Exam 2- Lecture 6 Flashcards
Comparator mirror
Using comparator mirror to project the subject one is painting on to the edge of the canvas
Eliminates need for eye movement between the canvas and to-be-painted subject, thus preserving sensory memory
Modal model of memory
Sensory input ->
Sensory memory (1/2 second) -(attention)>
Short term memory
Long term memory
Capacity and cognitive ability
Positive correlation between short term memory capacity and intelligence score
ERP signature of capacity
Max at 3 (memory array size)
fMRI evidence for capacity
Both CDA amp and IPS activities reach asym between 3 and 4
Capacity of LTM
Virtually infinite!
Study: Standing (1973)- almost perfect memory regardless of number of study items
IM, STM and LTM differences
Capacity
- IM: unlimited (spelling partial reports)
- STM: limited, 3-4 items
- LTM: infinite
Lifetime
- IM: <500 ms (typically 150 ms)
- STM: short-lived; 50% at 4 seconds
- LTM: lifetime memory; forgetting = retrieval failure
Retrieval
- IM: fragile, eliminated by eye movements
- STM: fast, parallel
- LTM: slow
STM length of time info is stored
Gradual decay
50% lost at 4 seconds
Sudden forgetting
significant increase in failure to remember between 4 - 10 seconds
LTM length of time info is stored
Lifetime memory
Forgetting in LTM may be entirely due to RETRIEVAL FAILURE
Iconic memory
1/2 gone at 150 (delay between array and tone)
Findings:
- sensory (iconic) memory exists
- sensory memory has vitally infinite storage capacity
- sensory memory decays rapidly
- > fades by 50% within aprox. 150 ms
- > almost entirely gone within 500 ms
- sensory memory is fragile and cannot survive eye movements
Spelling partial reports
Memory consolidation cue- beep during study
By 500 ms, iconic (sensory memory) no different from STM
Retrograde amnesia
Amnesia for past
Intact ability to store new memories
Anterograde with some retrograde amnesia
Partial recall of memories for events prior to the amnesia onset, but their ability to form new memories is impaired
Structures important for encoding and retrieval
Amygdala Hippocampus Parahippocampal gyrus -entorphinal cortex -periphinal cortex -parahippocampal cortex
Amnesia case study: H.M.
Unable to form new long term memories (anterograde amnesia)
Some loss of events 1-3 years prior to surgery (retrograde amnesia) [memory recall]
No ability to form new episodic memories
Star mirror experiment (implicit memory/ procedural memory)
-gradually improved, but could not remember previous events
Clive Wearing
Damaged bilateral hippocampi, surrounding temporal cortex, and some frontal
30 second memory
Intact STM
5-9 for semantic info to STM (beyond 7 is LTM)
Tip-of-the-tongue
Feeling of knowing a response, but being unable to produce it
To know (implicit memory) To remember (retrieval; conduct task and respond)
Dual-process theory of recognition
Recollection and familiarity
-memory retrieval can be based on either
Recollection (Hippocampus)
- relatively slow search process
- qualitative info about prior events retrieved
- re-experiencing the encoding event at the time or recall
- true EPISODIC memory
Familiarity (Perirhinal cortex)
- relatively fast
- ‘sense of recency’ is used as basis for recognition
- feeling seen before, but not remember exact encoding event
- NOT implicit because is conscious
Dissociation between recollection and familiarity
- single dis (hippo and recollection)
- kind of double dis, but not most clear
Patient NB
Resection perirhinal, intact hippo
Impaired familiarity with intact recollection
Can amnesiacs learn new semantic knowledge?
Some newly acquired knowledge, although more difficult to learn
- can learn facts (pop culture, news events, etc.)
- > semantic memory (maybe relies less on medial temporal lobe for encoding)
Can amnesiacs learn procedural skills?
Serial reaction time task (implicit sequence learning)
No different from control, no episodic memory
Similar to mirror tracing task
Nondeclarative memory
Explicit memory tests
-tasks that explicitly instruct subjects to use memory (e.g., recall, recognition)
Implicit memory tests (priming)
- tasks that do not explicitly instruct subjects to use memory
- > measure the unconscious influence of experience without asking to recall the past
Vowel counting task, followed by stem completion task
Implicit memory task
- increased likelihood of solving the words that have been studied
- likely related to “activation” parts of sensory cortex
Results:
Free recall [C > A] lowest results
Cued recall [C > A] highest results
Stem completion [C < A] A results same as A cued
False memories
Memory is reconstructive
-may “remember” something that never actually happened
Unaware of how unreliable our memory can be and overly confident in the accuracy of our memories
Semantic rep. of sleep, even though specific word never shown
Recall
~40% recalled “sleep”
Recognition
-remembering lure (sleep) during recall strengthened participants memories of the lure during recognition (vs. “knowing” it had been on the list”
