All language subtitles for Lecture06 Scientific Secrets for Powerful Memory

Over the course of these six sessions, we've explored the properties
and the limits of human memory.

I've talked at great length about how human memory functions
in terms of encoding, storing and then hopefully retrieving it.

We've pondered how the brain implements all of these functions.

I've talked a lot about how to maximize the performance of your memory

by recoding things from hard to remember formats
into the images and places that our memories are so good at remembering.

You can greatly enhance your ability to encode things

by this point in the course,
especially if you've been practicing things.

You should have a significantly better memory than you had at the start.

To be clear, your memory itself will probably not be a whole lot better,
but your ability to use that memory should be much better.

All that said,

your computer, your phone, the internet are still able to retain
a lot more information than even the best memory expert.

I've taught you how you can encode and remember
the names of the presidents and the atomic weights of the elements.

Very well.

But a quick search on Google will tell you
both of these pieces of information very easily.

In this final session,
I want to start by pondering a very fundamental question Why memory?

Why should we still strive to put and hold information in our brains
when the computer can do it very well for us?

I will argue, perhaps not surprisingly,

that information on the computer is very different from information
that you can actually think about in your own mind.

The last topic I want to consider,

however, are some important roles
that technology can and should play in backing up our memories.

When information storage breaks down on a computer or a camera.

You can tell that it's done so the information simply comes back garbled
or the image is seen as having missing parts.

That's not how human memory breaks down.

Our minds are very good at filling in missing pieces.

If you remember a photograph that you've seen, for instance,
you might only actually recall who was there,

that you were sitting at a table
and that there was a birthday party from those three facts.

You can infer a lot of other things.

You can infer the types of outfits, outfits
people had on a particular maybe what kinds of hats they were wearing.

You can imagine what the room would smell
and sound like and roughly what time of day it was.

When you think about that photograph,
especially if you do it on several occasions, you can lose track

of which parts of the photo memory were actually experienced
and which were filled in because parts were missing in your recall.

I'll describe the theory that human memory
is a process of reconstruction as much as a process of recall.

This reconstruction is great,
but knowing the limits of how your memory functions

is very important for making the best, most careful use of it.

Okay. So first a bit about technology in general.

We live in an age in which memory may seem much less important
than it was, say, a few hundred years ago, even a decade ago.

When I was a kid, I needed to memorize my friend's phone numbers.

Now, thanks to my trusty smartphone, I only need to know their names,
pressed a few buttons and a call is made.

In one recent study that was conducted in England.

It was found that more than half of all teens living
there don't even know their own phone numbers.

Their own phone numbers.

I used to need to memorize my class and meeting schedule for the week.

Now a little alarm linked to an electronic calendar beeps to remind me
whenever an event is coming up.

When it comes to questions about facts, things like the year
in which the American Civil War ended

or the name of the 17th President of the United States
or the atomic number of boron.

It used to be that a great effort was involved
in finding out those answers.

And so a lot of time and energy was committed
to encoding those types of facts and our memories.

Now we have the Internet.

In a few seconds, Google or another search engine can tell me these
and any of thousands of other facts.

In a sense,
these electronic devices are like an external extension of our memories.

Just like an extra computer hard drive for our heads.

So why should we care about improving our memories?

I think the story about EPI and other brain injured patients illustrates
an answer to this.

We can look up isolated facts that particular moments with a computer.

That certainly works.

But our brains do much more than simply regurgitate facts
that have been entered into them.

We think about those facts about how they relate to one another.

How did the timing of the end of the Civil War
relate to who was the 17th president and his political persuasions?

How does the atomic weight of boron relate to the weights
and reactivity of other elements with which it's mixed?

How might these new pieces of information relate in perhaps

unexpected ways to other information
that we learned a long, long time ago

without having groups of information in our minds and keeping it there?

Over time, we lose the ability to find to see these types of relations,
more complex connections between several sources of information.

Are things that computers are frankly quite bad at

for remembering simple facts. The computers may have a speed.

Actually, encyclopedias had a speed a long time before computers.

But for real thinking, real reasoning, real insight,
you have to be able to get the information

up into the network of neurons
that forms your brain, ultimately create your mind.

As long as thinking and insight are important.

Memory will be critical as well.

And the better your memory is, the more information you're able to have
at your immediate disposal, the better your thinking will be.

When I attend conferences with other cognitive scientists,
this need for memory becomes very clear.

There's a wealth of research on cognitive processes
being performed every month out there in the world of academia.

What is the nature of memory?

What are the best ways to enhance it?

Will exercise, promote increases in memory ability.

Any of these seemingly basic,
straightforward questions are actually quite complex.

What type of exercise? For how long? Each day. For how many years?

What types of memory improvement?

To really address almost any question in a scientific manner.

