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PROFESSOR: So let's talk about
memory today and the fragile

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power of memory.

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If memory didn't work, we
wouldn't remember anything.

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We wouldn't learn anything.

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So we know it has to
work reasonably.

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But it has a number of fragile
aspects we'll talk about

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where, of course, we
forget things.

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But on top of that, it turns out
there's ways in which our

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memories get less accurate and
distorted, are not actual

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records of our experience but
rather interpretations or our

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memory of our memory.

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And we'll talk about experiments
that reveal that.

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So to a large extent, we'll
talk about what do we know

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from scientific research about
why we remember some of our

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lives and why we forget so
many other things that we

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experience.

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And a version of the way people
sometimes think about

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it is in what sense is memory
like a camera, that every

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experience you have is stored
in your mind somewhere?

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We all have the experience,
perhaps, that something will

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remind you of something you
haven't thought about for

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days, weeks, or years.

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And you go, oh, well they must
be all stored there.

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I just need the right
cue or the right

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path to get that memory.

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So that's one version
of memory,

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everything is in us recorded.

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Sometimes we can get to it.

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Sometimes we can't.

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Another version is the way to
think about your memory.

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It's kind of like
a punch bowl.

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You put in some milk.

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And then you put in
some orange juice

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and swirl it around.

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And then you put in some
Coca-Cola and swirl it around.

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And it's not a desirable drink
that you have in your bowl.

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But you can no more get the
specific milk, or the specific

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orange juice, or the
specific Coke.

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Because they're all
mixed together.

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And is memory more like that?

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As life goes on, things
get mixed in.

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And the raw memory is never
recoverable from the mixture

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of subsequent experiences,
thoughts, and feelings.

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So we'll bring the same
perspective a little bit.

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Bottom-up memory might be really
the video camera if we

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had it, an actual recording of
what we hear, what we see,

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what we experience out
there in the world.

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Top-down processes are the
mental things we have in our

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minds that let us interpret
what's out there, concepts,

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expectations.

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Also, it turns out, you'll see
that subsequent experiences go

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back and change memories
from prior times.

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And which of these things, the
bottom-up original experience,

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or the top-down interpretation
grows over time to constitute

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your memory?

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So we can have a very simple
model of memory,

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a flash for a moment.

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I'll give you an example of
how people test this, a

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sensory memory, very
tiny moments only.

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Short-term memory that you can
rehearse in some cases.

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Somebody tells you a number, And
you can repeat it over and

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over again.

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You have that capacity.

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And then long-term memory,
things that

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last for a long time.

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You can define these things
many different ways.

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When we talk about the brain
organization of human memory,

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we'll say that short-term
memory is

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probably, lasts seconds.

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And everything after that
is long-term memory.

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Now, of course, if you just
experienced something, you'd

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remember it better.

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If it's a week, a month, a year,
five years from now,

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most likely less better.

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So time passes.

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But we think almost all of
that is in the context of

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long-term memory capacities
of your mind.

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So here's a kind
of experiment.

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We'll do a couple of exercises
at your seat.

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But this I'm just going
to give you a feeling.

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Because this would require
millisecond

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timing to do correctly.

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But the way they approached this
sensory memory, the flash

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of memory, just capturing for a
moment what's out there, is

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something like this.

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So imagine your job is
to report back the

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letters that you see.

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OK.

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Yeah, you're getting
a number of them.

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So you just did what's called
a whole report method.

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Tell me everything you saw.

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They did another approach,
which is present letters.

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And then just as it disappeared
did we get a tone,

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a high, medium, or low tone.

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And that would tell them which
row to report, the top row,

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the middle row, or the bottom
row depending on the tone they

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heard just after the flash,
immediately after the flash.

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Does make sense?

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OK.

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It's gone.

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But the tone is telling you
which one to report.

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And the striking finding
in this was this.

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If they showed you 12 letters
like you just saw, and said,

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tell me everything you see,
people could give you about

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four letters back.

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Maybe you had that experience,
about four letters accurately.

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If they gave you the letters,
they flashed them, then you've

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got the tone.

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For one row only, you've got
about three letters correct.

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Now this is interesting.

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The letters are gone.

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But it's kind of like as
if the photograph of

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your memory is fading.

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But if you put your attention
somewhere, you can still pull

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it back, but just a
little bit of it.

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Because here you get
four out of 12.

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Here you get three out of 12.

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Almost the same because your
attention can zoom in on that

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fading mental image of
what you just saw.

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So much is sensed.

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But attention only selects a
little bit to be remembered.

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So that's this very first
moment of memory.

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One of the more impressive lines
of research is the next

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moment, short-term memory,
keeping in mind something in

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your mind briefly.

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And one of the most striking
aspects of human short-term

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memory is limited in how
much it can hold.

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And across a tremendous range of
materials, words, letters,

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shapes, tones, and so on, you
can hold approximately 7 plus

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or minus 2 chunks of
information, limited

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short-term memory.

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So now I need somebody who's
willing, at their

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chair, to do something.

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I'm going to read to you
numbers, and ask you

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to repeat them back.

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But your eyes will need
to be closed.

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And it'll be fairly
challenging.

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All right, thank
you very much.

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OK.

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Close your eyes.

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And here we go.

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Ready?

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Keep your eyes closed
until we're done.

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Repeat after me.

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6, 1.

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AUDIENCE: We're repeating
as you say it or after?

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PROFESSOR: When I'm done.

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I'm sorry, yeah.

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Ready?

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6, 1, 9.

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4.

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Repeat.

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AUDIENCE: 6, 1, 9, 4.

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PROFESSOR: Right.

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Ready?

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3, 7, 8, 5, 2, repeat.

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AUDIENCE: 3, 7, 8, 5, 2.

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PROFESSOR: Great.

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Ready?

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9, 6, 5, 2, 8, 3, repeat.

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AUDIENCE: 9, 6, 5, 2, 8, 3.

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PROFESSOR: Great.

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Ready?

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4, 2, 6, 9, 8, 5, 1.

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repeat.

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AUDIENCE: 4, 2, 6, 9, 8, 5, 1.

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PROFESSOR: Very good.

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Ready?

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8, 1, 6, 3, 7, 2, 4, 9.

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Repeat.

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AUDIENCE: 8, 1, 6,
7, 4, 2, 1, 9.

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PROFESSOR: OK, perfect.

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OK your eyes.

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Thank you very much.

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You did terrific.

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You got four right, five right,
six right, seven right,

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eight right, you got
them mostly right.

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You just reversed one or two.

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Seven plus or minus two, it
doesn't matter how smart you

00:07:11.820 --> 00:07:14.360
are, how advanced you are.

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There used to be some confusions
about this.

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Because they would say kids in
different countries have

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different limits.

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And they'd say our country is
smarter than your country, or

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our educational system
is better than

00:07:24.320 --> 00:07:25.400
your educational system.

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It turned out that all of that
got equated around the world

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if you counted up the
number of syllables

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that are in the digits.

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The real unit of memory
here are syllables.

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So in English, most of the
numbers are one syllable.

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1, 2, 3, 4, 5, 6 are
all one syllable.

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7 gets two.

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8 is one syllable.

00:07:44.300 --> 00:07:45.480
9 is one syllable.

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In some other languages, the
words that go with the digits

00:07:48.810 --> 00:07:51.120
are two syllables.

00:07:51.120 --> 00:07:53.500
So countries that have two
syllables, they have lower

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spans not because they were
dumber or had a worse

00:07:56.000 --> 00:07:57.150
education system.

00:07:57.150 --> 00:07:59.940
It's because the real unit
is number of syllables.

00:07:59.940 --> 00:08:00.910
Because you're hearing it.

00:08:00.910 --> 00:08:03.210
It's language.

00:08:03.210 --> 00:08:06.140
So around the world, it's the
fundamental capacity of the

00:08:06.140 --> 00:08:07.960
human mind is that
you're limited to

00:08:07.960 --> 00:08:09.340
these kinds of stuff.

00:08:09.340 --> 00:08:11.200
So how do we get around that?

00:08:11.200 --> 00:08:16.010
Why are we not always barely
able to do anything with very

00:08:16.010 --> 00:08:17.200
small amounts of information?

00:08:17.200 --> 00:08:20.710
So it's just a constraint
of our minds.

00:08:20.710 --> 00:08:23.400
It's because background prior
knowledge, things you know

00:08:23.400 --> 00:08:25.690
before you have to learn
something, has a

00:08:25.690 --> 00:08:27.120
very powerful effect.

00:08:27.120 --> 00:08:28.830
It allows you for the
information to

00:08:28.830 --> 00:08:30.300
be retained in memory.

00:08:30.300 --> 00:08:32.600
But it has a double-edged sword,
which is kind of a

00:08:32.600 --> 00:08:33.870
theme a lot today.

00:08:33.870 --> 00:08:36.190
As much as it helps you remember
things, it can fool

00:08:36.190 --> 00:08:38.120
you into misremembering
things.

00:08:38.120 --> 00:08:40.330
And let me give you a
concrete example.

00:08:40.330 --> 00:08:45.000
So you can put chess displays
in front of people who are

00:08:45.000 --> 00:08:47.340
either beginning chess players,
have played for a

00:08:47.340 --> 00:08:50.000
while, or are masters.

00:08:50.000 --> 00:08:51.290
And they're not going to play.

00:08:51.290 --> 00:08:52.650
They're going to look at it.

00:08:52.650 --> 00:08:55.660
The pieces will be swept
to the side.

00:08:55.660 --> 00:08:58.010
And then they have to put all
the pieces back out of memory

00:08:58.010 --> 00:09:00.050
into the same location where
they just saw it.

00:09:00.050 --> 00:09:01.660
They know that's going
to happen.

00:09:01.660 --> 00:09:02.700
So it's a memory test.

00:09:02.700 --> 00:09:03.350
Here's the pieces.

00:09:03.350 --> 00:09:04.160
Take a look.

00:09:04.160 --> 00:09:06.310
The examiner sweeps the
pieces to the site.

00:09:06.310 --> 00:09:08.310
And you put them back
as well as you can.

00:09:08.310 --> 00:09:09.000
You see it.

00:09:09.000 --> 00:09:09.870
It gets swept to the side.

00:09:09.870 --> 00:09:12.920
And you reproduce it from memory
what you just saw.

00:09:12.920 --> 00:09:19.040
And here's the performance of
master players and beginner

00:09:19.040 --> 00:09:21.320
players in this case, so people
who have played a lot

00:09:21.320 --> 00:09:23.630
of chess and people who have
played very little chess.

00:09:23.630 --> 00:09:27.810
It's better to be high, the
number of correct pieces.

00:09:27.810 --> 00:09:30.760
And there's two kinds
of displays.

00:09:30.760 --> 00:09:32.060
In one kind of displays
is what we

00:09:32.060 --> 00:09:33.870
call the normal displays.

00:09:33.870 --> 00:09:35.340
Those are ones that
could really have

00:09:35.340 --> 00:09:36.160
happened in the game.

00:09:36.160 --> 00:09:40.190
They were kind of reasonable
configurations of pieces.

00:09:40.190 --> 00:09:43.680
The random displays are pieces
all over the place in a

00:09:43.680 --> 00:09:46.070
configuration that you're not
likely to see in a real game

00:09:46.070 --> 00:09:48.380
of chess, equal number
of pieces.

00:09:48.380 --> 00:09:49.500
And look what happens.

00:09:49.500 --> 00:09:53.890
The best performance are master
players who see a real

00:09:53.890 --> 00:09:56.320
normal chess configuration.

00:09:56.320 --> 00:09:58.120
Here are the players
who are beginners.

00:09:58.120 --> 00:10:01.830
And look at the worst
performances, the chess

00:10:01.830 --> 00:10:04.690
masters who see a
random set up.

00:10:04.690 --> 00:10:07.088
So what do you guess
is happening?

00:10:07.088 --> 00:10:08.040
Yeah?

00:10:08.040 --> 00:10:09.990
AUDIENCE: People who
play chess a lot

00:10:09.990 --> 00:10:11.802
memorize games and positions.

00:10:11.802 --> 00:10:14.366
So they're used to seeing
those patterns.

00:10:14.366 --> 00:10:17.238
And when they see a random
configuration, they can't

00:10:17.238 --> 00:10:18.230
recreate it as well.

00:10:18.230 --> 00:10:18.440
PROFESSOR: Right.

00:10:18.440 --> 00:10:20.590
So the people who have played
chess a lot have a lot of

00:10:20.590 --> 00:10:22.800
configurations in their mind,
background knowledge.

00:10:22.800 --> 00:10:25.790
They use that background
knowledge of what a chess

00:10:25.790 --> 00:10:27.030
array means.

00:10:27.030 --> 00:10:29.440
Somebody's in trouble,
somebody's winning, something

00:10:29.440 --> 00:10:31.220
interesting is happening
in this corner.

