Chapter 5 - Short term and working memory Flashcards
MEMORY
the process involved in retaining, retrieving, and using information about stimuli, images, events, ideas, and skills after the original information is no longer present
is active any time some past experience has an effect on the way you think or behave now or in the future
Sensory memory
First stage of memory (structural feature)
Takes in all sensory input
Short lasting - held for very brief amount of time
Short-term or working memory
Information that stays in our memory for brief periods, about 10 to 15 seconds if we don’t repeat it over and over
although people often mistakenly use the term “short-term memory” to refer to memory for events that happened minutes, hours, or even days ago, it is actually much briefer
Long-term memory
responsible for storing information for long periods of time—which can extend from minutes to a lifetime
MODAL MODEL OF MEMORY - who and what?
Richard Atkinson and Richard Shiffrin
flow diagram for memory which contains structural features and control process
input>sensory>short-term><long-term
output from short term
rehearsal in short term
What are the 3 structural features in the modal model of memory?
Sensory memory is an initial stage that holds all incoming information for seconds or fractions of a second
Short-term memory (STM) holds five to seven items for about 15 to 20 seconds.
Long-term memory (LTM) can hold a large amount of information for years or even decades
What is a control process?
Active (dynamic) processes that can be controlled by the person and that may differ from one task to another
What is the control process included in the modal model of memory?
rehearsal
Sensory memory
the retention, for brief periods of time, of the effects of sensory stimulation
persistence of vision
This retention of the perception of light in your mind - The lighted trail is a creation of your mind, which retains a perception of the sparkler’s light for a fraction of a second
how many projector frames are flashed per second in a regular film?
24 - sensory memory holds images between flashes
George Sperling
famous experiment in which he flashed an array of letters on the screen for 50 milliseconds (50/1000 second) and asked his participants to report as many of the letters as possible
-whole report method
-partial report method
-delayed partial report method
whole report method results in Sperling’s experiment
they were able to report an average of 4.5 out of the 12 letters (33%)
fading
some of the participants in Sperling’s experiment reported that they had seen all the letters, but that their perception had faded rapidly as they were reporting the letters, so by the time they had reported 4 or 5 letters, they could no longer see or remember the other letters
partial report method
Participants saw the 12-letter display for 50 ms, as before, but immediately after it was flashed, they heard a tone that told them which row of the matrix to report. A high-pitched tone indicated the top row; a medium-pitch indicated the middle row; and a low-pitch indicated the bottom row
partial report method results in Sperling’s experiment
they correctly reported an average of about 3.3 of the 4 letters (82 percent) in that row
delayed partial report method - purpose?
Sperling then did an additional experiment to determine the time course of this fading
delayed partial report method - results
when the cue tones were delayed for 1 second after the flash, participants were able to report only slightly more than 1 letter in a row
Conclusions of Sperling’s experiments (2)
a short-lived sensory memory registers all or most of the information that hits our visual receptors, but that this information decays within less than a second
This brief sensory memory for visual stimuli, called iconic memory or the visual icon (icon means “image”), corresponds to the sensory memory stage of Atkinson and Shiffrin’s modal model
echoic memory
Other research using auditory stimuli has shown that sounds also persist in the mind. This persistence of sound lasts for a few seconds after presentation of the original stimulus (e.g., when you hear someone say something, but you don’t understand at first and say “What?” But even before the person can repeat what was said, you “hear” it in your mind)
Recall experiments - what is it and what purposes (2)
Subjects are asked to report stimuli they have previously seen or heard
Used to answer the questions: What is the duration of STM? & What is the capacity of STM?
how long does short term memory last without rehearsal?
lasts 15 to 20 seconds or less
Lloyd Peterson and Margaret Peterson
presented participants with three letters, such as FZL or BHM, followed by a number, such as 403. Participants were instructed to begin counting backwards by threes from that number (to keep participants from rehearsing the letters)
After intervals ranging from 3 to 18 seconds, participants were asked to recall the three letters
Results of the Petersons’ experiment
Participants correctly recalled about 80 percent of the three letter groups when they had counted for only 3 seconds, but recalled only about 12 percent of the groups after counting for 18 seconds
estimates for how many items can be held in STM (capacity)
four to nine
digit span
The number of digits a person can remember. Digit span is used as a measure of the capacity of short-term memory
George Miller
According to measurements of digit span, the average capacity of STM is about five to nine items—about the length of a phone number
“The Magical Number Seven, Plus or Minus Two”
Steven Luck and Edward Vogel
measured the capacity of STM by using a procedure called change detection
change detection task - results
performance was almost perfect when there were one to three squares in the arrays, but that performance began decreasing when there were four or more squares. Luck and Vogel concluded from this result that participants were able to retain about four items in their short-term memory
Chunking
Combining small units into larger ones, such as when individual words are combined into a meaningful sentence. Chunking can be used to increase the capacity of memory
who introduced the concept of chunking?
