Chapter 6: Memory l Flashcards
memory
the process of using information that was obtained in the past to generate some cognitive function in the present
encoding
the initial processing of information by the nervous system
storage
the retention of information in the nervous system beyond initial encoding
retrieval
access and use of stored information by the nervous system
are human and computer memory similar?
yes
2 ways to measure memory
capacity & duration
capacity
how much information a memory system can hold
duration
how long information remains in memory
William James on memory
there may be two kinds of memory stores: one for information related to the current task and one for longer-term storage
who developed the modal memory of memory
Atkinson & Shiffrin
modal model of memory
explains how incoming input from the environment is conceptually stored in the mind. States that there are three basic kinds of memory: sensory memory, short-term memory, and long-term memory
sensory memory
briefly holds the information just encoded by the sensory organs
what moves information from sensory memory to STM
attention
short-term memory
serves to hold processed information for rehearsal or to produce a behaviour
what’s the estimated duration of STM
15-30 seconds
maintenance rehersal
the repetition of information in STM which prolongs its duration
long-term memory
a cold storage of information that may be retrieved back into STM as needed for a task or behaviour
what’s the estimated capacity of LTM
not agreed upon
how much information from STM is encoded in LTM?
only a small fraction
how long does sensory memory last
250 ms
what’s an example of persistence of vision
toys with LED light strips
Thaumatrope
a popular toy in the 19th century that consisted of a disk with different drawings on each side. When it was spun quickly, it would lead to the illusion of seeing both images at the same time
iconic memory
the visual form of sensory memory in which much of the visual input can be stored for a short period
echoic memory
an auditory form of sensory memory in which much of the auditory input can be stored for a short period
short-term memory capacity in the visual domain
4 items
short-term memory capacity in the auditory domain
7 items
Miller STM capacity experiment
presented participants with lists of letters, numbers, or words and asked them to repeat the items in order. Found that the average capacity to repeat items without any errors was 7, but that capacities ranged from 5-9
STM capacity between people vs. within people
Capacity ranges from person to person, but is relatively consistent across trials in a particular person
chunk
any combination of letters, numbers, or sounds that constitute a meaningful whole
Information is easier to remember when it is divided into chunks
Luck & Vogel STM capacity experiment
used a paradigm reminiscent of change blindness to visually test memory. Found that once the number of objects decreased to greater than 5, memory performance rapidly dropped off
Inoue & Matsuzawa STM capacity in chimps experiment
provided chimpanzees and humans with 5 digits that appeared on a screen from 210-650 ms. After that wait period, the subject was tasked with touching the squares to reveal the digits in numeric order. On average, humans’ memory performance for the 5 digits decreased when the presentation time dipped below 400 ms, but some chimps were able to still store 5 digits with only 200 ms
Mneumonists
people who are capable of memorizing long strings of letters or numbers
what causes mnemonists’ enhanced memory abilities
a skilled ability to form large chunks
chess STM capacity study
expert chess players recall more pieces on a chess board than new chess players because experts use knowledge of moves to chunk pieces together. This effect is not present if the pieces are on the board randomly
maintenance rehersal
the mental repetition of information in STM that allows information to be regenerated to prolong its duration
Brown Peterson task
Consists of a STM task in which participants have to memorize 3 letters, but then are presented a 2 digit number and had to begin counting backward by threes out loud, preventing rehearsal. Found that under these conditions, the memory of the letters began to fade after a few seconds and by 15-18 seconds, participants showed little or no memory of it
decay model
forgetting simply occurs because of the passage of time
interference model
new information comes into memory serves to displace older information
what are the two types of interference
proactive & retroactive inteference
proactive interference
cases in which learned information causes you to forget something that you learn in the future
retroactive interference
cases in which newer information causes you to forget something from the past
what model of forgetting did Brown & Peterson attribute their findings to
they attributed their findings to decay, but interference might also be at play
Keppel & Underwood trigram experiment & forgetting
in the first few trials, participants remembered the trigram for up to 15 seconds with relatively high accuracy, but on later trials, the decay over time began to appear, suggesting that both interference and decay are occurring
Lewandowsky et al., sequences & forgetting experiment
had participants remember sequences of letters by responding on a computer keyboard while repeating an irrelevant word out loud. Found that there was no effect of the speed at which participants had to type the letters on their recall of the items. Concluded that without interference, the passage of time alone doesn’t cause decay in STM
who developed the working model of memory?
