and form locus coeruleus from within the brain.

And it can, in parallel to all that, increase

the action or the efficacy of the action of dopamine.

So my typical way of approaching learning and memory

would be to drink some caffeine and then focus really hard

on whatever it is that I'm trying to learn.

Try and eliminate distractions

and then hope, hope, hope.

Or try, try, try to remember that information

as best as I could.

And frankly, I felt like it was working pretty well for me.

And typically, if I leveraged other forms

of pharmacology in order to enhance learning and memory,

things like Alpha GPC, or phosphatidyl serine,

I would do that by taking those things

before I sat down to learn

a particular set of information.

Or before I went off to learn a particular physical skill.

Now, for those of you out there listening to this

you're probably thinking, well, okay.

The results of McGaugh and Cahill pointed

to the fact that having adrenaline released after

learning something enhanced learning of that thing.

But a lot of these things like caffeine,

or Alpha GPC can increase epinephrine and adrenaline

or dopamine or other molecules in the brain and body

that can enhance memory for a long period of time.

So it makes sense to take it first,

or even during learning,

and then allow that increase to occur.

And the increase will occur over

a long period of time and will enhance learning and memory.

And while that is partially true,

it is not entirely true.

And it turns out it's not optimal.

Work that was done by the McGaugh laboratory,

and in other laboratories evaluated

the precise temporal relationship

between neuro chemical activation of these pathways

and learning and memory.

What they did is they had animals and or people,

depending on the experiment, take a drug.

It could be caffeine.

It could be in pill form.

Something that would increase adrenaline

or related molecules that create

this state of alertness that are related to emotionality.

And they had them do it either an hour before,

30 minutes before, 10 minutes before,

or five minutes before learning,

or during the about of learning, right?

The reading of the information or the performing

of the skill that one is trying to learn.

Or five minutes, 10 minutes, 15 minutes,

30 minutes, etc. afterwards.

So they looked very precisely at when exactly

is best to evoke this adrenaline release.

And it turns out that the best time window

to evoke the release of these chemicals,

if the goal is to enhance learning and memory

of the material is either immediately after

or just a few minutes, five, 10, maybe 15 minutes

after you're repeating that information.

You're trying to learn that information.

Again, this could be cognitive information

or this could be a physical skill.

Now this really spits in the face

of the way that most of us approach learning and memory.

Most of us, if we use stimulants like caffeine

or Alpha GPC, we're taking those before

or during an attempt to learn, not afterwards.

These results point to the fact that

it is after the learning and memory

that you really want to get that big increase

in epinephrine and the related molecules

that will tamp down memory.

So what this means is that if you are currently using

caffeine or other compounds,

and we'll talk about what those are

and safety issues and so forth in a moment.

If you're using those compounds in order

to enhance learning and memory

by taking them before or during a learning episode,

well then I encourage you to try

and take them either late in the learning episode

or immediately after the learning episode.

Now given everything I've told you up until now

why would I say late in the learning episode

or immediately after?

Well, when you ingest something by drinking it

or you take it in capsule form,

there's a period of time before that gets

absorbed into the body.

And different substances,

such as caffeine, Alpha GPC, etc

are absorbed from the gut and into the blood stream

and reach the brain and trigger these affects

in the brain and body at different rates.

So it's not instantaneous.

Some have effects within minutes,

others within tens of minutes and so on.

It's really going to depend

on the pharmacology of those things

and it's also going to depend

on whether or not you have food in your gut,

what else you happen to have circulating

in your blood stream, etc.

But at a very basic level we can confidently say

that there are not one, not dozens,

but as I mentioned before,

hundreds of studies in animals and in humans

that point to the fact that triggering

the increase of adrenaline late in learning

or immediately after learning

is going to be most beneficial

if your goal is to retain that information

for some period of time.

And to reduce the number of repetitions

required in order to learn that information.

Now, I want to acknowledge that

on previous episodes of this podcast

and in appearing on other podcasts,

I've talked a lot about things like non-sleep deep rest,

and naps, and sleep as vital to the learning process.

And I want to emphasize

that none of that information has changed.

I don't look at any of that information differently

as the consequence of what I'm talking about today.

It is still true that the strengthening

of connections in the brain,

the literal neural plasticity,

the changing of the circuits occurs

during deep sleep and non-sleep deep rest.

And it is also true,

and I've mentioned these results earlier

that two papers were published in Cell Reports,

Cell Press journal, excellent journal

over the last few years showing that

brief naps of about 20 up to 90 minutes

in some period of time after an attempt to learn

can enhance the rate of learning and memory.

However, those bouts of sleep,

the deep sleep that night, I should say,

or those brief naps,

or even the so-called NSDR as we call it,

non-sleep deep rest that was used

to enhance the learning and memory

of particular pieces of information.

Either cognitive or physical information or both.

That still can be performed,

but it can be performed some hours later,

even an hour later.

It can be performed two hours later or four hours later.