00:10:31.220 --> 00:10:34.080
That knowledge helps them escape
the boundaries of seven

00:10:34.080 --> 00:10:36.280
plus or minus two.

00:10:36.280 --> 00:10:39.910
And they do a lot better than
the beginners for whom it

00:10:39.910 --> 00:10:40.890
doesn't mean much.

00:10:40.890 --> 00:10:44.220
It's just a bunch of stuff out
there hard to remember.

00:10:44.220 --> 00:10:47.220
But what happens here when
the pieces are random?

00:10:47.220 --> 00:10:51.670
The chess masters are making
mistakes because they're

00:10:51.670 --> 00:10:54.930
putting the pieces in the places
they ought to be rather

00:10:54.930 --> 00:10:57.010
than the places they perversely

00:10:57.010 --> 00:10:58.410
were randomly located.

00:10:58.410 --> 00:11:02.290
If you're a chess player, you
don't like that random board.

00:11:02.290 --> 00:11:04.950
It doesn't feel right.

00:11:04.950 --> 00:11:06.500
But they're trying
to be accurate.

00:11:06.500 --> 00:11:09.410
But now they're misplacing their
memory for what they

00:11:09.410 --> 00:11:12.730
actually saw with their
mental model of what

00:11:12.730 --> 00:11:14.820
ought to be out there.

00:11:14.820 --> 00:11:17.890
Now the players who are not so
good, you don't see much of a

00:11:17.890 --> 00:11:19.430
difference between
these lines.

00:11:19.430 --> 00:11:21.170
They don't understand
when it's random.

00:11:21.170 --> 00:11:22.320
They don't understand
when it's organized.

00:11:22.320 --> 00:11:23.860
It's just a bunch of pieces.

00:11:23.860 --> 00:11:27.310
So the double-edge of background
knowledge.

00:11:27.310 --> 00:11:30.600
Background knowledge lets you
escape the bounds of limited

00:11:30.600 --> 00:11:35.060
short-term memory but at a cost
of sometimes substituting

00:11:35.060 --> 00:11:36.880
in for the actual experience
you have.

00:11:40.130 --> 00:11:41.730
So we'll try this.

00:11:41.730 --> 00:11:44.480
And people use the word
"chunking" as the way in which

00:11:44.480 --> 00:11:47.480
you use your background
knowledge to get big pieces of

00:11:47.480 --> 00:11:49.960
information stored that are
better than you think for

00:11:49.960 --> 00:11:51.100
short-term memory limits.

00:11:51.100 --> 00:11:52.820
So here's a quick one.

00:11:52.820 --> 00:11:55.085
I need a volunteer actually.

00:11:55.085 --> 00:11:56.335
It's not too bad.

00:11:58.814 --> 00:12:00.620
Wow, tough volunteer day.

00:12:00.620 --> 00:12:01.650
You're mad at me
about the exam.

00:12:01.650 --> 00:12:01.840
OK.

00:12:01.840 --> 00:12:03.350
Thank you.

00:12:03.350 --> 00:12:06.430
OK, ready?

00:12:06.430 --> 00:12:07.568
What were the letters?

00:12:07.568 --> 00:12:09.320
AUDIENCE: [INAUDIBLE].

00:12:09.320 --> 00:12:09.710
PROFESSOR: OK.

00:12:09.710 --> 00:12:11.486
How about these ones?

00:12:11.486 --> 00:12:13.500
[LAUGHTER]

00:12:13.500 --> 00:12:15.580
PROFESSOR: The same letters,
it's just that

00:12:15.580 --> 00:12:16.540
now you see the chunks.

00:12:16.540 --> 00:12:19.130
And you can map them onto
long-term memory more easily.

00:12:19.130 --> 00:12:20.330
Plus I showed them longer.

00:12:20.330 --> 00:12:24.840
Anybody else want to try
something like this?

00:12:24.840 --> 00:12:26.070
Thank you.

00:12:26.070 --> 00:12:27.320
Here we go.

00:12:30.020 --> 00:12:30.700
What letters do you see?

00:12:30.700 --> 00:12:32.912
Ready?

00:12:32.912 --> 00:12:35.750
AUDIENCE: [INAUDIBLE].

00:12:35.750 --> 00:12:36.230
PROFESSOR: OK.

00:12:36.230 --> 00:12:38.690
Now I'm going to let your
background knowledge triumph.

00:12:38.690 --> 00:12:39.940
Ready?

00:12:44.720 --> 00:12:45.970
It's the same letters.

00:12:48.520 --> 00:12:51.590
Same letters, all it is, is your
background knowledge is

00:12:51.590 --> 00:12:54.230
useless, your knowledge of
words, your knowledge of the

00:12:54.230 --> 00:12:55.575
alphabet, useless.

00:12:55.575 --> 00:12:58.390
It's the same information in a
sense, same number of letters,

00:12:58.390 --> 00:12:59.180
same identity of letters.

00:12:59.180 --> 00:13:00.765
But now your background
knowledge is powerful.

00:13:03.940 --> 00:13:07.680
I need somebody else,
one more volunteer.

00:13:07.680 --> 00:13:08.960
Thank you.

00:13:08.960 --> 00:13:10.020
I'm going to show
you a sentence.

00:13:10.020 --> 00:13:11.050
This is meant to be hard,
the first one.

00:13:11.050 --> 00:13:11.500
Don't worry about it.

00:13:11.500 --> 00:13:12.160
OK?

00:13:12.160 --> 00:13:14.950
Here we go.

00:13:14.950 --> 00:13:16.421
Can you tell me what
they were?

00:13:16.421 --> 00:13:18.730
AUDIENCE: Leaf, paper,
steer, car, beach.

00:13:18.730 --> 00:13:20.615
PROFESSOR: That's pretty good.

00:13:20.615 --> 00:13:23.890
Let me show you another
equal number of words.

00:13:23.890 --> 00:13:24.130
Ready?

00:13:24.130 --> 00:13:29.050
Go OK, what is it?

00:13:29.050 --> 00:13:32.410
AUDIENCE: While I was walking
around-- while I was walking--

00:13:32.410 --> 00:13:33.270
PROFESSOR: You would
do better.

00:13:33.270 --> 00:13:36.620
OK It's hard to pull
these things off.

00:13:36.620 --> 00:13:39.440
So 13 words, people would
do pretty miserably.

00:13:39.440 --> 00:13:41.860
Although you did very well,
a lot better at this.

00:13:41.860 --> 00:13:43.810
Because, again, you can use your
background knowledge of

00:13:43.810 --> 00:13:44.840
what does a sentence mean?

00:13:44.840 --> 00:13:46.030
What's the ergative syntax?

00:13:46.030 --> 00:13:47.580
All your background knowledge
can be applied.

00:13:47.580 --> 00:13:51.010
Again, the power of background
knowledge is immense.

00:13:51.010 --> 00:13:53.000
I can tell you that if you go
work somewhere, or if you're

00:13:53.000 --> 00:13:55.800
working in a lab now, or if
you're working in any place,

00:13:55.800 --> 00:13:58.320
you might be impressed by people
who are older than you,

00:13:58.320 --> 00:14:00.830
and what they know, and what
they can learn and pick up.

00:14:00.830 --> 00:14:02.580
It's background knowledge,
background knowledge,

00:14:02.580 --> 00:14:04.220
background knowledge.

00:14:04.220 --> 00:14:07.860
It lets you quickly understand
an idea, because you can

00:14:07.860 --> 00:14:11.150
interpret it from prior ideas
that you know, quickly read a

00:14:11.150 --> 00:14:13.950
paper, because you can slot it
into prior things you know.

00:14:13.950 --> 00:14:17.850
Background knowledge is
incredibly powerful to let you

00:14:17.850 --> 00:14:20.350
discover the signal and get
a lot of the specific

00:14:20.350 --> 00:14:22.706
information in any kind of
information out there.

00:14:26.140 --> 00:14:27.806
Tyler, I left with
you this time.

00:14:27.806 --> 00:14:28.560
Sorry.

00:14:28.560 --> 00:14:31.420
So we're going to do a
quick memory test.

00:14:31.420 --> 00:14:32.500
You will do it at
your own seat.

00:14:32.500 --> 00:14:34.300
It's voluntary.

00:14:34.300 --> 00:14:38.400
But I will ask you to share a
little bit of information.

00:14:38.400 --> 00:14:40.160
This is for everybody now,
not for one person to

00:14:40.160 --> 00:14:43.000
be put on the spot.

00:14:43.000 --> 00:14:48.600
So what I'm going to do is read
you a list of words, wait

00:14:48.600 --> 00:14:49.720
until the end.

00:14:49.720 --> 00:14:52.460
And when I say, recall,
write down the

00:14:52.460 --> 00:14:54.560
words from your memory.

00:14:54.560 --> 00:14:55.910
So I'll wait for a moment
for you to get a

00:14:55.910 --> 00:14:57.985
pencil or pen or something.

00:15:18.800 --> 00:15:20.050
OK.

00:15:23.000 --> 00:15:26.410
I see a few people still
getting stuff.

00:15:26.410 --> 00:15:27.210
OK, ready?

00:15:27.210 --> 00:15:27.840
Here comes the word.

00:15:27.840 --> 00:15:29.350
Just listen, don't write.

00:15:29.350 --> 00:15:30.505
That would be too easy.

00:15:30.505 --> 00:15:32.070
I'll say recall, and then
write them down.

00:15:32.070 --> 00:15:32.880
Here we go.

00:15:32.880 --> 00:15:39.590
Mailbox, sardine, shotgun,
peacock, credit, detail,

00:15:39.590 --> 00:15:44.610
flicker, airline, spinach,
clarinet.

00:15:44.610 --> 00:15:45.860
Recall.

00:16:06.570 --> 00:16:07.820
OK.

00:16:09.800 --> 00:16:11.050
Here are the answers.

00:16:13.160 --> 00:16:15.970
As you look at this list, put
your hand up if you've got all

00:16:15.970 --> 00:16:29.870
10, 9, 8, 7, 6, 5, 4, 3, 2.

00:16:29.870 --> 00:16:30.400
Thank you.

00:16:30.400 --> 00:16:30.950
All right.

00:16:30.950 --> 00:16:33.830
So think about this
for a moment.

00:16:33.830 --> 00:16:35.400
We said seven plus
or minus two.

00:16:35.400 --> 00:16:38.990
When the words are presented in
a random, unorganized list

00:16:38.990 --> 00:16:40.820
like this, you're pretty much
back to short-term memory

00:16:40.820 --> 00:16:43.790
limits in many senses, not
completely, but in many ways.

00:16:43.790 --> 00:16:45.860
So if you were to tell a person
on the street, I mean,

00:16:45.860 --> 00:16:48.110
I have to say two things about
you guys, which is certainly

00:16:48.110 --> 00:16:50.780
true and complimentary.

00:16:50.780 --> 00:16:55.210
Most of you, if you're somewhere
between 18 and 25,

00:16:55.210 --> 00:16:56.850
you're at your peak memory
capacity for the

00:16:56.850 --> 00:16:58.100
rest of your life.

00:17:00.680 --> 00:17:03.080
You will never do better
for rote learning then

00:17:03.080 --> 00:17:03.780
you are right now.

00:17:03.780 --> 00:17:05.300
There's a ton of research
that shows that.

00:17:05.300 --> 00:17:07.710
You will never do better
for rote learning

00:17:07.710 --> 00:17:09.470
than about 18 to 25.

00:17:09.470 --> 00:17:12.150
After that it's downhill.

00:17:12.150 --> 00:17:13.510
You get other benefits.

00:17:13.510 --> 00:17:14.730
Salaries go up a little bit.

00:17:14.730 --> 00:17:15.400
You get authority.

00:17:15.400 --> 00:17:18.150
That's a nice one.

00:17:18.150 --> 00:17:20.500
But rote memory, you're
at the top.

00:17:20.500 --> 00:17:23.960
Not only are you at the top,
but you are an incredibly

00:17:23.960 --> 00:17:26.690
selected academically
achieving group.

00:17:26.690 --> 00:17:28.450
You're MIT undergraduates.

00:17:28.450 --> 00:17:32.630
You're incredibly selected to be
the top of the top, in many

00:17:32.630 --> 00:17:36.730
senses, for learning between 18
to 25 as far as MIT could

00:17:36.730 --> 00:17:39.200
possibly figure this out.

00:17:39.200 --> 00:17:41.750
You are our hope
for the future.

00:17:41.750 --> 00:17:46.190
If you guys can't fix global
warming, we're in trouble.

00:17:46.190 --> 00:17:48.270
So you can't get 10 words?

00:17:48.270 --> 00:17:49.660
Come on.

00:17:49.660 --> 00:17:50.710
We have big problems to solve.

00:17:50.710 --> 00:17:54.660
It's a capacity of the human
mind that we just can't do

00:17:54.660 --> 00:17:56.020
about more than this.

00:17:56.020 --> 00:17:59.170
It's just amazing how limited
rote memory is

00:17:59.170 --> 00:18:00.080
without other things.

