ch 7 slide deck Flashcards
the atkinson and shiffrin model of memory stoarge
-
Why do people
overestimate the duration
of a lightning strike?
The individual sees an afterimage
of the original sensory input.
Duration of this afterimage = 0.2
to 0.3 seconds
- Duration of physical
stimulus = 0.05s
sensory memory : function, capacity, duration
holds info long enough to be processed for basic physical characteristics
can hold many items at once (large capacity)
duration - very brief retention of images (0.3 sec for visual info, 2 secs for auditory info
short term memory
store info for 20-30 seconds - after the info (sounds images or words) are either committed to long term memory or lost all together
Capacity of Short-Term Memory
Short-term memory is also limited in the number of items it can hold.
* On average, people can hold 7 items (or 7 chunks of information) in
short-term memory.
* The range is 7 ± 2
George Miller published a paper in 1956 with this title:
The magical
number seven, plus or minus two: Some limits on our capacity for
processing information
other names for sensory memory
iconic memory
after image
another name for short term memory
working memory
slide 10 diagram
slide 11 diagram
free recall
Free recall: subjects are free to recall a list of items in any order
serial recall
Serial recall: subjects are to recall the list of items in their original
order of presentation
Major difference between the two recall patterns
In serial recall: subjects have good memory for the beginning of the
list, performance is poorer toward the end of the list.
In free recall, subjects have good memory for both the beginning and
the end of the list (this is called the serial position effect).
primacy effect
people have a good memory for items at the beginning of a list (reflects long-term memory)
recency effect
people alos have a good memory for items at the end of a list (reflects working memory)
Long-Term Memory
Long-term memory is an unlimited capacity store that can hold information
over lengthy periods of time (i.e., it has infinite capacity and duration)
One viewpoint assumes that information is never lost from LTM. If you
cannot remember something, that thing is
lost in memory, not lost from it
Failing to find something does not mean that the thing has vanished (or
does not exist)
- This is the retrieval failure viewpoint
Another viewpoint assumes that information in LTM may decay, and hence,
is
lost from it over time. This is the decay viewpoint.
A recall test requires participants to reproduce information on their
own without
any cues
E.g., subjects learn 25 nonsense syllables. A recall test (also called free recall
test) asks the subjects to recall as many of the syllables as they can
remember
A recognition test requires participants
o select previously learned
information from an array of options.
* E.g., subjects learn 25 nonsense syllables and then see a list of 100 nonsense
syllables. The test asks the subjects to identify the syllables that they have
learned earlier (also called old/new recognition test).
What evidence suggests that information is
never lost from memory?
- Relearning of the forgotten information is faster than first-time
learning. This is not possible if the information has been lost from
memory
A relearning test asks subjects to memorize information a second
time to determine
how much time or effort is saved by having learned
it before
- Retention is measured as a saving score:
E.g., It takes you 20 minutes to learn a list of words the first time. It takes you
only 5 minutes to relearn it a week later. Saving = 15 minutes
* Saving score = 15/20 = 75% (you have retained 75% of the information)
what type of encoding goes with shallow processing
structural encoding
- emphasizes the physical structure of the stimulus
intermediate processing goes with which encoding level
phonemic encoding emphasizes what a word sounds like
what type of encoding goes with deep processing
semantic encoding
- emphasizes the meaning of verbal input
is the word wrritten in capital letters addresses which type of encoding
structual
Levels-of-processing (also called depth of processing) theory proposes
that deeper levels of processing result in
longer-lasting memory
codes
chunking study
A study by Chase & Simon (1973)
Participants: Three chess players at different chess playing levels
(master, intermediate, and beginner).
All players were given 5 seconds to study the positions of chess
pieces taken from 1) actual games; 2) random arrangements.
The players then reproduced the chess positions from memory.
results of chunk study- from game positions
When the to-be-remembered chess
positions were from actual games:
* The chess Master placed 16 (out of 24)
pieces correctly on his first trial.
* The beginner player placed only 4 correctly.
* The master only needed 4 trials to
accomplish 100% accurate criterion.
* The beginner still made errors on his 7th
trial.
results of chunk study when randomly arranged
Chess master performed as poorly as the beginner.
* They both recalled only 3 positions correctly.
Conclusions:
* Chess master’s advantage was due to his ability to
group the chess pieces into meaningful chunks.
* Chess master had stored in LTM many meaningful
patterns from real games.
* He saw the 24 pieces as 4 to 6 chunks.
good
memory involves some
sorts of organization
Organization = chunking
Things that are randomly put together are
hard to remember
Memory consolidation:
The neural process by which encoded information is stored in
memory
Brain plasticity revisited:
Memory consolidation is a process in which synaptic
connection is strengthened.
When a new memory is formed, the brain is changed. How?
the postsynaptic neurons are more easily activated by presynaptic neurons.
Traditional views of memory:
Encoded information remains unchanged
in storage.
