Hi, I'm Michael Corayer and this is Psych Exam Review.
In this video I want to explain
the first box of our box model of memory.
So this is the sensory memory store. It's
also known as the sensory register. Now
the sensory memory store is a highly
detailed representation of the sensory
information that's coming in from all of
our senses and it's a very limited
duration, it only lasts for about a
second or so. Now as I said, this refers
to information from all of our senses so
we can be more specific with sensory
memory we can talk about specific types
of sensory memory so for instance you
could refer only to your visual sensory
memory and that's known as iconic memory.
That's visual. Or you could refer
specifically to your auditory sensory
memory and that's known as echoic memory.
But for the most part we're going to be
referring to all of the senses at once
when we talk about sensory memory.
So why is sensory memory so limited,
why is it so short? Less than a second,
it's like it barely exists. So why is
that? Well it's sort of because of
necessity. If you think about it, you have
all this information coming in from your
senses and it's immediately being
followed by more information coming in
from your senses right. It's like this
onslaught of information and so you
can't hold onto all of it for very long.
You can imagine if you held onto
all that sensory information, I mean you'd
quickly be overwhelmed with the amount
of information that's coming in. So
it would be like setting a delay on
a guitar. If you've ever used a
delay pedal. So you play a note and
it rings out for a long time after you've
played it. If you set that delay really
long and you keep playing notes
I mean you end up with this
mishmash of sounds that doesn't sound
particularly good and that would be sort
of an analogy for what would happen if
you held onto your sensory memory for an
extended period of time. You need to
get rid of it because you've got more
information coming in and that might be
more relevant to you.
So this brings us to a myth that you may
have heard I want to dispel this myth. This is the idea that you have a
detailed memory of all of
your experiences, that somehow your mind
is able to keep a record of everything
that's ever happened to you and that if
you could just find the right technique
or use hypnosis or something that you
could somehow have access to all of this
information. That's simply not true.
The information isn't there, it's not
locked away in your mind somewhere. It's
simply gone. It was in your sensory
memory for about a second and then was
essentially discarded. Now this makes
sense because most of the information
that's coming in is irrelevant.
It doesn't matter to you, you don't need to recall it. There's no reason for your
mind to keep track of all of this
minutia and detail of everything
you've ever seen or everything you've
ever heard. You can imagine the
amount of information that that would be
it would be, I mean, it's unfathomable.
And why would you want to hold
onto all of that, particularly if it's
irrelevant? So it doesn't really make
sense that we would hold on to that
information. This hasn't
been
demonstrated. It's not the case that
you can recall things. You might feel
like you can recall them and when we
talk about hypnosis in the future maybe
we'll come back to this idea. You might
think you remember some experience from
your fourth birthday party, under
hypnosis you remembered what color shirt
your mom was wearing or something but if
we compare that to any actual evidence
like we find a photograph from that
party we see that a lot of times people
think they remember it, it turns out they're
wrong.
So they're confident but they're not
accurate. Anyway, that's a myth,
hopefully you can forget about that idea. So let's go onto how do we prove
that sensory memory exists? I mean it's
so short-lived
how do we even know that it's
happening? Well you have personal
experience of something like this like.
For instance, you see a flash of
lightning during a thunderstorm and you
feel like, I mean it's only there for
less than a second, but you kind of have
for a brief moment, this detailed picture
of exactly what it looked like.
But within about a second, it's gone.
If you try to draw it, by the
time you went to write it down
you wouldn't remember it in that level
of detail. So you have this feeling that
it exists and it's the same thing with a
sound that you hear. You can sort of
replay it exactly in your mind as soon
as you hear it but a few seconds later
it's gone, you don't remember exactly what it
sounded like.
So how do we demonstrate that it even
exists beyond just sort of this feeling?
Well this brings us to some research by
a guy named George Sperling. Sperling
designed a clever test to show that this
sensory memory did in fact exist and the
way that he did this was he used a device
called a tachistoscope and what this was
was that this was in 1960
before modern computer development that
would probably be how you do this type
of test now, but you looked through a little
viewfinder and they flashed letters on the
screen very very briefly, about a
twentieth of a second. Sperling would
flash an array of letters, so 12 letters
arranged into three rows, four
letters in each row. They would be
there very briefly, less than a second
and then he would ask people to tell
him what was on the top row or the
middle row or the bottom row. He found
that people were able to do this. They werre
able to recall one of the rows if he
asked immediately and the way that
he asked was by ringing a tone.
A high tone, a middle tone or a low tone and
ringing the tone a quarter of a second
after they saw the letters. So very briefly
you see the letters and almost at the
same time you hear this tone and you can
sort of read the letters off of your
mind. It's like they're there in your
sensory memory. But what Sperling found was
if he waited just one second to ring
that tone and ask for which row, within a
second
the letters were gone. People started
making lots more mistakes.
He also found people could recall, when
he asked within a quarter of a second,
people could recall any of the rows but
they couldn't recall all of the rows
because by the time they thought about
one of the rows, the others essentially
disappeared. So I can give you an idea of
what this sort of felt like for the
participants. Now I don't have the timing
set up to play a tone and we won't go
through this whole procedure but I'm
just going to flash some letters on the
screen and I'll immediately, as I flash
them, I'll say either top, middle, or
bottom and see if you can recall what
was on that row. So I'll try to do this, timing
might not be perfect.
We'll see. So...top.
Ok. Bottom. Even then, I probably delayed that was
probably longer than a quarter of a
second there. Top. You can see, if
you were, you might have had this
experience that you're sort of reading
it off of your mind, off of your sensory
memory. Where you had this store of it but
if you didn't read it right away, it was
gone. This brings us to the idea of
selective attention and that we can only
attend to some of the things in our
environment; some of the things that we
see, some of the things that we hear, some of the things that we feel. We can only
attend to so much at once right?
Our attention is by nature selective. We
can't attend to everything. So this
means that in the next box that we look
at, which is our short-term memory, we can
only move some of the things from
sensory memory to our short-term memory.
There's no way to move all of them, there's
simply too much information. It's
essentially infinite, the number of
things that you could pay attention to
and so what you choose to pay,
what you choose to focus your
attention on, what you deem as relevant
is the only things that you can
essentially move to your short-term
memory. So that's the next box that
we'll look at in the next video. I hope
you found this helpful, if so, please like
the video and subscribe to the channel
for more.
Thanks for watching