6 - Memory Flashcards
highly superior autobiographical memory
can remember their life really well like give them a date and they can remember exactly what they were doing that day and who they were with, etc
memory
the ability to store and retrieve information over time, residue of evidence of things we have thought/felt/done/experience
three key functions of memory
encoding, storage, retrieval
encoding
the process of transforming what we perceive, think, or feel into an enduring memory
storage
the process of maintaining information in memory over time
retrieval
the process of bringing to mind information that has been previously encoded and stored
people think that memory as a recording device that makes exact copies of information that comes in through our senses, then stores these copies for later used is…
simple, intuitive, and completely incorrect
How are memories made
by combining information we already have in our brains with new information that comes in through our senses
Memories are
constructed
three types of encoding processes
semantic, visual imagery, organizational
how we remember something depends on…
how we think about it at the time
semantic encoding
the process of relating new information in a meaningful way to knowledge that is already stored in memory
visual imagery encoding
the process of storing new information by converting it into mental pictures (shopping list + walking through house)
Why does visual image encoding work so well?
relates incoming information to knowledge already in memory
End up with two different mental placeholders for the items (visual and verbal)
What part of the brain does visual imagery encoding activate?
visual processing regions in occipital lobe; suggests people actually enlist the visual system when forming memories based on mental images
organizational encoding
the process of categorizing information according to the relationships among a series of items (servers at a restaurant)
memory and evolution study
three groups. one was asked to imagine they were on a deserted island and rated words based on how relevant it would be in the hypothetical situation, another was asked to image moving into a new home in foreign land, rated how useful the word would be in helping them set up a new home, and third group was asked to rate the words for their pleasantness. the people in the survival-encoding groups remembered more words than other non-survival-encoding tasks. also those in tasks that involved planning but not survival had good recall
sensory memory
a type of storage that holds sensory information for a few seconds or less
Iconic Memory Test
participants were flashed a grid of letters (3x4) for 1/20th of a second. when asked to rememeber all 12 letters, they remembered less than half. they could remember any row immediately after the grid was shown with high accuracy, showing that people could have recalled the same number of letters from any of the rows, but the information fades away too quickly for a person to recall everything
iconic memory
fast-decaying store of visual information
echoic memory
fast decaying store of auditory information
short term memory
holds non-sensory information for more than a few seconds but less than a minute
how long does short term memory last?
(class) 20-30 seconds
(textbook) 15-20 seconds
rehearsal
the process of keeping information in short term memory by mentally repeating it
how is short term memory limited
how long it can hold information and how much it can hold
how much information can short term memory hold?
7± 2 meaningful items
chunking
combining small pieces of information into larger clusters or chunks that are more easily held in short term memory
working memory
active maintenance of information in short term storage
what does working memory include?
the visual representation of the positions of the pieces, your mental manipulation of the possible moves, and your awareness of the flow of information into and out of memory, all stored for a limited amount of time
working memory model acknowledges…
both the limited nature of this kind of memory storage and the activities that are commonly associated with it
Experiment on the decline of short term memory
participants were given consonant strings to remember like CMD and HLS. After seeing the string, participants were asked to count backward from 100 by 3 for varying amounts of time and were then asked to recall the strings. Results: 80% after 3 second delay, <20% after 20 second delay
What suggest a link between the working memory system and the ability to learn language?
people with neurological damage to the verbal subsystem of working memory have problems holding onto strings of digits and letters for a few seconds, and difficulty learning novel words
working memory training
improved performance on the working memory task that was trained, but not in any other cognitive tasks
long term memory
a type of storage that holds information for hours, days, weeks, or years; no known capacity limits
Long-term memory and yearbooks
People can recall items from long term memory even if they haven’t thought of them for years. Even 50 years after graduation, people can accurately recognize about 90% of their high school classmates from yearbook photographs
HM
27 year old, suffered from intractable epilepsy. Temporal lobes removed, including the hippocampus and some surrounding regions. After surgery, HM could converse well, perform well on intelligence tests, etc, but he could not remember anything that happened to him after the operation. He could repeat a telephone number back fine, suggesting his short term memory was fine
Hippocapmus + memory
critical or putting new information into the long term stores
retrograde amnesia
the inability to retrieve information that was acquired before a particular date, usually the date of an injury or surgery
anterograde amnesia
the inability to retrieve information that was acquired before a particular date, usually the date of an injury or surgery
What did HM’s case suggest about the hippocampus?