Remember, it's in these naps and in deep sleep

that the actual reconfiguration

of the neural circuits occurs,

the strengthening of those neural circuits occurs.

It is not the case that you need to finish

a about of learning and drop immediately into a nap or sleep.

Some people might do that,

but if you're really trying to optimize

and enhance and improve your memory,

the data from McGaugh and Cahill

and many other laboratories that stemmed out

from their initial work really point

to the fact that the ideal protocol would be

focus on the thing you're trying to learn very intensely.

There are also some other things like error rates, etc.

Please see our episodes on learning.

We have a newsletter on how to learn better.

You can access that at HubermanLab.com.

It's a zero cost newsletter.

You can grab that PDF.

It lists out the things to do during the learning about.

Still try and get excellent sleep.

Again, fundamentally important for mental health,

physical health, and performance.

And we can now extend from performance

to saying including learning and memory.

Nap if it doesn't interrupt your nighttime sleep.

Naps of anywhere from 10 to 90 minutes.

Or non-sleep deep rest protocols

will enhance learning and memory,

but we can now add to that, that spiking adrenaline

provided it can be done in a safe way,

is going to reduce the number of repetitions

required to learn.

And that should be done at the very tail end

or immediately after a learning about.

Which is compatible with all

the other protocols that I mentioned.

And the reason I'm revisiting this stuff

about sleep and non-sleep deep rest

is I think that some people got the impression

that they need to do that immediately after learning

and today I'm saying to the contrary.

Immediately after learning you need to go into

a heightened state of emotionality and alertness.

Now it's vitally important to point out

that you do not need pharmacology.

You don't need caffeine.

You don't need Alpha GPC.

You don't need any pharmacologic substance

to spike adrenaline unless that's something

that you already are doing.

Or that you can do safely.

Or that you know you can do safely.

And I always say, and I'll say it again,

I'm not a physician so I'm not prescribing anything.

I'm a professor, so I profess things.

You need to what's safe for you.

So if you're somebody who's not used to drinking caffeine

and you suddenly drink four espresso after trying

to learn something, you are going to have

a severe increase in alertness and probably even anxiety.

If you're panic attack prone,

please don't start taking stimulants

in order to learn things better.

Please be safe.

I don't just say that to protect me,

I say that to protect you.

And I should mention that if you're

not accustomed to taking something,

you always want to first check with your doctor, of course,

but also move into that gradually, right?

Start with the lowest effective dose.

The minimal effective dose.

And sometimes the minimal effective dose

is zero milligrams, it's nothing.

Why do I say that?

Well, we already talked about results where

they put people's arms into an ice bath

in order to evoke adrenaline release.

You are welcome to do that if you want.

In fact, that's a pretty low cost, zero pharmacology.

At least exogenous pharmacology way

to approach this whole thing.

That's a way of evoking your own natural epinephrine

that turns out also dopamine release.

You could take a cold shower.

You could do an ice bath or get into

a cold circulating bath.

We've done several episodes

on the utility of cold for health and performance.

You can find those episodes at HubermanLab.com.

Also the episode with my colleague at Stanford

from the biology department, Dr. Craig Heller.

Lots of protocols, in particular in the episode

on cold for health and performance.

That describe how best to use

the cold shower or the ice bath or the circulating cold bath

in order to evoke epinephrine

and dopamine release.

The point is that the time in which

you would want to do those protocols

is after, ideally immediately after your learning about.

Meaning when you're sitting down to learn

new information or after trying

to learn some new physical skill.

Now whether or not that's compatible

with the other reasons you're doing

deliberate cold exposure,

and whether or not that's compatible

with the other things you're doing,

that depends on the contour of your lifestyle,

your training, your academic goals,

your learning goals, etc.

But if your specific purpose is to enhance

learning and memory, you want to spike adrenaline afterwards.

And so what I'm telling you is you can do that

with caffeine.

You can do that with Alpha GPC.

You can do that with a combination

of caffeine and Alpha GPC.

If you can do that safely.

Some of you I know are using

other forms of pharmacology.

I did a long episode all about ADHD.

I have to just really declare my stance very clearly

that I am not a fan, I am actually opposed

to people using prescription drugs

who are not prescribed those drugs

in order to enhance alertness.

I think there's a big addictive potential.

There also is a potential to really

disrupt one's own pharmacology around

the dopaminergic system.

However, some of you I know are prescribed

things like ritalin, Adderall and modafinil

and things of that sort in order

to increase alertness and focus.

So for those of you that are prescribed

those things from a board certified physician,

you're going to have to decide

if you're going to take them before trying to learn

or after trying to learn.

You also have to take into consideration

that some of those drugs are very long acting.

Some are shorter acting.

And time that according

to what you're trying to learn and when.

So that's pharmacology.

But as I mentioned, there are the behavioral protocols.

You can use cold and cold is an excellent stimulus

because first of all, it doesn't involve pharmacology.