Baddely
what does the working model of memory suggest
Describes the STM as an active workspace where information can be mentally manipulated based on the current task
Proposes that the STM is divided into three connected but distinct subunits
3 subunits of the STM in the working model of memory
visual-spatial sketchpad, phonological loop, central executive
visual-spatial sketchpad
the visual component of WM that both holds information and allows for the active manipulation and analysis of that information
phonological loop
the auditory component of WM that allows auditory information to be repeated and rehearsed
central executive
component of WM that determines what information makes it into STM and coordinates between the visual and auditory memory storages
acoustic confusions
difficulties repeating stimuli that sound more similar to one another
Brooks acoustic confusions experiment
participants had to do either an auditory-memory or visual-memory task and respond to the task either verbally or visually. Found that people did better on the task if they had to respond in a different modality than what they had to remember, suggesting that visual and auditory memory are processed separately and don’t interfere with one another
main hypothesis for differences in STM capacity
Differences in STM capacity may be due to differences in the central executive’s ability to filter out irrelevant information
Vogel high & low capacity STM experiment
gave participants a standard STM task and divided them into high or low memory capacities. Both groups then performed a specialized visual STM task while in an EEG. Found that ERP responses were similar to the two groups when only the red rectangles were present but when the blue distractor rectangles were present, low-capacity individuals showed a stronger ERP than high-capacity individuals. Demonstrates that low-capacity individuals couldn’t filter out the blue rectangles
criticisms of the working model of memory
- People can remember many more items when they form a coherent story
- Conscious experience appears to bind many different modalities
episodic buffer
a separate, time-limited memory store controlled by the central executive than can combine information from across different sources, including the phonological loop, the visual-spatial sketchpad, and LTM
working memory & cognition
Working memory capacity is predictive of other measures in cognition like general intelligence (g)
Li & Geary math abilities experiment
first graders’ skills for completing tasks dependent on visual working memory were predictive of their math abilities in fifth grade
Kali reasoning experiment
found that assessments of memory span administered to children at an early age can predict other measures of reasoning ability later in life
Gui musical training experiment
short-term musical training can lead to selective improvements in WM ability in young children
Lumosity scandal
Lumosity was fined by the Federal Trade Commission for making overly broad claims of cognitive improvement due to their program
what’s the neuronal basis for STM & working memory?
Consists of the initial perceptual encoding of information continuing on for as long as the information is being actively remembered
where does working memory happen?
Working memory happens all over the brain in modality-specific regions
Funahashi et al PFC neurons in monkeys experiment
identified a neuron in the PFC that responded when a square was presented somewhere in the visual field. They presented the square, then followed it with a delay period and found that during the delay, the neuron went into overdrive when the monkey had to remember its location.
Delayed-match-to-sample task
a task designed to test visual short-term memory. Participants are shown an image, then a delay, followed by a second image and are tasked with determining whether the two images are the same
what happens to neural activity when participants are shown an image followed by a delay, then a second image and are tasked with determining whether the images were the same?
increased activity in the PFC during the delay phase, suggesting an important role of the frontal cortex in working memory
what happens when the dorsolateral PFC is impaired?
patients show impairments on tasks similar to the delayed matching tasks
Clive Wearing
Some aspects of Clive’s memory were impaired, but other cognitive functions weren’t.
what does Clive Wearing’s memory loss demonstrate?
