Lecture 9 + 10 + 11: Memory Flashcards
1
Q
Memory in daily life
A
Routines and habits
* Brushing teeth, Riding bike
The sense of self
* The facts you have about yourself develop from your experiences
Solving problems
* You recall similar experience to solve a current problem
Social functions
* You might recall a funny story to connect with a person
2
Q
Memory is not one thing
Clive Wearing
A
- Profound case of amnesia
*Clive Wearing’s memory was impaired, not other cognitive functions. Selective defecits to memory. - Not all aspects of Clive’s memory were impaired
* Knew his wife
* Could play the piano - There are various kinds of memory
* Distinct capacity, duration, and relation to consciousness
3
Q
Memory processing stages
A
Encoding
Creating separate memory traces to represent experiences
- inputing information into memory
- creating memory traces (pattern for past event) for experiences you want to remember
Storage
Retaining encoded memory traces
- With time, we can consolidate some experience to make it stay in memory
encoding –> storage is memory consolidation
Retrieval
A memory is recovered when a cue activates part of a stored memory trace
- Can be external = cue causes memory trace to be active
- or internal = thinking
- when you recover the memory stored, enters conscious awareness
4
Q
Forming and Retrieving a memory
A
- When you encode a memory, what you do essentially is you’re breaking apart that experience in different details from a memory and you store that memory as a pattern of these pieces.
- You are engaging in pattern seperation to form a memory trace and then overtime memory consilidatiion will form a ling term lasting memory as this pattern.
- At retrieval, what happens is part of the memory trace might be in your environment (queue) and trigger the activation of the entire memory trace (the rest of the pattern) and that is when you have a memory.
5
Q
What happens when you are forming and retrieving a memory… in the brain?
A
Encoding: A memory trace is formed as a hippocampal-cortical activity pattern. The hippocampus is important for encoding new memories. It encodes our memory as a pattern of brain activity across the cortex.
Storage: Via consolidation, a memory is transformed into a stable cortical pattern. The particular areas of the cortex that are involved depends on the memory. Ex: If it is very visual = very visual cortex.
Retrieval: Part of a memory trace is activated by a cue that triggers pattern completion. The cue overlaps with part of storage pattern and then you remember it. Through consolidation, the memory trace becomes independent of the hippocampus.
6
Q
Memory systems
What is the pathway of of an input to LTM?
A
- Memory systems are very information processing.
- There are different systems that information is passing through.
1) Sensory input: You take a quick scan of your environment with one of your senses.
2) Sensory memory: the important information is transferred here.
3) STM: Holds information for 30 secs
4) LTM: Important information that is rehearsed is encoded into LTM.
7
Q
Further describe sensory memory, short term memory and long term memory
A
STM:
- has a limited capacity store
- can only attend to something for 30 secs
- Working memory = manipulatee information in STM.
8
Q
Sensory memory
A
- Sensory memory is information that is presented to you in its most unprocessed form. Make quick decisions based on what’s in our environment.
- The first and a “temporary” stage of memory. Requires no conscious effort.
Different senses:- Gustatory memory
- Olfactory memory
- Echoic memory
- Sound-byte held for ~ 3 seconds
- Brief memory of sound, helps us seperate streams of sound very rapidly
- Ex: distinguish when one person vs another is talking
- Haptic memory
- Very brief memory of a touch
- Useful for gripping and grasping
- Iconic memory
-Millisecond visual memory
-A ‘persistence of vision’
9
Q
Iconic Memory: Afterimages
A
Positive afterimage
* A visual memory that represents the perceived image
* Original image you saw it perceived in your memory
Negative afterimage
* A visual memory is the inverse of the perceived image
10
Q
A
- Both of these examples you see for a very brief period
- You see the same image colours are inverted due to receptors being over used.
- Negative afterimage
11
Q
How long does [sensory] memory last?
A
- Sperling (1960)
- Participants briefly (.05 seconds) viewed a visual display (3*4 letters)
- They showed a visual display very quickly
- Recalled the letters
- Whole report: reported letters from the whole display
- Partial report: reported only one row of letters at a time over trials
12
Q
Whole report
A
Report any and all of the letters that they saw from a brief flash of display
* people could remember about 4 or 5 out of 12.
13
Q
Partial Report
A
They heard one of 3 beeps.
* Before the xperiment started, they learned that each beep was associated with one of the 3 rows.
* They did not know what letters they would have to recall.
* He played different tones at different delays.
14
Q
What was the result of the whole report vs partial report condition?
How long does [sensory] memory last?
A
- There is a time delay between the visual display and the tone indicating what people should recall. The delay goes from 0 - 1sec.
- People can recall almost all the letters in the row when the tone is presented shortly after the visual display.
- For the whole report condition, participants are recalling very few words.
- These findings tell us that the sensory capacity is quite large. People can remember or recall a lot of information from sensory memory but only for a short period of time. People’s memory significantly decreased when the delay was increased to one second.