Second of all, you can generally access it

at low to zero cost, especially the cold shower approach.

And third, you can titrate it.

You can start with warmer water.

You can make it very, very cold if that's your thing

and you're able to tolerate that safely.

You can make it moderately cold.

How cold should it be in order to invoke adrenaline release?

Well, it should be uncomfortably cold

but cold enough that you feel like

you really want to get out,

but can stay in safely.

That's going to evoke adrenaline release.

If it quickens your breathing,

if it makes you go wide eyed.

That's increasing adrenaline release.

In fact, those effects of going wide eyed

and quickening of the breathing

and the challenges in thinking clearly,

those are the direct effects of adrenaline

on your brain and body.

And of course, there are other ways

to increase adrenaline.

You could go out for a hard run.

You could do any number of things

that would increase adrenaline in your body.

Which things you choose is up to you,

but from a very clear, solid grounding

in research data, we can confidently say

that spiking adrenaline after interacting

with some material, physical or cognitive material

that you're trying to learn,

is going to be the best time to spike that adrenaline.

Now I realize I'm being a bit redundant today

or perhaps a lot redundant.

In repeating over and over that

the increase in epinephrine should occur

either very late in an attempt to learn something

or immediately after an attempt to learn something.

I also want to emphasize the general contour

of pharmacologic effects and of behavioral tools

to create adrenaline.

What do I mean by that sentence?

What I mean is that McGaugh and colleagues

explored a huge number

of different compounds and approaches.

Everything from the hand into the ice bath

to injecting adrenaline, to caffeine,

to drugs that block the affects of adrenaline and caffeine.

Drugs like muscimol and picrotoxin.

Please don't take those.

These are drugs that reduce

or enhance the amount of adrenaline

and the overall takeaway is that anything

that increases adrenaline will increase

learning and memory and will reduce

the number of repetitions required to learn something.

Regardless of whether or not that something

has an emotional intensity or not.

Provided that spike in adrenaline occurs late

in the learning or immediately after.

And anything that reduces epinephrine and adrenaline

will impair learning.

And that's the key and novel piece of information

that I'm adding now.

Which is if you're taking beta blockers, for instance.

Or if you're trying to learn something

and it's not evoking much of an emotional response,

and you're not using any pharmacology

or other methods to enhance adrenaline release

after learning that thing, well,

you're not going to learn it very well.

In fact, McGaugh and Cahill did beautiful experiments

in humans looking at how much adrenaline

is increased by varying the emotional intensity

of different things that they were trying

to get people to learn.

Or by changing the dosage of epinephrine.

Or by changing the amount of epinephrine blocker

that they injected.

Lots and lots of studies.

The key thing to take away from those studies

is that for some people, adrenaline

was increased 600 to 700%.

So six to seven fold over baseline

in the amount of circulating epinephrine or adrenaline.

And keep in mind, sometimes that increase

was due to the actual thing they were trying to learn

being very emotional, positive or negative emotion.

And sometimes it was because they were using

a pharmacologic approach or the ice bath approach.

I don't think they ever used a cold shower approach,

but that would have been a very effective one

we can be sure.

However, other people had a zero to 10% increase.

So a very small increase in epinephrine.

What we can confidently say on the basis

of all those data is that the more epinephrine release,

the better that people remembered the material.

Over and over again this was shown.

Whether or not it was for cognitive material,

so learning a language, learning a passage of words,

learning mathematics.

Or whether or not it was for physical learning.

I want to emphasize something about physical learning

because I know a number of you are probably

drinking a cup of coffee or having

a cup of yerba mate or maybe even an energy drink

and taking some Alpha GPC or something

before physical exercise.

I'm not saying that's a bad thing to do

or you wouldn't want to do that.

But that's really to increase alertness.

It won't enhance learning,

at least not as well as doing those things after

the physical exercise.

Now again, many of you, including myself,

exercise for the sake of the physical benefits

of that exercise.

So cardiovascular, resistance training.

But we're not really focused on learning and memory.

So, I emphasize this just so it's

immensely clear to everybody.

If you want to use those approaches

of increasing adrenaline prior to

or during physical training,

or cognitive work for that matter, be my guest.

I think that's perfectly fine,

provided that's safe for you.

It's only by moving it to late

or after the learning that you're really shifting

the role of that adrenaline increase

to enhancing memory specifically.

And as a cautionary note, don't think

that you can push this entire system

to the extreme over and over again,

or chronically, as we say, and get away with it.

In other words, you're not going to be able

to take a Alpha GPC and a double espresso

do your focus about of work, cognitive or physical work,

and then spike adrenaline again afterwards

and remember that stuff you did better, right.

I'm not encouraging you, in fact I'm discouraging you

from chronically increasing adrenaline

both during and after a given about of work

if the goal is to learn.

Why do I say that?

Well, work from McGaugh and Cahill and others

has shown that it's not the absolute amount

of adrenaline that you release

in your brain and body that matters for enhancing memory.