George Miller introduced the concept to explain why it is possible to hold many more items in memory in some situations, as when words are arranged in a sentence
Chunk
a collection of elements that are strongly associated with each other but weakly associated with elements in other chunks. (e.g., the word ringtail is strongly associated with the word monkey but is not as strongly associated with the other words, such as child or city)
We can recall a sequence of 5 to 8 unrelated words, but arranging the words to form a meaningful sentence so that the words become more strongly associated with one another increases the memory span to ___ words or more
20
George Alvarez and Patrick Cavanagh
did an experiment using Luck and Vogel’s change detection procedure
in addition to colored squares, they also used more complex objects (e.g., shaded cubes, which were the most complex stimuli)
Results of Alvarez and Cavanagh’s change detection experiment
Memory capacity for the colored squares was 4.4, but capacity for the cubes was only 1.6. Based on this result, Alvarez and Cavanagh concluded that the greater the amount of information in an image, the fewer items that can be held in visual short-term memory
What kind of container can we compare with STM?
a leaky bucket that can hold a certain amount of water for a limited amount of time
Working memory - who and what
introduced in a paper by Baddeley and Hitch
Short-term memory is concerned mainly with storing information for a brief period of time (for example, remembering a phone number), whereas working memory is concerned with the manipulation of information that occurs during complex cognition
involves both holding information in memory and processing information
three original components of Baddeley’s working memory model
the phonological loop, the visuospatial sketch pad, and the central executive
phonological loop
The part of working memory that holds and processes verbal and auditory information
two components of the phonological loop
phonological store
articulatory rehearsal process
phonological store
has a limited capacity and holds information for only a few seconds
articulatory rehearsal process
responsible for rehearsal that can keep items in the phonological store from decaying
visuospatial sketch pad
The part of working memory that holds and processes visual and spatial information
central executive
The part of working memory that coordinates the activity of the phonological loop and the visuospatial sketch pad. The “traffic cop” of the working memory system
pulls information from long-term memory and coordinates the activity of the phonological loop and visuospatial sketch pad by focusing on specific parts of a task and deciding how to divide attention between different tasks
three phenomena that support the idea of a system specialized for language
phonological similarity effect
word length effect
articulatory suppression
phonological similarity effect
An effect that occurs when letters or words that sound similar are confused. For example, T and P are two similar-sounding letters that could be confused
R. Conrad
flashed a series of target letters on a screen and instructed his participants to write down the letters in the order they were presented. He found that when participants made errors, they were most likely to misidentify the target letter as another letter that sounded like the target (phonological similarity effect)
even though the participants saw the letters, the mistakes they made were based on the letters’ sounds
word length effect
The notion that it is more difficult to remember a list of long words than a list of short words
- it takes more time to pronounce and rehearse longer words and to produce them during recall
Baddeley and coworkers (1975) found that people are able to remember the number of items that they can pronounce in about ____ seconds
1.5-2.0 seconds
articulatory suppression
Interference with operation of the phonological loop that occurs when a person repeats an irrelevant word such as “the” while carrying out a task that requires the phonological loop
reduces memory because speaking interferes with rehearsal - overloads the phonological loop
how does articulatory suppression affect the word length effect?
eliminates the word length effect - eliminating rehearsal by saying “the, the, the …” removes this advantage for short words, so both short and long words are lost from the phonological store
visual imagery
A type of mental imagery involving vision, in which an image is experienced in the absence of a visual stimulus
-part of the visual sketch pad
Roger Shepard and Jacqueline Metzler
“Comparing Objects” demonstration involving mental rotation
-when one shape was rotated 40 degrees compared to the other shape, it took 2 seconds to decide that a pair was the same shape. However, for a greater difference caused by a rotation of 140 degrees, it took 4 seconds
Sergio Della Sala
presented his participants with patterns ranging from small (a 2 × 2 matrix with 2 shaded squares) to large (a 5 × 6 matrix with 15 shaded squares), with half of the squares being shaded in each pattern. He found that participants were able to complete patterns consisting of an average of 9 shaded squares before making mistakes
individual squares can be combined into subpatterns—a form of chunking that could increase the number of squares remembered
Lee Brooks
Holding a Spatial Stimulus in the Mind demonstration: involves visualizing a large “F” which has two types of corners, “outside corners” and “inside corners,”
pointing or saying - Most people find that the pointing task is more difficult
-holding the image of the letter and pointing are both visuospatial tasks, so the visuospatial sketch pad becomes overloaded
Baddeley describes the central executive as being an…
attention controller which is related to executive attention
One of the ways the central executive has been studied is by assessing the behavior of…
patients with brain damage
the frontal lobe plays a central role in…
working memory
A typical behavior of patients with frontal lobe damage is…
perseveration
-represents a breakdown in the central executive’s ability to control attention
episodic buffer
A component added to Baddeley’s original working memory model that serves as a “backup” store that communicates with both long-term memory and the components of working memory. It holds information longer and has greater capacity than the phonological loop or visuospatial sketch pad
Areas of the brain associated with working memory
the prefrontal cortex (PFC) but more recently research has expanded the “brain map” of working memory to include many additional areas: visual cortex, hippocampus, amygdala and frontal cortex
delayed-response task
example of animal research that explored the effect of frontal lobe damage on memory
if their PFC is removed, their performance drops to chance level, so they pick the correct food well only about half of the time
frontal and prefrontal cortex do not become adequately developed until about what age to hold a hidden object in their mind?