15
Q
Short term memory
A
- Attended information moves from sensory to short term memory. Intermediate between sensory and long term memory.
- The prefrontal cortex
- Limited time capacity: ~ 20 to 30 seconds (lasts longer than sensory).
- Limited capacity: “magical number seven plus or minus two” –> this is why phone numbers used to be 7 digits.
16
Q
Serial Position effects
A
- We do not forget information equally.
- The order that you learn it in will affect how you learn it and forget it.
17
Q
Primacy effects
A
Rehearsal –> long term memory
* You remember the first item/items presented early on the list because they often have the most rehearsal and can benefit from long term memory; accessing early words are supported by short term and long term memory.
18
Q
Recency effect
A
- If the study-recall delay duration > 30s, this effect is eliminated. If you go over the capacity of short term memory, the recency effect dissapears.
- The final items on the list are remembered very well by people.
- The recency affect is based only on short term memory processes.
*
19
Q
How can one enhance short term memory?
A
- Chunking
- Grouping items together in a meaningful way so more
information to be represented at one time (free up some space) - With chunking, you need to use some kind of knowledge.
- Remember these letters:
HEN CAT DOG PIG COW
20
Q
Chunking Effect
Chess study
A
- Chunking increases with knowledge
- Expert chess players recall more pieces on a chess board than new chess players. This only works when the pieces are arranged as an actual game in chess because they use their knowledge of chess moves.
- Experts use knowledge of moves to ‘chunk’ pieces together
- This effect is not present if the pieces are on the board randomly
21
Q
Working memory model
A
- How we hold information in the short term
Central executive:
* Manages and manipulates information in your short term.
* Moves us from the idea that short term memory is static to something that is actually very dynamic. We can process information and manipulate it online.
22
Q
Seperate short term memory stores
A
Neuroimaging studies
* Different areas of the brain are active for visual and verbal short term memory tasks
ex: if you hold an image or a song in your brain, when we scan your brain, we would fid different activity patterns. Visual and verbal short term memory stores must rely on distinct neural processes.
Double dissociation in neuropsychological cases
* Patient ELD has problems recalling visual-spatial but not verbal material in the short term. Can hold verbal but not not an image.
* Patient PV has problems recalling verbal but not visual material in the short term. Opposite of above.
Neuropsychological cases have found a dissociation between these forms of short term memory storage in cases of brain damage. Damage in the brain can lead to selective problems in the brain.
23
Q
Verbal Working memory: Phonological loop
A
** Phonological store:** Passive store for verbal information
* “The inner ear”
* Holds verbal information online
Articulatory control loop: Active rehearsal of verbal information
* “The inner voice”
* Helps you rehearse verbal information.
* Used to convert written material into sounds (reading)
* A specialized role in language
24
Q
Visuospatial sketchpad
A
The visual cache
* information about visual features (form, color and other)
Ex: remembering the color of someones dress in an episode in STM.
The inner scribe
* information about spatial location, movement and sequences
Ex: Holding in mind the sequence of the person dancing in STM.
You can dissociate these types of information: visual, verbal in working memory. This means that there can be a lot of variation and individual differences in people’s working memory system. Some people might be very good at holding visual information (visual catche) whereas others are very good at holding verbal information (inner scribe).
25
The working memory model: The
episodic buffer
Integrates information from short and long term memory
* Researchers added another element to this model called the episodic buffer.
* It is taking the informattion that is brought to you by sensory memory but you also have to bring information from your long term memory store. It helps explain how we can bring information from not only long term memory and sensory memory but also we can bring information together from these differentt storehouses.
* Without a episodic buffer it is hard to understand how something occurred.
* These models are not staic. We always update and change them.
26
Moving information to the long term
Encoding = when info from STM goes to LTM
Retrieval = A cue activates a memory. Something activates our patterrn of memory so that it is brought to our attention.
27
Ebbinghaus
* Tested how encoded nonsense syllables were retained and forgotten from memory over time
* He was testing how he himself could remember sets of these nonsense syllables which were in triplets of two consonants and a vowel, so they had no meaning so he could not access or use any knowledge.
- he had to remember these, no chunking.
28
Ebbinghaus result
* Created over 2000 cards of nonsense syllables
* Learned and relearned sets of the syllables under strict testing conditions
* Read the syllables without any inflection (read them very slowly to himself)
* Read them at a consistently fast pace: 2.5 items per second
* He did nothing else while running these experiments (Remove any sort of confounds)
29
The forgetting curve
* Forgetting is exponential
* Memory loss is largest early on and slows down
* This is the result from Ebbinghaus but was also replicated so many times with animals.
* Rate of forgetting is really fast initially.
* The initial strenght of the memory is very strong if you encode it very well and then you see a steep drop off in the strenght of the memory meaning a lot of information is forgotten early on and then it sort of flattens out. Memory loss is bigger ealry on
29
The spacing effect
* Memory is better when the same amount of learning is spread out over time.