00:18:00.080 --> 00:18:01.920
But there's a little bit
more than we can tell.

00:18:01.920 --> 00:18:05.520
How many of you got mailbox
and sardine?

00:18:05.520 --> 00:18:06.690
A fair number of hands.

00:18:06.690 --> 00:18:07.150
OK.

00:18:07.150 --> 00:18:09.090
How many of you got spinach
and clarinet,

00:18:09.090 --> 00:18:10.150
the last two words?

00:18:10.150 --> 00:18:12.650
How many of you got
credit and detail?

00:18:12.650 --> 00:18:13.710
Way fewer hands.

00:18:13.710 --> 00:18:16.300
And that's what happens under a
well-controlled experiment.

00:18:16.300 --> 00:18:17.510
So this is correct.

00:18:17.510 --> 00:18:18.890
High is correct.

00:18:18.890 --> 00:18:22.750
This is what order the word
was in the first word you

00:18:22.750 --> 00:18:24.430
heard, say the fifth.

00:18:24.430 --> 00:18:26.610
This experiment is 15 words.

00:18:26.610 --> 00:18:28.880
You can see that.

00:18:28.880 --> 00:18:30.200
Here's their performance.

00:18:30.200 --> 00:18:31.910
Two things are noteworthy.

00:18:31.910 --> 00:18:35.170
People do best for the first
couple of words.

00:18:35.170 --> 00:18:38.170
And sometimes they did best for
the last couple of words.

00:18:38.170 --> 00:18:39.540
So here's three delays.

00:18:39.540 --> 00:18:42.920
These delays are zero
seconds what we did.

00:18:42.920 --> 00:18:45.020
You get the list, you
immediately write them down

00:18:45.020 --> 00:18:46.180
and recall them verbally.

00:18:46.180 --> 00:18:47.950
That's zero, immediate.

00:18:47.950 --> 00:18:51.300
Or I wait 10 seconds and
then say, now recall.

00:18:51.300 --> 00:18:53.850
Or I wait 1/2 minute and
say, now recall.

00:18:53.850 --> 00:18:55.740
Now memory for the first two
items is what's called a

00:18:55.740 --> 00:18:56.920
primacy effect.

00:18:56.920 --> 00:18:58.170
It doesn't matter.

00:18:58.170 --> 00:19:00.500
In all three conditions, those
are the best two remembered

00:19:00.500 --> 00:19:04.400
words, on average, for most
of the experiment.

00:19:04.400 --> 00:19:07.410
And people think that's a
signature of long-term memory.

00:19:07.410 --> 00:19:08.650
You can get those one
or two words.

00:19:08.650 --> 00:19:10.540
And then you start to
get overwhelmed

00:19:10.540 --> 00:19:12.490
in long-term memory.

00:19:12.490 --> 00:19:16.460
Here, you only get the boost for
the last couple of words

00:19:16.460 --> 00:19:17.620
if there's zero second delay.

00:19:17.620 --> 00:19:20.700
If there's 10 seconds or 30
seconds delay, no boost.

00:19:20.700 --> 00:19:23.260
So people interpret this recency
effect, superior

00:19:23.260 --> 00:19:25.610
memory for the last couple of
words, as a signature of

00:19:25.610 --> 00:19:28.360
short-term memory that
lasts only seconds.

00:19:28.360 --> 00:19:29.790
And so in that simple
experiment, you can see

00:19:29.790 --> 00:19:32.020
long-term memory influences,
short-term memory influences.

00:19:32.020 --> 00:19:33.090
And short-term is
very short-term.

00:19:33.090 --> 00:19:34.340
It's just seconds.

00:19:37.300 --> 00:19:39.850
Now Ebbinghaus is one of the
founders of experimental

00:19:39.850 --> 00:19:40.630
studies of memory.

00:19:40.630 --> 00:19:43.310
And he was heroic.

00:19:43.310 --> 00:19:44.420
He would just train himself.

00:19:44.420 --> 00:19:46.160
He would use nonsense syllables,
because he wanted

00:19:46.160 --> 00:19:49.050
to get rid of a lot of
background stuff, rote memory.

00:19:49.050 --> 00:19:52.100
And he would learn thousands of
these and then test himself

00:19:52.100 --> 00:19:54.650
and score himself honestly.

00:19:54.650 --> 00:19:56.460
He did the bulk of the
work on himself.

00:19:56.460 --> 00:20:00.050
And he discovered something
that's pretty simple, but that

00:20:00.050 --> 00:20:01.180
has had a huge effect.

00:20:01.180 --> 00:20:03.790
So how well do you do since you
learned something all in

00:20:03.790 --> 00:20:06.170
long-term memory if you're
tested immediately?

00:20:06.170 --> 00:20:08.940
100% if it's small list
and you studied a lot.

00:20:08.940 --> 00:20:11.470
20 minutes later, an hour later,
nine hours later, you

00:20:11.470 --> 00:20:15.150
can see the steep forgetting
up until about 10 hours.

00:20:15.150 --> 00:20:16.875
And then it sort of
hangs in there.

00:20:16.875 --> 00:20:20.200
The forgetting curve of
long-term memory, immediately

00:20:20.200 --> 00:20:21.650
afterwards, we're pretty good.

00:20:21.650 --> 00:20:23.700
Then there's a lot of forgetting
in 20 minutes, and

00:20:23.700 --> 00:20:26.570
for a day, and then things
hang in there.

00:20:26.570 --> 00:20:32.210
This is a shaped asymptotic
curve of forgetting.

00:20:32.210 --> 00:20:35.460
OK now here's another
mission for you.

00:20:35.460 --> 00:20:36.240
You need a pencil.

00:20:36.240 --> 00:20:39.690
Or just your fingers will
work fine either way.

00:20:39.690 --> 00:20:40.830
You're going to see
a list of words.

00:20:40.830 --> 00:20:42.070
Some will be in uppercase.

00:20:42.070 --> 00:20:43.430
Some will be in lowercase.

00:20:43.430 --> 00:20:44.470
Capital letters, uppercase.

00:20:44.470 --> 00:20:45.070
All right.

00:20:45.070 --> 00:20:48.750
Your job as you see them from
top to bottom is to tap your

00:20:48.750 --> 00:20:52.970
left hand for each word that's
in the capital letter and your

00:20:52.970 --> 00:20:55.610
right hand for each word that's
a lowercase letter.

00:20:55.610 --> 00:20:56.480
Is that OK?

00:20:56.480 --> 00:20:59.260
So if the first work is capital,
you tap left. if the

00:20:59.260 --> 00:21:00.660
second word is lowercase,
you tap right.

00:21:00.660 --> 00:21:03.630
So you just tap, tap, tap until
you get to the bottom.

00:21:03.630 --> 00:21:04.430
And then it will go.

00:21:04.430 --> 00:21:04.720
You already?

00:21:04.720 --> 00:21:05.360
You ready to help me out?

00:21:05.360 --> 00:21:05.740
Here we go.

00:21:05.740 --> 00:21:06.850
Thank you very much.

00:21:06.850 --> 00:21:08.100
Here we go.

00:21:14.350 --> 00:21:14.890
Excellent.

00:21:14.890 --> 00:21:15.940
All right.

00:21:15.940 --> 00:21:17.514
What were words?

00:21:17.514 --> 00:21:22.910
[LAUGHTER]

00:21:22.910 --> 00:21:25.090
PROFESSOR: You might be
impressed that even though

00:21:25.090 --> 00:21:26.710
they were right in front of you,
and even though you were

00:21:26.710 --> 00:21:28.292
looking whether they were upper
and lowercase case so

00:21:28.292 --> 00:21:32.800
you really saw them, if you
don't bring the relevant

00:21:32.800 --> 00:21:34.830
background knowledge to
remembering it, which is the

00:21:34.830 --> 00:21:37.510
meaning of words most
the time, our

00:21:37.510 --> 00:21:39.660
memory is pretty hideous.

00:21:39.660 --> 00:21:40.150
All right.

00:21:40.150 --> 00:21:40.760
try another one.

00:21:40.760 --> 00:21:44.030
Now the trick is gone
a little bit.

00:21:44.030 --> 00:21:45.060
This is a little bit
of a set up.

00:21:45.060 --> 00:21:47.280
But I can tell you it's
scientifically true.

00:21:47.280 --> 00:21:48.810
So now it's the same idea.

00:21:48.810 --> 00:21:49.770
You can see words.

00:21:49.770 --> 00:21:53.580
You can read the word, if it's a
living thing like a dog, tap

00:21:53.580 --> 00:21:54.120
the left hand.

00:21:54.120 --> 00:21:56.140
If it's a nonliving thing like
a chair, the right hand.

00:21:56.140 --> 00:21:56.980
Ready?

00:21:56.980 --> 00:21:57.520
You did awesome.

00:21:57.520 --> 00:21:57.770
Thanks.

00:21:57.770 --> 00:21:59.020
Here we go.

00:22:05.690 --> 00:22:06.940
OK.

00:22:09.110 --> 00:22:11.470
Does it feel like you would
remember the words better?

00:22:11.470 --> 00:22:14.150
Does it feel like you would?

00:22:14.150 --> 00:22:14.530
OK.

00:22:14.530 --> 00:22:16.040
So here's what we did.

00:22:16.040 --> 00:22:17.850
The first list, is you
thought about the

00:22:17.850 --> 00:22:19.350
appearance of the word.

00:22:19.350 --> 00:22:21.830
In memory, that's called shallow
encoding, just if it's

00:22:21.830 --> 00:22:22.640
upper and lowercase.

00:22:22.640 --> 00:22:25.150
And typically, that leads
to pretty poor memory.

00:22:25.150 --> 00:22:28.260
If you think about the meaning
of the word, we think that

00:22:28.260 --> 00:22:29.210
optimizes memory.

00:22:29.210 --> 00:22:30.340
People would call it
deep encoding.

00:22:30.340 --> 00:22:31.350
And it leads to better memory.

00:22:31.350 --> 00:22:33.480
And in a well-controlled
experiment, now here we had a

00:22:33.480 --> 00:22:34.220
certain order.

00:22:34.220 --> 00:22:35.490
And you knew there
was a trick.

00:22:35.490 --> 00:22:37.340
But if you had a well-controlled
experiment,

00:22:37.340 --> 00:22:38.630
here's what you'd find.

00:22:38.630 --> 00:22:41.950
If you just think about the
appearance of the word, here's

00:22:41.950 --> 00:22:44.830
how well you do, pretty
low if you see the

00:22:44.830 --> 00:22:45.880
word once or twice.

00:22:45.880 --> 00:22:48.090
And if we look over here at the
meaning of the word you,

00:22:48.090 --> 00:22:52.270
can see one thought about the
meaning of the word is better

00:22:52.270 --> 00:22:55.870
than two presentations thinking
about the appearance.

00:22:55.870 --> 00:22:57.690
And two thoughts about the
meaning of the word, and your

00:22:57.690 --> 00:22:58.970
memory's really excellent.

00:22:58.970 --> 00:23:00.768
Yeah, question?

00:23:00.768 --> 00:23:02.205
AUDIENCE: So if you're forced
to think about--

00:23:02.205 --> 00:23:04.918
get confused by the uppercase
and the lowercase and the

00:23:04.918 --> 00:23:06.040
living versus the non-living--

00:23:06.040 --> 00:23:07.760
PROFESSOR: Were they confusing
to do one then the other?

00:23:07.760 --> 00:23:08.908
It was a little bit, right?

00:23:08.908 --> 00:23:11.150
AUDIENCE: Is that supposed to
make you remember it better?

00:23:11.150 --> 00:23:13.230
You have to think that
hard about it?

00:23:13.230 --> 00:23:14.480
PROFESSOR: No.

00:23:16.930 --> 00:23:19.340
The question is, is the
confusion of doing two

00:23:19.340 --> 00:23:20.670
different tests help you out?

00:23:20.670 --> 00:23:22.650
So, roughly speaking, the answer
is to the extent it

00:23:22.650 --> 00:23:24.780
draws your attention more
to the word, yes.

00:23:24.780 --> 00:23:25.730
To the extent you're
sitting there

00:23:25.730 --> 00:23:27.230
going, OK, was it uppercase?

00:23:27.230 --> 00:23:27.980
Or was it living?

00:23:27.980 --> 00:23:29.690
This is weirding me out.

00:23:29.690 --> 00:23:31.990
It's going to hurt you, because
your mind is filled

00:23:31.990 --> 00:23:33.810
with those thoughts
not looking at

00:23:33.810 --> 00:23:35.060
what's in front of you.

00:23:37.710 --> 00:23:43.320
In these demonstrations, they're
a little cloogy.

00:23:43.320 --> 00:23:45.450
Here's a fun one, the
effective context.

00:23:45.450 --> 00:23:47.230
So this is how they did
the experiment.

00:23:47.230 --> 00:23:48.070
You can do it different ways.