8 months
Shintaro Funahashi
found neurons that responded only when the square was flashed in a particular location and that these neurons continued responding during the delay
Mark Stokes
information can be stored by short-term changes in neural networks
activity-silent working memory
Short-term changes in neural network connectivity that has been hypothesized as a mechanism for holding information in working memory
activity state
information to be remembered causes a number of neurons, indicated by the dark circles, to briefly fire. This firing doesn’t continue, but causes the synaptic state
synaptic state
a number of connections between neurons, indicated by the darker lines, are strengthened
Meredyth Daneman and Patricia Carpenter
carried out one of the early experiments on individual differences in working memory capacity by developing a test for working memory capacity and then determining how individual differences were related to reading comprehension - reading span test
higher working memory capacity is related to…
individual differences in reading comprehension, better academic performance, better chance of graduating from high school, the ability to control emotions, and greater creativity
Edmund Vogel
focused on one component of working memory: the control of attention by the central executive
Participants in the high-capacity group were able to hold a number of items in working memory; participants in the low-capacity group were able to hold fewer items in working memory
event-related potential was measured, which indicated how much space was used in working memory as they carried out the task
Vogel’s results
The fact that adding the blue bars had only a small effect on the response of the high-capacity group means that these participants were very efficient at ignoring the distractors, so the irrelevant blue stimuli did not take up much space in working memory. Because allocating attention is a function of the central executive, this means that the central executive was functioning well
some people’s central executives are better at allocating attention than others
individual differences in cognitive control are closely related to individual differences in…
working memory
experiments have generally shown that high-capacity participants are better at
tuning out the distractors
Zhang & Simon
Visual coding: Chinese speakers are asked to recall strings of radicals and characters
Radical - no sound (can only be coded visually
Character - has sound
Characters were better recalled but participants are able to recall radicals (just not as well)
Wickets
Semantic coding: Listen to word list (3 words) Count backwards for 15 - to prevent rehearsal
3 Groups in experiment: Fruit group (word list of different fruit)
Meat group (different meats)
Profession group (different occupations)
On the 4th trial - every group got fruit words
In trials 2 and 3 the recall decreased in performance due to proactive interference
Then, in trial 4, the profession group performance increases the most, the meat group increases the least and the fruit group continues to decrease
proactive interference (PI)
previous info interferes with ability to learn/recall new info because the new info is from the same semantic category
Chase & Simon
chess experiment - using semantic coding, participants familiar with chess moves are able to chunk info
what type of coding does chunking use?
semantic
1st trial: 3 sec vs. 18 sec delay = accuracy very similar
3rd trial: 3 sec vs. 18 sec delay = large difference in accuracy
What is causing the difference in accuracy?
due to proactive interference (not decay)
Brandimonte
Briefly present image of an object
Then present part of the object
Task: mentally subtract the two images and indicate what is the remaining image - “Candy” image to “fish” image
Articulatory suppression (la la la) vs. none
Coding it as a candy requires the phonological loop so when this is suppressed with the “la la la” it actually becomes easier to then state the the remaining image is a fish because they did not first code the image as a candy
If someone is showing perseveration, then they’ve likely had damage to the ___ lobe of the brain.
frontal
Currently, it is generally believed that the upper limit for short-term memory is ___.
7 plus or minus 2 items
___ has helped to bolster the idea that the ___ is important for holding information for brief periods of time.
The delayed-response task; prefrontal cortex
What distinguishes working memory from short-term memory?
complexity
According to Baddeley, the central executive controls ________.
attention
According to the activity-silent working memory model, neurons fire ________.
at stimulus input and remembering
Daneman and Carpenter’s research on reading span looked at differences in memory ________ among individuals.
capacity
What is a key function of the phonological loop?
to prevent decay
Funahashi and Stokes both focused on which concept relating to memory?
delay
According to Broadbent, where does the process of rehearsal take place?
short-term memory
At this point in time, what is considered the primary function of the episodic buffer?
storing information
Which of the following likely led early telephone companies to create phone numbers using the format 213-555-1234 rather than a format such as 21776-551873-0633295?
a. phonological similarity
b. digit span
c. articulatory rehearsal
d. chunking
digit span
Which of the following has the shortest rate of decay?
a. an exit sign
b. a finger snap
c. a trumpet note
d. an opera aria
an exit sign