It's the amount of adrenaline you release

relative to the amount of adrenaline

that was in your system just prior.

Particularly in the hour or two prior.

So again, it's the delta, as we say.

It's the difference.

So if you're going to chronically increase adrenaline

you're not going to learn as well.

The real key is to have adrenaline modestly low.

Perhaps even just as much as you need

in order to be able to focus on something,

pay attention to it, and then spike it afterwards.

This is immensely important because

while much of what we're talking about

is actually a form of inducing

a neuro chemical acute stress.

Meaning a brief and rapid onset of stress.

Well, chronic stress, the chronic elevation

of epinephrine and cortisol

is actually detrimental to learning.

And there's an entire category of literature

mainly from the work of the great

and sadly the late Bruce McEwen

from the Rockefeller University.

And some of his scientific offspring

like the great Robert Sapolsky,

showing that chronic stress,

chronic elevation of epinephrine

actually inhibits learning and memory.

And also can inhibit immune system function.

Whereas acute, right, sharp increases

in adrenaline and cortisol actually can enhance learning

and indeed, can enhance the immune system.

So if you really want to leverage this information,

you might consider getting your brain and body

into a very calm and yet alert state.

So a high attentional state

that will allow you to focus on what it is

that you're trying to learn.

We know focus is vital for encoding information

and for triggering neuroplasticity.

But remaining calm throughout that time

and then afterwards spiking adrenaline

and allowing adrenaline to have these incredible effects

on reducing the number of repetitions

required to learn.

So if you're like me, you're learning about this information

this beautiful work of McGaugh and Cahill and others

and thinking, wow, I should perhaps consider

spiking my adrenaline in one form or another

at the tail end or immediately following

an attempt to learn something.

And yet, we are not the first

to have this conversation.

Nor were McGaugh and Cahill

or any other researchers that I've discussed today

the first to start using this technique.

In fact, there is a beautiful review

that was published just this year, May of 2022

in the journal Neuron, Cell Press Journal.

Excellent journal.

Called Mechanisms of Memory Under Stress.

And I just want to read to you the first opening paragraph

of this review, which is, as the name suggests,

all about memory and stress.

So here I'm reading, and I quote,

"In Medieval times communities threw"

"young children in the river when"

"they wanted them to remember important events."

"They believed that throwing a child in the water"

"after witnessing historic proceedings"

"would leave a life long memory"

"for the events in the child."

Believe it or not, this is true.

This is a practice that somehow people arrived at.

I don't know if they were aware of what adrenaline was.

Probably not.

But somehow in medieval times

it was understood that spiking adrenaline

or creating a robust emotional experience

after an experience that one hoped a child would learn

would encourage the child's nervous system,

they didn't even know what a nervous system was,

but would encourage the brain and body

of that child to remember those particular events.

Very counter intuitive if you ask me.

I would have thought that the kid would remember

only being thrown into the river.

My guess is that they remember that,

but the idea here anyway, is they also remember

the things that preceded being thrown into the river.

So both interesting and amusing

and somewhat, I should say thought stimulating, really.

That this is a practice that has been going on

for many hundreds of years.

And we are not the first to start thinking

about using cold water as an adrenaline stimulus.

Nor are we the first to start thinking about

using cold water induced adrenaline

as a way to enhance learning and memory.

This has been happening since medieval times.

So up until now I've been talking about

pretty broad contour of these experiments.

I've been talking about the underlying pharmacology,

the role of epinephrine and so forth.

I haven't really talked a lot about

the underlying neural mechanisms.

So we're just going to take a minute or two

and describe those for you

because they are informative.

We all have a brain structure called the amygdala.

A lot of people think it's associated with fear

but it's actually associated with threat detection

and more generally, and I should say more specifically,

with detecting what sorts of events

in the environment are novel and are linked

to particular emotional states.

Both positive emotional states

and negative emotional states.

So the neurons in the amygdala are exquisitely good

at figuring out, right, they don't have their own mind

but at detecting correlations between

sensory events in the environment

that trigger the release of adrenaline

and what's going on in the brain.

And because the amygdala is so extensively

interconnected with other areas of the brain.

It basically connects to everything

and everything connects back to it.

The amygdala is in a position to strengthen

particular connections in the brain very easily.

Provided certain conditions are met.

And those conditions are the ones

we've been talking about up until now.

Emotional saliency that results in increases

in epinephrine and cortisol.

Or circulating epinephrine and cortisol

being much higher than it was 10 minutes

or 15 minutes before.

And the net effect of the amygdala

in this context is to take whatever patterns

of neural activity preceded that increase

in adrenaline and corticosterone

and strengthen those synapses that were involved

in that neural activity.

So the amygdala doesn't have knowledge.

It's not a thinking area.

It's a correlation detector.

And it's correlating neural chemical

states of the brain and body,

different patterns of electrical activity in the brain.