00:23:48.070 --> 00:23:48.780
But this is a fun one.

00:23:48.780 --> 00:23:50.420
They actually went
in the United

00:23:50.420 --> 00:23:52.140
Kingdom to the shoreline.

00:23:52.140 --> 00:23:54.810
And they had people put on
these old style diving

00:23:54.810 --> 00:23:56.350
helmets, the old big helmets.

00:23:56.350 --> 00:23:58.550
And you go under the water with
the big hose in front of

00:23:58.550 --> 00:24:00.240
you to your air source.

00:24:00.240 --> 00:24:03.030
And they had them learn word
lists, like you were looking

00:24:03.030 --> 00:24:06.175
at word lists, on the
land or underwater.

00:24:08.860 --> 00:24:11.230
And then they were tested
for this on the

00:24:11.230 --> 00:24:12.780
land or in the water.

00:24:12.780 --> 00:24:16.100
And the core message was, you
do better remembering

00:24:16.100 --> 00:24:19.350
information if you're tested in
the same situation in which

00:24:19.350 --> 00:24:20.420
you learned it.

00:24:20.420 --> 00:24:24.430
So what we see here is here's
the words learned underwater.

00:24:24.430 --> 00:24:26.730
You're better if you're tested
underwater instead of

00:24:26.730 --> 00:24:27.990
going on the land.

00:24:27.990 --> 00:24:30.040
If you learned the word on the
land, you're better off if you

00:24:30.040 --> 00:24:32.590
test on the land than if
you go underwater.

00:24:32.590 --> 00:24:36.710
The context in which you learned
something helps you.

00:24:36.710 --> 00:24:39.960
Studying underwater and tested
under water, you do better

00:24:39.960 --> 00:24:43.240
than studying underwater and
going on land or vice versa.

00:24:43.240 --> 00:24:47.690
Being in the same room, same
time of day, all those things

00:24:47.690 --> 00:24:49.760
help you a little bit to
bring a memory back.

00:24:49.760 --> 00:24:52.300
Because those are parts of the
memory in the context in which

00:24:52.300 --> 00:24:54.250
you experience it.

00:24:54.250 --> 00:24:56.010
Another approach that people
have taken, this is about

00:24:56.010 --> 00:24:56.430
organization.

00:24:56.430 --> 00:24:59.070
They'll present a set of words
like this and ask people to

00:24:59.070 --> 00:25:00.090
try and remember them.

00:25:00.090 --> 00:25:02.170
It's a pretty big list.

00:25:02.170 --> 00:25:06.930
But if you take the same words
and do that, same words people

00:25:06.930 --> 00:25:09.460
remember a lot better,
because there's an

00:25:09.460 --> 00:25:11.880
organization that helps you.

00:25:11.880 --> 00:25:14.420
Your background knowledge of
what is a career, what is

00:25:14.420 --> 00:25:18.820
housework, what is a food all
contribute to helping your

00:25:18.820 --> 00:25:22.260
memory for these items
be better.

00:25:22.260 --> 00:25:24.400
So let's think about
forgetting.

00:25:24.400 --> 00:25:25.730
We know something
from last year.

00:25:25.730 --> 00:25:26.320
We forgot it.

00:25:26.320 --> 00:25:27.900
There's a least two ideas that
people have said, what's the

00:25:27.900 --> 00:25:30.150
core reason we forget things?

00:25:30.150 --> 00:25:31.390
One of them is like passive.

00:25:31.390 --> 00:25:34.920
Well, I haven't used
it in a while.

00:25:34.920 --> 00:25:35.930
It's just not available
anymore.

00:25:35.930 --> 00:25:37.020
Because time has passed.

00:25:37.020 --> 00:25:37.410
It's not been used.

00:25:37.410 --> 00:25:38.480
It's not available.

00:25:38.480 --> 00:25:40.520
That's passive forgetting.

00:25:40.520 --> 00:25:43.190
The other way to think about why
we forget is not that it's

00:25:43.190 --> 00:25:45.560
a passive loss of knowledge.

00:25:45.560 --> 00:25:50.100
But that experiences you have
after that moment when you

00:25:50.100 --> 00:25:53.560
learned something, will go
back and write over, and

00:25:53.560 --> 00:25:56.230
muddy, and confuse your memory
for the original event.

00:25:56.230 --> 00:25:59.505
It's active interference of
subsequent experience.

00:25:59.505 --> 00:26:02.020
It's not passive withering.

00:26:02.020 --> 00:26:05.770
Other stuff is getting in your
head that's writing over and

00:26:05.770 --> 00:26:07.810
modifying the original memory.

00:26:07.810 --> 00:26:09.410
And the original memory
is never there again.

00:26:12.150 --> 00:26:14.320
And people have talked about it
in two different directions

00:26:14.320 --> 00:26:15.560
that you can think about this.

00:26:15.560 --> 00:26:18.490
One of them is what you call
proactive interference where

00:26:18.490 --> 00:26:22.050
things from before mess up your
learning on something.

00:26:22.050 --> 00:26:25.620
Or retroactive interference, you
already have the memory.

00:26:25.620 --> 00:26:29.085
And now new things mess you up
and write over the memory.

00:26:29.085 --> 00:26:32.150
So memory is threatened by
what came before they

00:26:32.150 --> 00:26:35.440
experience or what happens after
the experience In the

00:26:35.440 --> 00:26:38.060
way that it interferes with
accuracy of memory.

00:26:38.060 --> 00:26:40.190
So here's a fun experiment.

00:26:40.190 --> 00:26:40.810
It's just two subjects.

00:26:40.810 --> 00:26:42.560
But there's a lot of other
studies that looked at this.

00:26:42.560 --> 00:26:45.600
This is the original
demonstration where people had

00:26:45.600 --> 00:26:47.040
to remember syllables.

00:26:47.040 --> 00:26:50.190
And they taught them the
syllables just before they

00:26:50.190 --> 00:26:54.180
went to sleep or as
they woke up.

00:26:54.180 --> 00:26:57.050
And in each case, they were
tested, for example, some

00:26:57.050 --> 00:26:57.800
number of hours later.

00:26:57.800 --> 00:26:59.240
Let's say eight hours later.

00:26:59.240 --> 00:27:01.490
And their idea in the study--
and there's one wrinkle I'll

00:27:01.490 --> 00:27:03.160
mention now that we
know things--

00:27:03.160 --> 00:27:07.380
their idea was when you go to
sleep, there's no retroactive

00:27:07.380 --> 00:27:08.100
interference.

00:27:08.100 --> 00:27:09.550
Because you're not learning
anything else.

00:27:09.550 --> 00:27:10.240
You're not experiencing.

00:27:10.240 --> 00:27:10.850
You're not talking.

00:27:10.850 --> 00:27:11.380
You're not reading.

00:27:11.380 --> 00:27:13.810
So when you wake up in the
morning, nothing has messed up

00:27:13.810 --> 00:27:15.580
your memory from when you
just went to sleep.

00:27:15.580 --> 00:27:16.720
Does that make sense?

00:27:16.720 --> 00:27:19.110
If you study in the morning,
now you go and

00:27:19.110 --> 00:27:19.720
you have your day.

00:27:19.720 --> 00:27:21.000
You go to classes you
talk to people.

00:27:21.000 --> 00:27:21.850
You read things.

00:27:21.850 --> 00:27:25.800
All those new experiences can go
back and mess up the memory

00:27:25.800 --> 00:27:26.810
you acquired to start with.

00:27:26.810 --> 00:27:28.540
So in both cases, you get the
memory to start with.

00:27:28.540 --> 00:27:30.400
But in one case, you're sleeping
for eight hours.

00:27:30.400 --> 00:27:31.830
It's not messed up.

00:27:31.830 --> 00:27:32.980
In the other case, you were
out in the world.

00:27:32.980 --> 00:27:34.370
Lots of new things are
happening that are

00:27:34.370 --> 00:27:36.350
retroactively messing
up the memory.

00:27:39.810 --> 00:27:42.280
And you can see the people who
slept after who slept after

00:27:42.280 --> 00:27:44.330
they learned, when they woke up,
did a lot better than the

00:27:44.330 --> 00:27:47.290
people who walked around
during the day.

00:27:47.290 --> 00:27:51.570
And that thought can be one of a
huge line of research saying

00:27:51.570 --> 00:27:54.800
that one of the reasons that
memories become available to

00:27:54.800 --> 00:27:58.970
us is not simply passive
withering, but active other

00:27:58.970 --> 00:28:02.940
mental experiences that block
right over and change the

00:28:02.940 --> 00:28:03.383
original memory.

00:28:03.383 --> 00:28:03.910
Question, yeah.

00:28:03.910 --> 00:28:08.002
AUDIENCE: Studying at night, and
they going to sleep, does

00:28:08.002 --> 00:28:11.236
just having those memories
hanging around in your brain

00:28:11.236 --> 00:28:12.210
strengthen them?

00:28:12.210 --> 00:28:13.180
Because you're going to
wake up and do stuff--

00:28:13.180 --> 00:28:13.490
PROFESSOR: Yeah.

00:28:13.490 --> 00:28:15.290
So now there's a second thing.

00:28:15.290 --> 00:28:17.380
The question is, is there
something good about going to

00:28:17.380 --> 00:28:18.220
sleep after studying?

00:28:18.220 --> 00:28:21.480
And the answer is, there's
a lot of evidence now in

00:28:21.480 --> 00:28:25.360
animals, and increasingly in
humans, that sleep is a period

00:28:25.360 --> 00:28:29.030
that fixes memories from
the prior day.

00:28:29.030 --> 00:28:31.320
And if you don't get the right
kind of sleep or something

00:28:31.320 --> 00:28:34.215
like that, those memories from
the prior day don't seem to

00:28:34.215 --> 00:28:36.610
get as well fixed into
long-term memory.

00:28:36.610 --> 00:28:38.250
So this is mixing those
two issues.

00:28:38.250 --> 00:28:40.250
These people have two advantages
now we think.

00:28:40.250 --> 00:28:42.450
One advantage they have is
they're not having new

00:28:42.450 --> 00:28:45.010
experiences during the night
that are messing up

00:28:45.010 --> 00:28:46.790
the memory they got.

00:28:46.790 --> 00:28:49.030
And they're having this
consolidation

00:28:49.030 --> 00:28:50.440
period during sleep.

00:28:50.440 --> 00:28:53.360
People have long studied
what's the use of sleep

00:28:53.360 --> 00:28:55.060
besides making you not sleepy?

00:28:55.060 --> 00:28:57.920
And one of the most fascinating
things-- and

00:28:57.920 --> 00:29:00.170
there's just more and more
evidence for this--

00:29:00.170 --> 00:29:02.310
it's a period where because our
brain is kind of quiet in

00:29:02.310 --> 00:29:05.760
many ways, it seems to work a
lot on fixing memories from

00:29:05.760 --> 00:29:09.910
that day into a better
long-term unit.

00:29:09.910 --> 00:29:11.800
So those people have two
advantages by our current

00:29:11.800 --> 00:29:13.650
understanding.

00:29:13.650 --> 00:29:14.730
So that's retroactive
interference.

00:29:14.730 --> 00:29:17.760
Let me give you an example of
proactive interference.

00:29:17.760 --> 00:29:18.800
And here's how they study it.

00:29:18.800 --> 00:29:19.490
We won't to try it.

00:29:19.490 --> 00:29:21.480
But let me give you
an example.

00:29:21.480 --> 00:29:25.090
They would have you hear
three words like

00:29:25.090 --> 00:29:26.080
banana, peach, and apple.

00:29:26.080 --> 00:29:27.000
They're all related.

00:29:27.000 --> 00:29:30.250
Then they'd have you count aloud
from 138 backward by

00:29:30.250 --> 00:29:32.330
sevens for a few moments.

00:29:32.330 --> 00:29:33.340
They say, what were the words?

00:29:33.340 --> 00:29:34.550
And you give what you can.

00:29:34.550 --> 00:29:36.360
Then they give you a plum,
apricot, and lime, count

00:29:36.360 --> 00:29:38.060
backwards by sevens.

00:29:38.060 --> 00:29:39.520
Melon, lemon, we can see
all of these are

00:29:39.520 --> 00:29:41.450
from the same category.

00:29:41.450 --> 00:29:44.290
And then they switch
the category.

00:29:44.290 --> 00:29:46.550
So we said, typically,
background knowledge helps.

00:29:46.550 --> 00:29:48.730
But here's the way it can
get weirdly not helpful.

00:29:48.730 --> 00:29:50.910
So here's the performance
of healthy young

00:29:50.910 --> 00:29:51.870
people doing this.

00:29:51.870 --> 00:29:52.930
So this is percent correct.

00:29:52.930 --> 00:29:53.370
Good is high.

00:29:53.370 --> 00:29:54.880
The first list, they're
really good.

00:29:54.880 --> 00:29:56.570
Occasionally they forget
one of the three words.

