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Matakuliah : L0014 / Psikologi Umum
Tahun
: 2007
MEMORY
Pertemuan 9
MEMORY
THREE STAGES OF MEMORY
FORGETING AND WHY IT OCCURS
BIOLOGICAL BASIS OF MEMORY
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DEFINITION
• memory is an organism's ability to store, retain, and subsequently
retrieve information
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PROCESS
• Encoding or registration (processing and combining of received
information)
• Storage (creation of a permanent record of the encoded
information)
– Stages theory of memory : a model of memory based on the idea that we
store information in three separate but linked memory
• Sensory Register
• Short Term Memory
• Long Term Memory
• Retrieval or recall (calling back the stored information in response
to some cue for use in a process or activity)
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Stage model of memory
Sensory input
Sensory register
Short Term Memory
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Long Term Memory
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STAGES THEORY OF MEMORY
Sensory Register (1)
• The first stages of memory, in which an exact image of each sensory
experience is held briefly until it can be processed
• The ability to look at an item, and remember what it looked like with
just a second of observation, or memorization
• Characteristics :
– corresponds approximately to the initial 200 - 500 milliseconds after an item
is perceived
– A complete replica of the sensory experiences :
• For visual information : lasting about 1/4 of a second
• For auditory information : a vivid image of what we hear is retain about 1/4 of a
second, but a weaker echo is retained for up to 4 seconds
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STAGES THEORY OF MEMORY
Sensory Register (2)
• Research by George Sperling (1960) "partial report paradigm”
• Subjects were presented with a grid of 12 letters, arranged into three rows of 4.
After a brief presentation (1/20 seconds), subjects were then played either a high,
medium or low tone, cuing them which of the rows to report.
• Sperling was able to show that the capacity of sensory memory was
approximately 12 items, but that it degraded very quickly (within a few hundred
milliseconds). Because this form of memory degrades so quickly, participants
would see the display, but be unable to report all of the items (12 in the "whole
report" procedure) before they decayed.
• This type of memory cannot be prolonged via rehearsal.
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STAGES OF MEMORY
Short Term Memory – STM (1)
• The 2nd stage of memory, in which five to nine bits of information can be stored
for brief periods of time
• Short-term memory allows one to recall something from several seconds to as
long as a minute without rehearsal, Its capacity is also very limited
• George A. Miller, when working at Bell Laboratories, conducted experiments
showing that the store of short term memory was 7  2 items (the title of his
famous paper, "The magic number 72").
• Modern estimates of the capacity of short-term memory are lower, typically on
the order of 4-5 items
Two important examples of STM control processes :
• Rehearsal
• Chunking
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STAGES OF MEMORY
STM – REHEARSAL (2)
• Rehearsal is mental repetition of information to retain it longer in
STM
• Research by Lloyd and Margaret Peterson (1959)
single combination of three consonants
counting backwards (intervals 0 – 18 seconds)
LRP  10 9 8 7 6 5 4 3 2 1  recall LRP
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STAGES OF MEMORY
STM – CHUNKING (3)
• The memory capacity can be increased through a process called chunking. For
example, if presented with the string:
FBIPHDTWAIBM
People are able to remember only a few items.
• However, if the same information is presented in the following way:
FBI PHD TWA IBM
• people can remember a great deal more letters. This is because they are able to
chunk the information into meaningful groups of letters.
• Beyond finding meaning in the acronyms above, Herbert Simon showed that the
ideal size for chunking letters and numbers, meaningful or not, was three.
• This may be reflected in the tendency to remember phone numbers as several
chunks of three numbers with the final four-number groups generally broken
down into two groups of two.
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LONG TERM MEMORY - LTM (1)
•
•
•
The 3rd stage of memory, involving the storage of information that
is kept for long periods of time
can store much larger quantities of information for potentially
unlimited duration (sometimes a whole life span).