* You are most likely to remember information, if you learn it at different time periods rather than all at once.
* You need to take breaks between encoding information.
* It is also important that there is variations between the sessions, it is not always the same time.
30
Theories of forgetting
**Decay Theory**
* Forgetting from time
* We forget information simply from the passing of time. Information is just going to fade away.
**Interference Theory**
* Forgetting from interfering information
* Information that is processed between or before encoding and retrieval effects what we can remember
31
Interference Theory
**Retroactive interference (‘backward in time’)**
* Newly learned information interferes with old
information
* E.g., Trouble remembering your old phone number
**Proactive interference (‘forward in time’)**
* Previously learned material interferes with new
information.
* Trouble learning something new because you keep remembering a new one.
* E.g., Trouble learning a new phone number
32
Proactive interference
*Previously learned material interferes with new material
* I lived by Parc Lafontaine and took my dog there
* After moving near Parc Marquette, someone asks me at which park I now walk my dog, and I say “ Lafontaine!”
33
Retroactive Interference
* New information interferes with the recall of old information
* I take my dog to Parc Marquette
* Someone asks me which park I first walked my dog, I say ‘Parc Marquette’ and not ‘Parc Lafontaine’!
34
Getting Information into memory
* Levels of processing: the strength of a memory depends on the depth of processing when encoding
* The approach that you take to form a memory trace will depend on how well it can be activated later on
* Memories can be processed at different levels
* Focus on sensory information (shallow processing) à integrate higher-level knowledge (things we know/ figuring out the meaning; deep processing)
* Memory is stronger with deep processing
35
Deep and Shallow encoding of faces
When you have to think about something in terms of the meaning, you have to evaluate it and link it to prior knowledge.
Shallow condition: people decided if the face was upright or inverted.
Deep condition: The person presented to them looked more like an actor or politician --> forced to think about that person at a deep, meaningful level.
Result: people recognized the faces in the deep encoding condition more than in that shallow encoding condition.
People are much better at remembering faces in the upright orientation then when its inverted. You process the face as one sort of unitized object. Inverted faces do not have that priveledge so its harder to recognize those faces.
The depth of processing an item will determine how well you can remember it.
36
Mnemonics
*Organizational strategies that help encode to-be-remembered information
* Often involves chunking
* Naming mnemonic: "ROY G. BIV" for the colors of the rainbow
* Story mnemonic: Create a story out of a list of words
* Method of Loci: Associate pieces of information with a location or a visual image
37
‘Method of Loci’ in non-experts
Three participant groups
* Mnemonic training group
* Active control group
* Passive control group
Memory assessed with word lists at
* 20 minutes, 24 hour and 4 months
* Measured the change in the number of words remembered at these timepoints
They were all given a memory test in which they had to learn and remember a list of 72 words and they had to remember this at different time points.
The group that learned the method of Loci actually had improvements in their ability to retain words from the list.
There were different neural connections in the people who werre trained with the method of loci. If you engage in different strategiess for your memory that it can really have lasting effectss and leave a neural imprint.
38
Implications for studying
* Review your work regularly at shorter sessions (spacing effect)
* Focus on important material at the beginning and end
of sessions (primacy and recency effects)
* Link what you are learning to what you know (depth of
processing)
39
What's important about working memory?
* It has a limited capacity and duration
* It is where incoming information can relate to prior knowledge and be manipulated
* It is where information enters consciousness and awareness
* It is critical for long-term memory formation
40
Working memory model
* Working memory components are dissociable in the brain.
* They are processed in their respective processing areas.
* Central executive: manuipulating and processing of information
41
Working memory components work together
* How many windows are in your house?
* **Episodic buffer** – access information
from long-term memory
* **Visuospatial sketchpad** – imagine the
layout
* **Phonological loop** - count the number of windows
* **Central executive** - guide the process (coordinate processes together)
42
Go deep for the long term
* Attaching information to prior knowledge within working memory will help form lasting memories.
* Meaningful encoding iss best for forming lasting memories.
43
Deep encoding
* Self-reference effect (link itt to prior knowledge)
1. Do these adjectives describe you? Happy, Talkative
2. Are these common words? Happy, Talkative
* The first condition led to better memor (Leshikar et al., 2015)
* Generation effect (when you generate content rather than read content, you will remember it better)
1. Read these pairs: king – crown; horse - saddle
2. Generate the word: K___g – crown; H___e-saddle
* The second led to better memory (Norman et al., 1978)
44
The encoding specificity hypothesis
* Memory retrieval is better when there is overlap with encoding context (overlap with encoding and retrieval context)
* Context can act as a retrieval cue
* Context can be:
* Internal state (e.g., mood)
* External environment (e.g., room)
45
State-dependent learning
Alcohol dependent learning
* Memory was better for individuals that were sober at learning and recall
* Drunk at both was better than mistmatch. Stronger match between state at learning and recall will facilitate learning.
