Memory Flashcards
3 processes of memory
- encoding- formation of initial memory traces and receiving information
- storage- retention of information
- retrieval-accessing and recovering information from memory stores
William James
- divided memory into primary (short term) and secondary memory (long term)
- 3 forms of memory are now recognised
Sensory memory
- large capacity
- each sense has it’s own memory
- no processing is involved
- if attention is paid during sensory memory then this is moved to short term memory
- visual memory lasts 0.5s. Auditory lasts 2 s
Short term memory
- Miller says 7+/-2 items
- lasts 15-30 seconds
- by maintenance rehearsal the duration n can be increased e.g learning phone number
- Brown Paterson Task- distract immediately after counting 3 numbers backwards
- recall is effortless and error free
- loss of information usually occurs through displacement and decay
Displacement
-newly acquired items entering the short term memory displace existing items
Decay
-older items in short term memory have a weaker trace strength than the recently acquired items
Elaborative encoding
- Daniel Schacter
- move of information from temporary to long term storage by rehearsal
Working memory
- used to describe most of short term memory
- working memory allows cognitive processes to be performed on data that is briefly stored in short term memory
Long term memory
- unlimited capacity
- lasts for indefinite duration
- encoding is mostly semantic but some visual and acoustic encoding occurs
Atkins and Shiffrin
- short term memory and long term memory are structural components
- rehearsal can move short term memories to long term memory
Recent memory
-ability to remember what has experienced within the past few minutes (recall of items after 5 minutes), hours or days
Remote memory
-the ability to remember events in the distant past
Tulving
-long term memory has two forms- declarative (explicit- includes semantic and episodic memory) and non-declarative (implicit memory)
Declarative memory
- explicit!
- includes semantic and episodic memory
Semantic memory
-factual knowledge about the world
Episodic memory
-autobiographical
Non-declarative memory
- implicit
- procedural memory
- skills etc
Priming
- form of learning that occurs without conscious recall of the episode of learning
- performance shows that the information is learnt but conscious recall is absent
Baddley and Hitch
- working memory model
- working memory has a central executive and two arms- phonological loop and visuospatial sketchpad
- central exectutive is like an attention system
- phonological loop is auditory rehearsal loops
- visuospatical scratch pad is pattern recognition and movement perception components
- episodic buffer
Episodic buffer
- also a component of the working memory model
- integrates information into long term memory
- important in chinking
Serial position effect
-primary and recency effect
Recency effect
- last words in a list remembered more easily than the middle ones
- better preserved in organic anterograde amnesia
Primacy effect
Modes of retrieval (3 Rs)
- Recognition
- Recall
- Reintegration/reconstruction
Forgetting
- Decay
- Displacement
- retrieval failure
- interference theory
Hermann Ebbinghaus
- forgetting curve
- sharp drop over the first 9 hours, particularly the first hour
- after the first 9 hours the forgetting slows and declines little
- forgetting is never complete
- continous motor skills are not forgotten (cycling) but discrete motor skills can be
Decay theory
-neural engrams breakdown over time
Displacement
-due to capacity limitation, new info replaces old info
Retrieval failure
- due to lack of proper cues to recall we forget things
- recall improves if the cues available at the initial encoding are present during recollection
Interference theory
- forgetting occurs due to interference
- new information can interfere with old material recall-retroactive interference
- proactive interference refers to interference of new learning from older learnt material
Chunking
-method of increasing the capacity of short term memory by combining units or information into chunks
Encoding specificity principle
-the more similar the retrieval situation is to the encoding situation , the better the retrieval
Amnesia
-marked impairment of episodic memory
Ribot
- recent memories are more vulnerable to brain damage than remote memories
- if hippocampal memory system is damaged then patients tend to lose their recent memories
Anterograde amnesia
- loss of the ability to form or retain new episodic memories after injury/lesion/event
- lack of memory for events taking place in the immediate future after an event
- often involve hippocampal damage
- they cant learn anything new
- nothing can be moved from short term to long term memory
Retrograde amnesia
- loss of episodic memories that were stored before brain damage had occurred
- lack of memory immediately before events
- follows head injury
- they fail to consolidate the STM and move it to LTM
Transient global amnesia
- caused by transient cerebral ischemia
- sudden onset of severe anterograde amnesia with a retrograde amnesia for the preceding days or weeks
Psychogenic amnesia (hysterical)
- suffer traumatic or emotionally disturbing lide event
- can be global (e.g fugue state) or situation specific (crime)
Fugue state
- psychogenic global amnesia
- forgets everything about themselves
- usually resolves within a few days but can last forever
Situation specific
- offenders can claim amnesia at the offence- 25-45% homicides
- most common in crimes of passion
- in PTSD there is reduction in the hippocampal volume-?due to glucocorticoids
Amnesic syndromes
- various disorders can cause amnesic syndromes
- features:
1. immediate memory is unimpaired
2. anterograde amnesia-inability to acquire new information
3. retrograde amnesia of variable extent and severity
4. preserved global intellectual abilities
5. preserved implicit/procedural memory
Korsakoff’s syndrome
- frm of amnesic syndrome caused by thiamine deficiency
- may have severe anterograde amnesia and extensive retrograde memory loss
- can lose some autobiographic memory
- working memory and procedural memory are unimpaired
- 3 word learning tak-apple, table, penny
Post-traumatic amnesia
- time between injury and recovery of normal memory function seen in head injury patients
- the longer the PTA, the more severe the brain damage and prognosis
- PTA retrograde amnesia is also possible after head injury-cant recall last night’s dinner=poor prognosis
Memory loss following ECT
- usually temporary
- there may be both anterograde or retrograde amnesia
- 1/3 of patients report persistent memory loss following ECT
- memory impairment is less pronounces with unilateral ECT
Tests of memory
- digit span
- 3 word learning task
- Rey-Osterrieth complex figure
- Wechsler memory test
Digit span
- tests short term memory
- forward and backward digit span
- forward= 6+/- 1
- reverse is 5+/-1
Three word learning task
- apple penny clock
- test of anterograde memory and learning
Name and address recall
- 7 items
- common test of recent verbal memory
- recall as many items in five or ten minutes
Rey-Osterrieth complex figure
- non-verbal memory test
- person is asked to copy a complex geometric figure and then draw from memory after 30 minutes
- impaired in dementia and amnesic syndrome
Weschler memory tests
-asked to recall a short story from the Wechsler memory scale containing 25 elements and both immediate and delayed recall after an interval or 30 mins
Infantile amnesia
- earliest recall is 3.5 years old
- prior to this is infantile amnesia
- amnesia for events occurring in first 2-5 years of life is variable
Mood-congruent effect
-more easy to recall nformation if it is congruent with current mood
Mood-state dependent retrieval
-the phenomenon wherein retrieval of information is easier if the emotional state at the time is the same as the emotional state at the time of the encoding
Elaboration
-material that is fully elaborated produces stronger memory trace as it is believed that the consolidation is linked to the depth with which the data is processed
Schemas
- mechanisms for elaborating and reconstructing memory at test
- organised sets of facts
Interference
-known, easily accessible information is used to piece together the retrieved information, resulting in a biased recall
Distortion
-can occur in order to ensure the information fits the person’s schemas-this impacts the recall of information
Pre-frontal lobes
-mediate performances of short term memory
Phonological short term memory system
-mediated by the left hemisphere regions of Broca’s area and prefrontal cortex
Visuospatial short term memory system
-mediated by the parietal and prefrontal areas of the right hemisphere
Brain areas responsible for long term memory
-regions of the limbic system, specifically the hippocampus and the entorhinal cortex of the medial temporal lobe
