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.