Memory (1)
Welcome to the section on Memory.
In this section we will discuss the aspects of Memory that Scientists have discovered.
We’ll talk about some of the problems with Memory, and some of the ways that we can improve our memory.
Discovering Psychology Series - "Remembering and Forgetting" is a 28 minute video.
The Crash course in Psychology video that is less than 12 minutes.
I find that older students enjoy the Discovering Psychology video and the younger students like the Crash course videos.
First of all, what is memory? Gosh - we have no idea!
Truly. We can measure certain aspect of it and we know how to improve it
and how to damage it. We even know some of the brain parts associated
with it. Although we can name it (an engram) and study it we still have
no idea how it works in the biological sense. We've traced the motor and
sensory cortexes to the specific areas they control but we can't isolate
memories that way. It is a huge area of research.
Any system, in human, animal, or machine, that encodes information, stores the
information, and has some process of retrieving that information is considered
a memory system. Unlike a computer, which has nearly perfect
memory, the memory for a human is more like an outline. It’s not a
perfect representation of the facts. When we want to remember something, we
pull up the outline and each time we do that, we fill in that outline
differently than the last time we pulled it up. We remember the event
with all the rest of the information in our brain (both new and old), and that
leads to errors. We fill in the outline with new information which
we didn’t have previously, but we place that new information in the same time
frame as the old memory. We believe the new information was part of the
memory. We do the same with older information. We think events that
happened to us earlier in life actually happened during the time frame of the
newer memory. We’ll see in this section that our memories are not very
good - certainly not perfect.
The three memory processes are sensory memory, working memory, and long-term
memory. All the information we know went from sensory memory into working
memory and was then stored in long term storage.
Sensory memory preserves very brief impressions from all our sense
organs. They remain in sensory memory for a quarter of a second. Up
to 16 items per sense is recorded, so you can have 16 brief sensory impressions
through your eyes, 16 through your ears, 16 through your fingertips (body),
your sensations of touch, through your nose, through your mouth, there’s 16
items per sense. All of them together are your sensory memories.
That’s a lot of information! It’s a heck of a lot of data every quarter
of a second! Since sensory memory only lasts for a quarter of a second we
need to analyze that data very rapidly and pull out the information that we
need - the information that is most important to us.
Two major types of Sensory memory are Iconic and Echoic memories. Iconic
is easy to remember because it sounds like eyes, and it is our brief memory
senses from our vision. When I say Echoic, of course everyone knows echoes
are what you hear, and Echoic is your brief sensory impressions from your
ears. So, Iconic is visual, and Echoic is hearing. There is a
special form of Iconic memory. Some people have what is called eidetic
memory. This is the ability to immediately preserve (place) visual
sensory images into long term memory (almost like bypassing working memory).
The impression goes directly from sensory memory right into long term memory
and it is very easily retrieved. Most of the time our sensory memory is gone in
a quarter of a second, and hopefully we’ve pulled it into working memory to use
it, or it’s gone forever. Many of us would love to have eidetic memory, we also
call it photographic memory, but those who have it report negative
issues with that memory. A lot of us wish we had photographic
memory, but if you talk to someone who actually does, they will tell you it’s
not all it’s cracked up to be. Imagine a cellophane sheet of paper.
You can see through it. Now use a magic marker and write on that cellophane.
Now take another and write on it. Then another and another. Now
hold up one page of cellophane and read it. Not any issue correct!