46
External Context
* Participants: Deep sea divers
* Encoded/retrieved words
* Encode: On land ; Recall: On land
* Encode: Underwater; Recall: Underwater
* Encode: On land ; Recall: Underwater
* Encode: Underwater ; Recall: On land
47
Long term memory
Semantic: culturally shared general knowledge
Episodic memory: spatial and context
48
Episodic and semantic memory
* **Episodic memory:** specific events and episodes
* Retrieve encoding context (what, where and
when)
* “Dancing at my high school prom”
* Ability to learn and remember particular events. Need to remember the context (what, where and when)
* * **Semantic memory:** facts and general information
* No retrieval of context of learning
* “Proms occur at the end of high school”
* Recalling facts and general info about you or something. Does not require you to kow the what and when.
49
Episodic memory and the hippocampus
* Children with hippocampal damage
* Episodic memory impairment: Cannot copy images after a delay
* Semantic memory preservation: Normal factual knowledge
* Episodic is dependent on the hippocampus
* Amnesia is often regarded as a condition where episodic memory is impaired - damage to hippocampus
50
Semantic Dementia
* Different from Alzeihmer's
* Relatively spared at episodic memory tasks
* Impaired at word naming and picture matching tasks --> cannot access facts
51
Patient KC
* Can recognize his own inspection report.
* Recognize his own writing
* Cannot remember where whe worked
* Can answer semantic questions about his past but not about specific episodes/instances.
52
Long term memory may be a matter of consciousness?
implicit memory: us doing procedures - not consciously aware in remembering how to engage in these processes.
Episodic memories: by nature these memories are self reflective (what makes us human)
53
An intermediary (between episodic and semantic): Personal semantics
- Facts we have about ourselves or general workings about autobiographical events.
- Now, this idea that we have personal semantics, or maybe there's some blurring between episodic and semantic memory, comes from early case studies of people with amnesia.
54
Semantic and episodic neural overlap
* Episodic and semantic memory might lie on a continuum rather than be separate systems.
* They overlap quite a bit: you are often not remembering a semantic memory vs an episodic memory - they are very interconnected.
* These results have prompted researchers to think that maybe episodic and semantic memories are not separate systems but are actually on a continuum.
* Recent fMRI studies have found a lot of overlap in activity when people engage in episodic and semantic memory tasks.
* Looked at the common areas among the semantic tasks and episodic tasks within the default mode network: important for forming internal representations or thinking about knowledge.
55
Blurring the lines of retrieval
* Semantic knowledge can affect the ability to retrieve detailed instances.
* If you are really at one end of the continuum you might have trouble accessing info from the other end.
* Draw a bicycle from memory -artist then created structures from drawing - people forgot a lot of aspects of the bike.
56
Episodic memory: The reappearance hypothesis
* We build or construct memories every time we remember something - was not always the case.
*An episodic memory trace is recalled the same way at each retrieval
* It is reproduced, not reconstructed
* Based on clinical observations that recurrent memories are unchanged from the original event in cases like PTSD - rooted in observations of people with PTSD in the same way so that memory trace must be fixed.
* Does this happen for highly emotional memories? Memories that are associated with PTSD -flashbulb memories
57
Flashbulb memories
* Vivid memories of significant events (emotional or suprising events)
* Where were you when you learned that ….
* Donald Trump was elected?
* Kobe Byrant died?
* Vivid memories of significant events that are:
* Emotionally arousing or shocking events
* Retrieve specific details about the time and place when hearing about the event
* These are imprinted in mind and do not change.
58
Are flashbulb memories special?
* Collected memories from event and random autobiographical events
* Recall 9/11 (flashbulb) and other autobiographical events at these
delays:
* Dependent variables:
* details used to describe these events
* ratings on vividness of the recollection
* belief and confidence in their memory
Asked the people to rate their experience for remembering the even through many different scales.
59
Are flashbulb memories special?
* Scored detailed descriptions across retrievals for
* details that didn’t change over time (consistent details) = events consistently remembered at every time point.
* details that changed over time (inconsistent details) = switch an aspect of your recollection/memory.
60
Are flashbulb memories special?
* Objectively the memories are changing.
* What you find is that people rated their experience of remembering flashbulb memories as more vividly recollected and with more belief and confidence overtime.
* So there was no diminish in the vivid recollection or the belief that what they were saying was accurate for flashbulb memories, but you do see those ratings declined for every day events
61
Flashbulb memories change
* The 1997 verdict for the O.J. Simpson murder trial
* Participants recalled the verdict and rated emotional
reaction initially and then 15 months and 32 months delay (for 80% of individuals this was a subjective memory)
* From initial to 15 months, 50% recollections changed
(inaccurate)
* From initial to 32 months, 70% recollections changed
(inaccurate); 40% major distortions
=change the details of what happened.
