Memory chapter 1-4
Notes
Access course readings online.
Week 1 — Chapters 1 and 2
Clive Wearing lost his short-term memory, but could still play piano after his illness.
Maybe there is something different between types of memory systems?
Theories
Based on multiple observations and levels of analysis to ask a question.
Reductionism.
Macro level: social psychological level
How is memory impacted by the people around you?
Cognitive perspective
Memory within you; your interpretation. Metamemory: your knowledge of what memory is.
Physiological level
Brain structure.
Biochemical
Calcium channels.
Physical level
Location of memories.
No perspective is better than the other; an interdisciplinary approach will be included to gather information.
Brain like a computer.
Encoding → Storage → Retrieval
Computer metaphors used to be common.
Atkinson and Shiffrin's Modal Model
States that things come in from the environment; memory is then briefly stored in sensory memory, then in short-term and long-term memory.
Environmental input is then briefly stored in sensory memory.
Model does not acknowledge that information and memory are bidirectional
Once something is in long-term memory, it can be brought back to short-term memory.
Sensory memory:
Shortest time span.
Visual or auditory.
Held long enough to integrate with what’s coming next.
Delay: …
Visual mask: interference by vision that impacts what was seen prior (e.g., a flash of an image).
Visual sensory memory:
Iconic memory: visual memory; fast early stage when something is coming in from the environment. Stores information; primacy advantage.
Recognition buffer: info from iconic memory; memory is more durable and stored at a slower rate.
Echoic memory: storage for auditory info
Recognition buffer
Recency advantage: we remember the last things spoken. Presented later in the list due to a precategorical acoustic store.
Short-term memory: stored information in the exact same way it was given to us; you would have to rehearse that info for it to stay in short-term memory.
Can hold info from any domain.
Working memory: takes info from a source and stores it, but can also manipulate it and work with it.
Basis for symbolic manipulation of items and thought.
Long-term memory
Explicit memory / declarative memory
Episodic: vivid memories that make up your life; help you know who you are. Mental time travel.
Semantic: facts and knowledge of the world and society
Some memories start as episodic memory and then change to semantic.
Implicit / non-declarative memory
Harder to talk about (e.g., explaining how to ride a bike).
Things we know or do, but can’t easily verbalize.
Motor skills, automatic processes, classical conditioning, priming.
Priming: unconscious ability to recall things we’ve seen or done prior to recalling
Reading about fish and then doing an enneagram and finding more words relating to fish.
Brain damage allowed us to understand the different types of memory.
Amnesia:
Struggle to recall episodic memory.
No issues with implicit tasks.
Indicates differences between episodic memory and implicit memory
Different brain areas involved
Memories have to go through episodic to become semantic (can’t create semantic) if episodic memory is damaged
Memory in the lab
Pros: control; easier to develop and test theories.
Cons: not natural; lack of context; reduced generalizability of findings; less ecological validity; diversity is reduced.
Disease-related studies
Can look at the differential impacts based on the disease and assess which area is impacted.
Alcoholic: Korsakoff — deficit of vitamin B12 from too much alcohol.
Can be difficult to disentangle memory impairments from other deficits.
Lesion studies
Can identify causal links between brain and behavior.
Double dissociation: 2 people with lesions to different areas doing the same tasks; what they are NOT able to do demonstrates the brain area responsible for such behavior.
Good to draw causal links.
Lesions created in rats.
Structural imaging
CT scan: multiple X-rays to make a 3D image of the brain.
MRI strong magnet
DTI detects water not moving through the fatty myelin sheath.
Planting electrodes in the brain is not for humans because if you touch the electrodes, they could die.
TMS — non-invasive
Creates temporary lesions by reducing activity in cortical areas.
Repeated TMS is required to create these lesions, which can last a few minutes.
tCDCS — increases activity in cortical areas.
EEG — cap on brain; electrodes on the skull read action potentials (electrical activity).
Repeated tasks over hundreds of times to create an average of where the activity in the brain is happening — event-related potential: action potential that’s related to a specific event.
MEG:
Magnetic instead of electrical activity is read.
More expensive and not commonly used.
Blood flow–based measures
PET scan: radioactive tracer is injected into the bloodstream, and areas that use more blood flow become more radioactive.
Potentially dangerous and costly.
Multi-voxel pattern analysis
fMRI analysis of specific voxels (graph a small tiny part of the brain = a voxel)
Cellular basis of memory
Sensitization: react faster.