Now hold all the pages together and try to read them. Now they all jumble
together. That is how people with photographic memory report what
happens. This memory is sort of a visual representation of what
they’ve seen before and it interferes, overlays over top of everything else
that they’re trying to see or remember. It is very rare to find an adult
with photographic memory, but I had a boss who did. We worked in a
computer center and there was an entire wall of documents to tell us what to do
with these computers if anything ever broke. When something went wrong he
would tell me exactly what book to go to, where the book was on the shelf and
what page to turn to find the answer. He never did tell me what the
answer was, because he wanted me to look it up myself. That’s the way
that we learn. We don’t learn by somebody telling us the answers, we
learn by looking those answers up ourselves. So he was training me along
with impressing me very greatly by his ability to remember that kind of
information. Interestingly photographic memory and reading interfere with
each other. Many children have eidetic memory before they learn to read
and as they learn to read their eidetic memory declines. If we go to an
aboriginal tribe that does not read, we find a large number of adults with
photographic memory. When we teach them to read, their eidetic memory
starts to fade.
Now let's talk about working memory which preserves the important
recently perceived events from your sensory memory for about 20 seconds. When
sensory memories that we want to work with are put into working memory the
experiences last for approximately 20 seconds, unless we are rehearsing -
unless we are repeating that information over and again. The
working memory is also called short term memory or STM. Unfortunately it
has a total limit of 5 to 9 items at one time. Whereas sensory memory has
16 items per sense, the working memory can only hold a total of 5 to 9 items
(we call it 7 plus or minus 2). So, here is one of the big issues, a
problem of memory, the sensory memory is giving working memory access to at
least 80 items every quarter of a second, but we can only take 5 to 9 items of
that information at a time. That’s one of our roadblocks for
memory. The link between working memory and sensory memory is a bottle
neck.
The bottle neck - Working vs sensory memory:
Here is a short video as an example of sensory memory interacting with working
memory. Click the link and you will see a series of letters for about one
second. I want you to try and remember as many letters as you can viewing
it only one time for 1 second. Remember that sensory memory is fast and only lasts
about a quarter of a second, so 1 second should give your brain plenty of time
to view and review four times.
Click here to see an example of the bottle neck:
How many of those items can you recall? You move the sensory memory into
working memory and most of you can start to write them down on a piece of
paper. As you write one letter another one in your memory fades
away. You cannot get all of them. Why does working memory fade so
fast? The biological basis for this is that there's just too much
information coming at us through our senses. You might be able to remember that
the picture viewed was 3 by 3 square of letters. There were 9 pieces of
information in the video. Supposedly our visual system can pick up 9
pieces of information easily. We already learned that the sensory systems
can pick up 16 at a time which would be a 4 X 4 display. When push
comes to shove and we try to remember all 16 it is nearly impossible. It
is difficult for us to do because we only have 20 seconds, and then the working
memory starts to fade. We have to keep the data in working memory while
we try to access it and write the letters on paper. It will only store in
working memory for about 20 seconds. While we try to list the 9 items, we
run out of 20 seconds really fast. Think about it: If everything from our
senses was placed into working memory where it remained for 20 seconds, we
would have no room for all the sensory input, because we're getting 16 items
from sensory memory every quarter of a second and working memory only holds 9
items - at the most. Sensory input is always changing, so if all that
information ended up in working memory everything would just get jumbled up and
we'd be unable to function - We would have a nervous breakdown! (As an aside -
this may be part of the issues of people described as autistic). Sensory
information is gone within a quarter of a second, and we have to determine in
that quarter of a second what is important and move that information into
working memory as fast as we can. Then we have to use that information in
working memory as fast as we can because it's only there for about 20
seconds. Click on the link again and see how you do the second time
around. Hopefully you noticed that you cannot remember all that
information because we just can't hold a lot of information in our working
memory and because it goes away so fast. If that is the case, how
do researchers know that we can remember 16 items? When we do this
experiment we do not ask the subjects to write down everything they can
remember. Instead we immediately ask the subject to name the letters in
the right column, and they can! If we ask them to name the letters in the
middle row, they can! We could ask them to name any 4 letters in any
pattern in a 4 X 4 square and, they can, but after that - the memory of the
rest of the letters is already fading. This is how we know that the
sensory memory acquires all 16 letters in a 4 x 4 grid.
