Chapter 7: Memory ll Flashcards
what memories are classified as long-term memory?
anything that is remembered from beyond 15 seconds to an infinitely
how much storage does LTM have?
it’s infinite
STM vs. LTM
- Short-term memory can no longer be accessed after its duration has passed
- STM retains physical details while LTM retains abstract semantic information
amnesia
severely impaired long-term memory capacities due to trauma or brain damage
retrograde amnesia
events taking place leading up to the incident are often forgotten
anterograde amnesia
memories formed after the trauma or brain damage are lost
Patient HM
suffered from anterograde amnesia following the removal of his hippocampus, demonstrating that the hippocampus is critical in the formation of new long-term memories. He had regular STM demonstrating the different brain mechanisms underlying STM & LTM
Clive Wearing
a concert pianist also suffered from anterograde amnesia following rare herpes that led to encephalitis and damage to the hippocampus
double dissociation
the gold standard of neuropsychological evidence for different mechanisms, where each function can be shown to be preserved while the other is compromised
patient KF
had a limited STM capacity following an accident, but a normal LTM. Researchers found that he had overlapped damage in the left hemisphere near regions of the parietal lobe that contribute to verbal processes
STM in Alzheimer’s patients
suffer from STM difficulties in the early stages of the disease and show less connectivity between the prefrontal lobe and the hippocampal regions than control patients
how does information enter LTM according to the modal model?
STM gradually transfers to LTM
what type of information is likely to enter LTM?
information that is retained in STM via rehearsal
maintenance rehearsal
repeating information over and over without any additional thought
elaborative rehearsal
repeating information over and over while elaborating on its meaning
what type of rehearsal leads to greater LTM encoding
elaborate rehearsal
serial position effect
States that if people are given a long sequence of words to remember and repeat, their performance often resembles a U-shaped curve (better at repeating information given at the beginning and the end)
primacy effect
better performance for words presented earlier
why does the primacy effect occur?
because words at the beginning of the sequence have a chance to be rehearsed because there is sufficient time, allowing them to be stored in LTM
recency effect
better performance for words presented later
why does the recency effect occur?
because words are still in STM
study-recall delay and the recency effect
the recency effect disappears when participants have to wait 30 seconds before recalling the words
who proposed the levels of processing theory?
Craik & Tulving
levels of processing theory
States that the depth of meaning during processing determines how likely an item is to be recalled
free-recall task
a type of memory task where participants must remember as many items as they can from a list without cues or prompts
Craik & Tulving, 1972 experiment
found that memory performance was greater for items considered in connection to other things (sentences as opposed to case or rhyme). Also found that when the answer to the question they asked was “yes”, people remembered the words better because they processed the meaning more deeply when they matched the question. Concluded that there are 3 levels of processing
what are the three levels of processing according to Craik & Tulving?
- Superficial processes (case, font, rereading)
- Creating associations (rhymes, pleasantness)
- Fitting into networks (How will I use this?)
Mnemonic devices
short-cut that can help improve your memory by allowing for deeper processing
who proposed transfer-appropriate processing
morris, 1977
transfer appropriate processing
Argues that how well information is remembered depends not only on how it was initially encoded but also on how well some later memory cue matches the way it was encoded
Morris, 1977 transfer-processing experiment
presented participants with words using the rhyme and sentence conditions employed by Craik & Tulving and tested their ability to remember the words in a free-recall & cued-recall task. Found that participants performed better in the cued-recall task when they had encoded words based on rhyming
Tulving & Pearlstone, 1966 transfer-processing experiment
had subjects learn lists of words that were members of different categories. Found that when they had no cues, they only remembered 40% of words, but when they had cues, they remembered 75%
encoding specificity
A principle in long-term memory retrieval in which a match in condition between encoding and retrieval facilitates recall
deep sea divers experiment
people remembered more words if they were underwater at encoding and retrieval or on land at encoding and retrieval
context-dependent memory
a memory benefit when the external conditions match between encoding and retrieval
state-dependent memory
a memory benefit when the internal conditions match between encoding and retrieval
the spacing effect
a benefit in LTM that occurs when information is repeated in spaced-out intervals
how far apart should information be spaced to take advantage of the spacing effect?
it’s best to space out information around 10-20% of the interval at which it will later need to be retrieved
testing effect
a benefit in LTM that occurs when people retrieve information on their own rather than observing it passively
explicit/declarative memory
memory that includes all of the information that can be verbally reported
episodic memory
a memory of events that have happened directly to us in our lives. Retrieve encoding context (what, where, when)
mental time travel
recalling episodic memory in sequence with sensory imagery
semantic memory
information is recalled as a set of facts without
retrieval of the context of learning
transformation of memories
Many memories begin as episodic and transform into semantic over time
patient KC
suffered damage to his hippocampus and surrounding areas. Following his accident, KC had no episodic memory but some of his semantic memory remained intact
Levine et al., 2004 fMRI & explicit memories experiment
recorded brain activity using fMRI as participants listened to themselves recite semantic and episodic memories. Found that when people heard semantic memory, the frontal and parietal lobes were activated, but when they heard episodic memories, the occipital and temporal lobes were activated.