00:29:56.570 --> 00:29:58.320
But looks what's happening as
they go along for the second

00:29:58.320 --> 00:29:59.590
list and the third list.

00:29:59.590 --> 00:30:02.720
They're getting worse
and worse.

00:30:02.720 --> 00:30:04.510
That's proactive interference.

00:30:04.510 --> 00:30:07.310
The experience in the first
list is messing you up to

00:30:07.310 --> 00:30:09.190
learn the new information
in the second list.

00:30:09.190 --> 00:30:12.130
And most of the errors people
make are substitutions.

00:30:12.130 --> 00:30:15.540
They go plum, apricot, apple.

00:30:15.540 --> 00:30:18.450
By the third list, they're
going melon, lime, apple.

00:30:18.450 --> 00:30:19.770
Do you see what's happening?

00:30:19.770 --> 00:30:23.900
Because they're related, because
they're related, now

00:30:23.900 --> 00:30:26.370
you're getting confused.

00:30:26.370 --> 00:30:28.810
If I heard the word grape
recently, was that in the

00:30:28.810 --> 00:30:29.490
first group?

00:30:29.490 --> 00:30:30.740
I'm not reporting that
one right now.

00:30:30.740 --> 00:30:33.100
Was it in the one before that
or the one I'm supposed to

00:30:33.100 --> 00:30:34.430
report right now?

00:30:34.430 --> 00:30:38.240
The relations among them mess
you up because it's hard to

00:30:38.240 --> 00:30:39.480
tell when you heard them.

00:30:39.480 --> 00:30:40.550
And they're all related.

00:30:40.550 --> 00:30:42.610
And just to convince you that
it's true, because you might

00:30:42.610 --> 00:30:45.520
say well, maybe you're just
getting tired like list, and

00:30:45.520 --> 00:30:47.120
list, and counting.

00:30:47.120 --> 00:30:48.400
Then they give you a new list.

00:30:48.400 --> 00:30:49.570
And look what happens.

00:30:49.570 --> 00:30:52.110
If it's fruits, still fruits,
you're still stuck.

00:30:52.110 --> 00:30:54.740
But if it's another list like
vegetables, flowers, and

00:30:54.740 --> 00:30:56.770
meats, or professions,
very different.

00:30:56.770 --> 00:30:59.080
Your memory zooms
right back up.

00:30:59.080 --> 00:31:02.650
Because all the interference you
had here about fruits is

00:31:02.650 --> 00:31:06.290
no longer relevant for learning
a set of professions.

00:31:06.290 --> 00:31:07.590
And it's kind of
graded, right?

00:31:07.590 --> 00:31:11.340
We think the flowers as more
related to fruits kind of.

00:31:11.340 --> 00:31:14.730
And professions is very
unrelated, doctor, lawyer,

00:31:14.730 --> 00:31:16.160
programmer.

00:31:16.160 --> 00:31:18.450
The more unrelated it is, the
more your memory goes right

00:31:18.450 --> 00:31:19.360
back to where it was.

00:31:19.360 --> 00:31:20.710
Because the proactive
interference

00:31:20.710 --> 00:31:21.960
is no longer happening.

00:31:24.610 --> 00:31:29.490
Another thing that researchers
have focused on as we read

00:31:29.490 --> 00:31:33.000
things, what do we focus on?

00:31:33.000 --> 00:31:37.650
So here's an example where they
read people sentences.

00:31:37.650 --> 00:31:41.160
And then they tested them either
for the meaning or for

00:31:41.160 --> 00:31:42.790
the style of the sentence.

00:31:42.790 --> 00:31:44.890
Usually when we read stuff,
we're focused on the meaning,

00:31:44.890 --> 00:31:46.090
not the style.

00:31:46.090 --> 00:31:47.110
Style, we might notice it.

00:31:47.110 --> 00:31:48.580
But usually, what
am I reading?

00:31:48.580 --> 00:31:49.830
What's the point?

00:31:53.040 --> 00:31:55.460
If they weren't unwarned,
they read the sentence.

00:31:55.460 --> 00:31:56.230
Then you're tested.

00:31:56.230 --> 00:31:58.790
It's much better for meaning
than for style.

00:31:58.790 --> 00:32:00.630
Because we automatically
go for meaning.

00:32:00.630 --> 00:32:03.120
That's what we go for when
we read by and large.

00:32:03.120 --> 00:32:04.630
When we think about poetry
or something,

00:32:04.630 --> 00:32:05.300
that might be different.

00:32:05.300 --> 00:32:07.430
But reading typical text,
what's the meaning?

00:32:07.430 --> 00:32:09.630
We strip away, almost,
the style.

00:32:09.630 --> 00:32:12.320
We want to get to the content.

00:32:12.320 --> 00:32:15.450
And they're terrible if they're
asked about the style

00:32:15.450 --> 00:32:17.760
or the specific organization of
the sentence, the word by

00:32:17.760 --> 00:32:18.950
word organization.

00:32:18.950 --> 00:32:20.480
But, of course, if they
focus on it, they

00:32:20.480 --> 00:32:21.870
can do a lot better.

00:32:21.870 --> 00:32:24.000
So this is just saying
that we naturally go

00:32:24.000 --> 00:32:25.610
for gist and meaning.

00:32:25.610 --> 00:32:28.130
And we try to throw away a lot
of the specific particulars

00:32:28.130 --> 00:32:29.510
like the way the sentence
was organized, the

00:32:29.510 --> 00:32:32.160
style of the writing.

00:32:32.160 --> 00:32:32.960
OK.

00:32:32.960 --> 00:32:35.240
So now I'd like to do a
demonstration that will work

00:32:35.240 --> 00:32:36.140
better for some than others.

00:32:36.140 --> 00:32:38.660
But here we go.

00:32:38.660 --> 00:32:40.740
So here we go.

00:32:40.740 --> 00:32:42.250
I'm going to read you
a list of words.

00:32:42.250 --> 00:32:46.010
And then I'm going to ask you
for a couple different words

00:32:46.010 --> 00:32:47.635
and ask you if they
were on the list.

00:32:47.635 --> 00:32:48.060
OK.

00:32:48.060 --> 00:32:48.560
Here we go.

00:32:48.560 --> 00:32:49.930
Ready?

00:32:49.930 --> 00:32:57.410
Door, glass, pane, shade, ledge,
sill, house, open,

00:32:57.410 --> 00:33:03.760
curtain, frame, view, breeze,
sash, screen, shutter.

00:33:03.760 --> 00:33:05.300
OK, was the word glass?

00:33:05.300 --> 00:33:07.020
AUDIENCE: Yes.

00:33:07.020 --> 00:33:08.720
PROFESSOR: Was the word
potato on the list?

00:33:08.720 --> 00:33:09.480
AUDIENCE: No.

00:33:09.480 --> 00:33:11.026
PROFESSOR: Was the word
shade on the list?

00:33:11.026 --> 00:33:11.780
AUDIENCE: Yes.

00:33:11.780 --> 00:33:13.870
PROFESSOR: Was the word
car on the list?

00:33:13.870 --> 00:33:14.590
AUDIENCE: No.

00:33:14.590 --> 00:33:15.836
PROFESSOR: Was the word
window on the list?

00:33:15.836 --> 00:33:16.172
AUDIENCE: Yes.

00:33:16.172 --> 00:33:16.790
No.

00:33:16.790 --> 00:33:16.930
PROFESSOR: OK.

00:33:16.930 --> 00:33:18.310
How many people said window?

00:33:18.310 --> 00:33:20.110
Put your hands up.

00:33:20.110 --> 00:33:22.060
I heard a lot of window.

00:33:22.060 --> 00:33:22.750
All right.

00:33:22.750 --> 00:33:24.230
You're not helping
me out here.

00:33:24.230 --> 00:33:27.690
Smart undergraduates like you,
at the peak of your memory,

00:33:27.690 --> 00:33:29.440
will about half the time
say yes to window.

00:33:29.440 --> 00:33:31.460
You saw this demonstration
before, or

00:33:31.460 --> 00:33:33.260
you heard it before.

00:33:33.260 --> 00:33:36.890
The way they compose these lists
is they ask students to

00:33:36.890 --> 00:33:38.890
say what's the first word you
think of that goes with door?

00:33:38.890 --> 00:33:40.200
The second word?

00:33:40.200 --> 00:33:42.050
And the first word that goes
with door, the most common

00:33:42.050 --> 00:33:44.410
one, they'll put over here.

00:33:44.410 --> 00:33:46.440
That's the trick word,
the lure word.

00:33:46.440 --> 00:33:48.850
And then these are other words
that people think kind of goes

00:33:48.850 --> 00:33:50.160
with the word door.

00:33:50.160 --> 00:33:54.530
So if you hear this list, and
you're tested for did you hear

00:33:54.530 --> 00:33:56.510
the word window or see the
word window-- it doesn't

00:33:56.510 --> 00:33:58.180
matter whether you see
it or hear it--

00:33:58.180 --> 00:34:01.720
about half the time
undergraduates will say yes, I

00:34:01.720 --> 00:34:02.910
heard it or saw it.

00:34:02.910 --> 00:34:04.710
Because they're getting
the gist of the list.

00:34:04.710 --> 00:34:07.420
This is all about door
and window stuff.

00:34:07.420 --> 00:34:09.949
So when the word window appears,
they have a false or

00:34:09.949 --> 00:34:12.150
illusory memory.

00:34:12.150 --> 00:34:14.230
The rate of false or illusory
memories goes

00:34:14.230 --> 00:34:16.929
up with age as well.

00:34:16.929 --> 00:34:18.580
For every decade that will
pass, you'll add

00:34:18.580 --> 00:34:21.110
a few more of those.

00:34:21.110 --> 00:34:24.659
But even undergraduates,
typically, about half the time

00:34:24.659 --> 00:34:26.929
they'll falsely recall they
heard the word window.

00:34:26.929 --> 00:34:30.400
Again, the idea is here's
this double-edged sword.

00:34:30.400 --> 00:34:34.540
It's about words that go
with doors and windows.

00:34:34.540 --> 00:34:35.420
That's the gist.

00:34:35.420 --> 00:34:36.050
That's the main idea.

00:34:36.050 --> 00:34:38.270
When you get the word window,
you falsely believe that you

00:34:38.270 --> 00:34:39.310
saw it or heard it.

00:34:39.310 --> 00:34:43.830
So that's the way that people
try in the laboratory to

00:34:43.830 --> 00:34:46.830
create false memories that are
experimentally testable.

00:34:46.830 --> 00:34:49.150
We'll talk about real life
ones in a moment.

00:34:49.150 --> 00:34:53.320
So we said all these things make
it feel like memory is

00:34:53.320 --> 00:34:56.350
more the punch bowl metaphor
than the camera.

00:34:56.350 --> 00:34:58.840
Because it's all swished
together, the proactive stuff,

00:34:58.840 --> 00:35:02.600
the interpretation, the
retroactive changes that are

00:35:02.600 --> 00:35:06.500
created in memory are all
altering the memory based on

00:35:06.500 --> 00:35:11.170
the interpretation or based
on subsequent experience.

00:35:11.170 --> 00:35:15.200
So let me stop for one moment
to tell you, OK,

00:35:15.200 --> 00:35:16.360
so memory is shaky.

00:35:16.360 --> 00:35:18.930
Wouldn't it be cool to have
truly photographic memory?

00:35:18.930 --> 00:35:20.590
I mean, that would be awesome
as a student.

00:35:20.590 --> 00:35:22.460
It wouldn't be bad in life.

00:35:22.460 --> 00:35:25.020
There's only been one
well-described case of a

00:35:25.020 --> 00:35:27.610
person who seems to have truly
photographic memory.

00:35:27.610 --> 00:35:29.280
You hear various stories.

00:35:29.280 --> 00:35:32.495
Most of the people who are
things like memory performers,

00:35:32.495 --> 00:35:35.040
or there's memory Olympics and
things like that, they train

00:35:35.040 --> 00:35:37.760
the heck out of themselves to
use different methods that can

00:35:37.760 --> 00:35:38.670
enhance your memory.

00:35:38.670 --> 00:35:40.560
And they can do amazing
things.

00:35:40.560 --> 00:35:43.160
But it's all hard work.

00:35:43.160 --> 00:35:45.720
It's all hard work as far
as we understand.

00:35:45.720 --> 00:35:48.390
But here's a guy who was
different, studied by Luria, a

00:35:48.390 --> 00:35:51.440
psychologist in Russia,
about 100 years ago.

00:35:51.440 --> 00:35:53.810
So this is a guy who was a
reporter at a newspaper.

00:35:53.810 --> 00:35:57.980
And he would go out and come
back and type up the report of

00:35:57.980 --> 00:36:00.140
what he had seen at some event
for the newspaper.

00:36:00.140 --> 00:36:03.730
And the editor noticed that
this guy never took notes.

00:36:03.730 --> 00:36:05.300
He came back and just
started typing.