There are various kinds of memory with distinct capacities, duration, and relation to consciousness
memory consolidation
encoding -> storage
neural basis of encoding
a memory trace is formed as a hippocampal-cortical activity pattern
neural basis of storage
via consolidation, a memory is transformed into a stable cortical pattern
neural basis of retrieval
part of a memory trace is activated by a cue that triggers pattern completion
function of sensory memory
Allows us to make quick decisions based on what’s in our environment
gustatory memory
sensory memory for taste
olfactory memory
sensory memory for smell
haptic memory
a very brief moment of touch
persistence of vision
an afterimage of something you have previously perceived
two types of afterimages
positive & negative
positive afterimage
a visual memory that represents the perceived image
negative afterimage
a visual memory is the inverse of the perceived image
Sperling, 1960 sensory memory experiment procedure
Participants briefly (0.05 seconds) viewed a visual display of 3x4 letters
Recalled the letters as either
- Whole report: reported letters from the whole display
- Partial report: reported only one row of letters at a time over trials
Within 0.01-1 seconds, a high/medium/low tone signals which row to report
Sperling, 1960 sensory memory experiment findings
People could recall almost all the items when the sum of their trials were considered
This was only the case when the beeps were presented less than 1 second after they were shown the visual display
what did Sperling find about the capacity of sensory memory?
it’s quite large but only for a short period of time
what brain structure is involved in short-term memory?
PFC
STM capacity
7 plus or minus 2
the chunking effect
chunking increases with knowledge
neuroimaging evidence for the working memory model
different areas of the brain are active for visual and verbal STM tasks
Patient ELD
has problems recalling visual-spatial but not verbal material in the short term. provides evidence for the working memory model
Patient PV
has problems recalling verbal but not visual material in the short term. provides evidence for the working memory model
what are the two kinds of evidence for the working memory model?
neuroimaging studies and double dissociation in neuropsychological cases
two subcomponents of the phonological loop
the phonological store (inner ear) & the articulatory control loop (inner voice)
phonological store
- A passive store for verbal information
- aka inner ear
articulatory control loop
- active rehearsal of verbal information
- used to convert written materials into sounds
- specialized role in language
- aka inner voice
two subcomponents of the visuo spatial sketchpad
the visual cache & the inner scribe
the visual cache
information about visual features
the inner scribe
information about spatial location, movement and sequences
Hermann Ebbinghaus
- Tested how encode nonsense syllables were retained and forgotten from memory over time
- Created over 2000 cards of nonsense syllables
- Learned and relearned the sets of syllables under strict testing conditions
- Developed the forgetting curve following these experiments
the forgetting curve
- Forgetting is exponential
- Memory loss is largest early on and slows down
what can help slow down forgetting?
active rehearsal
the spacing effect
- Memory is better when the same amount of learning is spread out over time
- Variation helps with the spacing effect (ex. Studying 30 mins or 60 mins alternative each day rather than consistently studying for 30 mins)
levels of processing
the strength of a memory depends on the depth of processing when encoding
types of processing
shallow & deep
what type of processing is memory stronger with
deep processing
Marzi & Viggiano, 2010 levels of processing experiment
had participants encode faces that were either upright or inverted in either a shallow or a deep condition. Found that people recognized the faces in the deep encoding condition more than in the shallow condition. They were also able to recognize upright faces much better because of the engagement of the FFA.
shallow processing
processing that focuses on sensory information
deep processing
processing that integrates high-level knowledge
what’s important about working memory?
- It has a limited capacity and duration
- It’s where incoming information can relate to prior knowledge and be manipulated
- It’s where information enters consciousness and awareness
- It’s critical for long-term memory formation
what part of the brain controls the central executive?
the PFC
what part of the brain controls the phonological loop?
Broca & Wernicke’s areas
what part of the brain controls the episodic buffer?
parietal lobe
what part of the brain controls the visuospatial sketchpad?
the occipital lobe
are parts of working memory mutually consistutive?
no, they work together
