The structure of memory Flashcards
importance of memory
- 100,000 words
- episodic memory for events
- procedural memory for riding a bike
- Tends to deteriorate as We get older
Encoding VS Retrieval
- encoding = converting info into a useable form
- Then enters storage = Holding info in memory
- Then retrieval = Taking memories out of storage
The case of HM
-Had severe epilepsy so had his bilateral hippocampus removed
- could retrieve LT memories existing long before surgery
- couldn’t create new LT memories
- could retrieve LT but unable to encode new memories
- emphasises distinction between encoding + retrieval
HM + Amnesia
- post surgery he had anterograde amnesia + temporally graded retrograde amnesia
-retrograde amnesia = loss of memory to info before injury/disease - Anterograde amnesia = loss of ability to create new memories after onset of amnesia
- Temporally graded = occurred not instantly but 11 years
short Term vs long term memory
- HMs ST memory + procedural still in tact post surgery
- supports distinction between ST + LT memory stores
capacity of ST vs LT memory
-Miller -> magical number 7+/- 2 = ST capacity - some limits on capacity for processing info
- standing -> ppts shown up to 10,000 pictures + able to recognise previously seen images with 83 % accuracy = LT capacity limitless
Duration + concurrent task during storage for ST + LT memory
- Duration of ST 15-30 seconds or longer with reversal
- Duration of LT = permanent
-concurrent task during storage is affected in ST not LT
sensory memory - sperling
- sperling: 4.5 items remembered = span of immediate
-Is a memory not perceptual limit - Tests were full report tests: presented with grid of letters + asked to report everything
- sensory memory As a copy or mental photograph- no meaning assigned
sensory Memory + sperling- Partial report
-partial report = report a sub-set of items which are cued
- partial report superiority- didn’t know which row of letter grid to report in advance so nearly all items must be remembered
- often presented with a tone indicating which row to remember
- performance is better when giving a que + asking for partial report
Types of sensory memory
- iconic = visual stimuli
- echoic = auditory stimuli
- Haptic = touch stimuli
-sensory memory has high capacity but very short duration
What info is held in sensory memory
- The items + their positions (colour, shape_size)
- partial report advantage for all physical characteristics
- No partial report advantage when asked to report items of a curtain category (sperling)
Brief time span of sensory memory - sperling
- gave them an array + manipulated time before hearing the tone indicating which row of letters to recall
- 0.5 seconds is where he found partial report superiority
- gave stimulus field, before letters = light pre + post or dark pre + post field
- able to extend duration to about 5 seconds
visual patterning mask - sensory memory
- Visual noise mask can be presented before or after stimulus
- forward (before) stops any processing before stimulus
- Backward (after) stops processing after stimulus
- Interruption masking: replacement
- sperling - presented backwards masking
-number of letters reported reduced when backwards visual mask - show stimuli to 1 eye+ mask to other
- mask influences visual processing after info from eyes is combined into a single percept
3 system stores/filter memory model - Broadbent
- s system sensory memory - unlimited capacity
- p system ST memory = limited capacity, processed 1 at a time, fed back to s through reversal
- Long term memory
- unattended info doesn’t reach higher level processing
- cocktail party effect contradicts
- changed + said unattended salient (important) info is processed
- ST forgetting = decay
- LT forgetting = interference
The modal model of memory - Atkinson -Shiffrin Model
- ST VS LT memory
- components are horizontal faculties (same MeMory constraints apply to visual, auditory + haptic stimuli)
- control processes regulate flow of info between stores
- sensory input -> sensory memory -> ST -> LT
unitary models of memory
- models unifying mechanisms of STM + LTM
Distinctions between ST + LT memory
- ST seen as fixed number of slots
- when full, new item displaces old one
- Displaced item is sent to LTM reversal loop + is forgotten
serial order task
- Primacy + recency effect
- position in sequences determines now well you are able to remember the number
- find it easier to remember first + last ones
-recency effect (end) -> read Out from STM - Murdock supported recency effect by using different list lengths + rates of presentation + still saw recency effect
- Primacy effect (start) -> read at from LTM
Glanzer + Cunitz -> immediate recall + primacy/recency effect
- Asked people to do another task for 10 + 30s after presentation
-immediate recall has strong recency effect -10s delay reduced recency effect - varied rates of presentation + primacy effect was altered
- As time increased per item, accuracy increases as they have longer to secure items in LTM
Bjork + Whitten (1974)- contradicting evidence for recency effect
- manipulated rehersal for items but still SaW primacy effect -> encouraged to remember middle items
- Number distractor task at end but recency effect was unaffected
Long term effects on primacy + recency- Baddeley + Hitch
- asked indies to remember rugby match scores
- found memory decreased as number of intervening matches increased
Broadbent t forgetting in ST + LT memory
- forgetting in ST = lost by decay
- LTM lost by interference
Brown-Peterson TaSK + prevention of reversal on ST + LT memory
- pairs of consonants to remember
- interference tease to prevent rehersal
- resulted in items decaying t being lost from STM
- Peterson did similar with numbers + found same
- decay occurs even when number of items to remember is below capacity (7 +/ - 2)
proactive interference- Keppel + underwood
- Backwards counting for 3 or 18 seconds
- 6 trials
- Accuracy better for 3s interference
- on first trial no difference between 3 + 18 s
- Difference increased as trial number increased
- Proactive interference = neg influence of old material on new