00:36:05.300 --> 00:36:06.750
And the editor said, you've
got to take notes.

00:36:06.750 --> 00:36:08.210
Because you won't know exactly
what happened,

00:36:08.210 --> 00:36:09.750
who said what exactly.

00:36:09.750 --> 00:36:10.850
You'll make mistakes.

00:36:10.850 --> 00:36:11.380
The guy said, no.

00:36:11.380 --> 00:36:12.630
I'm always perfect.

00:36:12.630 --> 00:36:15.270
The editor said, OK.

00:36:15.270 --> 00:36:17.010
We're going to teach you
a lesson about this

00:36:17.010 --> 00:36:19.160
just to show you.

00:36:19.160 --> 00:36:20.290
He got some material.

00:36:20.290 --> 00:36:22.070
He said, everybody
come around.

00:36:22.070 --> 00:36:23.950
He's going to embarrass
the guy.

00:36:23.950 --> 00:36:24.730
I'm going to read
you something.

00:36:24.730 --> 00:36:25.940
You tell me every word I said.

00:36:25.940 --> 00:36:28.020
He read him some gibberish.

00:36:28.020 --> 00:36:31.550
And the guy repeated every
word perfectly.

00:36:31.550 --> 00:36:33.490
This guy truly had photographic
memory.

00:36:33.490 --> 00:36:36.210
And kind of interestingly, when
they said, wow, you have

00:36:36.210 --> 00:36:37.030
photographic memory.

00:36:37.030 --> 00:36:37.640
He didn't go, yes.

00:36:37.640 --> 00:36:38.090
I'm awesome.

00:36:38.090 --> 00:36:39.380
I'm a superhero.

00:36:39.380 --> 00:36:42.420
He said, doesn't everybody?

00:36:42.420 --> 00:36:46.150
He was not aware that most of us
don't remember every single

00:36:46.150 --> 00:36:50.590
thing that we study easily and
for the rest of our lives.

00:36:50.590 --> 00:36:55.720
So he would be presented rows
of digits like these, study

00:36:55.720 --> 00:36:59.630
them for three minutes, and he
could recall them days, weeks,

00:36:59.630 --> 00:37:01.130
and months later perfectly.

00:37:04.370 --> 00:37:06.810
This is almost the only case
we have well-described and

00:37:06.810 --> 00:37:07.890
well-analyzed.

00:37:07.890 --> 00:37:10.900
So it's really rare.

00:37:10.900 --> 00:37:13.350
He would say when he had to
think back at a particular

00:37:13.350 --> 00:37:15.523
list, like tell me the one from
last year, or tell me the

00:37:15.523 --> 00:37:17.750
one from two years ago, he would
have to think where he

00:37:17.750 --> 00:37:19.790
was and reinstate.

00:37:19.790 --> 00:37:21.760
So that in his mind's eye, he
would see the room or hear the

00:37:21.760 --> 00:37:24.600
voice of the person
reading it to him.

00:37:24.600 --> 00:37:27.480
But even 15 years later,
perfect memory

00:37:27.480 --> 00:37:28.610
for a list like this.

00:37:28.610 --> 00:37:31.350
Wouldn't you like to have
that right now?

00:37:31.350 --> 00:37:32.600
I wouldn't mind it either.

00:37:35.300 --> 00:37:36.630
He also was synesthetic.

00:37:36.630 --> 00:37:39.450
That is, when he heard things in
one modality, it triggered

00:37:39.450 --> 00:37:42.290
perception like experience
is another modality.

00:37:42.290 --> 00:37:46.280
He could change his resting
pulse from 70 to 100.

00:37:46.280 --> 00:37:49.370
He could change his temperature
by two degrees by

00:37:49.370 --> 00:37:50.260
force of will.

00:37:50.260 --> 00:37:51.510
He's an unusual person.

00:37:55.240 --> 00:37:57.950
We would love to discover
another person like this in

00:37:57.950 --> 00:37:58.720
the place of the planet.

00:37:58.720 --> 00:38:00.785
We have not seen another
one well-documented.

00:38:00.785 --> 00:38:02.170
Probably there is.

00:38:02.170 --> 00:38:05.630
But they're sitting somewhere
in some village remembering

00:38:05.630 --> 00:38:07.880
everything perfectly going, I
thought you all remembered

00:38:07.880 --> 00:38:10.810
everything perfectly.

00:38:10.810 --> 00:38:11.930
So you could think, wow,
that's awesome.

00:38:11.930 --> 00:38:13.900
That's a nice superpower
to have.

00:38:13.900 --> 00:38:15.370
But he was not a happy person.

00:38:15.370 --> 00:38:16.550
This is kind of an interesting
question.

00:38:16.550 --> 00:38:19.390
Because he complained that when
somebody spoke to him

00:38:19.390 --> 00:38:21.990
like a family member, what would
happen was he would be

00:38:21.990 --> 00:38:25.390
flooded by a word with some
memory for some list or some

00:38:25.390 --> 00:38:28.730
event last week, last month,
or 10 years ago.

00:38:28.730 --> 00:38:31.720
His family members said, you're
not listening to me.

00:38:31.720 --> 00:38:34.940
Yeah, because every word
triggered back or brought back

00:38:34.940 --> 00:38:37.310
a flood of memory.

00:38:37.310 --> 00:38:40.850
He got so miserable that things
in his environment

00:38:40.850 --> 00:38:44.590
would trigger perfect floods
of memory into his mind--

00:38:44.590 --> 00:38:47.320
and this is truly
like a novel--

00:38:47.320 --> 00:38:49.540
at one point, in order to get
rid of memories-- and this did

00:38:49.540 --> 00:38:52.007
not work-- he wrote them down on
a piece of paper and threw

00:38:52.007 --> 00:38:55.080
them into the fire thinking
somehow that would work.

00:38:55.080 --> 00:38:59.350
So this is one of these Twilight
Zone, O. Henry kinds

00:38:59.350 --> 00:39:03.430
of stories where you think
it's awesome to have

00:39:03.430 --> 00:39:04.710
photographic-like memory.

00:39:04.710 --> 00:39:08.060
But, in fact, it seems to have
blocked, in many ways, his

00:39:08.060 --> 00:39:09.810
development as a person.

00:39:09.810 --> 00:39:12.660
Once he realized he had such
a rare memory, he became a

00:39:12.660 --> 00:39:15.190
professional memory performer.

00:39:15.190 --> 00:39:17.790
And then all kinds of jobs and
finally retreated into a

00:39:17.790 --> 00:39:20.390
countryside kind of unhappy,
treating people with herbs

00:39:20.390 --> 00:39:21.690
with his wife and son.

00:39:21.690 --> 00:39:23.870
He did not have a happy,
awesome life.

00:39:23.870 --> 00:39:26.140
I don't know if in this world
he would do better?

00:39:26.140 --> 00:39:29.810
Because you could get on TV
shows and become a celebrity

00:39:29.810 --> 00:39:31.060
or something if you
could do this.

00:39:33.390 --> 00:39:36.260
So what's the problem with
photographic-like

00:39:36.260 --> 00:39:38.220
memory do you think?

00:39:38.220 --> 00:39:40.980
Why is it that we kind of wish
we had it at certain moments?

00:39:40.980 --> 00:39:42.230
But what's the drawback?

00:39:44.750 --> 00:39:48.660
Well the drawback seems to be,
imagine if you had in your

00:39:48.660 --> 00:39:50.290
head a photograph
of everything.

00:39:50.290 --> 00:39:54.440
You would have so much stuff
that you wouldn't be analyzing

00:39:54.440 --> 00:39:57.000
it for the basic point
of what it's about.

00:39:57.000 --> 00:39:59.470
So we just said, the risk of
analyzing things for their

00:39:59.470 --> 00:40:03.590
basic point, their basic gist,
is that we want to get the

00:40:03.590 --> 00:40:04.240
bottom message.

00:40:04.240 --> 00:40:05.850
And we give up a lot
of the particulars.

00:40:05.850 --> 00:40:07.190
It's not like a photograph.

00:40:07.190 --> 00:40:10.290
It's like a very small abstract
or a note about a

00:40:10.290 --> 00:40:12.110
photograph that's
in your mind.

00:40:12.110 --> 00:40:14.090
But that's a very powerful way
to approach the world.

00:40:14.090 --> 00:40:15.890
Because then all your background
knowledge is

00:40:15.890 --> 00:40:18.580
instantly available to help you
interpret what's going on.

00:40:18.580 --> 00:40:21.150
Because you're using lots of
connections and very few

00:40:21.150 --> 00:40:22.250
particulars.

00:40:22.250 --> 00:40:25.660
Too many particulars are as
burdensome as probably having

00:40:25.660 --> 00:40:28.160
too many generalities.

00:40:28.160 --> 00:40:30.410
Let me talk a minute about
flashbulb memories.

00:40:30.410 --> 00:40:32.525
So this is a kind
of funny thing.

00:40:32.525 --> 00:40:36.280
You might have the experience
in your own life of very

00:40:36.280 --> 00:40:40.070
salient moments, big moments in
your life with your family,

00:40:40.070 --> 00:40:42.690
other things you're doing in
your life, where you say, I'll

00:40:42.690 --> 00:40:43.960
never forget this moment.

00:40:43.960 --> 00:40:46.590
Because just everything
is so vivid for me.

00:40:46.590 --> 00:40:47.840
People call this flashbulb.

00:40:51.290 --> 00:40:54.100
We can never know how accurate
your flashbulb memory is.

00:40:54.100 --> 00:40:56.340
I'll never forget when I got
into MIT, the moment.

00:40:56.340 --> 00:40:58.150
Because I was wearing
my lucky socks.

00:40:58.150 --> 00:40:59.080
And it was sunny outside.

00:40:59.080 --> 00:41:01.070
And you might be right,
or you might be wrong.

00:41:01.070 --> 00:41:06.210
So there's a slightly gruesome
research enterprise which

00:41:06.210 --> 00:41:10.190
takes public events that are
very emotional for people.

00:41:10.190 --> 00:41:13.070
So some of them will be very
historical for you somewhere

00:41:13.070 --> 00:41:14.500
in your lifetime.

00:41:14.500 --> 00:41:18.300
John F. Kennedy's assassination,
the Challenger

00:41:18.300 --> 00:41:21.550
blowing up as a high school
teacher was going up to be the

00:41:21.550 --> 00:41:23.600
first high school teacher
to do that.

00:41:23.600 --> 00:41:27.940
The O.J. Simpson verdict, were
you even alive for this?

00:41:30.760 --> 00:41:31.700
I can tell you that got an

00:41:31.700 --> 00:41:33.110
unbelievable amount of interest.

00:41:33.110 --> 00:41:34.320
Because I'm from Buffalo.

00:41:34.320 --> 00:41:35.540
That's where O.J. Simpson
played football.

00:41:35.540 --> 00:41:37.350
So I have a particular
interest.

00:41:37.350 --> 00:41:40.500
It was like everything you
wanted in a TV show.

00:41:40.500 --> 00:41:41.870
Tragically, two people died.

00:41:41.870 --> 00:41:43.990
Because O.J. Simpson is a super
famous football player,

00:41:43.990 --> 00:41:46.390
there was huge debate about
whether he had murdered his

00:41:46.390 --> 00:41:48.840
wife and another person
in the house.

00:41:48.840 --> 00:41:50.290
And there was an exact
moment when they

00:41:50.290 --> 00:41:52.030
said, get on your TVs.

00:41:52.030 --> 00:41:55.000
Here comes a verdict.

00:41:55.000 --> 00:41:56.250
Or the 9/11 attack.

00:41:58.620 --> 00:42:01.230
So here's this funny
research business.

00:42:01.230 --> 00:42:03.050
What people do is they go.

00:42:03.050 --> 00:42:05.460
And as soon as these horrible
things happened, they ask

00:42:05.460 --> 00:42:08.440
people to write down where were
you, what were you doing,

00:42:08.440 --> 00:42:10.895
how did you learn about it, what
were your feelings, what

00:42:10.895 --> 00:42:12.970
were the feelings of the people
around you, and what

00:42:12.970 --> 00:42:15.540
did you do in the next hour?

00:42:15.540 --> 00:42:17.430
You can't be prepared for
this other than wait

00:42:17.430 --> 00:42:18.800
for something horrible.

00:42:18.800 --> 00:42:21.050
Everybody says, I'll never
forget where I was when 9/11

00:42:21.050 --> 00:42:22.160
happened or things like that.

00:42:22.160 --> 00:42:23.860
People feel that way.

00:42:23.860 --> 00:42:27.730
And they certainly remember that
day more in some sense

00:42:27.730 --> 00:42:30.410
than a typical quiet day.

00:42:30.410 --> 00:42:31.360
But here's what they do.

00:42:31.360 --> 00:42:33.680
They test them on their
own answers.

00:42:33.680 --> 00:42:35.800
So you gave the information
just a little bit after.