62
Forming Flashbulb memories
- The distance from the site of a disaster. What led individuals to have a flashback vs not. Closer they were to the trade building the more likely they were to say that they experienced 911 as a flashbulb memory.
* New Yorkers recalled memories of 9/11
* Half of the participants has a flashbulb-like memory for this event predicted by distance to the World Trade Center
63
Flashbulb memories do not reappear
* Flashbulb memories are not recurrent recordings of events
* Flashbulb memory retrieval changes over time and are not resistant (they change overtime) to memory distortion, even though memory feels strong for these events
* Distinction subjective and objective memory
* Accept the theory that memories are reconstructed
64
Constructing and episodic memory trace
* A memory that you have has a bunch of different details (sights, sound, smell...). These are processed in different regions of the brain.
* Hippocampus is really important for episodic memory.
* During retrieval, the hippocampus is going to bind together whatever details are accessed and activated at that time of retrieval to form a representation of an episodic memory.
* Because the hippocampus is binding or bringing together these details, you can remember the same event with different sets of combination of details depending on the time that you are remembering them.
65
Memory consolidation
* Experiences are encoded and then consolidated into a long term memory trace
* The formation of stable cortical representations of memories
* Memories change upon retrieval.
* How you retrieve a memory might change the underlying memory trace.
* Consolidation is forming a permanent memory and when this trace is reactivated from long term memory it becomes destabilized and malleable (fragile).
66
Memory Re-consolidation
* When a trace representation becomes activated, it becomes de-stable
* Cortical connections can be strengthened and modified during this time, which alters how the memory trace is reconsolidated
* Retrieval changes a memory trace
* Process of re-consolidation can cause corrections or alterations within that cortical network.
67
Application of re-consolidation
* PTSD, Phobias
* The brain stores and restores memories.
* Use fMRI to understand how the brain processes fear.
* Can use the knowledge of how are brain stores and restores memories to manipulate our memories in a way that we get rid of fear.
* Developed a technique to block the return of fear.
* Paired a yellow square with a shock. During reconsolidation, they have a window of time (10 mins after consolidation to 1 hour), during this time we are able to add to the file (memory).
- Show them yellow square many times with no shock so now they are learning the yellow square is safe. "essentially rewrote that file" Stored as a "safe yellow square".
68
Memory reconstruction
* Reconstructing memories at retrieval open them up to distortion
* 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
* Memories are constructive which is a good thing, it might help you be more flexible with your thinking
69
Schemas distort memories
* Schemas help us organize and categorize new information, provide expectations about how things should occur
* They are safe predictions about how events will unfold and how people are going to act. They can effect the way that we encode new information.
* Bartlett (1932)
* The War of Ghosts experiments
* Participants read an unfamiliar Native American folk story
* Content: young men hunting seals in a river with unfamiliar supernatural details to tested participants
* Did not match Western folk story structure (schema)
* Examined how the story changed with repeated retrievals
*Bartlett was looking at how these participants might change this novel story and if they did this to align it with their schemas.
70
The War of Ghosts experiments (results)
* Participants remembered a simplified version of the story and it became more conventional with repeated retrievals (the story would lose details overtime).
* Memories changed to match people's schemas or expectations of what would happen in an event like the one that was being described.
* Engaged in assimilation: changing new, learned information to match our schemas
* Omissions and alterations to match Western schema
* Excluded uncommon details; “a black thing rushed out of his mouth”
* Changed uncommon activities to conventional activities, according to their schemas: Hunting seals became fishing
71
Schemas can lead to false memories
* Study scenes associated with schema consistent items removed
* Classroom without a chalkboard (remove element strongly correlated with schema of classroom).
* Auditory word recognition test for items from the scenes
* Studied items: “Desks”
* Schema-related lures: “Chalkboard” --> falsely indorse having memory of chalkboard.
* Non-schema-related items: “Ball”
72
Deese, Roediger, McDermott (DRM)
* Studied words all related to a category and then asked if they saw that word.
* Participants tend to falsely remember semantically related lure words (Sweet - similar in terms of meaning) more than unrelated words
* Illustrates the influence semantic memory (expectations) on episodic memory
73
False Memories
1. A familiar feeling can lead to incorrect associations
2. Details can be added to memories during retrieval
- Memories can be distorted
- Feeling of familiarity can lead to misremembering information because you retrieve the information from the wrong stream.
74
The Misattribution effect
* Retrieving familiar information from the wrong source (place)
* A failure in source monitoring (not remembering the where or when accurately)
* Misattribute something to the wrong memory.
75
The Misinformation effect
* Leading questions can cause false memory
formation ( the way they ask someone to recollect information will change how they remember it)
* Participants viewed a simulated car crash and
after, asked:
* “how fast were the cars going when they
CONTACTED each other?”
* “how fast were the cars going when they
SMASHED into each other?”