This is important because it really emphasizes

the fact that both negative and positive emotional states

and the different but somewhat overlapping

chemical states that they create,

or the conditions, as we say the and gates

through which memory is laid down.

And gates will be familiar to those

of you who have done a bit of a computer programming.

An and gate is simply a condition

in which you need one thing and another to happen

in order for a third thing to happen.

So you need epinephrine elevated and you need

robust activity in a particular brain circuit

if in fact that brain circuit is going to be strengthened.

It's not sufficient to have one or the other, you need both.

Hence, the name and gate.

And the amygdala is very good at establishing

these and gate contingencies.

It's also a very generic brain structure

in the sense that it doesn't really care

what sorts of sensory events are involved

provided they correlated in time

with that increase in adrenal and corticosterone.

This has a wonderful side and a kind of dark side.

The dark side is that PTSD and traumas

of various kinds often involve an increase

in adrenaline because whatever it was

that caused the PTSD was indeed very stressful.

Caused these big increases in these chemicals.

And because the amygdala is rather general in its functions.

Right, it's not tuned or designed

in any kind of way to be specifically active

in response to particular types

of sensory events, or perceptions.

Well, then what it means is that

we can start to become afraid

of entire city blocks where one bad thing happened

in a particular room of a particular building

in a city block.

We can become fearful of anyplace that contains

a lot of people if something bad happened to us

in a place that contained a lot of people.

The amygdala is not so much of a splitter,

as we say in science.

We talk about lumpers and splitters.

Lumpers are kind of generalizers,

if that's even a word.

And I think it is, someone will tell me

one way or the other.

And splitters are people that are ultra precise

and specific and nuanced about every little detail.

The amygdala is more of a lumper than a splitter

when it comes to sensory events.

Other areas of the brain only become active

under very, very specific conditions

and only those conditions.

And similarly, epinephrine is just a molecule.

It's just a chemical that's circulating

in our brain and body.

There's no epinephrine specifically for

a cold shower that is distinct from the epinephrine

associated with a bad event

which is distinct from the epinephrine

associated with a really exciting event

that makes you really alert.

Epinephrine is just a molecule, it's generic.

So these systems have a lot of overlap

and that can explain, in large part,

why when good things happen in particular locations

and in the company of particular people,

we often generalize to large categories

of people, places, and things.

And when negative things happen

in particular circumstances,

we often generalize about people places and things

associated with that negative event.

So now I'd like to talk about other tools

that you can leverage that have been shown

in quality, peer-reviewed studies

to enhance learning and memory.

And perhaps one of the most potent

of those tools is exercise.

There are numerous studies on this

in both animals and fortunately now also in humans.

Thanks to the beautiful work of people like Wendy Suzuki

from New York University.

Wendy's lab has identified how exercise works

to enhance learning and memory

and other forms of cognition, I should mention.

As well as things that can augment,

can enhance the effects of exercise

on learning and memory and other forms of cognition.

Wendy is going to be a guest on this podcast.

It's actually the episode that follows this episode.

And it includes a lot of material

that we have not covered today.

And she's an incredible scientist

and has some incredible findings

that I know everyone is going to find immensely useful.

In the meantime, I want to talk about some

of the general effects of exercise on learning

and memory that she's discovered

and that other laboratories have discovered.

If you recall earlier, I mentioned

that learning and memory almost always involves

the strengthening of particular synapses

and neural circuits in the brain.

And not so much the increase in the number

of neurons in the brain.

There is one exception, however.

And we now have both animal data and some human data

to support the fact that cardiovascular exercise

seems to increase what we call dentate gyrus neurogenesis.

Neurogenesis is the creation of new neurons.

The dentate gyrus is a subregion of the hippocampus

that's involved in learning and memory

of particular kinds.

Right, certain types of events,

particular contextual learning,

but some other things as well.

Sometimes involved in spacial learning.

There's a lot debate about exactly what

the dentate gyrus does, but for the sake

of this discussion, and I think everyone

in the neuroscience community would agree

that the dentate gyrus is important

for memory formation and consolidation.

The dentate gyrus does seem to be one region in the brain,

certainly in the rodent brain,

but more and more it's seeming also in the human brain

where at least some new neurons

are added throughout the lifespan.

And, as it turns out, that cardiovascular exercise

can increase the proliferation

of new neurons in this structure.

And that those new neurons, excuse me,

are important for the formation

of certain types of new memories.

There are wonderful data showing that

if you use X-irradiation, which is a way

to eliminate the formation of those new cells

or other tools and tricks to eliminate

the formation of those cells

that you block the formation of certain kinds

of learning and memory.

What does this mean?

Well, there are a lot of reasons for the statement

I'm about to make that extend far beyond

neurogenesis and the hippocampus learning and memory.

But it's very clear that getting anywhere

from 180, or I should say a minimum

of 180 to 200 minutes of so called zone two

cardiovascular exercise, so this is cardiovascular exercise

that can be performed at a pretty steady state

which would allow you to just barely hold a conversation.