00:42:35.800 --> 00:42:37.470
Presumably, it's roughly
correct.

00:42:37.470 --> 00:42:40.760
If you're tested a year later,
yes, you remember that day

00:42:40.760 --> 00:42:42.320
better than other days.

00:42:42.320 --> 00:42:44.770
But it's full of errors.

00:42:44.770 --> 00:42:46.520
It's full of errors.

00:42:46.520 --> 00:42:48.470
And people are way
overconfident.

00:42:48.470 --> 00:42:51.030
They say, I know where
I was a year later.

00:42:51.030 --> 00:42:52.620
And I know I was with
my friends.

00:42:52.620 --> 00:42:54.050
And you say, a year
ago, you wrote

00:42:54.050 --> 00:42:55.110
down you were by yourself.

00:42:55.110 --> 00:42:56.680
Oops.

00:42:56.680 --> 00:42:59.530
But I'm pretty sure I was
wearing my raincoat.

00:42:59.530 --> 00:43:01.430
And you go, oops, you
wrote down you

00:43:01.430 --> 00:43:02.330
were wearing a sweater.

00:43:02.330 --> 00:43:03.520
Oops.

00:43:03.520 --> 00:43:05.240
Your memory is way higher.

00:43:05.240 --> 00:43:07.990
But it's full of inaccuracies,
even though people

00:43:07.990 --> 00:43:09.490
are sure it's not.

00:43:09.490 --> 00:43:13.280
They're sure that's
not a inaccurate.

00:43:13.280 --> 00:43:16.430
So the next horrible public
event that happens, there will

00:43:16.430 --> 00:43:18.810
be a bunch of memory researchers
running around.

00:43:18.810 --> 00:43:20.300
And they'll be saying,
where were you?

00:43:20.300 --> 00:43:20.800
What were you doing?

00:43:20.800 --> 00:43:21.520
What were you feeling?

00:43:21.520 --> 00:43:24.150
Because we need that to be able
to verify whether your

00:43:24.150 --> 00:43:27.060
memory for emotionally intense
experience is accurate or not

00:43:27.060 --> 00:43:28.310
and how long it lasts.

00:43:33.030 --> 00:43:35.770
A couple of experiments
and then a video.

00:43:35.770 --> 00:43:37.970
So here's eyewitness
testimony.

00:43:37.970 --> 00:43:41.320
There's nothing more dramatic in
court on the TV shows or in

00:43:41.320 --> 00:43:43.470
real life, if you have to
be around these things.

00:43:43.470 --> 00:43:45.500
Where the person says,
who was a person who

00:43:45.500 --> 00:43:46.430
murdered your neighbor?

00:43:46.430 --> 00:43:47.760
And you go, that's the woman.

00:43:47.760 --> 00:43:48.720
That's the man.

00:43:48.720 --> 00:43:50.990
And the jury's looking.

00:43:50.990 --> 00:43:53.950
So how accurate is eyewitness
testimony?

00:43:53.950 --> 00:43:55.490
Of course it has to be
somewhat accurate.

00:43:55.490 --> 00:43:57.290
We're not living in a crazy
world where people are

00:43:57.290 --> 00:43:59.160
randomly imagining things.

00:43:59.160 --> 00:44:01.730
But how accurate is it really?

00:44:01.730 --> 00:44:03.350
So here's a kind of an
experiment they did.

00:44:03.350 --> 00:44:04.900
This is work from Elizabeth
Loftus who's a

00:44:04.900 --> 00:44:06.130
leader in this area.

00:44:06.130 --> 00:44:07.950
She would have people
just see slides--

00:44:07.950 --> 00:44:10.170
this is before computers,
basically--

00:44:10.170 --> 00:44:12.160
where a sports car would come
to an intersection, would

00:44:12.160 --> 00:44:15.080
turn, and would hit a pedestrian
in the slides.

00:44:15.080 --> 00:44:16.580
So it's not the drama
of really seeing it.

00:44:16.580 --> 00:44:18.390
It's a stage thing.

00:44:18.390 --> 00:44:23.100
And it would be either a yield
sign or a stop sign just

00:44:23.100 --> 00:44:26.630
before the car turns that
you would clearly see.

00:44:26.630 --> 00:44:28.360
And let's pretend you were in a
condition where you saw the

00:44:28.360 --> 00:44:29.470
yield sign.

00:44:29.470 --> 00:44:32.360
Then afterwards, they would say,
did another car pass the

00:44:32.360 --> 00:44:34.510
red Datsun while it was stopped
at the yield sign?

00:44:34.510 --> 00:44:35.880
That's consistent,
the world yield.

00:44:35.880 --> 00:44:38.870
Or did another car pass the
Datsun while it was stopped at

00:44:38.870 --> 00:44:39.650
the stop sign?

00:44:39.650 --> 00:44:42.750
See you slipped in
the word stopped?

00:44:42.750 --> 00:44:43.950
Or in neutral, you don't
say anything.

00:44:43.950 --> 00:44:46.540
And now you say, which
slide did you see?

00:44:46.540 --> 00:44:48.290
You show them the actual
slide with a stop

00:44:48.290 --> 00:44:49.890
sign or a yield sign.

00:44:49.890 --> 00:44:50.740
You saw the yield sign.

00:44:50.740 --> 00:44:53.140
But here's what happens.

00:44:53.140 --> 00:44:57.280
If you saw the yield sign, and
you are shown this yield sign,

00:44:57.280 --> 00:44:59.440
you do pretty well,
consistent.

00:44:59.440 --> 00:45:03.630
Look what happens if you
saw the yield sign.

00:45:03.630 --> 00:45:07.040
You've got the question, did
you see a stop sign?

00:45:07.040 --> 00:45:10.160
And now you're tested, what
did you actually see?

00:45:10.160 --> 00:45:11.190
You're pretty much wrong.

00:45:11.190 --> 00:45:13.820
You're pretty much saying,
I saw a stop sign.

00:45:13.820 --> 00:45:15.280
That's retroactive
interference.

00:45:15.280 --> 00:45:16.970
You saw the yield sign.

00:45:16.970 --> 00:45:19.130
You were asked about
a stop sign.

00:45:19.130 --> 00:45:22.150
And now you believe you
saw a stop sign.

00:45:22.150 --> 00:45:25.040
That's why it's so important
how police or other people

00:45:25.040 --> 00:45:27.500
interrogate witnesses.

00:45:27.500 --> 00:45:30.920
Because if they slip in certain
words, people have a

00:45:30.920 --> 00:45:32.630
hard time going back to
the original memory.

00:45:32.630 --> 00:45:34.260
They'll have a memory that's
a mixture of the original

00:45:34.260 --> 00:45:39.240
experience and the questions
asked about that experience.

00:45:39.240 --> 00:45:42.310
So people say, oh that's just
a laboratory experiment.

00:45:42.310 --> 00:45:44.140
In real life, that
wouldn't happen.

00:45:44.140 --> 00:45:47.390
So they did this experiment.

00:45:47.390 --> 00:45:49.600
Jim, a graduate student,
reminded his younger brother

00:45:49.600 --> 00:45:54.450
Chris that they lost Chris in
a mall when Chris was five,

00:45:54.450 --> 00:45:57.230
and an older tallish man
brought him back.

00:45:57.230 --> 00:45:58.845
So that would be a pretty
traumatic thing for a

00:45:58.845 --> 00:46:01.130
five-year-old to be lost in
a mall and have an old

00:46:01.130 --> 00:46:03.660
man take you back.

00:46:03.660 --> 00:46:05.410
Certainly for the parents,
you're going where's the kid?

00:46:05.410 --> 00:46:05.900
Where's the kid?

00:46:05.900 --> 00:46:11.400
So two days later, Chris says,
the younger kid, yeah.

00:46:11.400 --> 00:46:13.130
I was with you guys
for a second.

00:46:13.130 --> 00:46:15.750
And then I went over to look at
the toy store, the KB Toys.

00:46:15.750 --> 00:46:16.490
And then we got lost.

00:46:16.490 --> 00:46:17.170
And I was looking around.

00:46:17.170 --> 00:46:19.180
I thought, I'm in trouble now.

00:46:19.180 --> 00:46:20.100
And then I thought it
was never going to

00:46:20.100 --> 00:46:20.960
see my family again.

00:46:20.960 --> 00:46:22.150
I was really scared.

00:46:22.150 --> 00:46:24.060
And this old man, I think he
was wearing a blue flannel,

00:46:24.060 --> 00:46:24.660
came up to me.

00:46:24.660 --> 00:46:25.250
He was kind of old.

00:46:25.250 --> 00:46:26.500
He was kind of bald.

00:46:29.380 --> 00:46:30.630
Chris was never lost.

00:46:33.880 --> 00:46:36.510
Jim, the graduate student,
being mean to his younger

00:46:36.510 --> 00:46:39.170
brother, but for good science
reasons, told

00:46:39.170 --> 00:46:40.320
him this slight story.

00:46:40.320 --> 00:46:42.310
He didn't give him any
of these details.

00:46:42.310 --> 00:46:44.320
He just said remember when you
were five years old and got

00:46:44.320 --> 00:46:48.230
lost in the mall, and the old
tall man brought you back?

00:46:48.230 --> 00:46:51.560
But what's happening is our
memories of when we're kids

00:46:51.560 --> 00:46:53.340
are pretty vague.

00:46:53.340 --> 00:46:55.970
Chris is sort of mixing in some
real things that happened

00:46:55.970 --> 00:46:57.290
in the story.

00:46:57.290 --> 00:46:59.520
And he's fabricating.

00:46:59.520 --> 00:47:00.870
He's not trying to get
away with anything.

00:47:00.870 --> 00:47:02.350
He's just creating this
false memory.

00:47:05.140 --> 00:47:05.850
And he said, oh no.

00:47:05.850 --> 00:47:08.110
We want it even more
lifelike than that.

00:47:08.110 --> 00:47:09.820
So here's the experiment
they did.

00:47:09.820 --> 00:47:13.540
They had 120 students see
an ad for Bugs Bunny at

00:47:13.540 --> 00:47:14.970
Disneyland to evaluate the ad.

00:47:14.970 --> 00:47:15.840
So you're brought into a room.

00:47:15.840 --> 00:47:19.090
They say, we want to market test
whether this is a good ad

00:47:19.090 --> 00:47:20.340
for Disneyland.

00:47:24.710 --> 00:47:27.100
All these people had been to
Disneyland some years ago with

00:47:27.100 --> 00:47:29.050
kids in real life.

00:47:29.050 --> 00:47:31.540
Then they said, by
the way we're

00:47:31.540 --> 00:47:32.400
thinking about Bugs Bunny.

00:47:32.400 --> 00:47:33.580
When you were there,
did you meet him?

00:47:33.580 --> 00:47:36.060
Did you shake his hand?

00:47:36.060 --> 00:47:37.960
Now, what's the big trick
about Bugs Bunny and

00:47:37.960 --> 00:47:38.180
Disneyland?

00:47:38.180 --> 00:47:40.820
I saw some smiles right away.

00:47:40.820 --> 00:47:42.880
Bugs Bunny is one of the few
cartoon characters that many

00:47:42.880 --> 00:47:46.050
kids know that's not a Disney
character and, by law, cannot

00:47:46.050 --> 00:47:48.940
be found at Disneyland
or Disney World.

00:47:48.940 --> 00:47:55.240
But one out of three college
students remembered seeing

00:47:55.240 --> 00:47:58.150
Bugs Bunny at Disney World or
Disneyland when they were a

00:47:58.150 --> 00:48:01.890
kid after they had just seen
some promotional material

00:48:01.890 --> 00:48:03.710
showing Bugs Bunny
shaking hands.

00:48:06.380 --> 00:48:07.660
Because they had been there.

00:48:07.660 --> 00:48:08.710
They don't remember stuff.

00:48:08.710 --> 00:48:09.020
OK.

00:48:09.020 --> 00:48:12.130
Bugs Bunny, sure.

00:48:12.130 --> 00:48:16.640
How potent is this way that we
mix up new information with

00:48:16.640 --> 00:48:17.500
the original experience.

00:48:17.500 --> 00:48:20.260
So we can't tell apart the
original memory from the mixed

00:48:20.260 --> 00:48:22.350
up new relevant information.

00:48:22.350 --> 00:48:24.450
I mean, this would not have
worked, of course, if they

00:48:24.450 --> 00:48:25.960
show you King Kong.

00:48:25.960 --> 00:48:27.590
You'd be like, there's no
way I saw King Kong.

00:48:27.590 --> 00:48:29.680
It has to be slightly
credible.

00:48:32.190 --> 00:48:34.740
But it's a pretty big difference
in some cases.

00:48:34.740 --> 00:48:38.470
So here's one example
in real life.

00:48:38.470 --> 00:48:39.220
This is a real case.

00:48:39.220 --> 00:48:41.940
In a dark, October night, a
man picks up on Pacific

00:48:41.940 --> 00:48:45.042
Highway, south of Seattle,
hitchhiker.

