Chapter 7
In this chapter, we discuss some of the
data collected by researchers trying to
solve the problems of memory structures
and processes.
The chapter is divided into two sections –
short-term memory and long-term
memory.
SHORT-TERM MEMORY
-
Neurocognition and STM
Capacity of STM
The Coding of Information in STM
Retrieval of Information from STM
LONG-TERM MEMORY
-
Neurocognition and LTM
LTM: Storage and Structure
Very Long-Term Memory (VLTM)
Autobiographical Memories
SHORT-TERM MEMORY
Peterson and Peterson (1959)
subjects were read a three-letter cluster
and asked to recall it after varying periods.
During these periods (between hearing the
letters andattempting to recall), subjects
counted backward by threes from a threedigit number presented immediately after
the three-letter cluster, as here:
Experimenter says: CHJ/506
Subject responds: 506, 503, 500, 497,
494, and so on
STM - Peterson & Peterson
Results: Recall seriously eroded in the
absence of rehearsal.
experiment demonstrated that our capacity
to store information in a temporary memory
bank is severely limited and susceptible to
forgetting if we do not havethe opportunity to
rehearse the information.
Their experiment represented a turning point
in our experimental conceptualization of
short-term retention (2 memory banks).
2 memory banks?
1. Casual observation suggests some
things are remembered for a short time
and others for a long time
2. Physiological studies indicate that
short term functions can be interrupted,
while long term functions seem to
remain intact
3. Psych. experiments suggest retrieval
of some info is characteristic of a shortterm function while other is
NEUROCOGNITION AND
STM
Brenda Milner (1966)
The case of H.M.
severe epilepsy, bilateral surgical excision (of
the medial temporal region) was done
procedure removed parts of the temporal lobe,
including the hippocampus.
H.M. became profoundly amnesic and could
not seem to store new information in LTM; his
STM was unimpaired.
STM Theory
Hebb’s Dual Trace Theory
If original activity continues for some time,
structural changes at the synaptic
contacts among cells could carry the
memory thereafter. These structural
changes would correspond to long-term
memory, and the earlier continued
identified with short term memory
STM Capacity
Magic Number 7 +/- 2
(Miller, 1950’s)
Chunking (coding single units into larger
units)
can greatly expand STM capacity
doesn’t work without activating LTM
(provides the framework)
FBI, PHD, TWA, IBM easier than FB, IPH,
DTW,...
CODING OF INFORMATION
IN STM
- Auditory Code
predominate method in STM, even if info
presented visually (research)
- Other research suggests visual or semantic
codes
LOOK UP!
Research on the Duration of STM
The Brown-Peterson Paradigm
Research on the capacity of STM
Research on the Acoustic Code in STM
Research on Verbal Rehearsal and STM
The Serial Positions Effect
Searching through STM: Serial search
S. Sternberg
LTM
General findings:
Relatively permanent storage
Unknown capacity
Organized as seen in Free Recall Tasks
LONG-TERM MEMORY
Some experiences are remembered better
than others, such as, exciting, egoinvolving are, or even traumatic
experiences seem to stick in memory
better than complicated political theories.
Neurocognition and LTM
Where do memories reside? (PET)
Frontal area involved in deep processing of
info
Hippocampus and thalamus involved in
formation of memories
Cerebral Cortex - permanently stores
memories
Conclusion - very generalized, all over
Neurocognition and LTM
How does brain store info?
Donald Hebb - STM info converted to LTM if
active for long enough period of time. LTM is
chemical and/or structural change
LONG-TERM MEMORY
SUGARCOATED GOLDEN MEMORIES:
For example: animal studies have indicated
that blood stream of epinephrine (adrenaline),
which has now been demonstrated to enhance
consolidation of a memory (McGaugh, 1990).
It is likely that epinephrine does not directly
stimulate the brain’s synapses (there is matter
of crossing the blood brain barrier), but
converts stored glycogen to glucose (a sugar),
thereby raising the blood level of glucose,
which nourishes the brain.
LTM: Storage and
Structure
CODES: In LTM, information is clearly
coded acoustically, visually, and
semantically.
Multidimensional coding
little research on taste, smell, and touch, but
probably also coded this way
LTM: Storage and
Structure
Organization:
assumed some order to LTM
network of interrelated and associated info,
very complex
new info is recorded in existing info
LTM: Storage and
Structure
Capacity and Duration
Huge, Almost Permanent
Loss of recall can be due to interference or
decay
Very Long Term Memory
VLTM - memories more than 3 months old
Research on yearbook pictures showed:
recognition about 90% correct over 34 years
Name recognition and name matching
declined after 15 yrs
sharp decline in recogniton and recall after
35 yrs. May reflect a degenerative process of
aging
Very Long Term Memory
Research on memory for Spanish
language
decline the most over first 3 yrs, then
relatively stable over 30 yrs.
Much of orignially learned info still usable
after 50 years - suggested a “permastore”
LTM: Storage and
Structure
Autobiographical Memory
Memories of your past history
Hard to study objectively - why?
Linton’s “Journal” study - found linear
forgetting, and 2 types - interference and
decay
Flashbulb memories - special mechanism?
Fallability of Memory
Eyewitness Testimony and False Memory
memory is reconstructive
“recovered Memories” can be false
memories
very susceptible to change