Reconsolidation
Memories can change each time they are retrieved. Each memory is of the
previous retrieval, not the original experience.
Bartlett’s “War of the Ghosts” Experiment - constructive nature of memory
The subject was given a story, or an argumentative prose passage, or
a simple drawing to read/study.
* The subject attempted a first reproduction usually after an interval of
15 minutes.
* Thereafter, the subject gave further reproductions at intervals of
increasing length.
* The most well-known story that Bartlett had used is called “War of
the Ghosts.”
* The reproduced story is considerably shortened, mainly by omissions.
* Terminology becomes more modern, more “journalistic.”
* Subsequent reproductions become more and more coherent.
* Specific terminology was replaced by more general expression (e.g.,
canoe becomes boat; hunting seals becomes fishing).
* Proper names (e.g., Egulac and Kalama) disappeared.
* Direct speech was dropped.
* Smaller details were forgotten, e.g., the weather; other canoes; heard
the noise of paddles; face became contorted.
* The excuse of having family ties is better remembered than the
excuse of having no arrows.
* Less salient expressions were transformed to similar representations:
- river became lake, beach, island, etc.
- the log became a rock, a tree or a bush.
- “something black came out of his mouth” became “a clot of blood
came from his mouth,” or he foamed at the mouth
what happened when participants were asked to repeat the repeated story
- In repeated reproductions, subjects tended to use the same
expression to paraphrase the same part of the original description. - Although some information from the original story was omitted in
reproductions, some new information was added, and these extra
parts do not only remain but become more elaborated in subsequent
reproductions. - Readers keep good memory of what they actively create, not what
they read in the original story. - There is closer resemblance between two short-distant reproductions
than between the first reproduction and the original story. - But what has been forgotten continued to be forgotten.
- Readers demonstrate a strong tendency to rationalize mystical
occurrences. - The same direction of rationalization is pursued in subsequent recalls.
- Each retelling is a re-encoding. In terms of neural activity, each
retelling is a reconsolidation
in the Reconstructive Memory: Bartlett’s “War of
the Ghosts” Experiment - some readers can even produce verbatim recall of their own
sentences this is known as
hypermnesia.
Testing does more than assessing the outcomes of learning it
improves learning
Which strategy produces the best learning outcome?
* Highlighting
* Rereading
* Self-testing
self testing
Each retrieval is a reconsolidation. During the reconsolidation
process, misconception is corrected/modified; correct concepts are
strengthened
slide 37 diagram
semantic memory
object knowledge learned over many interactions
declarative memory
facts and events
procedural memory
skills and tasks
episodic memory
events and experiences
semantic network
an item’s characteristics and associates are linked to it
- the closer the noses the stronger the association will be
- activating one node increases the likelihood that closely associated nodes will aslo be activated
surprise test (what is in the office)
If you have desks (or tables) and chairs, these are “hits.”
* If you have books or filling cabinets, these are “false alarms.”
* If you don’t have bottle, basket, or umbrella, these are “misses.”
* The actual experiment (Brewer & Treyens, 1981)
* 30 subjects were tested
* Most subjects recalled desks and chairs.
* Few subjects recalled the wine bottle or the picnic basket.
* Nine subjects falsely recalled that the office had book
A schema is
an organized cluster of knowledge about a particular
object or event abstracted from previous experience with the object
or event
A typical office usually has desks, chairs, books, pens, paper,
and computers (today’s standard). This is the ____ which explains
office schema
- People are more likely to remember things that are consistent with
their schemas than things that are not.
- This explains why most people remembered the desks and chairs,
some falsely remembered seeing books, and few remembered the
wine bottle and the picnic basket (because these items are not
consistent with the office schema).
retrograde amnesia
poor memory for events that occurred before brain injury
The loss displays a gradient across time—memories that are more
distant in time from the brain damage are less impaired by the
amnesia.
anterograde amnesia
poor memory for events occuring after brain injury
Anterograde amnesia often seems more extensive because it disrupts
learning from the time of the brain damage.
* A read-only memory
Patient K. C.
* Suffered from a serious brain injury in the frontal regions in a
motorcycle accident.
* Shows a complete loss of episodic memory—keeps no
autobiographical knowledge.
* Cannot remember any personally experienced events from both
before or after his accident—has profound retrograde and
anterograde amnesia
K. C.’s semantic memory is intact.
* He cannot remember episodic events but can remember facts about
some events (e.g., he could not remember that he had a brother but
said that his brother’s funeral was sad because he knew that funerals
are sad events).
* His episodic memory is damaged, but his semantic memory is not
affected by the damaged parts of the brain.
Patient H. M.
* Suffered from severe epileptic seizures.
* Had a part of his temporal lobes and his hippocampus in both the left
and right hemispheres removed surgically.
* Outcome: pervasive anterograde amnesia.
* Unable to learn or recall anything new.
* But memory of events before the surgery remains intact (no evidence
for retrograde amnesia).