So breathing hard but not super hard.

Such as in sprints or high intensity interval training.

But doing that for 180 to 200 minutes per week total

is it appears the minimum threshold

for enhancing some of the longevity effects

associated with improvements in cardiovascular fitness

and we believe that it is indirectly,

I should say indirectly, through enhancements

in cardiovascular fitness that there are improvements

in hippocampal dentate gyrus neurogenesis.

What does that mean?

The improvements in cardiovascular function

are indirectly impacting the ability

of the dentate gyrus to create these new neurons.

To my knowledge there's no direct relationship

between exercise and stimulating

the production of new neurons in the brain.

It seems that it's the improvement in blood flow

that also relate to improvements

in things like lymphatic flow,

the circulation of lymph fluid within the brain

that are enhancing neurogenesis

and that neurogenesis, it appears is important.

Now in fairness to the landscape of neuroscience

and my colleagues at Stanford and elsewhere.

There is a lot of debate as to whether or not

there is much if any neurogenesis in the adult human brain.

But regardless, I think the data are quite clear

that the 180 to 200 minutes minimum

of cardiovascular exercise is going to be important

for other health metrics.

Now it is clear that exercise can impact learning

and memory through other non-neurogenesis,

non-neuron type mechanisms.

And one of the more exciting ones

that has been studied over the years

is this notion of hormones from bone traveling

in the blood stream to the brain

and enhancing the function of the hippocampus.

If the words hormones from bones is surprising to you,

I'm here to tell you that yes, indeed,

your bones make hormones.

We call these endocrine effects.

So in biology we hear about autocrine, paracrine,

and endocrine.

Those different terms refer to over what distance

a given chemical has an affect on a cell.

For instance, a cell can have an affect on itself.

It can have an affect on immediately neighboring cells

or it can have an affect on both itself,

immediately neighboring cells and cells far,

far away in the body.

And that last example of a given chemical

or substance having and affect on the cell that produced it

plus neighboring cells, plus cells far away

is an endocrine effect.

And a lot of hormones, not all, work in this fashion.

Hence why we sometimes hear about endocrine and hormone

as kind of synonymous terms.

Your bones make chemicals that travel in the blood stream

and have these endocrine effects.

So they're effectively acting as hormones.

And one such chemical is something called osteocalcin.

Now these findings arrived to us through various labs

but one of the more important labs

for the sake of this discussion today

is the laboratory of Eric Kandel at Columbia Medical School.

Eric is now, I believe in his mid to late 90s,

still very sharp.

And has studied learning and memory.

It also turns out that he is an avid swimmer.

Now, I happen to know that Eric swims anywhere

from a half a mile to a mile a day.

And again, this is anecdotal.

I'm not referring to the published data just yet.

But he credits that exercise as one of the ways

in which he keeps his brain sharp

and has indeed kept his brain sharp

for many, many decades.

And as I mentioned before, he's well into his 90s.

So pretty impressive.

His laboratory has studied the effects

of exercise on hippocampal function and memory.

And other laboratories have done that as well.

And what they've found is that cardiovascular exercise

and perhaps other forms of exercise too,

but mainly cardiovascular exercise creates

the release of osteocalcin from the bones

that travels to the brain and to sub regions

of the hippocampus and encourages

the electrical activity and formation and maintenance

of connections within the hippocampus

and keeps the hippocampus functioning well

in order to lay down new memories.

Now osteocalcin has a lot of effects

besides just improving the function of the hippocampus.

Osteocalcin is involved in bone growth itself.

It's involved in hormone regulation.

In fact, there's really nice evidence

that it can regulate testosterone and estrogen production

by the testes and ovaries.

And a bunch of other effects in other organs of the body.

Because again, it's acting in this endocrine manner.

It's arriving from bone to a lot

of different organs to have effects.

Load bearing exercise, in particular,

turns out to be important for inducing

the release of osteocalcin.

And when you think about this, it makes sense.

A nervous system exists for a lot of reasons,

to sense, perceive, etc.

You've got taste, you've got smell,

you've got hearing.

But the vast majority of brain real estate,

especially in humans, is dedicated to two things.

One, vision.

We have an enormous amount

of brain real estate devoted to vision.

Certainly compared to other senses.

And to movement.

The ability to generate course movements of the body.

The ability, excuse me, to generate fine movements

of the body, like the digits,

or to wink one eye, or to tilt your head

in a particular way, or move your lips

and move your face and do all sorts of different things

in a very nuanced and detailed way.

So much of our brain real estate

is devoted to movement that it's been hypothesized

for more than a half century,

but especially in recent years

as we've learned more about the function

of the brain in a really detailed circuit level,

that the relationship between the brain and body

and the maintenance and perhaps even

the improvement of the neural circuitry in the brain

depends on our body movements and the signal

from the body that our brain is still moving.

So think about that.

How would your brain know if your body

was moving regularly and how would it know

how much it was moving?