The structure of our short term (working) memory can actually be broken into smaller
units. We know this because people have damage to specific sections of
their working memory. From this damage we have learned that there are 3
specific aspects to our working memory. One is the central executive
which directs our attention to specific items coming in from short term memory,
so we can pay attention to those things that are important to us. There
is a phonological loop which attends our memory to specific
sounds. We also have a sketchpad of short term memory which stores
images. There are two specific aspects of working memory for specific
types of information: one, for the Echoic information coming in from hearing
centers and one for the Iconic coming in from the visual centers. That’s
why I told you earlier that Echoic and Iconic memories are so important to our
memory systems, because the working memory actually has specific parts that
attend to that information.
Here is a great 4 minute video explaining a little about the central executive
from the man who developed the idea - Alan Braddeley.
Working memory has a process known as Acoustic encoding through our phonological
loop which is the conversion of information to sound patterns in working
memory. It makes memorizing some information easy. We like words that
sound alike and we like songs. The singing group "The Beatles"
traveled to Japan for a concert. They though that they would not be able
to talk to their Japanese fans because they did not know how to speak
Japanese. However, most of the people in the audience were singing along
with them. When the concert was over they went out to meet their fans and
talk with them. They couldn't, because the audience did not know
English. They memorized the sounds through acoustic coding and reproduced
those sounds, but the meaning of the words was not as easy to use.
I lived in Japan for three years as a child and learned some children
songs. I can still sing them today, but I have no idea what they
mean. I have amused many a Japanese adult by singing the songs to
them. They say my pronunciation is perfect, but it is funny to hear an
adult sing a children's song and it is even funnier that I cannot tell them
what the sounds mean, or even what sounds make up a single Japanese word.
In American English (as opposed to British English) we have a saying
" I before E accept after C or in sounding like “AY” as in Neighbor or
Weigh". It rhymes and acoustic coding helps us remember the
poem. The saying is a heuristic not an algorithm because there are about
a page worth of words that do not fit the rule. We talk about heuristics and
algorithms in the Intelligence unit. Knowing this "poem"
we can correctly spell most words that have an "I" and an
"E" together. If everything we have to learn in school
was given to us in poetry or song, it would be much easier to learn!
Unfortunately, this also gets in our way, because when we are trying to
remember certain words “C”, “B”, and “D” can get mixed up. The letters
“E” and “F” are less likely to be mixed up even though they look alike.
This is because “E” and “F” sound different. Our phonological loop
actually interferes with our memory process for the letter “C”, “B”, and “D”,
because they sound alike. When we’re trying to remember something that
might start with a “C”, we have trouble and get stuck on “D”. We think
the word starts with a "D" when it actually starts with a
"C”. The two letters "C” and “D” don’t look alike, but they do
sound alike. When my wife gets stuck like this, she just throws the alphabet at
it. She starts with the letter "A" thinking of all the possible
"A" words that might fit. Then "B" and "C"
until the word pops into her brain.
Long term memory stores material, organized according to some personal
meaning (so it is stored based on a subjective principle). It is also
written as LTM. It appears to be unlimited in its capacity and its
storage time. I know some of you think, "if I learn one more thing,
I am going to forget my name", but there appears to be no limit to LTM.
However there appears to be a transient version and a permanent version
of long term memory. There is material that you can remember for a couple
of days, like maybe what you had for breakfast today. You remember it a
lot longer than 20 seconds, so it is part of the LTM system, but by tomorrow or
the next day you won’t be able to remember it anymore. It is a transient
long term memory. It is in your long term storage for a very short time
and then it disappears. Most of the memory that we have in long term
memory is permanent memory and it is stored forever, it doesn’t
disappear. Memories that you may not have even thought of for years are
still there. If somebody asks an old man about pets he had as a preschooler
it would be very difficult for him to remember anything about that time.