Habituation: react less to a stimulus.
LTP: long-lasting increase in the strength of synaptic connections between neurons.
Connected to sensitization.
LTD: long-term depression, or a decrease in the strength of synaptic connections between neurons.
Week 2: Chapter 3
Brain capacity and memory span
Digit span is limited to about six or seven digits for most people.
some as few as four or as many as ten plus
Chaining
Method for remembering order as the individual links each item to the next in the series.
Helps remember what comes after.
Predicts that forgetting one link will result in the others being forgotten — however, this is not true.
Chunking
Remembering phone numbers.
Group random numbers or letters into chunks, which increases recall.
George Miller: memory span is limited not only by items but also by chunks.
3 chunks variant sizes are best for maximizing recall.
e.g., “wed nes day” spelling
Errors
Short-term memory for consonants relies on an acoustic code.
likely to confuse letters that sound similar (P and V)
impacted by acoustic similarities with other consonants, making it more likely to make such errors
Not more likely for visual similarity; auditory.
Verbal Short-Term Memory
Phonological loop: auditory verbal part of memory — Baddeley and Hitch (1974)
2 components
Short-term store: limited in capacity; decays within seconds unless you rehearse.
Articulatory rehearsal process: the process where we verbally repeat things to keep them in the short-term memory store
Can be out loud or sub-vocally.
Phonological Similarity Effect: Memory span is greatly
reduced for similar sounding items, much more than it is for
lists with similar meanings
◼ List 1 (Easy to remember/dissimilar phonology and semantics):
◼ PIT, DAY, COW, PEN, HOT
◼ List 2 (Only slightly harder than List #1/similar semantics) :
◼ HUGE, WIDE, BIG, LONG, TALL
◼ List 3 (Much harder than List #1/similar phonology) :
◼ CAT, MAP, MAN, CAP, MAD
Errors in memory:
Remembering something that’s part of a list when it wasn’t
e.g., omitting an item in the list
Long-term memory is impacted by semantic similarity.
Short-term memory: phonetic sounds.
Phonological Similarity Effect
Why does this happen?
Info has to be said or heard first for it to go into the phonological loop.
Auditory speech goes directly into phonological loop → most likely to name the objects sub-vocally (articulatory rehearsal)
Works for what we can name/know/familiar.
Unknown is harder to name and process.
Block articulatory rehearsal process: repeating another unrelated word — articulatory suppression impacts memory
Vice versa for names that sound the same,
Word length effect
Recall decreases as word length increases.
people can remember about as many words as they can say in 2 seconds
harder to repeat and rehearse long words
Articulatory suppression eliminates the word-length effect for both spoken and visually presented items because it blocks rehearsal of both types.
Long words interfere in recalling; that’s why we use short forms.
interference: more complex; can forget or mix with others
fragmentation: longer words are composed of more parts and are vulnerable to fragmentation and forgetting (suffix and prefix)
Articulatory suppression eliminates the word length effect for both spoken and visually presented items because it blocks rehearsal of both types.
Now the short words are just as bad as long ones.
Irrelevant sound effects
All auditory info is coming into the brain and can interfere with memory.
Music also disrupts retention (vocals are more disruptive than purely instrumental).
White noise doesn’t have this same effect.
Changing state of the distractor is changing over time (e.g., a TV show keeps grabbing you back in).
Impacts recall later on, and internalization; you might forget items and serial order due to irrelevant sounds.
Object-oriented episodic record (O-OER) hypothesis: An alternative
explanation based on theories of auditory perception, which does not
assume the involvement of a phonological loop
The Phonological Loop and Serial Order
limitations
we don’t know how serial order is stored — is it a big loop?
no understanding of retrieval of information from the phonological loop
where does it even exist in the brain?
Rehearsal is assumed to involve the retrieval of items from the phonological store and their subsequent re-entry as rehearsed stimuli.
Competing Theories of Verbal STM
STM (short-term memory) storage
The feature model: one unitary memory system rather than separate LTM and STM
Nairne’s (1988; 1990)
Modality dependent: group based on presentation modality (font, size, colour of a visually presented word*)*
Modality independent: features that are not linked to presentation (e.g., meaning, semantic)
could impact longer word lists
The feature model cannot explain why the word-length effect
disappears in mixed lists of long and short words, leading many
to abandon their support for the model.