Estimated speed based on how they asked about the crash ("smashed" = faster estimated speed than "contacted")
76
Implanting memories
* Participants recalled childhood experiences recounted by their parents over three experimental sessions. Came to the lab 3 times, collected memories from their parents, scientist would ask questions about memories that did not happen.
* A false memory was added to the list of experiences by the experimenter: An overnight stay in a hospital
* 20% of people had a false memory of this event by the end of the third session (some would describe it very detailed)
77
Virtues of reconstructive memory
* The same processes that help us construct the past help us imagine the future and plan for our lives
* These are processes of the hippocampal episodic
memory system
* A advantage of memories being reconstructive is that we can grab details from past events that we have experienced and imagine our future.
* Help us imagine new scenarios that we have never experienced before - helpful for decision making, creativity and problem solving.
This idea came from experiment where they compared fMRI of people thinking about past and imagining future events and what they found is that there is was astonishing overlap in the neural activity during these two tasks. A lot of overlap in the hippocampus, so the hippocampus is critical for constructing both past and future experiences.
You need your past to imagine your future.
78
Recap of memory pt 1 and 2
* Episodic memories are reconstructed at retrieval
* Memories are not reflections of the truth, and are subject to distortion
* Retrieving an episodic memory is something that is constructive - we construct them at retrieval. Our memories can be distorted - not exactly what we perceive.
* Episodic memories are impacted by prior knowledge
* We remember what we know
* Both can lead to false memories yet both characteristics are
adaptive
79
A benefit of reconstructive memory
1. Mental simulation of novel events
- You can stimulate events in your mind using hypocampal memory - hypothetical situations.
- These are helpful to plan for the future and figure out which plan will be most effective. Also allows you to be creative.
- Hippocampus can combine details from different memories to from novel mental simulations of events.
2. Useful to solve a problem; plan for the future; be creative
- Lets us predict how events could go wrong or right in the future.
- Important for survival
- Maybe episodic memories are for predicting the future (real function of episodic memories).
80
A benefit of prior knowledge
* Schemas can lead to distorted memories (War of the Ghosts experiment) and false retrieval (DRM studies)
- Schemas are conceptual knowledge frameworks
- If you flash a bunch of words that are related together - later on if you give a concept that is related to those words (that was not seen), they will likely to falsely indorse seeing that item.
* Memory integration: related memories become interconnected via medial prefrontal cortex (prior knowledge) – hippocampal (episodic) processes to form generalized knowledge
- Process that involves the medial PFC (processes schemas and prior knowledge) and the hippocampus. These two regions work together when you are encoding a new memory episodic memory to support memory integration. The medial PFC will activate memory or knowledge that is related to what episodic event is being processed. The related event (knowledge) and new event will be integrated together = interconnected generalized knowledge structure. You are essentially associating a new episodic event with prior knowledge.
* Generalize knowledge requires to make inferences about the world and think flexibly
81
Example of benefit of prior knowledge.
* Walking in a park and see a women walking dog in the park
* You will encode the women and the dog as a connected neural code = women/dog association.
* The next day, you see a man walking the same dog. Activate the previous memory because there is an overlap and then you will create a neural code that is incorporating the women and the man and the dog.
* This allows you to make inferences: the woman and the man know each other and share ownership of the dog.
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Long term memory
add image!
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Implicit memory: Procedural memory
* Use well established behaviours or skills without really thinking about it.
* Learned abilities to perform an automatic behavior/action (walking, swimming, riding a bike).
* The brain has encoded patterns of movements
* Basal Ganglia – motor sequence (refining action sequences, shaping procedures and habits) ; Prefrontal cortex - organization (organizing procedures and organizing them)
* More immune to forgetting compared to other types of memory
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Habits: Deliberate actions become routine
* Initially rely on explicit memory; with training and or exposure then rely on implicit memory
* Motor action sequences (e.g., remember your phone’s password by just moving your fingers over the pad) --> relies on procedural memory.
* Repetitive thoughts and emotions [Obsessive Compulsive Disorder (OCD)]
* Basis of some addictions - habits is the basis of a lot of adictions, they can be goof or bad.
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Forming and breaking habits
Habit Formation
* Rats trained on a T-shaped maze with tones to signal
reward (chocolate milk; sugar water) at left or right end
* One tone = turn left to get chocolate milk
* Other tone = turn right to get sugar.
*Formed the habit and were able to use the cue (tone) to turn and get their reward.
* Required the striatum
Breaking Habits
* Removing a reward at one end, or making one reward gross (non-rewarding) did not break the habit
* Required inhibiting prefrontal cortex, region that monitors habit. Link the habit of turning (movement) to particular rewards.
* Used optogenetics - inhibit cells in the PFC, this stop the rats from engaging in that habit. Even though these habits seem to be automatic, they are under the control of the PFC. That region has to be online for the habit to be acted.
* Replace the habit/behaviour with something else.