One can't simply do a single magic bullet kind of experiment.

Answering most real world questions involves performing dozens,
some cases, hundreds of different experiments,

and then pulling the results of them all together
to develop a rounded understanding of how things work.

Now, all of the best experiments that have been performed
have been published.

The details of what was done, what the results of those studies were,
and what the authors think they mean.

All of that's out there in print.

Most of it's accessible with a few key presses and some downloading.

Why would one ever need to commit all of it to memory?

As soon as you start having a discussion with someone
about this research or a group of people about this research.

You find that in the midst of those discussions,
let alone in the midst of arguments, there just isn't time to go

looking up references and say,
okay, hold on, I'm going to go check my computer.

You need to have the details of those experiments
in your mind, at your fingertips.

To be able to find it somewhere on a computer just isn't sufficient.

Even if you're not having a discussion, if you're just pondering
these issues in isolation, say, sitting by your computer

and trying to figure out how the mind works,
it isn't enough to have a stack of papers or a computer desk

full of PDF files with the information in them
in order to think through how different facts relate to one another.

You just need to have them all stored within the same device,
the same thinking device.

Your brain.

From an educational perspective,
I think there may be a bit of a coming crisis here.

I don't know if research on this specific topic,
but it seems almost certain to come to pass in some form

in order to think about any

complex set of information
and how it relates to any complex real world issue.

You need to have a lot of information stored in your mind.

Our educational system has produced a generation
of very creative and impressive thinkers,

but I'd be surprised if there isn't a deficit in the ability
to use memory relative to earlier generations.

It might be that we need to relearn some of these important skills

in order to make progress
with modern, intellectual, environmental and political issues.

Almost any issues that are relevant and important to us and complex.

So computers are great.

They are, in a way, a nice extension of our long term memories,
but they're not a replacement for them.

Not by a long shot.

Human memory still matters and it will continue to matter for the
foreseeable future as long as there's important thinking to be done.

Memory will matter.

So I've argued that human memory is great and very important.

Now, going to switch gears a little and talk about a big problem
with human memory.

We've already talked about forgetting.

Forgetting can be bad, but that's not the real problem
I want to talk about here.

The problem arises when we've actually forgotten something,
but don't realize it.

A false memory can be much worse than no memory at all.

Watch the following words and remember them. After I present them.

I'll delay for a minute or two
and then ask you to recall as many as you can.

This is one of those demos where I won't actually know
if you've participated or not, but there's a compelling point here

that will be much more salient if you try it.

So you'll need a piece of paper and a pen or a pencil to write with.

But please don't write the words while they're actually being presented.

That would defeat the purpose of the demo.

I want you to watch and try to remember the words.

And only when I tell you.

Try to write down as many as you can recall

a door

glass

pane, shade

ledge

sill, house, open

a curtain and

frame

view, freeze sash

screen, shutter.

Okay, so you've seen that list of words.

If you're like most people preparing for a recall test,
you might be rehearsing them in your head right now.

You'll likely get those first few, but there were far more than seven,
so you probably can't rehearse the whole word list.

Hopefully you encoded them into your long term memory in some fashion.

The demonstration I'm doing here
is about that long term storage and retrieval and how it functions.

Let's give it just about 20 more seconds.

Probably work even if we did the recall right now that a full minute
is best for maximizing the probability of this particular effect.

I can, of course, tell you what's supposed to have happened,
but it's far more convincing.

I think if you have produced the effect yourself.

Okay, Go ahead now and take a minute
to try to recall as many of those words as you can.

I'll stop talking for one minute or so and let you concentrate.

Here's that list of words again.

I would bet that you got those first two or three.

Door, glass and pain,
if only because they were the first two on two or three on the list.

This is called the primacy effect.

In the forgetting session, we talked about how that's due in part
to the fact that you don't have any retroactive interference

in this task situation yet.

I would similarly guess that you likely remembered
the last two on the list

screen and shudder this tendency to remember things
that at the end of lists is what's called the recency effect.

There's a minimum of proactive interference for these,
but probably more importantly, you had less time to forget those

since they were presented most recently in time.

The third thing I would predict is that there's about a 5050 chance
that your list contains the word window.

That is your first note that the word window was not presented.

It's not there in the list.

And yet you wrote it on your list.

If you didn't, then take my word for it that many people do.

And if I were to continue doing this type of demo again
and again, eventually, I promise you would almost certainly fall

for this same kind of memory error.

If you did write down window.

Then you've just had a false memory experience.

The word was never presented,
but you remember the word window appearing on the screen.

You've just had a memory for something that didn't occur.

It's pretty easy to see why it would happen here.

Of course, these aren't randomly selected words from the dictionary.

They're all words that are specifically strongly
related to the word window.

