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Memory Notes:
Memory is like a car…we all wish we had a better one!
Memory is the retention of information over time. Psychologists study how
information is initially placed, or encoded, into memory; how it is retained, or stored,
after being encoded; and how it is found, or retrieved, for a specific purpose later.
A silly joke…have you heard that we only use 10% of our brains? Do you know
what’s in the other 90% Song lyrics!
•Encoding involves transforming information into a form that can be stored in
memory…like writing info down on a file card.
•Storage involves keeping or maintaining information in memory…like filing the card
in a drawer.
•Retrieval occurs when information stored in memory is brought to mind…like
finding the card when you need it!
•Tip-of-the-tongue phenomenon (TOT) is a type of “effortful retrieval” (you have to
work hard to retrieve it) that occurs when people are confident they know something
but just can’t quite seem to pull it out from memory…like knowing the card is in the
drawer, but you can’t find it.
1. SENSORY MEMORY holds information from the world in its original sensory
form for only an instant, not much longer that the brief time for which one is
exposed to the visual, auditory, and other senses. This is different from the visual,
auditory and kinesthetic learning that you learned about in the last lesson. These
sensory memories take place in your sensory organs (eyes and ears), not in your
brain.
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Visual (iconic) sensory memory lasts only for a fraction of a second.
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Auditory (echoic) last about 2 seconds.
2. SHORT TERM MEMORY is also called the “working” memory.
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Has a capacity of 5 to 9 bits of information (also called “memory span”).
This may be one of the reasons that telephone numbers only have seven
digits…they are easy to remember long enough to dial a phone!
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Bits of information can be made larger by a process called chunking,
which is the grouping or “packing” of information into higher-order units
that can be remembered as single units.
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Short term memory last less than 30 seconds.
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Information can be kept in short term memory by rehearsal, and transferred
to long-term memory with more rehearsal. This why you may need to
repeat that phone number over and over again until you can find that
phone.
3. LONG TERM MEMORY holds huge amounts of information for along period of
time, relatively permanently.
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Information gets into long-term memory by rehearsal, repetition or
elaborative rehearsal
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Long-term memory has two subsystems, declarative memory and
nondeclarative memory.
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Declarative memory stores information that can be brought to mind
verbally or stored in the form of images.
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Episodic memory is a part of declarative memory that stores
the memory of the events of your life.
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Semantic memory stores general knowledge, or objective
facts and information.
Nondeclarative memory (or “procedural” memory) consists of
motor skills, habits, simple classically conditioned responses. You
don’t have to think about how to drive a car anymore, you just do
it!
How memory systems work…
1. Sensory input is detected by your sensory organs (eyes or ears, usually). You lose
this data very quickly (information loss), or…
2. The data is transferred to your short term memory. You lose this data within a
minute (decay or forgetting) unless you rehearse to keep it in your short-term
memory. Or…
3. You work to memorize it by transferring it to your long-term memory. You may
eventually forget it, or you may periodically retrieve it into your conscious shortterm memory system.
The levels-of-processing model of memory is described as an alternative to the threememory systems approach. It proposes that information processed according to
meaning (deep processing) is more likely to be retained than information processed
according to surface characteristics, such as spelling or sound (shallow processing). If
it’s important to you, you’ll remember it; if it’s not, you won’t.
The brain and memory…
•Hippocampus. Researchers believe that memory processing (not the memories
themselves) takes place in the hippocampus at the center of the brain. A study of
licensed taxi drivers in London revealed that their posterior (rear) hippocampus was
significantly larger than the same part of the hippocampus of control subjects who did
not have extensive navigation experience (Maguire et al., 2000). This study shows that
the posterior hippocampus is important for navigation ability. The study indicated that
the more experience the taxi drivers had, the more the hippocampal region had
expanded. The authors indicated that the study reveals a plastic capability in the
structure of the adult human brain that responds to environmental demands (Maguire
et al., 2000).
It is known that one important role of the hippocampus is to handle spatial memory
for navigation. In many small mammals, as well as birds, the hippocampal volume
increases seasonally when the need for navigational skills and for spatial maps of
where food is hidden are most critical for survival (Clayton, 1998; Colombo &
Broadbent, 2000).
•Cerebral cortex. Memories are stored in the neurons throughout the cerebral cortex,
in the “grey matter” (cells in the outer layer of the brain). Physiological changes must
occur during the process of consolidation (process in which a permanent memory is
formed) when new information is stored in memory, ready to be retrieved as needed.
These physiological changes require the synthesis of new proteins in order to convert
a new memory that endures over time (Lopez, 2000). Even when the proteins break
down, the memories survive! How then, are so many memories able to survive for so
long? Current research suggests that new gene products formed to consoidate a
memory at the brain's synapses. And, the new gene products cause changes at the
activated synapses enabling them to form a memory that will endure (Dudal, 2000). A
few hours time is required for the new pattern of gene expression and the resulting
changes at the synapses to encode a memory.
•Anterograde amnesia. The inability of a person with damage to the hippocampus to
put current memories into long-term memory. Caused by damage to the
hippocampus, patients cannot encode memories. If you haven’t seen the movie
“Memento”, you should!
•Retrograde amnesia involves memory loss for a segment of the past but not for new
events. As in those movies such as “The Bourne Identity” or “The Majestic” where
someone can’t remember his/her name or where they came from, but can process all
new information. Due to physical or emotional trauma.
The ability to forget information is crucial to keeping memory from being cluttered
with unneeded details. Your brain can’t remember everything it’s been exposed to – it
needs to make room for new data. Forgetting can be caused by encoding failure or the
failure to enter long-term memory in the first place; by the decay of the memory; by
interference of one memory with another and by consolidation failure, or by the
failure to form a permanent memory. Forgetting may also be motivated as a means of
protecting oneself from painful or unpleasant memories. Forgetting may also result
from errors in how the memory was framed or how it was recalled (retrieval failure).
1. Encoding failure. Information is not properly encoded by the hippocampus.
2. Decay theory and Alzheimer’s disease. We all know that some memories seem to
fade over time; this may be literally true as the gene products mentioned on the
previous slide break down, memories are lost (especially those that are never or
rarely retrieved). Patients with Alzheimer’s disease notice the loss of memory
first. In fact these patients are experiencing a breakdown of ALL types of neurons,
not just those that have memories. The breakdown of these neurons is the
eventual cause of death.
3. Interference. We forget not because memories are actually lost from storage; but
because other information gets in the way of retrieving what we want to
remember.
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Proactive Interference occurs when material that was learned earlier
disrupts the recall of material learned later.
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Retroactive Interference occurs when material learned later disrupts
retrieval of information learned earlier.
1. Consolidation failure. Information is not permanently consolidated on the
neurons.
2. Motivated forgetting, or intentional forgetting
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Repression. Forcing oneself to push aside painful memories. Repression
always comes from emotional trauma.
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Amnesia. See previous slide.
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Cue-dependent forgetting. A form of forgetting information because of
failure to use effective retrieval cues.
One of my favorites! This film from 2000 showcases a man who suffers from
anterograde amnesia. He is unable to move memories from the short term to long
term storage.
Short-term memory only lasts for 30 seconds. So how would you keep those
memories for a longer period of time if your brain wasn’t cooperating? His methods
are fairly effective.
The most difficult task in watching this film is the narrative. It takes place at the end
of the story and moves forward. In order to follow it, you have to keep your own
memory skills in good working order, don’t you?