what brain areas are activated by semantic memory?
frontal & parietal lobes
what brain areas are activated by episodic memory?
occipital & temporal lobes
implicit memory
A form of LTM that an individual doesn’t have explicit awareness of, but that affects their behaviour
procedural memory
a form of implicit memory consisting of knowledge of how to perform a task
prejudice
a type of implicit memory that refers to an inclination to automatically judge someone negatively or positively based on past experiences
IAT
detects underlying biases that people have towards certain groups by having participants make decisions as quickly as they can about whether certain words belong to a given category. Quicker reaction times indicate that concepts are more linked in the mind
familiarity effect
people will often rate something more favourably if they have encountered it before
Perfect & Askew, 1994 familiarity effect experiment
participants rated magazine ads more positively when they have previously seen them even when they didn’t remember having seen them
propaganda effect
a phenomenon in which people tend to rate statements they have heard before as being more likely to be true than statements they hadn’t heard before
what type of memory is conditioning?
implicit memory
amygdala
a pair of almond-shaped nuclei located in the two temporal lobes
what is the amygdala’s role in memory
involved in implicit fear conditioning
patient SM
experienced an absence of fear following bilateral amygdala damage
durability of implicit vs. explicit memory
Implicit memory tends to be less susceptible to forgetting than explicit memory
procedural memory & amnesia patients
People with amnesia like HM can be trained to learn new procedural tasks and their performance improves even if they don’t remember ever doing the task
what’s the basis of learning
stable changes taking place throughout various brain structures
consolidation
the process of making memories durable
two types of consolidation
systems & synaptic consolidation
synaptic consolidation
changes at the synapses of neurons that lead to long-term storage of memories
long-term potentiation
a form of synaptic consolidation in which a neuron becomes more likely to fire based on the same number of incoming neurotransmitters
why does long-term potentiation occur?
1) the sending neuron releases more neurotransmitters OR 2) the receiving neuron develops more receptor sites for the neurotransmitter to bind with
systems consolidation
a process of making long-term memories more durable based on connections between the cortical areas.
what brain structure is responsible for systems consolidation?
the hippocampus
hippocampal relay
a phenomenon in which sequences of brain activity in the hippocampus that occurred during behavioural activity are repeated or replayed in a sequence after the event
what is thought to be the the mechanism behind systems consolidation
hippocampal relay
what type of consolidation is quicker?
Systems consolidation is a much slower process than synaptic consolidation
when does the formation of fear responses occur?
We can form fear responses in response to previous experiences even if we have forgotten the original experience
Naming mnemonic example
ROY G. BIV for the colours of the rainbow
story mnemonic
create a story out of a list of words
method of Loci
associated pieces of information with a location or a visual image
methods of loci in non-experts
those in the mnemonic training condition performed better across all recall lengths
implications of memory for studying
- Review your work regularly at shorter sessions (spacing effect)
- Focus on important material at the beginning and end of sessions (primary and recency effects)
- Link what you are learning to what you know (depth of processing)
self-reference effect
relating words to oneself creates better memory
generation effect
generating words leads to better memory
context for encoding specificity can be…
- Internal state (ex. mood)
- External environment (ex. room)
Alcohol-dependent learning
people remembered things better if they were sober at encoding and retrieval or drunk at encoding and retrieval
memory in children with hippocampal damage
Episodic memory impairment: cannot copy images after a delay
Semantic memory preservation: normal factual knowledge
what brain structure controls episodic memory?
the hippocampus
semantic dementia
- Relatively spared at episodic memory tasks
- Impaired at word naming and picture matching tasks
anoetic consciousness
no awareness or personal engagement (implicit memory)
noetic consciousness
awareness, but no personal engagement (semantic memory)
autonoetic consciousness
awareness and personal engagement (episodic memory)
3 types of consciousness
anoetic, noetic, autonomic
personal semantics
Autobiographical facts and repeated events
evidence for episodic & semantic memory as a continuum
- Recent MRI studies have shown lots of overlap when people engage in semantic & episodic memory tasks
- Semantic knowledge can affect the ability to retrieve detailed instances
the reappearance hypothesis
An episodic memory trace is recalled the same way at each retrieval
It is reproduced not reconstructed
flashbulb memories
Vivid memories of significant events that are
- Emotionally arousing or shocking
- Retrieve specific details about the time and place when hearing about the event
flashbulb memories of 9/11 study
For flashbulb memories of 9/11, ratings of belief and recollection (vividness) increased over time. However, there was no detailed difference between flashbulb memories and everyday memories.