When you think about a door
and you think about it a little bit about houses and windows,

when you think about pain,
you probably think of glass and a bit about windows.

When you think about shutters, you also think a bit about windows.

All of these words are strongly associated with window
such that you're thinking at least a little

about windows with every single word that's presented.

Ironically, even though a window

never appears on the list, you're probably thinking about window
more than for any of the words that were actually presented.

It's reasonable to infer that any list of this type contains a window.

It doesn't contain the word, but it sure contains the concept of window.

As you were recalling the list of words,
you weren't playing back a video record of the event.

In your mind might have felt that way.
But that's not how our memory functions.

You were thinking of words that you'd recently read

and scanning your mind
for which words were most strongly associated with that prompt window

because it was so activated during the list, presentation
likely popped out in your mind as relevant when we recall any event.

Not just a list of words. We do a similar sort of process.

We think of the event that we're trying to recall

mentally process the elements that come to mind,
and then we stitch them together into a sensible memory.

If any pieces are missing, we are masters at filling in those missing
parts and inferring what's there if it can't be directly recalled.

There's a classic study that was conducted by Helen Interop
in which she showed people

pictures, photographs, much like the ones that we used
in our initial session for the image memory test

when she tested people's ability to remember them, however,
she gave them a choice of which image they'd see in the key condition.

People saw the original image as well as an image that had been extended
beyond the borders of the original picture.

Most people pick the image in which the borders
have been slightly extended beyond the edges of the photograph.

They saw one picture,
but they remember seeing more than was in the original photo.

How would they do that?

The basic basic explanation here

is that when we look at a picture, we can make a pretty good guess about
what's just beyond the edges of the photo.

Edges tend to continue along their visible path.

We can infer what the other half of an object looks like.

You can't actually see what's beyond the edges,
but we know what's there.

You know, it's so clearly that we remember having seen it.

Even though that pattern of light has never fallen on our eyes.

People interested in eyewitness
testimony are interested in these types of effects a lot.

In one study on how questioning by a detective can mold your memory,
Elizabeth Loftus conducted a study in which people witnessed

a car accident actually was a series of images depicting a car accident
afterwards, during a simulated questioning phase.

Participants were asked one of three different probe questions.

One, How fast was the car going when it bumped into the pole?

Two, how fast was the car going when it crashed into the pole?

Or three, how fast was the car going when it smashed into the pole?

All of these people witnessed the same replay of a car accident.

But on a later visit to the lab, they remembered it differently.

People in the smashed condition remembered the car as moving faster

and they were significantly more likely to remember
seeing broken glass on the ground after the accident.

When the witnesses were asked to recall the event,
it wasn't just their experience of the event itself that mattered.

Their memory for the episodes that they had witnessed
changed as a function of that post-incident interview.

Perhaps the most critical part of this study
is that most people were completely unaware of this effect.

It was undoubtedly the conversation that they had after seeing the
accident that changed their memory of it, but they never reported that.

Presumably, when the time came to recall the event,

the participant thought about the accident
and then reported the things that came to mind.

Some of those things that came to mind were entered into the head at the
time of witnessing the actual accident, but others came in afterwards.

This is often described as a problem of source memory.

We pull out information in our memories
that's derived from many different sources,

but it all gets mixed together into a single narrative.

The biggest problem with this effect is that a lack of source memory
doesn't dampen our confidence in the veracity of our own memories.

The most relevant studies here
come from experiments on the nature of flashbulb memories.

These types of memories arise
when some salient, typically emotional experience occurs.

It used to be, for instance,
that people would say they all remembered where they were

when they first heard that JFK had been shot
or that Neil Armstrong had first stepped on the moon.

Most of the careful studies of these effects
have been done with more recent events.

Where were you when you first heard

that the space shuttle Challenger had exploded
or that the World Trade Center was on fire?

For events like these?

If you're like most people,
you can remember just where you were when you learned this news.

More than that, what you were doing when you heard the news
and who you are with, perhaps even what you were wearing.

Something about the emotion of these events

seems to strongly imprint our memories in our mind,
as if a flashbulb had gone off at the time,

as such.

These memories persist in great detail for many years after.

Even for the rest of our lives.

Or do they all work nicer performed?

My favorite study on this topic.
Many people report having flashbulb memories.

But up until he did his study,
no one had ever tested to see if they were accurate.

The day after the Space shuttle Challenger exploded.

Nicer had the foresight to distribute a questionnaire
to his interest students.

The form asked them to indicate where they were, what they were doing,

who they were with, and a host of other information
about what was happening when they heard about the event.

He also asked them to rate their confidence
in the accuracy of these memories.

Not surprisingly, given that only about 24 hours had elapsed.

Most people rated their confidence as nearly 100%,
and they reported the event in great detail.

Fast forward several years.