How would it know which limbs it was moving?

Well, you could say, if the heart rate

is increased then the blood flow will be increased

and then the brain will know.

Ah, but how does your brain know

that its increased blood flow due to movement

and not to, for instance, just stress, right?

Maybe you actually can't move

and you're very stressed about that

and so the increased blood flow

is simply a consequence of increased stress.

The fact that osteocalcin is released from bone

and in particular can be released

in response to load bearing exercise.

So this would be running, again weightlifting

hasn't been tested directly,

but one would imagine anything that involves

jumping and landing, or weightlifting,

or body weight movements and things of that sort.

That's a signal to release osteocalcin,

and we know that signal occurs.

That is directly reflective

of the fact that the body was moving

and moving in particular ways.

In fact, you could imagine that big bones

like your femur are going to release more osteocalcin

or be in a position to release more osteocalcin

then fine movements like the movements of the digits.

And this idea that the body is constantly

signaling to the brain about the status

of the body and the varying needs of the brain

to update its brain circuitry,

is a really attractive idea that fits entirely

with the biology of exercise, osteocalcin,

and hippocampal function.

I do want to mention that I'm not

the first to raise this hypothesis.

This hypothesis actually was discussed

in a fair amount of detail by John Ratey

who's a professor at Harvard Medical School.

He wrote a book called, "Spark"

which was one of the early books

at least from an academic about brain plasticity

and the relationship between exercise

and movement and plasticity.

And John, who I have the good fortune to know,

has described to me experiments,

or I should say observations of species

of ocean dwelling animals that have,

at least for the early part of their life,

a very robust and complicated nervous system.

But then these particular animals

are in the habit of plopping down unto a rock.

They find kind of a safe, comfy space

and they actually stick to that rock

and they don't move anymore for a certain portion,

I should say the later portion of their life.

And it is at the transition between moving a lot

and being stationary that those animals

actually digest their own brain.

The literally metabolize a good portion

of their nervous system because they decide, oh,

don't need this anymore.

And gobble it up, use it for its nutritional value

and then sit there like a moron version of themselves

with a limited amount of brain tissue

because they don't need to move anymore.

Now, I certainly don't want to give the message

that just moving, just exercise,

is sufficient to keep the neural architecture

of your brain healthy, young, and able to learn.

While that might be true,

it's also important to actually engage

in attempts to learn new material.

Either physical material, so new types of movements

and skills and or new types of cognitive information.

Languages, mathematics, history, current events.

All sorts of things that involve your brain.

Nonetheless, it's clear that physical movement

and cognitive ability and the potential

to enhance cognitive ability

and the ability to learn new physical skills

are intimately connected.

And osteocalcin appears to be at least one way

in which that brain-body relationship

is established and maintained.

So given the information about osteocalcin and movement,

and given the information about spiking adrenaline late

or after a period of an attempt to learn,

you might be asking when is the best time to exercise?

Now unfortunately, that has not been addressed

in a lot of varying detail,

where every sort of variation on the theme

has been carried out.

And yet, Wendy Suzuki's lab has done

really beautiful experiments where

they have people exercise, generally it was in the morning.

But at other periods of the day as well.

And what they find is that at least as late as

two hours after that exercise,

there is an enhancement in learning and memory.

Now I want to be clear, we don't know

whether or not that exercise led

to big increases in adrenaline.

It may be that those forms of exercise

were modest enough, or didn't challenge people enough

that they merely got a lot of blood flow going

and that the improvements in learning

and memory were related to blood flow

and we presume increases in osteocalcin.

However, you could imagine a couple

of different logical protocols based

on what we've talked about.

Let's say you were going to do a form of exercise

that was going to spike adrenaline a lot.

So this would be exercise that really challenges

your system and forces you to kind

of push through a burn.

Right, so here I'm mainly thinking about

cardiovascular exercise.

But it could even be yoga,

it could be resistance training.

If it's going to give you a big spike

in adrenaline, it's going to take some serious effort,

then logically speaking you would want to place that

after a learning about in order to increase

learning and memory.

However, if you're using the exercise

in order to enhance blood flow

and to enhance osteocalcin release.

In efforts to augment the function of your hippocampus,

I think it stands to reason that doing

that exercise sometime within

the hour to three hours preceding an attempt to learn

makes a lot of sense.

And there I'm basing it on the human data

from Wendy Suzuki's lab.

I'm basing it on the studies from Eric Kandel

and from others labs.

Again, right now, there hasn't been

an evaluation of a lot of different protocols

to arrive at the peer-reviewed laboratory super protocol.

However, since what we're talking about

is using activities like exercise that most

of us probably, perhaps all of us,

should be doing regularly anyway.

And I do believe most if not all of us should

regularly be trying to learn

and keep our brain functioning well

and acquire new knowledge.

Because it's just a wonderful part of life.

And there is evidence that actually can keep

your brain young, so to speak.