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Implicit memory: Priming
* Prior exposure facilitates information processing without awareness
* Word-fragment completion test
* First, participants shown a list of words
* Then, they are asked to complete word fragments
* Result: likely to use prior words to complete the fragments
People are more likely to complete the words with words that they previously saw even if they are not aware of it (implicit)
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Implicit emotional responses
* Conditioned emotional responses
* Fear response to snakes, the dark and other scary stimuli
* Automatic response to something scary, automatic arousal response
* Amygdala critical for implicit emotional memory (as well as modulating explicit memory … recall emotional enhancement effect on memory).
* amygdala is very important for these types of memories. Important to have this for survival - stay away from scary/dangerous things.
*Amygdala is also involved in explicit memories.
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No fear and no amygdala responses
Free Climbers!!
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Semantic memories
- Semantic memories is out abstract representation of knowledge. Semantic memories are often learned through repeated common episodic memories.
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How semantic memory stores concepts
* We store them within an interconnected network of them.
* The are stored in a network that goes from regenerating a knowledge at a general level then a more specific level.
* General concepts lined to its properties and features.
* Links beween 2 concepts
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Spreading activation in the semantic network
* Spreading activation
* Automatic activation spreads from an activated concept to other interconnected aspects
* Thinking about a canary will trigger activation in related bird concepts. If you are focusing on a canary and on a particular feature like it can sing, this can spread activation to other concepts that share that feature.
* Spreading activation to features
* This can explain how you can have a wild train of thoughts - concepts are activating each other through spreading.
* Semantic priming
* Related ideas triggered at retrieval
* Trains of thought that might seem nonsensical
* Activating a concept will effect processing other meaning based information or semantically related ideas.
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The structure of semantic representations
* These networks and your knowledge are dynamic - they will always update.
* Modality-specific representational forms of concepts
* E.g., Action, sound, emotion, color
* Widely distributed network for concepts - when we activate a concept, we activate the brain regions based on what we are thinking about for those regions.
* Evidence for abstracted representations in “convergence zones” (in red)
* inferior and lateral temporal lobes
* inferior parietal cortex
* concepts that are characterized by visual features (moose with big antlers activate the visual system). This suggests that maybe we store concepts in these perceptual processing complexes.
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Dissociation in long term memory: Amnesia
* Experimental neurosurgery to reduce seizure activity
* Bilateral medial temporal lobe, including the hippocampus, removed
* Selective episodic memory loss
HM case
- severe epilepsy, early on
- Experimental surgery - removed left and right medial temporal lobe.
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HM
* Intact short-term memory
* Can remember a short list of word for 30 seconds
* Intact procedural memory
* Could learn new skill-based tasks
* Intact semantic memory
* Could recall major historic events of childhood
* Profound episodic memory loss
* He couldn’t learn new information and recalled his past in sparse detail
Removed all of his hippocampus
- Early evidence that memory systems can dissociate.
- Could not retain or learn new episodic memories
- Could not remember people, places and thoughts so it was hard for him to learn more semantic memories.
- Permanently in the present: no past or future.
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HM (continued)
* He could not remember the people, places, and objects he saw, even after repeated encounters
* He forgot conversations
* He could not remember what he had eaten that day, or if he ate at all
* He had difficulty describing experiences that had occurred from his life
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Retrograde and anterograde amnesia
* Anterograde amnesia: the inability to form new episodic memories
* Clive Wearing (cannot form new conscious memories)
* The loss of memories from before the onset of amnesia
* Temporally graded, according to Ribot’s law
* Remote memories are less affected than recent memories. More recent memories are more affected then older or remote memories. Older memories do not rely on hippocampus.
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Dissociative amnesia (fudge state)
*Sometimes referred to as fuge state
* A very rare psychiatric disorder
* Varies widely in presentation.
* Commonly retrograde amnesia for episodic memories and autobiographical knowledge
* Leads to shifts in lifestyle such as moving to a new place, assuming a new identity
* Usually, a response to psychological or physical trauma (crime, death, abuse)
* You see a loss in personal identity. Big life shifts, ex: form a new identity. No awareness of their previous life (amnesia for their previous life).
* Not from brain injury or malingering
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Dissociative amnesia (pt 2)
* Hypometabolism in the lateral prefrontal cortex (reduced activity in the PFC not in the hippocampus). This suggests to us that this deficit is caused by executive processes that are supported by the PFC.
* Impaired executive processes
* A retrieval deficit, not a storage deficit issue
* Episodic events themselves are not effected, it is the retrieval of episodic events that are.
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Dementia
* Progressive cognitive and functional impairments due to neuronal death. Dementias are neurodegenerative diseases that result from cell death.
* 63% of all dementia cases are Alzheimer's disease
* Earliest symptom is a deficit in episodic memory (Collie & Maruff, 2000) - First sign of neurodegenerative disease are problems with episodic memories.
* Medial temporal lobe (MTL) regions are the first to be by AD pathology (Braak & Braak, 1991)
* Someone with alzheimers, in the earliest stages their episodic memory is impaired . Because this is a progressive disease the rest of the brain starts to be effected. Then you see decline in other forms of memory, emotion and personality.