because he had worse anterograde than retrograde amnesia, hippocampal region is not the site of long-term memory
Hippocampal region index like a printed recipe
the first time you make a pie, you need the recipe to help you retrieve all of the ingredients and then mix them together in the right amounts, but as you bake more pies, you don’t need to rely on printed recipe anymore. similarly, although the hippocampal region index is critical when a new memory is first formed, it may become less important as the memory ages
Hippocampal index and cooking analogy
the hippocampal index remains involved over long periods of time with some memories (highly detailed recollections of personal experiences, the kinds of memories that give us the feeling that we are almost reliving a past experience), but does not stay involved in less detailed, more general memories
you might need to rely on a recipe each time you cook a complex meal with many details, but not when you cook a simpler meal with a less detailed recipe
consolidation
the process by which memories become stable in the brain
memories and likelihood to be disrupted
shortly after encoding, memories exist in a fragile state in which they can be easily disrupted, but once consolidation has occurred, they are more resistant to disrupted
two types of consolidation
operates over seconds and minutes; the other over days, weeks, months, and years, likely involves the transfer of information from the hippocampus to more permanent storage sites in the cortex
the key to consolidation of memories
sleep
what experiment proved how sleep helps us remember what’s important and discard what’s trivial?
after studying a list of words, half of the group was told that they were going to be tested on their memory of the words after they slept, but the other group was not informed of this. The latter did not show improvement in recall after sleep compared with wakefulness.
the picture location task
participants studied pictures of buildings/furniture that were associated with particular locations on the slide. After, the participants received a memory test for the picture-location associations. They were instructed that they would be retested on either the building or the furniture slides and not the other. Those who slept in between tests did better in the relevant category, but there was no difference in the ones who did not sleep.
Reconsolidation
memories can become vulnerable to disruption when they are recalled, thus requiring them to be consolidated again
Describe the experiment that gave evidence for reconsolidation
rats were cued to retrieve a new memory that was acquired a day earlier. giving the rats a drug or electric shock that prevented initial consolidation caused forgetting. If the rat was not actively retrieving the memory, the same drug/shock had no effect when given a day after initial encoding
Implications of reconsolidation
If reconsolidation/consolidation is interrupted, the traumatic symptoms of the trauma can be reduced
Adding non-fearful information to fearful memories
Adding non-fearful information to a reactivated memory a few minutes later, when the memory is vulnerable to reconsolidation, resulted in long-lasting reduction of fear responses to the object, whereas adding non-fearful information to the reactivated memory 6 hours later when the memory was no longer vulnerable did not have a long-lasting effect
Amygdala and fearful memories
Disrupting reconsolidation can seemingly eliminate a conditioned fear memory in the amygdala
Where does research suggest memory storage depends critically on?
The synapse
sending a nt across a synapse isn’t like sending a toy boat across a pond because…
…the act of sending actually changes the synapse. It strengthens the connection between two neurons, making it easier for them to transmit to each other the next tme. “cells that fire together wire together”
Eric Kandel
Studied the Apylsia , won a Nobel Prize for his work in 2000
Aplysia
tiny sea slug, relatively uncomplicated and has an extremely simple nervous system consisting of only 20 000 neurons compared to 100 billion in human brain. When experimenter stimulates tail with mild electric shock, slug immediately withdrawls its gill, and if the experimenter does it again a moment later, Aplysia withdraws its gill even more quickly. If they are shocked again and hour later, the withdrawal of the gill is as slow as it was at first, like it can’t remember. But if Aplysia is shocked over and over, it does develop an enduring “memory” that can last for days or weeks.
What does research with the Aplysia suggest?
learning in the Aplysia is based on changes involving the snyapses for both short-term storage (enhanced neurotransmitter release) and long-term storage (growth of new synapses). Any experience that results in memory produces physical changes in the nervous system
LTP
long term potentiation; a process whereby communication across the synapse between neurons strengthens the connection, making further communication easier
What indicates to researchers that it LTP plays an important role in long-term memory storage?