Scale Invariant Memory, Perception, and Learning
(SIMPLE)
Emphasizing temporal discriminability → a detailed, mathematical model of STM and LTM
Importance of the accuracy of time in memory.
More distinct memories are easier to retrieve (e.g., emotional).
Primacy effect: first few items on a list enjoy a recall advantage.
Depends on long-term memory.
Recency effect: last few items are very well recalled.
The following factors, known to affect LTM, also influence
performance on recall of the early and middle parts of study
lists; the recency effect is largely immune to these factors:
◼ Presentation rate: Slower presentation enhances recallability of
items
◼ Word frequency: More familiar (frequent) words are easier to recall
◼ Imageability: Words that are more visualizable are easier to recall
◼ Age: Younger adults remember more than children/elderly
◼ Physiological state: Drugs such as marijuana and alcohol impair
performance
Spatial STM
Memory for where things are located in space.
Lasts for about 30 seconds without interference or active maintenance.
Retention declines when the retention interval is filled.
Short term.
Object memory
Ability to remember what objects were.
Complexity is irrelevant; it’s about the objects themselves.
Shorter than spatial memory (under 30 seconds).
If an object is nameable, memory is best.
Can hold about 4 objects in memory.
Object permanence, e.g., what item is missing?
Week 3: Chapter 4
Atkinson and Shiffrin’s (1971) Modal
Model
from environmental input
Environmental Input
Sensory Registers
Detect sensory input from the various modalities
visual, auditory, haptic, etc.
Memories are held for only a few hundred milliseconds
Short-Term Store (STS)
Lasts a few seconds and is made up of:
◼ Temporary working memory
◼ Control processes:
◼ Rehearsal
◼ Coding
◼ Decisions
◼ Retrieval strategies
Long-Term Store
◼ Permanent memory store
Issues with the Modal Model
Levels of Processing Evidence
assumes that holding items in the short-term store is sufficient for long-term learning
but data from Craik and Lockhart's (1972) study challenged this assumption
learning depends on the WAY material is processed, rather than short-term storage (levels of processing theory)
Levels of processing: The theory proposed
by Craik and Lockhart that asserts that items
that are more deeply processed will be better
remembered
Neurophysiological evidence
Modal model
Assumes that STM is crucial in transferring information into and out of LTM.
Any STM deficit will greatly impair LTM learning, and reasoning/comprehension.
But: a number of patients had severe STM deficits without apparent working memory or LTM deficits.
Baddeley and Hitch (1974)
Tested participants repeating a sequence of digits aloud (filling STM) while simultaneously performing a variety of cognitive tasks.
increased STM loads should cause more interference in reasoning, assuming that the STM system reflects a working memory system that supports these cognitive functions
results: participants were able to reason without difficulty, even when repeating sequences up to 8 digits
Proposed the model of working memory:
“Working” implies that the system supports
complex cognitive activities like reasoning,
distinguishing it from earlier models of STM,
which simply focused on storage
Baddeley and Hitch: Multicomponent model
Central Executive: an attentionally limited system that selects and manipulates materials in two slave systems.
Phonological Loop
Assumed to be specialized for holding: model of verbal STM — general theory of working memory.
Assumes a temporary store and a verbal rehearsal process.
Increases span by 2 or 3 items when repeating back numbers.
Evolved to assist language comprehension and language learning.
evidence:
patient PV had a phonological loop deficit as an adult, resulting in a digit span of 2 items
minor comprehension issues with long sentences
inability to learn a new language: suggests that the phonological loop evolved to aid language acquisition
Visuo-spatial sketchpad
Assumed to be responsible for the temporary maintenance of visual and spatial information.
Semantic coding: processing an item in terms of its meaning, therefore relating it to other information in LTM
The Phonological Loop and
Action ControlVocally or sub-vocally reminding oneself of the relevant task often improves performance.
Articulatory suppression limits this ability and disrupts performance.
Vygotsky (1962) and Luria (1959) emphasized the use of verbal self-instruction to control behavior
Studied as a means to help brain-damaged patients rehabilitate and to understand childhood development.
Largely underappreciated and under-investigated currently.
Visuo-spatial sketchpad
People’s subjective sense of the vividness of their visual imagery is largely unrelated to performance on visual tasks.
results are poorer performance on visual memory tasks by participants with strong visual imagery
often mistake vividness of memories for a sign of accuracy
more vivid memory ≠ better memory
Image manipulation
Shepard and Feng (1972) found that the time it takes to answer the image manipulation question depends on the number of folds required
involves spatial thinking
somewhat better preformed by men than women
this gender bias can be eliminated with strategies of spatial manipulation
The Central Executive
Thought to be an attentional controller with two main modes of operation (Norman & Shallice, 1986)
Frontal lobes.