LTM vs. STM
1. The way which information is recalled – using cues
2. The form in which information is stored in memory – meaning or semantic
codes
3. The reasons that forgetting occurs
4. The physical location of these functions in the brain
–
–
STM : frontal lobes, cerebral cortex
LTM : integrated in Hippocampus, then transferred to the areas of the cerebral
cortex involved in language and perception for permanent storage
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LONG TERM MEMORY – LTM (2)
TYPES
Declarative Memory
Procedural Memory
Semantic Memory
Episodic Memory
• Declarative Memory requires
conscious recall, in that some
conscious process must call back the
information. It is sometimes called
explicit memory, since it consists of
information that is explicitly stored
and retrieved.
• Procedural Memory is not based on the conscious recall of information, but on
implicit learning. Procedural memory is primarily employed in learning motor skills
and should be considered a subset of implicit memory. It is revealed when we do
better in a given task due only to repetition - no new explicit memories have been
formed, but we are unconsciously accessing aspects of those previous experiences.
Procedural memory involved in motor learning depends on the cerebellum and basal
ganglia.
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LONG TERM MEMORY – LTM (3)
TYPES : DECLARATIVE MEMORY
• Declarative memory can be further sub-divided into
– semantic memory, which concerns facts taken independent of context
– episodic memory, which concerns information specific to a particular context,
such as a time and place.
• Semantic memory allows the encoding of abstract knowledge about
the world, such as "Paris is the capital of France".
• Episodic memory, is used for more personal memories, such as the
sensations, emotions, and personal associations of a particular
place or time. Ex. Autobiographical memory
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LONG TERM MEMORY – LTM (4)
ORGANIZATION
• Make a story
• Associative network : memories are associated, linked together,
through experience
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RETRIEVAL
• Recall
– A measure of memory based on the ability to retrieve information from long –
term memory with few cues
– Serial position effect : the finding that immediate recall of items listed in a
fixed order is often better for items at the beginning and end of the list that
those in the middle
– The tip of the tongue phenomenon
• Recognition
– A measure of memory based on the ability to select correct information from
among the options provided
• Relearning/savings
– A measure of memory based on the length of time it takes to relearn
forgotten material
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RETRIEVAL (2)
• Serial learning
– Serial position effect : The finding that immediate recall of items listed in a fix
order is often better for items at the beginning and end of the list than for
those in the middle
– The first item – rehearsed enough time to transfer to LTM
– The last/end item – still in STM
• The Tip of the Tongue phenomenon
– Trying to recall a fact that we can almost remember – by cues
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An alternative to stage model
• Elaboration
– The process of creating associations between a new memory and existing
memories
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FORGETTING (1)
• Decay Theory
– The theory that forgetting occurs as the memory trace fades over time
– Happen in Sensory Register and STM
• Interference Theory
– The theory that forgetting occurs because similar memories interfere with
the storage or retrieval of information
• Proactive interference : interference created by memories from prior learning
• Retroactive interference : interference created by memories from later learning
– Happen in LTM – semantic memory and STM
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FORGETTING (2)
• Reconstruction (schema) Theory
– The theory that information stored in the LTM sometimes changes over time
to become more consistent with our beliefs, knowledge and expectation
(schema)
– False memory : remembering an event that did not occur or that occurred in a
way that was substantially different from the memory of the event
• Theory of Motivated forgetting
– Forgetting that is believed to be based on the upsetting or threatening nature
of the information that is forgotten
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MEMORY DISORDERS
•
Amnesia : Loss of memory
–
Retrograde amnesia :
• a memory disorder characterized by an inability to retrieve old LTM, generally for a specific period of
time extending back from the beginning of the disorder
• Caused by seizures, brain damage of various sorts, a blow to the head, highly stressful events
–
Anterograde amnesia
• Disorder in memory characterized by an inability to store and/or retrieve new information in LTM
• Not affect the LTM – procedural memory
•
Korsakoff’s syndrome
–
•
A disorder involving both anterograde and retrograde amnesia caused by excessive use of
alcohol
Others :
–
–
Alzheimer's disease can also affect memory and cognition.
Impaired memory can be a symptom of hypothyroidism
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