Well then, exercising either before

or after a learning about makes a lot of sense.

With the emphasis on after a learning about

if the form of exercise spikes a lot of adrenaline

for all the reasons we talked about before.

Okay, so we've talked about two major

categories of protocols to improve memory

that are grounded in quality, peer reviewed science.

And there is yet another third protocol

that we'll talk about in a few minutes.

But before we do that,

I want to briefly touch on an aspect of memory,

in fact, two aspects of memory

that I get a lot of questions about.

The first one is photographic memory.

To be clear, there are people out there

who have a true photographic memory.

They can look at a page of text,

they can scan it with their eyes,

and they can essentially commit that to memory

with very little if any effort.

While it might seem that having a photographic memory

is a very attractive skill to have,

I should caution you against believing that

because it turns out that people

with true photographic memory are often very challenged

at remembering things that they hear.

And often times are not so good

at learning physical skills.

It's not always the case, but often that's the case.

So be careful what you wish for.

If you do have a photographic memory

there are certain professions that lend themselves

particularly well to you.

And indeed a lot of people with photographic memory

have to find a profession and have to move through life

in a way that is in concert

with that photographic memory.

So again, it's a super ability,

it's a hyper ability and yet it's not necessarily one

that is desirable for most people.

There's also this category of what are called

super recognizers.

These people are, I should mention,

highly employable by government agencies.

These are people that have an absolutely astonishing

ability to recognize faces and to match faces to templates.

They can look at a photograph

of say somebody on a most wanted list

and then they can look at video footage

of let's say an airport, or a mall,

or a city street at fairly low resolution

and they can spot the person who's face

matches that photograph that they looked at.

Even if that video or other footage

is of people's profiles or even

the tops of their heads and just

a portion of their forehead.

These people have just an incredible ability

to recognize faces and to template match.

And again, these people often will take

jobs with agencies where this sort of thing is important.

Some of you out there probably

are super recognizers and may or may not notice it.

If you've ever had the experience

of watching a movie and thought to yourself,

wow, her mouth looks so much like my cousin's mouth.

Or you look at a character in a movie

or a television show and you think,

wow, they look almost like the younger sister of so and so.

Well, then it's very likely that you have this,

or at least a mild form of this super recognizer ability.

That is not memory per se.

That is the hyper functioning of an area

of the brain that we call the fusiform gyrus.

The fusiform gyrus is literally

a face recognition area, and a face template matching area.

And it harbors neurons that respond to faces generally.

So as humans and other non-human primates,

we care a lot about faces and their emotional content.

And the identity of faces is super important to us

for all the kinds of reasons that are probably obvious.

Knowing who's friend, who's foe.

Who do you know well?

Who's famous, who's not famous?

Etc.

That is not memory, per se.

And yet, if you're a super recognizer,

or I guess you could call it a moderate face recognizer

or not very good at recognizing faces

because indeed, there are some people

that are kind of face blind.

They don't actually recognize people

when they walk in the room.

I used to work with somebody like this.

I'd walk into his office and he'd say,

are you Rich or are you Andrew?

And I would say, well am I rich, rich.

Like, you know, wealth rich?

No.

And he'd say, no, are you Richard or are you Andrew?

And I'd say, I'm Andrew.

We know each other really well.

And he'd say, oh I'm sorry.

I'm kind of face blind.

And it actually tended to be better or worse

depending on how much he was working.

Ironically, the more rested he was

the more face blind he would become.

So it wasn't a sleep deprivation thing.

That exists, that's out there.

There's the full constellation

of people's ability to recognize faces.

That's not really memory.

And yet, visual function is a profoundly powerful way

in which we can enhance our memories.

So whether or not you're a super recognizer of faces,

whether or not you are face blind

or anything in between.

Next I'm going to tell you about a study

which points out the immense value of visual images

for laying down memories.

And you can leverage this information

and this involves both the taking of photographs,

something that's quite easily

done these days with your phone.

As well as your ability to take mental photographs

by literally snapping your eyelids shut.

So I just briefly want to describe this paper

because it provides a tool that you can leverage

in your attempt to learn and remember things better.

The title of this paper is Photographic Memory,

the Effects of our Volitional Photo-Taking

on Memory for Visual and Auditory Aspects of an Experience.

I really like this paper because it refers

to photographic memory not in the context

of photographic memory that we normally hear about

where people are truly photographic,

look at a page and somehow absorb all that information

and commit it to memory.

But rather the use of camera photographs

or the use of mental camera photographs.

Literally looking at something deciding, blink,

snapping a, so to speak, snapping a snapshot

of whatever it is that you are looking at

and remembering the content.

The reason I like this paper

and the reason I'm attracted to this issue

of mental snapshots is this is something

that I've been doing since I was a kid.

I don't know why I started doing it,

but every once in a while, I would say maybe twice a year

I would look at something and decide to just

snap a mental snapshot of it.

And I've maintained very clear memories