A semi-automatic conflict-resolution system, based on existing habits and requiring little attention
conflicts are routinely resolved without much conscious awareness
e.g., driving a car, taking turns, and slowing down but not being hyper-aware of the action
Supervisory Attentional System (SAS): Norman and Shallice
Based on an attentionally-limited executive.
Able to intervene when a new, novel situation arises and automatic conflict resolution is not possible.
Crucial to the central executive.
E.g., a road block appears, or a traffic accident.
Failures of the SAS
Damage to frontal lobes results in:
Perseverate: repeatedly performing the same act/mistake over and over.
Fail to focus attention, resulting in utilization behaviors (uninhibitedly making use of whatever cues are afforded by the behavior)
Results in habit-based control.
Confabulation: recollection of something that did not happen.
They often fail to monitor behavior (making sure it is appropriate for the situation).
Attentional Focus
Major function of the central executive is to direct attention to the task at hand.
Robins et al. tested expert and novice chess players
Articulatory suppression (active recall of the chess positions) had no influence, suggesting the phonological loop was not involved.
Disruption of the sketchpad (spatial tapping) did impair performance, but not as much as random generation (attentionally demanding task, e.g., producing a random stream of numbers)
Indicating an important role for both the sketchpad and central executive in planning as well as remembering the chess position.
Dividing attention is another capacity of the central executive
E.g., talking to a passenger while driving, can impair judgment even through skill remains intact
Alzheimer's patients have difficulties dividing attention between simple simultaneous tasks
The Episodic Buffer
newly proposed 4th component of the working memory (WM) system
originally assumed to be controlled by the central executive
storage system: capacity of around 4 chunks of info in a multidimensional code
links between subsystems as well as LTM
information is retrived through conscious awarness
binding of previous unrelated concepts from diffrent systems
Current Model
arrow A: language aquisitio
B: visual and spatial mapping
Individual diffrences in working memory
task: Read a series of sentences and try to recall the last word of
each
WM Span about 2-5 sentences worth of final words
predits comprehension, following complex instructions- take notes, IQ, fluid intellegance, preformance in computer programming courses
theories of WM
most analysis agree with Baddeley and Hitch model of WM
include attention based control system - like central executive
subsystems dealing with the simple storage of verbal and visuo-spatial material
Cowans Embedded processe theory
WM depends on activation that takes place within LTM and is controlled by attentional process
activation is temporary and decayes- unless maintained through active verbal rehersal or continued attention
activated memory is multidimensioanl; some resembalnces to the episodic bugger
WM capactity is limited to around 4 chunks
Turner And Engle: operation span measures
task: remember words each of which is followed by arithmetic operations
correlates highly with the original complex span (sentances)
Engels Inhibitory Control Theory
individuals with a low operation span are more susceptible to proactive interference than those with high operation spans
an inability to resist interferance also predits ones suscpetibility to the cocktail party effect
conclusion: the ability to inhibit irrelevant material is tied to complex span/WM
Two components of WM
primary memory: dynamic attention capacity for the temporary maintenance of items
recency effect
secondary memory: capacity for due-dependent search in LTM
reflected in attention control capacity
the task at hand decides which type of WM is being used
Training WM
training on owkring memory has shown improvement in that task and some near transwe and little lasting power (improvements not seen weeks/months later)
possible brain areas involved in WM
prefrontal cortex
basal ganglia
parietal cortex
Neuroimaging WM
Paulesu, Frith, and Frackowiak
used PET to finf
A. area between left parietal and temporal lobes related to phonological storage
B. frontal region called Brocas area: involved in spreech production
linked to subvocal rehersal
Neuroimaging WM: Smith and Jonides
also used PET to directly compare visual and verbal WM
verbal task: replicated the two activations for verbal STM in the left himisphere
visuak task: found right hemispheric areas assosiated with visuo-spatial sketchpad
Further studies supported the dorsal (“where”) stream vs. ventral (“what”) stream distinction
Spatial memory activates more dorsal regions of the brain
Object/pattern memory activates more ventral areas
N back Task: press a button whenever an item was seen N-items before
frontal lobe is engaged during task and its involvement increases with executive load