It occurs in several pathways within the hippocampus, it can be induced rapidly, and it can last for a long time
Drugs that block LTP in rats
turn them into rodent versions of HM; the animals have great difficulty remembering where they’ve been recently and become easily lost in a maze
Retrieval cue
external information that is associated with stored information and helps bring it to mind
Retrieval Cue Experiment
students were given words like “table”, “peach”, “bed”, and “apple” to study and told to write down the ones that they remembered. When they were sure they had written everything they could possibly remember, they were given retrieval cues like “furniture” and “fruit” they were able to remember more of the words. This suggests that information is sometimes available in memory even when it is momentarily inaccessible, and retrieval cues help us bring that information to mind
Encoding specificity principle
A retrieval cue can serve as an effective reminder when it helps recreate the specific way in which information was initially encoded (learning/remembering things on dry land vs water)
State dependent retrieval
the tendency for information to be better recalled when the person is in the same state during encoding and retrieval
Transfer appropriate processing
the idea that memory is likely to transfer from one situation to another when encoding and retrieval contexts of the situations match
“what rhymes with ‘brain’?”
two people are given the word “brain”, one is asked “what does brain mean” and the other is asked what “brain” rhymes with. The next day, the former will remember the word “brain” better when asked “what was that word you saw yesterday?”, and the latter will remember better when asked “what was that word that rhymed with ‘train’?”
Memory testing benefits long term retention
With 5 minute retention interval, the study-study conditions were slightly higher in recall than study-test conditions. But study-test conditions did dramatically better with retention intervals of 2 days and 1 week.
Retrieval induced forgetting
a process by which retrieving an item from long term memory impairs subsequent recall of related items
Retrieval induced forgetting experiment
recall of “orange” would be practiced with “fruit or ____” and other options on the fruit list like “apple” would be suppressed, though the participant would be aware of the word on the list. Once “orange” is recalled during a test, recall “apple” is poor.
Retrieval and subsequent retrieval
Retrieval can change the subsequent memory, as reactivating a memory temporarily makes it vulnerable to disruption and change
Brain regions involved with recall
Left frontal lobe shows heightened activity when people try to retrieve information, but hippocampal region shows heightened activity when people successfully retrieve information
First memories and culture
- Memories fade or disappear as children age
- The first memories of 14 year old Chinese children come from later age than first memories of 14 year old Canadian children
- Onset of childhood amnesia in Chinese 14 year olds was identical to that of North American adults
.:. First memories are seen later in cultures that place less emphasis on talking about the past, and culture has a significant impact on even our earliest memories
Greg and his dad’s death, HM and the video game
Greg can’t make new day-to-day memories, but after he was told his father died, he was sad and withdrawn for years after he was told the news, even though he couldn’t consciously remember it; HM couldn’t make new memories after his surgery, but when he played a game that involved tracking a moving target, his performance gradually improved; both showed clear signs of having been permanently changed by experiences they had forgotten, suggesting there are several kinds of memory, some of which are accessible to conscious recall, and others that are not.
Explicit memory
when people consciously or intentionally retrieve past experiences
Implicit memory
past experiences influence later behavior and performance, even without an effort to remember or an awareness of the recollection
Procedural memory
the gradual acquisition of skills as a result of practice, or “knowing how” to do things
Forms of memory
Long term > explicit memory (conscious recall) > semantic memory (facts and general knowledge) OR episodic memory (personally experienced events)
Long term > implicit memory (without conscious recall) > procedural memory (motor and cognitive skills) OR priming (enhanced identification of objects or words)
priming
enhanced ability to think of a stimulus, such as a word or object, as a result of recent exposure to the stimulus
Long term priming of visual objects experiment
Participants who viewed drawings of common objects, and 17 years later were given a test in which they tried to identify the objects from fragmented drawings showed a strong priming effect; by contrast, participants who had not seen the drawings 17 years earlier showed non significant priming
parts of frontal lobe and occipital lobe involved in visual processing + priming
more activated without priming, less active with priming
Two distinct types of priming
perceptual and conceptual
Perceptual priming
reflects implicit memory for the sensory features of an item (eg. the visual characteristics of a word or a picture)
Conceptual priming
reflects implicit memory for the meaning of the a word or how you would use the object
Semantic Memory
a network of associated facts and concepts that make up our general knowledge of the world
Episodic memory
the collection of past personal experiences that occurred at a particular time and place
The common network of brain regions involved in remembering the past and imagining the future
Includes the hippocampus, a part of the medial temporal lobe long known to play an important role in episodic memory
Collaborative Memory
aka transactive memory; how people remember in groups
Nominal Group
the combined recall of several individuals recalling target items of their own.
Collaborative inhibition
individuals working together recall fewer items than they would on their own
Why might collaborative inhibition happen?