00:48:45.042 --> 00:48:47.210
It turns into an
isolated road.

00:48:47.210 --> 00:48:49.040
The man brutally rapes
her and leaves her by

00:48:49.040 --> 00:48:49.670
the side of the road.

00:48:49.670 --> 00:48:52.420
24 hours later, she looks at
an array of photos, and she

00:48:52.420 --> 00:48:53.850
picks out a man who
was convicted.

00:48:53.850 --> 00:48:57.020
Because she says, that's the
man who brutally raped me.

00:48:57.020 --> 00:48:59.150
A few months later, another
man was arrested

00:48:59.150 --> 00:49:00.110
for a series of rapes.

00:49:00.110 --> 00:49:01.600
She sees his picture in
the newspaper, and

00:49:01.600 --> 00:49:03.240
she realizes oops.

00:49:03.240 --> 00:49:07.740
Sadly, this is the man who
attacked and raped me.

00:49:07.740 --> 00:49:10.620
He's released from jail.

00:49:10.620 --> 00:49:12.580
By then, he's lost his money,
his job, his fiance, his

00:49:12.580 --> 00:49:12.885
reputation.

00:49:12.885 --> 00:49:14.730
He spends four years
pursuing a lawsuit.

00:49:14.730 --> 00:49:17.480
He dies 11 days prior
to the trial.

00:49:17.480 --> 00:49:20.280
10 months later, his estate gets
$2.8 million because the

00:49:20.280 --> 00:49:23.140
police weren't very careful how
they did the photo lineup.

00:49:23.140 --> 00:49:26.150
It turns out if you look at the
photo lineup, his was a

00:49:26.150 --> 00:49:29.950
slightly outlier picture
of the six pictures.

00:49:29.950 --> 00:49:31.320
So the woman went
for that guy.

00:49:31.320 --> 00:49:32.720
So when she's accusing
him in court, she's

00:49:32.720 --> 00:49:35.220
not trying to lie.

00:49:35.220 --> 00:49:37.920
what's she mixing up?

00:49:37.920 --> 00:49:41.030
Her memory for the photo array
versus for memory for the

00:49:41.030 --> 00:49:42.040
original event.

00:49:42.040 --> 00:49:43.720
Those two have gotten
blended in the

00:49:43.720 --> 00:49:44.635
punch bowl of her memory.

00:49:44.635 --> 00:49:45.520
Does that make sense?

00:49:45.520 --> 00:49:47.580
Perfectly with good intention.

00:49:50.160 --> 00:49:53.690
And there's 80,000 trials
you estimate the rely on

00:49:53.690 --> 00:49:54.710
eyewitness testimony.

00:49:54.710 --> 00:49:57.120
And many, many of those
are mistaken.

00:49:57.120 --> 00:49:59.190
It's just human nature to
mistake them, especially

00:49:59.190 --> 00:50:01.830
because trials are not boom
one minute later.

00:50:01.830 --> 00:50:05.600
There's lots of discussion,
lots of interviews with

00:50:05.600 --> 00:50:07.610
policeman, or prosecutors,
or lawyers.

00:50:07.610 --> 00:50:10.510
Lots of things happen from the
original crime moment until

00:50:10.510 --> 00:50:11.990
that moment in court.

00:50:11.990 --> 00:50:14.460
Every discussion, and thought,
and feeling you have from the

00:50:14.460 --> 00:50:18.240
original experience blends in
with the original experience.

00:50:18.240 --> 00:50:19.800
And it can be hard to
pull those apart.

00:50:22.660 --> 00:50:26.050
Here's another sort
of weird example.

00:50:26.050 --> 00:50:28.150
A woman at home in Australia,
she's brutally

00:50:28.150 --> 00:50:28.980
raped in her home.

00:50:28.980 --> 00:50:30.790
She identifies Donald Thompson--
now you'll see why

00:50:30.790 --> 00:50:32.960
this is a bit ironic
and a weird story--

00:50:32.960 --> 00:50:36.050
a renowned Australian
psychologist who studies

00:50:36.050 --> 00:50:39.630
eyewitness memory problems.

00:50:39.630 --> 00:50:42.970
It turns out he was on
television at the moment that

00:50:42.970 --> 00:50:43.840
she was being raped.

00:50:43.840 --> 00:50:45.340
And, obviously, she's in a very

00:50:45.340 --> 00:50:46.840
disturbed difficult moment.

00:50:46.840 --> 00:50:50.590
And so she conflates the face on
the TV with the face of the

00:50:50.590 --> 00:50:53.460
actual horrible perpetrator.

00:50:53.460 --> 00:50:54.530
So he has a good alibi.

00:50:54.530 --> 00:50:55.410
He's on TV somewhere.

00:50:55.410 --> 00:50:59.410
But in a perfectly good way,
she's trying to be correct.

00:50:59.410 --> 00:51:02.720
These things get jumbled
together.

00:51:02.720 --> 00:51:04.240
So you're going to see
it in one minute, a

00:51:04.240 --> 00:51:06.000
film of Susan Nason.

00:51:06.000 --> 00:51:08.990
This is an amazing story.

00:51:08.990 --> 00:51:09.320
Sorry.

00:51:09.320 --> 00:51:10.630
You'll see the film of
Eileen Franklin.

00:51:10.630 --> 00:51:12.090
But Susan Nason was an
eight-year-old girl.

00:51:12.090 --> 00:51:16.626
She was missing and found
murdered in October 31, 1969.

00:51:16.626 --> 00:51:20.820
20 years later, Eileen
Franklin-- you'll see later--

00:51:20.820 --> 00:51:23.940
remembers that her father
murdered Susan Nason.

00:51:23.940 --> 00:51:25.790
She testifies against him,
and he's found guilty.

00:51:25.790 --> 00:51:26.870
And he goes to jail.

00:51:26.870 --> 00:51:28.670
He's been subsequently
released.

00:51:28.670 --> 00:51:30.720
Because she says I was
with him when he

00:51:30.720 --> 00:51:33.370
murdered my little friend.

00:51:33.370 --> 00:51:35.950
But she doesn't remember
continuously.

00:51:35.950 --> 00:51:38.990
She remembers it because a
therapist has had her think

00:51:38.990 --> 00:51:40.140
about her past.

00:51:40.140 --> 00:51:42.560
And all of a sudden, what she
feels like was a repressed

00:51:42.560 --> 00:51:44.160
memory comes back.

00:51:44.160 --> 00:51:47.720
So we're going to show a
movie about this topic.

00:51:47.720 --> 00:51:50.090
It's your next paper topic.

00:51:50.090 --> 00:51:51.560
What's the status of memory?

00:51:51.560 --> 00:51:54.640
So let's separate two things,
because it's really important.

00:51:54.640 --> 00:52:00.930
Cases where women or men--
more often women--

00:52:00.930 --> 00:52:05.920
remember being abused, sexually
abused, remember it

00:52:05.920 --> 00:52:06.580
all the way through.

00:52:06.580 --> 00:52:07.970
That may not like to
think about it.

00:52:07.970 --> 00:52:09.970
But they remember it all
the way through.

00:52:09.970 --> 00:52:11.520
That's not what we're
talking about.

00:52:11.520 --> 00:52:15.030
What we're talking about are the
rare cases where a man or

00:52:15.030 --> 00:52:17.100
a woman says, I haven't
thought about this.

00:52:17.100 --> 00:52:19.510
I feel like I've repressed
this for 20,

00:52:19.510 --> 00:52:21.710
or 30, or 40 years.

00:52:21.710 --> 00:52:25.250
And now, more often than not
because of working with maybe

00:52:25.250 --> 00:52:27.550
a psychologist or clinical
psychologist to help me with

00:52:27.550 --> 00:52:32.540
problems I have, I recover
my repressed memory.

00:52:32.540 --> 00:52:33.780
And it's a brutal thing.

00:52:33.780 --> 00:52:36.980
Because you can imagine on the
one hand, you have a young

00:52:36.980 --> 00:52:40.410
woman accusing her father, or
uncle, or the father we'll

00:52:40.410 --> 00:52:44.020
say, of doing something that we
think is terrible, which is

00:52:44.020 --> 00:52:47.830
sexually abusing her, the
biggest failure of trust you

00:52:47.830 --> 00:52:51.710
can have in a father,
a huge violation.

00:52:51.710 --> 00:52:54.200
So he's horrible
if she's right.

00:52:54.200 --> 00:52:56.260
But if her memory's inaccurate,
what's more

00:52:56.260 --> 00:52:58.650
horrible than an innocent man
being accused by his own

00:52:58.650 --> 00:53:02.310
daughter of sexually
abusing her because

00:53:02.310 --> 00:53:04.080
her memory's incorrect.

00:53:04.080 --> 00:53:06.380
So what we'll show you
two films briefly.

00:53:18.390 --> 00:53:19.670
So the father went to jail.

00:53:22.350 --> 00:53:26.380
The lawyers who were defending
the father wanted to tell the

00:53:26.380 --> 00:53:29.250
jurors the following thing,
which in every account you

00:53:29.250 --> 00:53:30.500
read is accurate.

00:53:33.320 --> 00:53:36.430
That everything that she
described about the death of

00:53:36.430 --> 00:53:40.110
that girl, Susan Nason, every
detail she described was in

00:53:40.110 --> 00:53:42.830
the newspaper accounts
of the time.

00:53:42.830 --> 00:53:48.330
And that no detail that she
provided was verifiable and

00:53:48.330 --> 00:53:50.860
different than newspapers had
reported at the time.

00:53:54.080 --> 00:53:56.100
One of the things that people
like to do, investigators, is

00:53:56.100 --> 00:53:59.555
have the person know something
that wasn't publicly released.

00:53:59.555 --> 00:54:02.530
And everything that she spoke
about in regards to the little

00:54:02.530 --> 00:54:05.450
girl's murder, Susan Nason's
was publicly available

00:54:05.450 --> 00:54:08.400
information that had been on
television or in newspapers.

00:54:08.400 --> 00:54:10.820
And the judge originally
ruled that the jurors

00:54:10.820 --> 00:54:13.190
could not be told that.

00:54:13.190 --> 00:54:15.890
And then later on, they
retried the father.

00:54:15.890 --> 00:54:17.190
And the jurors were told that.

00:54:17.190 --> 00:54:20.770
And the Father was
let go from jail.

00:54:20.770 --> 00:54:22.450
So there was this huge
pendulum swing.

00:54:22.450 --> 00:54:24.520
Because, originally, as these
repressed memory cases were

00:54:24.520 --> 00:54:27.450
brought, people wondered, well,
why would the woman lie

00:54:27.450 --> 00:54:28.750
about such a horrible thing?

00:54:28.750 --> 00:54:29.880
It's so horrible.

00:54:29.880 --> 00:54:31.960
Of course she must be
telling the truth.

00:54:31.960 --> 00:54:36.040
And of course the father must
be lying to protect himself.

00:54:36.040 --> 00:54:38.570
But now, especially in the
context of repressed

00:54:38.570 --> 00:54:40.190
memories-- again, very different
than continuing

00:54:40.190 --> 00:54:43.140
memories, the ones that are
recovered after decades--

00:54:43.140 --> 00:54:45.665
there's a suspicion that some
of them might be inaccurate.

00:54:48.636 --> 00:54:52.250
And some psychologists working
with some patients might be

00:54:52.250 --> 00:54:54.810
having patients think about
possible sources of their

00:54:54.810 --> 00:54:55.850
difficulty.

00:54:55.850 --> 00:54:58.560
And these memories get
falsely constructed.

00:54:58.560 --> 00:55:00.670
And the hard part, and the part
that you'll write your

00:55:00.670 --> 00:55:02.650
paper about, is knowing
which is which.

00:55:02.650 --> 00:55:04.600
Because it's heartrending.

00:55:04.600 --> 00:55:06.260
It's heartrending to have
a woman who was

00:55:06.260 --> 00:55:09.600
abused be not believed.

00:55:09.600 --> 00:55:12.040
It's heartrending for a father
who was not an abuser to be

00:55:12.040 --> 00:55:14.190
accused of being an abuser.

00:55:14.190 --> 00:55:16.570
And it's incredibly hard to
have direct evidence about

00:55:16.570 --> 00:55:19.740
who's telling the truth and
who's not in these kinds of

00:55:19.740 --> 00:55:25.000
cases that are so far from when
the crime occurred or

00:55:25.000 --> 00:55:28.710
might have occurred, and where
there's such a long period of

00:55:28.710 --> 00:55:30.150
nondiscussion about it
because it's been

00:55:30.150 --> 00:55:31.140
repressed for decades.

00:55:31.140 --> 00:55:32.110
So you'll look at that.

00:55:32.110 --> 00:55:33.370
It's a big task.

00:55:33.370 --> 00:55:34.460
It takes you into courts.

00:55:34.460 --> 00:55:37.760
It takes you into clinical
complexities of people.