However, when we have brain surgery it can be conducted with only a local
anesthesia because the brain has no pain fibers in it. You may be given
the choice to stay awake during the surgery. If you so choose then you get
a local anesthesia on your scalp but you are awake. The bone and brain
have no pain fibers so they do not need anesthesia to kill any pain in those
areas. They can cut open the skull without pain and when the skull is
open they can touch the brain with a very small electrical charge on a specific
area of the brain. This is how they map the motor and sensory
cortexes. A small electric stimulation to the motor area associated with
the finger will cause your finger to move. A small stimulation to the sensory
area for the face and you think someone touched your face and - since you are
awake - you can tell the doctor what you feel. Well, a small electrical
stimulation to another part of the brain and you may remember things that you
did not think of for 50 or 60 years and yet - there they are. The old man
remembers the cat he had as a preschooler, what she looked like, her name and
other information. The memory’s still there! What was missing was
the trace to it, the pathway to that memory engram. When the electric
charge is applied it reactivates those traces or recreates the traces.
So, your memories are forever, your long term permanent memories are forever,
but the traces, the pathways, can disappear.
Long term memory has unlimited
capacity as I said before, it also has different subdivisions and how we know
this is because there are people who lose parts of their long term memory, and
still have others parts intact. We can perform experiments with these
people to determine the extent of their damage. First let me define procedural
memory. This is the division of long term memory that stores memories
for how things are done. It includes habits. For instance:
the way you speak, your accent, may be a habit and part of your procedural
memory. You don’t have to think about it anymore. When you speak
the words just come to you. If you learned to ride a Bicycle but have not
done so for a while, you can more easily pick it up and ride it today, because
it is a part of your procedural memory. The way you eat, chew and swallow
are part of procedures that you no longer think about. Procedural memory
is extremely strong memory and is hard to destroy. It is the last memory
to be destroyed in a person with Alzheimer disease.
Declarative memory is the division of long term memory that stores very
explicit information. It’s also called fact memory.
Declarative memory has two subdivisions, episodic memory and semantic
memory.
The semantic memory remembers the facts of your life. One fact for
me is that I am married. I know this as a fact of my life like I know my
name and my phone number. The semantic memory is a subdivision of the
declarative memory that stores general knowledge which also includes words, the
meaning of those words, and also the meanings of concepts.
Episodic memory is the part of the declarative memory that stores
memories for the “episodes” of your life. Just like an episode of
your favorite television show, you can relate the events as they occurred in
your life. It is like your own movie theater in your mind. The
memory of the actual events that you know occurred can be played out as an
episode of your life. I can remember my wedding. In my head I can
"see" my wife standing at the door of the chapel ready to walk down
the aisle with her father. I can remember her father bending over to
whisper something to her and she laughed and they started down the aisle.
I asked her later what her father whispered and she said "if you don't
want to do this, I'll take you anywhere else you want to be right
now". Of course she went through with it and we've been married for
over 20 years. The reason we know that there’s a difference between the
two is because a person may be able to remember that they’re married but have
absolutely no ability to bring up that episode of their life. It is the
Episode that gives us the flavor of our lives. Without the Episode - who
are we? The Magnificence of who we are does not simply boil down to
facts. Our episodes give us the flavor of our lives. Episodic
memory is the most fragile of the memory partitions. It is the first to
be destroyed by Alzheimer disease.
For those people who need the visual to remember something by, here it is. Long
term memory is broken into parts: Declarative memory and procedural memory,
procedural memory includes memory for motor skills, operant and classical
conditioning. The declarative memory is broken up into semantic and
episodic memory, where semantic includes memory for language, facts, and
general knowledge, and episodic includes memory for events or personal
experiences in your life
It's time for a break guys, and gals.
Go get a cup of coffee.
Go do something other than study (maybe play the hangman game).
There is one crossword puzzle for the entire unit, but the hangman games are made for each slide.
Take 15 minutes or so before you go to the next slide.
Distributed learning is the best learning.
We will continue the study of Memory in the next lecture.
Talk with you then.