Actually, a follow up was run several months later,
but the best data is from that several year delay.

Nicer tracked down
many of the students and had them fill out a similar questionnaire

about where they'd been and what they'd been doing on that historic day
when they first heard that news.

Most people reported having a flashbulb type memory for the event.

Almost everyone, actually, they all reported that they remembered
in great detail with great confidence where they'd been

when they received the news, what they were doing, who they were with,
all the same things that they said on the original questionnaire.

Only one problem.

Many of them were wrong about the details.

About 25% of the accounts that were given after
the delay were strikingly different from the initial accounts.

About half were somewhat different.

Only about 10% of the students got all of their details right.

Regardless of their accuracy, however.

All of the students were extremely confident
about the details that they listed.

I personally remember just where I was.

I was walking my dog in Evanston, Illinois, on Forest Avenue.

I was wearing headphones, a knit hat.

I was listening to the news on NPR.

The day was chilly, but it wasn't windy.

I remember one of the cars
exactly what the car looked like on the street that I was passing.

I remember worrying that the dog leash would get tangled
in the side view mirror because of the the way my dog was pulling me.

I remember that event in vivid detail.

I feel very confident of my accuracy,
but I didn't have a video recorder or a camera or anything.

NASA's experiment and many like them, make clear that there's
a decent chance that at least some of those details are wrong.

There's about a 25% chance that it's altogether inaccurate.

Where do these errors come from?

You have to speculate about that a little bit,
but it's likely related to the study of

how memory can be influenced
by that post-event questioning in the Loftus accident witness study

after the shuttle crash event. I talked to a lot of people about it.

I think everybody did.
Those people told me where they had been and what they were doing.

It might be that I'm actually remembering someone else's story.

I see other people doing things all the time also.

Perhaps I saw someone doing something on that day
and have subsequently swapped out my own memory for that one.

When I try to remember anything, I think about the probe concept.

So shuttle crash and then scan my memory for what comes to mind.

I think of a dog, a walk, a car,
and then I need a story around those things that I can recall.

You do the same thing we all do all the time.

Whenever we're remembering something, we recall details.

But the full memory of any episode involves
reconstructing a story around those details.

So what should we do with this information?
Should we stop trusting our own memories?

Absolutely not.

Even in the flashbulb case,
remember the vast majority of people were mostly correct.

What I recommend here is to trust your memory to a point.

But you should never trust your memory

as much as some source of physical evidence, like a photo
or a documentation of an event that's made shortly thereafter.

Our memories are fantastic, but they are far from perfect.

Our confidence in the accuracy of some memory is driven
by the detail of our recall, not, unfortunately, by its accuracy.

Our technology is, in a sense,
very complementary to the strengths and weaknesses of our memory.

When you write things down, if you later forget them, they can't
really help you in terms of creative thinking and problem solving.

They can't help you anymore because they're on the paper.

They're fixed in the notebook or computer where they're stored.

If you want to think about them, you need to get them up
into your head again where they can be processed.

Once they're in your head, however, they become subjective.

They become subject to the flexible, creative, powerful,
inferential engine of our mind.

As such, the information might itself be affected and changed such
that it might be inaccurate, at least to some extent, at a later time.

Documenting

information either in writing or on the computer, performs
the opposite functions.

Things are stored accurately, but in a fixed and flexible fashion.

Both functions are important.

Fortunately, we have both types of information
processing at our disposal here in the 21st century.

In this course, you've learned a lot about memory.

You've learned to use the method of loci, the major system,
and how to use mental imagery to enhance your memory performance.

You've learned how to schedule the timing of your study sessions
to match your brain's learning and forgetting characteristics.

You've learned the importance of exercise and nutrition, sleep
and dreaming for maintaining your mental function.

We've also explored the science behind how human memory functions.

Your brain is very good at representing certain types of information.

You've learned that if you translate hard to remember information
into these easy to remember formats, your memory works better.

Much, much better.

There are always new teeth, new techniques
being developed to enhance memory.

More importantly, individuals
figure out systems that work for themselves almost every day.

There's no need for you to stick to using
just those methods that I've described here.

If you develop one that works better for you,
what works best is what works best.

Thank you for joining me on this fascinating journey into memory.

As I mentioned in the opening of the course,
I've had my own struggles with my memory.

But I think the information I've presented in
this course has helped me in some important ways.

I'd like to hear more about your experiences and ideas as well.

If you have a good memory story or a question,
you should feel free to contact me either by email or letter.

I can't promise that I'll reply right away,
but I do promise that I will remember to eventually.

I hope you have a much better appreciation of your own mind.

Human memory is an amazing thing.

A seemingly limitless.

There will never come a time when you have used up all your memory.

Indeed, science suggests that the more you know, the more you can learn.