* He could talk about his childhood and family.
* He could explain the rules of baseball.
* His I.Q. was not affected by the surgery.
* His language comprehension is normal, his vocabulary is above normal.
* However, any task that requires him to retain information across a delay
shows severe impairment, especially the delay is filled with an interfering
task.
* These impairments apply equally to nonverbal and verbal materials.
* Surgery had interfered with the process of storing new memory but had
not touched previously stored memories.
* What will happen when someone can only read, but not write anything on
LTM?
The researchers who worked with him for 40 years had to introduce
themselves every time they met.
* He could hold a normal conversation but forgot the conversation in a
minute or less.
* He kept talking about the same subject/event without knowing that
he had already talked about it.
* H. M. became the research subject in hundreds of tasks, and he didn’t
get bored!
* In his words, “every day is alone in itself.”
H. M. Learned a mirror-drawing
task: he had to trace between
the lines of a double-star
pattern while looking at the
pattern and pencil only in a
mirror.
H. M.’s performance on the mirror-drawing task showed a completely
normal learning curve, with very few errors on the third day of
practice.
* On day 2 and 3, he did not remember ever having done the mirror-
drawing task before.
* H. M.’s motor memory is normal even though he had no conscious (or
episodic) memory of having learned the drawing task that involved
motor learning.
* It suggests that motor learning is a type of implicit memory that by-
passes consciousness.
slide 58 and slide 59
Perceptual priming (also
called repetition priming)
Exposure to a stimulus
will facilitate a future
response (more quickly
or more accurately) to
the same stimulus
- Definition: A previous encounter with information facilitates later
performance on the same information (or the fragments of the
original information), even unconsciously.
example: elephant experiment, the word stem completion task
Conceptual priming (also
called semantic priming)
Exposure to a stimulus
will facilitate a future
response to a new
stimulus closely related
to it.
- Definition: A previous encounter with information facilitates later
performance on semantically related information, even unconsciously
- example: You see the picture of a rabbit or hear the word “rabbit” first. Later you
hear the sound “hair/hare.” When asked to write down the word that you
heard, you are more likely to write down “hare” because “rabbit” and
“hare” are semantically related words
- You fully understand what “negative reinforcement” means. But you
choose the word “decreases” to fill in the blank of this statement: Negative
reinforcement ____ the rate of responding.
- Warrington & Weiskrantz (1970) asked amnesic patients to read a list
of words and then tested their
free recall and recognition of the
words
Warrington & Weiskrantz (1970)
The patients did worse than healthy individuals.
* However, amnesic patients’ performance on the word fragment
completion task was the same as healthy individuals (both groups of
participants were equally likely to think of a previously read word
when presented with its fragments).
* Amnesic patients did not have explicit memory of the learned words
but had implicit memory of them.
How do you know I know something that I don’t know I know? Answer from cognitive psychologists:
our behavior
* You are faster to respond to a relevant cue or
* You are better than chance to make a correct guess when presented with a
relevant cue
People forget information because
of competition from other
materials. Competition gets stronger when the to-be-remembered target bears
a close resemblance to the interfering item.
Empirical studies demonstrating the theory of interference:
Manipulate amount of interference by varying the degree of similarity
between the target and the interfering material.
* Prediction: Decreasing the similarity should reduce interference and cause
less forgetting.
Proactive Interference
Proactive Interference
* Proactive interference occurs when previously learned information
interferes with the retention of new information
Retroactive Interference
Retroactive interference occurs when new information impairs the
retention of previously learned information.
A case of recovered memory
* DJ reported that following a dinner with a neighbor whom she had not seen
in many years, she suddenly recalled that this individual molested her
numerous times between the ages of 5 and 7
This case is very similar to a recognition test—when you see the target again,
you recall that you saw it earlier.
Context-dependent memory
* Also called
encoding specificity
Divers learned a list of words under water or on land and later
recalled the words either under water or on land. The encoding and
retrieval environments either matched or mismatched
The results (on next slide) show very typical encoding specificity
effect: Performances in the two congruent conditions were better
than performances in the two incongruent conditions.
Misinformation effect
occurs when people’s
recall of an event is
altered by misleading
post-event information
A Study by Loftus & Palmer (1974)
Loftus & Palmer showed participants a videotape of an automobile
accident.
* After viewing the video:
* 50 subjects were asked: “About how fast were the cars going when they hit
each other?”
* 50 subjects were asked: “About how fast were the cars going when they
smashed into each other?”
* 50 subjects were not asked anything about the speed of the cars
* One week later…
* Participants were given a memory test. One question asked: “Did you see
any broken glass?
- Subjects who had earlier been asked
about the cars smashing into each other
estimated a higher speed of the cars and
were more likely to “recall” broken glass.
- All memories are
reconstructions of the past.
Biased or incomplete encoding leads to
biased recall
Misleading cues in the retrieval process may also lead to
biased recall