flashbulb memories of O.J. Simpson trial study
Participants who recalled the verdict for the O.J. Simpson murder trials experienced more distortions and changed recollections over time
flashbulb memories and new yorkers 9/11 study
Half of New Yorkers had flashbulb-like memories of 9/11. People who were physically closer to the World Trade Centre were more likely to remember this event as a flashbulb memory. This demonstrates that personal experiences shape flashbulb memories.
are flashbulb memories subject to change?
yes, flashbulb memory retrieval changes over time and is not resistant to memory distortion, even though memory feels strong for these events
how are episodic memory traces constructed?
During retrieval, the hippocampus binds together whatever details are accessed to form a representation of an episodic memory
memory consolidation mechanism
- The formation of stable cortical representations of memories
- Experiences are encoded and then consolidated into an LTM trace
memory reconsolidation mechanism
- When a trace representation becomes activated, it becomes unstable
- Cortical connections can be strengthened and modified during this time, which alters how the memory trace is reconsolidated
- Retrieval changes a memory trace
application of memory consolidation
Can be applied to fear and anxiety disorders by changing thought patterns during reconsolidation
distortion of memory
- We may infer the way things must have been in a recalled memory based on our schemas (interplay with semantic memory)
- We may include new and false information in the underlying memory trace
schemas
higher level representations that organize and categorize information, provide expectations about how things should occur
Barlett, 1932 “War of Ghosts” experiment
had participants read an unfamiliar Native American folk story, which did not match Western folk story schemas. Found that participants remembered a simplified version of the story and it became more conventional with repeated retrievals. They engaged in assimilation and alterations to match Western schemas
Miller & Gazzaninga scene consistency experiment
removed schema-consistent items from study scenes and had participants do an auditory word recognition test for items from the scene. Found that participants remembered study items better, but falsely endorsed seeing schema-congruent lures.
Deese, Roediger, McDermott (DRM)
Participants tend to falsely remember semantically related lure words more than unrelated words. Illustrates the influence of semantic memory on episodic memory.
false memories takeaways
- A familiar feeling can lead to incorrect associations
- Details can be added to memories during retrieval
the misattribution effect
- Retrieving familiar information from the wrong source
- A failure in source monitoring (not remembering the where or when)
leading questions and memory formation
Leading questions can cause false memory formation
car crash study
Participants viewed a simulated car crash and depending on how the question was asked, they estimated different speeds of the cars
implanting childhood memories study
participants recalled childhood experiences that were recounted by their parents over three experimental sessions. A false memory was added to the list of experiences by the experimenter and by the third session, 20% of people had a false memory of this event
memories of the past vs. future
The same processes that help us construct the past help us imagine the future and plan for lives
fMRI and planning the future study
looked at brain activity when people are thinking about a past event or imaging a future event. Found that there was significant overlap in the hippocampus during these two tasks.
benefits of reconstructive memory
- The mental stimulation of novel events
- Useful to solve problems, plan for the future, and be creative
benefit of prior knowledge
- memory integration
memory integration
related memories become interconnected via the medial PFC and hippocampal processes to form generalized knowledge
role of medial PFC in memory
prior knowledge
role of the hippocampus in memory
encoding episodic memories
how do we encode overlapping events?
we encode a combined event, allowing us to make inferences about things we’ve never seen before
types of implicit memory
- procedural memory
- priming
- conditioning
- emotional responses
role of the basal ganglia in procedural memory
motor sequence
role of the PFC in procedural memory
organization
what differentiates procedural memory from other types of memory
- More immune to forgetting compared to other types of memory
- Longer evolutionary history than other forms of memory
what type of memory are involved in habits?
Initially rely on explicit memory, but with training or exposure, they rely on implicit memory
examples of habits
- Motor action sequences
- Repetitive thoughts and emotions (OCD)
- Basis of some addictions
what part of the brain is required for habit formation?
the striatum
what part of the brain monitors habits?
the PFC
what part of the brain is required for breaking habits?
requires inhibiting the PFC
how to change habits?
we have to replace the habit behaviour with something else, not just simply remove the reward
priming
Prior exposure facilitates information processing without awareness
word-fragment completion test
- First, participants were shown a list of words
- Then, they are asked to complete word fragments with the first word that comes to mind
- Result: people are likely to use prior words to complete the fragments
implicit emotional responses
An automatic, conditioned arousal response
what part of the brain is critical for implicit emotional memory?
the amygdala
why are emotional memories adaptive?
they help us stay away from dangerous stimuli
people without amygdala responses
experience dampened emotional and fear reponses
how do semantic memories store concepts?