(probably not) social loafing: letting others do the work
(more likely) the retrieval strategies used by individual members of the group disrupt those used by the people around them
Computers and memory
People seemed to use computers in an efficient way to remember facts, while relying n their own meories to recall where those facts could be found. Suggests people may be adapting their memories to the demands of new technology, relying on computers in a way that is similar to how we sometimes rely on other people to remember things that we may no remember ourselves, like collaborative memory
Seven Sins of Memory
Transience, absentmindedness, blocking, memory misattribution, suggestibility, bias, persistence
Seven Sins of Memory: Transience
forgetting what occurs with the passage of time; memories aren’t forgotten at a constant rate, it is an exponential curve
Retroactive interference
situations in which later learning impairs memory for information acquired earlier
Proactive interference
situations in which earlier learning impairs memory for information acquired later
Seven Sins of Memory: Absentmindedness
a lapse in attention that results in memory failure (Yo-Yo Ma forgetting to take his cello when he left a cab, but remembering that he left it in the trunk of the cab when he remembered to remember it)
What makes people absentminded?
lack of attention, failure in prospective memory
Divided attention study
Participants tried to learn a list of word pairs while researchers scanned brains with PET scans, people who simultaneously performed a task that took little attention (moving a bar over and over in the same way) had greater activity in lower left frontal lobe, while those who were performing tasks that required a lot of attention (moving a bar in unpredictable ways) had less activity.
Lower left frontal lobe region associated with…
better memory, esp in semantic encoding
Prospective memory
remembering to do things in the future; avoiding these problems often requires having a cue at the moment you need to remember to carry out the action (a cue earlier is as good as no reminder at all)
Seven Sins of Memory: Blocking
a failure to retrieve information that is available in memory even though you are trying to produce it; tip-of-the-tongue state, knowing career/occupation but not names of public figures
Seven Sins of Memory: Memory Misattribution
assigning a recollection or an idea to the wrong source
Faulty eyewitness memory was a factor in __% of the first 250 cases in which individuals were shown to be innocent by DNA evidence
more than 75%
Source memory
recall of when, where, and how information was acquired
False Recognition
a feeling of familiarity about something that hasn’t been encountered before
deja vecu
feeling strongly but mistakenly that one has already lived through an experience and remembers details of what happened; watching a TV episode and thinking you’ve seen it before even though it’s a completely new episode\
True or False: using PET and MRI, it can be shown that the hippocampus is only active during true recognition
False; many of the same brain regions are active during both true and false recognition, including the hippocampus
Instance of false recognition reduction
Given a choice between an object actually seen and a visually similar one, the object chosen is almost always the object actually seen
Why (might) false recognition happen?
false recognition occurs in part because when presented with a similar new object on its own, participants don’t recollect specific details about the object they actually studied, but these details need to be retrieved in order to correctly indicate that the similar object is new.
Seven Sins of Memory: Suggestibility
the tendency to incorporate misleading information from external sources into personal recollections.
Seven Sins of Memory: Bias
the distorting influences of present knowledge, beliefs, and feelings on recollection of previous experiences
consistency bias
the bias to reconstruct the past to fit the present
Consistency bias experiment
in 1973, people were asked about their opinions on controversial social/political topics. when asked in 1982 on their opinions on the same topics and what they thought back in 1973, the participants recollections of their 1973 attitudes in 1982 were more closely related to what they believed in 1982 than to what they actually believed in 1973.
change bias
the tendency to exaggerate the similarity between the past and the present (ex: couples asked one years into their relationship to rate the strength of their relationships, after four years they recalled the events and they reported that their love had increased, however the actual rating did not show any increases in love and attachment, by they did from a subjective perspective of memory)
egocentric bias
the tendency to exaggerate the change between present and past in order to make ourselves look good in retrospect (reporting being more nervous before donating blood than they actually were)
Seven Sins of Memory: Persistence
the intrusive recollection of events that we wish we could forget; often happens after traumatic incidents; memories of emotional experiences are far more accurate than nonemotional
Flashbulb memories
detailed recollections of when and where we heard about shocking events (where were you when you heard of 9/11?)
Why do our brains succumb to persistence?
the amygdala; stress related hormones like adrenaline and cortisol enhance memory for the experience, but damage to the amygdala does not result in memory deficit. however, this does mean that emotional memories are remembered the same as nonemotional ones.
Which part of the brain is associated with semantic encoding?
lower left frontal lobe and inner left temporal lobe