* Increase risk: genetic factor, sleepchnia, clinical depression
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AD trajectory linked to the brain
Offset demantia:
- Sleeping well
- Engage your brain in a lot of different activities
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Alzheimer's disease and music
* AD patients can learn and play songs (Fornazzari, et al., 2006)
* Recognition of familiar songs intact in AD (Vanstone et al., 2009)
* Music creates an alternate procedural memory pathway
* Music improves mood, reduces stress ~ improves cognition
* Music can help people with alzheimers manage their symptoms. It can help them recover memories and emotions and perform cognitive tasks.
- One explanation is that music effects so many parts of the brain, including areas that might not be damaged early on.
- When music is used the spared pathways is procedural memories which is less effected in alzheimers can help reawaken memories.
- People with alzheimers are very good at recognizing familiar songs.
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Semantic Dementia
* Early on there is atrophy in the anterior temporal lobe. This is a convergent zone, it is a hub for conceptual meaning - you represent info abstractly.
* People with amnesia have trouble with accessing concept knowledge. Semantic memory network is broken.
* Neurodegeneration begins in the left anterior temporal lobe
* Convergence zone for semantic concept representations
* Deficits recognizing faces of friends, words, and uses of objects, loss of fine grain information about concepts.
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Semantic dementia (continued)
* A loss of word meaning and finding (anomia)
* Calls common objects ‘thingys’
* Impairments naming function of objects
* Problems accessing fine-grained information about concepts
* All four-legged animals are considered dogs
* Will draw a camel without atypical features
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Healthy aging
* Volume loss ~ 5% per decade after age of 40 (volume of our brain shrinks)
* Not all areas affected equally
* Primary effects on PFC and hippocampus --> will therefore impact memory.
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Healthy again (continued)
* Implicit memory is intact
* Semantic memory intact (vocabulary and concept knowledge is maintained)
* Episodic memory (and working memory) is impaired - being able to remember what they did, where and flashbulb memories.
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Domain-general cognitive aging theories
* Older adults have deficits in general executive cognitive processes from frontal lobe atrophy. General cognitive executive processes that decline from frontal lobe atrophy.
* Slower at processing information
* Can’t inhibit irrelevant information
* Older adults will have trouble focusing on one
picture and ignore all other pictures on a busy wall (hard time focusing their attention and inhibiting other things surrounding.
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The associative deficit hypothesis
* Problems associating things together within episodic memory.
* Older adults have problems encoding and retrieving
associations in memory due to hippocampal atrophy
* Familiarity or single items: recognizing a face (non-hippocampal)
* I know I know you from somewhere … They can recognize something/someone
* Recollection: remembering a face and place (hippocampal)
* I know you from the dog park and we met yesterday morning. remembering that they know somebody from where.
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The associative deficit hypothesis (continued)
* Younger adults: 20 years old; Older adults: 72 years old
*Studied name faces and name-faces airs
* Presented with the name and then two faces and had to say which was paired with it.
* Their deficit in the name-face associative test was far more severe.
* Added new set of young adults under divided attention (their attention was split) - they still outperformed the older adult.
* Not due to genera attentional problems.
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Adaptive cognitive aging
Testing groups:
* Young adults (YA)
* High memory performing old adults (Old-high)
* Low memory performing old adults (Old-low)
* Memory test in the scanner showed that YA and Old-low recruited the right PFC but Old-high recruited the bilateral PFC
* Evidence of neural compensation
This suggests that as we get older, the older adults that are aging well are engaging in neural compensation. They have more bilateral activity of their cortex to help compensate for any deficit.
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Cases of extreme memory: Taxi drivers
* Memory and space are intimately linked
* ‘The knowledge’: memorize a labyrinth of 25,000 streets within a 10- kilometer radius
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London Taxi Driver
* Superior memory: great spacial memory
* Increase in hippocampus
* Taxi drivers performed better on tests of spatial memory than bus drivers, due to greater posterior hippocampus grey matter volumes
* The volume of the posterior hippocampus in taxi drivers is related to years of experience as a taxi driver
* The posterior hippocampal section is important for spatial navigation
* A larger posterior hippocampus in taxi drivers comes with a reduced anterior hippocampus.
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Highly superior autobiographical memory
* HSAM people can remember every single day from their lives in detail
* Enhanced Autobiographical memory
* Recalling very detailed daily memories
* HSAM does not involve mnemonic strategies
* These are not memory athletes
* This is not photographic memory
* HSAM people do not remember a word list any better than the average person
* HSAM is specific to autobiographical memory
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Downsides of superior memory
*Consistency in recalling memories (not forgetting details of the past) relates to OCD symptoms
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Individual differences in remembering
* Episodic remembering
* Retrieve vivid details and rich images
* Semantic remembering
* Retrieve the associated facts and thematic links