Semantic concepts are stored in a network that goes from general to specific
units
individual concepts
properties
things that describe concepts
pointers/links
specify the relation between a concept and its features and the relationship of concepts to one another
spreading activation
Automatic activation spreads from an activated concept to other interconnected aspects (process)
semantic priming
related ideas triggered at retrieval (behaviour)
how are semantic representations structured?
Modality-specific representational forms of concepts
How are semantic memories stored in convergence zones?
abstracted representations
who had anterograde amnesia?
Clive Wearing & HM
what memories are most affected by retrograde amnesia?
according to Ribot’s law, they are temporally graded; the most recent memories are more affected than more remote memories because they don’t rely as much on the hippocampus
dissociative amnesia
a rare psychiatric disorder that commonly involves retrograde amnesia for episodic memories and autobiographical knowledge
effects of dissociative amnesia on lifestyle
Results in a loss of identity, which leads to shifts in lifestyle such as moving to a new place and assuming a new identity
what causes dissociative amnesia?
Usually a response from psychological or physical trauma (NOT brain injury)
brain irregularities in dissociative amnesia patients
Hypometabolism (reduced activity) in the lateral PFC, resulting in impaired executive processes
what type of deficit is dissociative amnesia?
retrieval
dementia
progressive cognitive and functional impairments due to neuronal death
frequency of Alzheimer’s disease
63% of all dementia cases are Alzheimer’s disease
what is the first symptom of Alzheimer’s disease?
a deficit in episodic memory
what brain area is the first to be affected by AD pathology?
Medial temporal lobe (MTL)
mild cognitive impairment due to AD
- spreads to lateral temporal and parietal lobes
- symptoms include reading problems, poor object recognition, and poor direction sense
moderate cognitive impairment due to AD
- spreads to the frontal lobe
- symptoms include poor judgment, impulsivity, and short attention
severe cognitive impairment due to AD
- widespread brain atrophy
- symptoms include loss of language, basic motor skills, and function problems
music and AD patients
- AD patients can learn and play songs
- Recognition of familiar songs remains intact
- Music creates an alternative procedural memory pathway
- It improves mood, reduces stress, and improves cognition
where does neurodegeneration begin in semantic dementia
left anterior temporal lobe
left anterior temporal lobe
convergence zone for semantic concept representations
semantic dementia
- Deficits recognizing faces of friends, words, and uses of objects
- A loss of word meaning and finding (anomia)
- Impairments naming the function of objects
- Problems accessing fine-grained information about concepts
rate of volume loss in healthy aging
~5% per decade after age 40
what parts of memory are most impacted by aging?
- Episodic memory and working memory are impaired
- The hippocampus and PFC are most affected
domain-general cognitive aging theories
Older adults have deficits in general executive cognitive processes from frontal lobe atrophy
associative deficit hypothesis
Older adults have problems encoding and retrieving associations in memory due to hippocampal activity
familarity of single objects
recognizing a face (non-hippocampal)
recollection
remembering a face and place (hippocampal)
name-face assocaitive recognition task in older vs. younger adults
Young people using divided attention performed better than older adults at a name-face associative recognition task
adaptive cognitive aging study
- Had young adults, high memory performing old adults, and low-memory-performing old adults undergo a memory test in a scanner
- Results showed that young adults and old low-memory performing adults recruited the right PFC but old high-memory performing adults used the bilateral PFC, providing evidence of neural compensation
flashbulb memories vs. regular memories
No real difference in their content, but rather in the way they are experienced
the memory of London taxi drivers vs. bus drivers
Taxi drivers performed better on tests of spatial memory than bus drivers
brains of London taxi drivers vs. bus drivers
Taxi drivers have greater posterior hippocampi but smaller anterior hippocampi than bus drives
Posterior hippocampus volume in taxi drivers
is related to the year of experience as a taxi driver
Posterior hippocampus
important for spatial navigation
Highly Superior Autobiographical Memory (HSAM)
- HSAM people can remember every single day of their lives in detail
- HSAM doesn’t involve mnemonic strategies
- They don’t remember a list of words any better than the average person
- They don’t have a photographic memory
2 ways of testing HSAM abilities
dates quiz & public events quiz
dates quiz
describe a certain date (day of the week, what they did, etc.)
public events quiz
describe when a particular public event happened
downsides of superior memory
- Consistency in recalling memories (not forgetting details of the past) relates to OCD symptoms
- Problems with accessing general concept knowledge
Luria HSAM case study
HSAM Patient:
- Recalled conversations word for word
- Recalled detailed events from years ago
- Could reproduce 70 digits without error
